<?php

namespace RoosterLMS\Core;

use RoosterLMS\Content\PostTypes;
use RoosterLMS\Content\StaffRole;
use RoosterLMS\Data\SqlPart;
use RoosterLMS\Domain\Services;

defined( 'ABSPATH' ) || exit;

final class InstructorCaps {

	public const TYPES = array(
		PostTypes::COURSE => 'rooster_courses',
		PostTypes::LESSON => 'rooster_lessons',
		PostTypes::QUIZ   => 'rooster_quizzes',
	);

	public const CREATE_COURSES = 'create_rooster_courses';

	public const MANAGE_STAFF = 'rooster_lms_manage_course_staff';

	private const POST_META = array( 'edit_post', 'read_post', 'delete_post', 'publish_post' );

	public const LIST_LIMIT = 5000;

	private static bool $registered = false;

	private static bool $bypass = false;

	private static int $rest_post = 0;

	private static array $courses_of_post = array();

	private static array $list_posts = array();

	public function register(): void {
		if ( self::$registered ) {
			return;
		}
		self::$registered = true;
		add_filter( 'map_meta_cap', array( self::class, 'map' ), 20, 4 );
		add_filter( 'rest_request_before_callbacks', array( self::class, 'rest_context' ), 10, 3 );
		add_filter( 'rest_request_after_callbacks', array( self::class, 'rest_context_end' ), 10, 1 );
		add_filter( 'wp_insert_post_data', array( self::class, 'status_guard' ), 20, 2 );
		add_action( 'pre_get_posts', array( self::class, 'scope_admin_list' ), 20, 1 );
		add_action( 'rooster_lms_course_staff_changed', array( self::class, 'forget' ), 10, 0 );
	}

	public static function forget(): void {
		self::$courses_of_post = array();
		self::$rest_post       = 0;
		self::$list_posts      = array();
	}

	public static function map( $caps, $cap, $user_id, $args ): array {
		$caps = is_array( $caps ) ? $caps : (array) $caps;
		if ( self::$bypass || ! is_string( $cap ) ) {
			return $caps;
		}
		$user_id = is_numeric( $user_id ) ? (int) $user_id : 0;
		$args    = is_array( $args ) ? array_values( $args ) : array();
		if ( self::MANAGE_STAFF === $cap ) {
			return self::manage_staff( $user_id, is_numeric( $args[0] ?? null ) ? (int) $args[0] : 0 ) ? array( 'exist' ) : array( 'do_not_allow' );
		}
		if ( self::CREATE_COURSES === $cap ) {
			return array( 'edit_rooster_courses' );
		}
		if ( $user_id <= 0 || ! isset( Services::course_staff()::staff_users()[ $user_id ] ) ) {
			return $caps;
		}
		if ( in_array( $cap, self::POST_META, true ) ) {
			return self::map_post( $caps, $cap, $user_id, is_numeric( $args[0] ?? null ) ? (int) $args[0] : 0 );
		}
		if ( ! str_starts_with( $cap, 'edit_rooster_' ) && ! str_starts_with( $cap, 'publish_rooster_' ) ) {
			return $caps;
		}
		$type = array_search( substr( $cap, strpos( $cap, '_rooster_' ) + 1 ), self::TYPES, true );
		if ( false === $type || $user_id <= 0 || self::has_all( $user_id, $caps ) ) {
			return $caps;
		}
		if ( str_starts_with( $cap, 'edit_' ) ) {
			return array() !== Services::course_staff()->instructed_course_ids( $user_id ) ? array( 'exist' ) : $caps;
		}
		$post = get_post( self::context_post() );
		if ( $post instanceof \WP_Post && $post->post_type === $type && self::is_principal_of_post( $user_id, $post ) ) {
			return array( 'exist' );
		}
		return $caps;
	}

	private static function map_post( array $caps, string $cap, int $user_id, int $post_id ): array {
		if ( $user_id <= 0 || $post_id <= 0 || in_array( 'do_not_allow', $caps, true ) ) {
			return $caps;
		}
		$post = get_post( $post_id );
		if ( ! $post instanceof \WP_Post || ! isset( self::TYPES[ $post->post_type ] ) || ( 'auto-draft' === $post->post_status && 'edit_post' !== $cap ) ) {
			return $caps;
		}
		if ( self::has_all( $user_id, $caps ) ) {
			return $caps;
		}
		if ( 'read_post' === $cap && 'publish' === $post->post_status ) {
			return $caps;
		}
		if ( in_array( $cap, array( 'edit_post', 'read_post' ), true ) ) {
			if ( (int) $post->post_author === $user_id && PostTypes::COURSE !== $post->post_type && array() !== Services::course_staff()->instructed_course_ids( $user_id ) ) {
				return array( 'exist' );
			}
			$mine = array_intersect( self::courses_of( $post ), Services::course_staff()->instructed_course_ids( $user_id ) );
			return array() !== $mine ? array( 'exist' ) : $caps;
		}
		return self::is_principal_of_post( $user_id, $post ) ? array( 'exist' ) : $caps;
	}

	private static function is_principal_of_post( int $user_id, \WP_Post $post ): bool {
		$courses = self::courses_of( $post );
		if ( array() === $courses ) {
			return false;
		}
		$staff = Services::course_staff();
		foreach ( $courses as $course_id ) {
			if ( StaffRole::PRINCIPAL !== $staff->role_of( $user_id, $course_id ) ) {
				return false;
			}
		}
		return true;
	}

	public static function courses_of( \WP_Post $post ): array {
		$post_id = (int) $post->ID;
		if ( ! isset( self::$courses_of_post[ $post_id ] ) ) {
			if ( PostTypes::COURSE === $post->post_type ) {
				$course = Services::course_repo()->id_for_post( $post_id );
				$out    = $course > 0 ? array( $course ) : array();
			} else {
				$unit = Services::unit_repo()->id_for_post( $post_id );
				$out  = $unit > 0 ? Services::curriculum_repo()->course_ids_for_units( array( $unit ) ) : array();
			}
			self::$courses_of_post[ $post_id ] = $out;
		}
		return self::$courses_of_post[ $post_id ];
	}

	private static function manage_staff( int $user_id, int $course_id ): bool {
		if ( $user_id <= 0 || $course_id <= 0 ) {
			return false;
		}
		$course = Services::course_repo()->get( $course_id );
		if ( null === $course ) {
			return false;
		}
		if ( StaffRole::PRINCIPAL === Services::course_staff()->role_of( $user_id, $course_id ) ) {
			return true;
		}
		return $course->home_post_id > 0 && self::can_without_staff( $user_id, 'edit_post', $course->home_post_id );
	}

	public static function can_without_staff( int $user_id, string $cap, ...$args ): bool {
		$was          = self::$bypass;
		self::$bypass = true;
		try {
			return \RoosterLMS\Domain\Users::can( $user_id, $cap, ...$args );
		} finally {
			self::$bypass = $was;
		}
	}

	private static function has_all( int $user_id, array $caps ): bool {
		$user = \RoosterLMS\Domain\Users::get( $user_id );
		if ( null === $user ) {
			return false;
		}
		foreach ( $caps as $primitive ) {
			if ( 'exist' !== $primitive && empty( $user->allcaps[ $primitive ] ) ) {
				return false;
			}
		}
		return true;
	}

	public static function context_post(): int {
		if ( self::$rest_post > 0 ) {
			return self::$rest_post;
		}
		if ( ! is_admin() || 'post.php' !== ( $GLOBALS['pagenow'] ?? '' ) ) {
			return 0;
		}
		$id = isset( $GLOBALS['post_ID'] ) && is_numeric( $GLOBALS['post_ID'] ) ? absint( $GLOBALS['post_ID'] ) : 0;
		if ( $id <= 0 ) {
			return 0;
		}
		$method = isset( $_SERVER['REQUEST_METHOD'] ) && is_string( $_SERVER['REQUEST_METHOD'] ) ? strtoupper( sanitize_key( wp_unslash( $_SERVER['REQUEST_METHOD'] ) ) ) : 'GET';
		return 'POST' !== $method || \RoosterLMS\Admin\Request::posted_nonce_valid( '_wpnonce', 'update-post_' . $id ) ? $id : 0;
	}

	public static function rest_context( $response, $handler = null, $request = null ) {
		unset( $handler );
		self::$rest_post = 0;
		if ( $request instanceof \WP_REST_Request && 1 === preg_match( '#^/wp/v2/([a-z0-9_-]+)/(\d+)(?:/autosaves)?/?$#', $request->get_route(), $m ) ) {
			$id   = (int) $m[2];
			$type = get_post_type( $id );
			if ( is_string( $type ) && isset( self::TYPES[ $type ] ) ) {
				self::$rest_post = $id;
			}
		}
		return $response;
	}

	public static function rest_context_end( $response ) {
		self::$rest_post = 0;
		return $response;
	}

	public static function status_guard( $data, $postarr = array() ) {
		if ( ! is_array( $data ) || ! is_array( $postarr ) || empty( $postarr['ID'] ) || ! isset( self::TYPES[ (string) ( $data['post_type'] ?? '' ) ] ) ) {
			return $data;
		}
		$user_id = get_current_user_id();
		$post    = get_post( (int) $postarr['ID'] );
		if ( $user_id <= 0 || ! $post instanceof \WP_Post || (int) $post->post_author === $user_id ) {
			return $data;
		}
		if ( ! isset( Services::course_staff()::staff_users()[ $user_id ] ) ) {
			return $data;
		}
		$old  = (string) $post->post_status;
		$new  = (string) ( $data['post_status'] ?? $old );
		$live = array( 'publish', 'future', 'private' );
		if ( $old === $new || ( ! in_array( $old, $live, true ) && ! in_array( $new, $live, true ) ) || 'trash' === $new ) {
			return $data;
		}
		if ( current_user_can( 'publish_post', (int) $post->ID ) || self::can_without_staff( $user_id, 'edit_others_' . self::TYPES[ $post->post_type ] ) ) {
			return $data;
		}
		$data['post_status'] = $old;
		return $data;
	}

	public static function scope_admin_list( $query ): void {
		if ( ! $query instanceof \WP_Query || ! is_admin() || ! $query->is_main_query() || 'edit.php' !== ( $GLOBALS['pagenow'] ?? '' ) ) {
			return;
		}
		$type = $query->get( 'post_type' );
		if ( ! is_string( $type ) || ! isset( self::TYPES[ $type ] ) ) {
			return;
		}
		$ids = self::admin_list_scope( $type, get_current_user_id() );
		if ( null === $ids ) {
			return;
		}
		$query->set( 'post__in', array() === $ids ? array( 0 ) : $ids );
	}

	public static function admin_list_scope( string $type, int $user_id ): ?array {
		if ( $user_id <= 0 || ! isset( self::TYPES[ $type ] ) || self::can_without_staff( $user_id, 'edit_others_' . self::TYPES[ $type ] ) ) {
			return null;
		}
		$courses = Services::course_staff()->instructed_course_ids( $user_id );
		if ( array() === $courses ) {
			return null;
		}
		$key = $type . '|' . $user_id . '|' . implode( ',', $courses );
		if ( ! isset( self::$list_posts[ $key ] ) ) {
			self::$list_posts[ $key ] = self::list_post_ids( $type, $user_id, $courses );
		}
		return self::$list_posts[ $key ];
	}

	public static function list_post_ids( string $type, int $user_id, array $courses ): array {
		global $wpdb;
		$own = \RoosterLMS\Data\Db::col( SqlPart::of( 'SELECT ID FROM %i WHERE post_type = %s AND post_author = %d LIMIT %d', $wpdb->posts, $type, $user_id, self::LIST_LIMIT ) );
		$tbl = \RoosterLMS\Data\Db::table( 'object_posts' );
		$sql = PostTypes::COURSE === $type
			? SqlPart::of( 'SELECT post_id FROM %i WHERE object_type = %d AND object_id IN (' . implode( ', ', array_fill( 0, count( $courses ), '%d' ) ) . ') LIMIT %d', array_merge( array( $tbl, \RoosterLMS\Content\ObjectType::COURSE->value ), $courses, array( self::LIST_LIMIT ) ) )
			: SqlPart::of( 'SELECT DISTINCT op.post_id FROM %i i JOIN %i op ON op.object_type = %d AND op.object_id = i.unit_id JOIN %i p ON p.ID = op.post_id AND p.post_type = %s WHERE i.course_id IN (' . implode( ', ', array_fill( 0, count( $courses ), '%d' ) ) . ') LIMIT %d', array_merge( array( \RoosterLMS\Data\Db::table( 'items' ), $tbl, \RoosterLMS\Content\ObjectType::UNIT->value, $wpdb->posts, $type ), $courses, array( self::LIST_LIMIT ) ) );
		$ids = array_merge( $own, \RoosterLMS\Data\Db::col( $sql ) );
		return array_values( array_unique( array_map( 'intval', $ids ) ) );
	}
}