<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Auth;

use Unsupervised\Schedular\Val;

class RegistrationController {

	/**
	 * Option storing the page ID that hosts the [us_student_register] shortcode.
	 */
	public const OPTION_PAGE = 'us_registration_page_id';

	public function __construct( private InviteRepository $invites ) {}

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

		$newInviteUrl = '';
		$inviteError  = '';
		if ( isset( $_POST['usc_action'] ) && check_admin_referer( 'usc_invite_action' ) ) {
			[ $newInviteUrl, $inviteError ] = $this->handleFormAction();
		}

		$pendingInvites      = $this->invites->findPending();
		$registrationPageId  = Val::int( get_option( self::OPTION_PAGE, 0 ) );
		$registrationPageUrl = $registrationPageId > 0 ? (string) get_permalink( $registrationPageId ) : '';

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

	/**
	 * Handle a posted admin action. Returns `[link, error]`: 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 error message when creation
	 * failed; both empty for every other action.
	 *
	 * @return array{string, string}
	 */
	private function handleFormAction(): array {
		// 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 ( 'set_page' === $action ) {
			update_option( self::OPTION_PAGE, absint( Val::int( $_POST['registration_page_id'] ?? 0 ) ) );
		}

		if ( 'invite' === $action ) {
			$email = sanitize_email( Val::string( wp_unslash( $_POST['email'] ?? '' ) ) );

			if (
				! is_email( $email )
				|| false !== email_exists( $email )
				|| null !== $this->invites->findPendingByEmail( $email )
			) {
				return [ '', esc_html__( 'Could not create the invite: enter a valid email address that has no account and no pending invite.', 'unsupervised-schedular' ) ];
			}

			$rawToken = wp_generate_password( 32, false );

			$id = $this->invites->insert(
				new Invite(
					email:     $email,
					token:     Invite::hashToken( $rawToken ),
					invitedBy: get_current_user_id(),
				)
			);

			return $this->linkOrError( $id, $rawToken );
		}

		if ( 'group_invite' === $action ) {
			$expiresAt = $this->normalizeExpiry( sanitize_text_field( Val::string( wp_unslash( $_POST['expires_at'] ?? '' ) ) ) );

			if ( null === $expiresAt ) {
				return [ '', esc_html__( 'Could not create the group link: choose an expiry date of today or later.', 'unsupervised-schedular' ) ];
			}

			$rawToken = wp_generate_password( 32, false );

			$id = $this->invites->insert(
				new Invite(
					email:     '',
					token:     Invite::hashToken( $rawToken ),
					invitedBy: get_current_user_id(),
					kind:      Invite::KIND_GROUP,
					expiresAt: $expiresAt,
				)
			);

			return $this->linkOrError( $id, $rawToken );
		}

		if ( 'revoke' === $action ) {
			$inviteId = absint( Val::int( $_POST['invite_id'] ?? 0 ) );
			if ( $inviteId > 0 ) {
				$this->invites->revoke( $inviteId );
			}
		}
		// phpcs:enable WordPress.Security.NonceVerification.Missing

		return [ '', '' ];
	}

	/**
	 * The registration link for a stored invite, or an error when the insert
	 * failed — a link must never be shown for a token that was not persisted,
	 * since it could only ever dead-end as "invalid or expired".
	 *
	 * @return array{string, string}
	 */
	private function linkOrError( int $insertedId, string $rawToken ): array {
		if ( $insertedId <= 0 ) {
			return [ '', esc_html__( 'Could not save the invite. Deactivate and reactivate the plugin to update the database, then try again.', 'unsupervised-schedular' ) ];
		}

		return [ $this->registrationLink( $rawToken ), '' ];
	}

	/**
	 * Validate a submitted group-link expiry date (strict `Y-m-d`, today or
	 * later) and expand it to the end of that day; null when invalid or past.
	 */
	private function normalizeExpiry( string $date ): ?string {
		$day = \DateTimeImmutable::createFromFormat( '!Y-m-d', $date );
		if ( false === $day || $day->format( 'Y-m-d' ) !== $date ) {
			return null;
		}

		if ( $date < Val::string( current_time( 'Y-m-d' ) ) ) {
			return null;
		}

		return $date . ' 23:59:59';
	}

	/**
	 * 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( '/' ) );
	}
}