<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Offering;

use Unsupervised\Schedular\Auth\AccessSettings;
use Unsupervised\Schedular\Auth\RoleManager;
use Unsupervised\Schedular\Val;

class OfferingController {

	public function __construct(
		private OfferingRepository $repository,
		private ClassSlotReconciler $reconciler,
		private AccessSettings $access = new AccessSettings(),
	) {}

	public function renderPage(): void {
		if ( ! current_user_can( RoleManager::CAP_MANAGE_OFFERINGS ) ) {
			wp_die( esc_html__( 'You do not have permission to manage offerings.', 'unsupervised-schedular' ) );
		}

		$instructorId = get_current_user_id();
		$manageAll    = current_user_can( RoleManager::CAP_MANAGE_INSTRUCTORS );

		$notice = '';
		if ( isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_offering_action' ) ) {
			$notice = $this->handleFormAction( $instructorId, $manageAll );
		}

		// Studio admins may assign any instructor to a class; a plain instructor
		// only ever creates classes for themselves, so the picker is theirs alone.
		$instructors = $manageAll ? $this->instructorOptions() : [];

		// View-state query param only (which offering the form is editing) —
		// nothing is mutated from it, so no nonce applies.
		// phpcs:disable WordPress.Security.NonceVerification.Recommended
		$editId = absint( Val::int( $_GET['usc_edit'] ?? 0 ) );
		// phpcs:enable WordPress.Security.NonceVerification.Recommended

		$editing = null;
		if ( $editId > 0 ) {
			$candidate = $this->repository->findById( $editId );
			if ( $candidate && ( $manageAll || $candidate->instructorId === $instructorId ) ) {
				$editing = $candidate;
			}
		}

		$offerings = $manageAll
			? $this->repository->findAll()
			: $this->repository->findAll( $instructorId );

		include USC_PLUGIN_DIR . 'templates/admin/offerings.php';
	}

	/**
	 * Process the posted add/update/delete action, returning a status notice for
	 * display (e.g. how many booking slots a scheduled class cleared, or that a
	 * booked lesson clashes with it). An empty string means nothing to report.
	 */
	private function handleFormAction( int $instructorId, bool $manageAll ): string {
		// Nonce is verified by the caller (renderPage) before this method runs.
		// phpcs:disable WordPress.Security.NonceVerification.Missing
		$action = sanitize_key( Val::string( wp_unslash( $_POST['usc_action'] ?? '' ) ) );

		if ( 'add' === $action ) {
			$offering = $this->offeringFromPost( $instructorId, $manageAll );
			if ( null !== $offering ) {
				$this->repository->insert( $offering );

				return $this->reconcileNotice( $offering );
			}
		}

		if ( 'update' === $action ) {
			$offeringId = absint( Val::int( $_POST['offering_id'] ?? 0 ) );
			if ( $offeringId > 0 ) {
				$existing = $this->repository->findById( $offeringId );
				if ( $existing && ( $manageAll || $existing->instructorId === $instructorId ) ) {
					$offering = $this->offeringFromPost( $instructorId, $manageAll, $existing );
					if ( null !== $offering ) {
						$this->repository->update( $offeringId, $offering );

						return $this->reconcileNotice( $offering );
					}
				}
			}
		}

		if ( 'delete' === $action ) {
			$offeringId = absint( Val::int( $_POST['offering_id'] ?? 0 ) );
			if ( $offeringId > 0 ) {
				$offering = $this->repository->findById( $offeringId );
				if ( $offering && ( $manageAll || $offering->instructorId === $instructorId ) ) {
					$this->repository->delete( $offeringId );
				}
			}
		}
		// phpcs:enable WordPress.Security.NonceVerification.Missing

		return '';
	}

	/**
	 * Clear the assigned instructor's open booking slots that collide with a
	 * scheduled group class and describe the result, warning about any booked
	 * lesson that clashes (which the studio must resolve by hand).
	 */
	private function reconcileNotice( Offering $offering ): string {
		if ( Offering::KIND_GROUP_CLASS !== $offering->kind ) {
			return '';
		}

		$result = $this->reconciler->reconcile( $offering );
		$parts  = [];

		if ( $result['removed'] > 0 ) {
			$parts[] = sprintf(
				/* translators: %d: number of open booking slots removed. */
				_n(
					'%d open booking slot was removed to hold the class time.',
					'%d open booking slots were removed to hold the class time.',
					$result['removed'],
					'unsupervised-schedular'
				),
				$result['removed']
			);
		}

		foreach ( $result['conflicts'] as $startDt ) {
			$parts[] = sprintf(
				/* translators: %s: date and time of the already-booked lesson that clashes. */
				esc_html__( 'Conflict: a lesson is already booked at %s during this class.', 'unsupervised-schedular' ),
				(string) mysql2date( 'M j, Y g:i a', $startDt )
			);
		}

		return implode( ' ', $parts );
	}

	/**
	 * Instructors offered in the assignment select, by display name.
	 *
	 * Includes everyone holding the `us_instructor` role plus, when the site owner
	 * has left administrators acting as instructors (the default single-account
	 * setup), WordPress administrators — who teach through the dynamic capability
	 * grant rather than the role. Without them a solo studio owner running the
	 * business from an admin account would find no one to assign a class to.
	 *
	 * @return list<array{id: int, name: string}>
	 */
	private function instructorOptions(): array {
		$roles = [ RoleManager::INSTRUCTOR ];
		if ( $this->access->adminsAreInstructors() ) {
			$roles[] = 'administrator';
		}

		$users = array_filter(
			get_users(
				[
					'role__in' => $roles,
					'orderby'  => 'display_name',
					'order'    => 'ASC',
				]
			),
			static fn( mixed $u ): bool => $u instanceof \WP_User
		);

		return array_values(
			array_map(
				static fn( \WP_User $u ): array => [
					'id'   => (int) $u->ID,
					'name' => '' !== (string) $u->display_name ? (string) $u->display_name : (string) $u->user_email,
				],
				$users
			)
		);
	}

	/**
	 * Build an offering from the submitted add/edit form, or null when the
	 * submission is invalid. When `$existing` is given the result is an edit:
	 * it keeps the existing id and currency so an update can never rewrite those
	 * from whoever submits the form.
	 *
	 * The owning instructor normally stays fixed (the creator on add, the existing
	 * owner on edit). A studio admin (`$manageAll`) may instead assign the class to
	 * any instructor via the picker; a blank or absent choice keeps the default.
	 */
	private function offeringFromPost( int $instructorId, bool $manageAll, ?Offering $existing = null ): ?Offering {
		// Nonce is verified by the caller (renderPage) before this method runs.
		// phpcs:disable WordPress.Security.NonceVerification.Missing
		$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 null;
		}

		$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'] ?? '' ) ) ) );

		// Reject over-long fixed-size fields rather than let the DB silently drop them.
		if ( mb_strlen( $title ) > Offering::MAX_TITLE_LENGTH
			|| ( null !== $scheduleNote && mb_strlen( $scheduleNote ) > Offering::MAX_SCHEDULE_NOTE_LENGTH )
			|| ( null !== $etransferEmail && mb_strlen( $etransferEmail ) > Offering::MAX_ETRANSFER_EMAIL_LENGTH )
		) {
			return null;
		}

		$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( Val::int( $_POST['duration_minutes'] ?? 0 ) );
		$capacity = absint( Val::int( $_POST['capacity'] ?? 0 ) );

		// A blank cutoff means "use the studio default" (null); any entered value
		// (including 0 — cancel any time) is a per-offering override.
		$cutoffRaw   = trim( sanitize_text_field( Val::string( wp_unslash( $_POST['cancellation_cutoff_hours'] ?? '' ) ) ) );
		$cutoffHours = '' === $cutoffRaw ? null : absint( Val::int( $cutoffRaw ) );

		// Term dates: a class either meets once (term ends the day it starts)
		// or repeats weekly for a set number of sessions.
		$termStart = Offering::normalizeDate( sanitize_text_field( Val::string( wp_unslash( $_POST['term_start'] ?? '' ) ) ) );
		$termEnd   = null;
		if ( null !== $termStart ) {
			$recurrence = sanitize_key( Val::string( wp_unslash( $_POST['term_recurrence'] ?? 'single' ) ) );
			$sessions   = absint( Val::int( $_POST['term_sessions'] ?? 1 ) );
			$termEnd    = 'weekly' === $recurrence ? Offering::weeklyTermEnd( $termStart, $sessions ) : $termStart;
		}

		$classTime = Offering::normalizeTime( sanitize_text_field( Val::string( wp_unslash( $_POST['class_time'] ?? '' ) ) ) );

		// A blank (or invalid) deadline means "use the default" — the first class
		// day (term_start), applied by Offering::effectiveEnrollmentDeadline().
		$enrollmentDeadline = Offering::normalizeDate( sanitize_text_field( Val::string( wp_unslash( $_POST['enrollment_deadline'] ?? '' ) ) ) );

		// A blank (or invalid) withdrawal deadline leaves the column NULL, which
		// keeps self-withdrawal open for the class's whole life
		// (Offering::isWithdrawalOpen()). A set date closes it after that day.
		$withdrawalDeadline = Offering::normalizeDate( sanitize_text_field( Val::string( wp_unslash( $_POST['withdrawal_deadline'] ?? '' ) ) ) );

		return new Offering(
			instructorId:    $this->resolveInstructorId( $instructorId, $manageAll, $existing ),
			kind:            $kind,
			title:           $title,
			price:           max( 0.0, (float) sanitize_text_field( Val::string( wp_unslash( $_POST['price'] ?? '0' ) ) ) ),
			currency:        null !== $existing ? $existing->currency : 'CAD',
			billingMode:     $billingMode,
			description:     $this->nullableText( sanitize_textarea_field( Val::string( wp_unslash( $_POST['description'] ?? '' ) ) ) ),
			durationMinutes: $duration > 0 ? $duration : null,
			allowWeekly:     isset( $_POST['allow_weekly'] ),
			capacity:        $capacity > 0 ? $capacity : null,
			termStart:       $termStart,
			termEnd:         $termEnd,
			classTime:       $classTime,
			enrollmentDeadline: $enrollmentDeadline,
			withdrawalDeadline: $withdrawalDeadline,
			scheduleNote:    $scheduleNote,
			etransferEmail:  $etransferEmail,
			cancellationCutoffHours: $cutoffHours,
			accessMode:      isset( $_POST['invite_only'] ) ? Offering::ACCESS_INVITE_ONLY : Offering::ACCESS_PUBLIC,
			isActive:        isset( $_POST['is_active'] ),
			id:              $existing?->id,
		);
		// phpcs:enable WordPress.Security.NonceVerification.Missing
	}

	/**
	 * The instructor the offering should belong to. A studio admin may reassign it
	 * via the posted `class_instructor_id`; otherwise it stays with the existing
	 * owner (edit) or the current user (add). A plain instructor can never change
	 * the owner, so the posted value is ignored unless `$manageAll` is set.
	 */
	private function resolveInstructorId( int $instructorId, bool $manageAll, ?Offering $existing ): int {
		$fallback = null !== $existing ? $existing->instructorId : $instructorId;

		if ( ! $manageAll ) {
			return $fallback;
		}

		// Nonce is verified by the caller (renderPage) before this method runs.
		// phpcs:ignore WordPress.Security.NonceVerification.Missing
		$posted = absint( Val::int( $_POST['class_instructor_id'] ?? 0 ) );

		return $posted > 0 ? $posted : $fallback;
	}

	private function nullableText( string $value ): ?string {
		return '' === $value ? null : $value;
	}
}