// ===== PHASE 1: ENDPOINT - Rename & Update Description =====
function aiofilm_update_playlist( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['id'];
    $new_name = isset( $request['name'] ) ? sanitize_text_field( $request['name'] ) : '';
    $new_description = isset( $request['description'] ) ? wp_kses_post( $request['description'] ) : '';

    // Validate playlist ID
    if ( empty( $playlist_id ) ) {
        return new WP_Error( 'invalid-id', __( 'شناسه پلی لیست معتبر نیست.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    // Check if at least one field is provided
    if ( empty( $new_name ) && empty( $new_description ) ) {
        return new WP_Error( 'no-data', __( 'حداقل یک فیلد (نام یا توضیح) الزامی است.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    
    // Get current playlist and verify ownership
    $playlist = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    if ( ! $playlist ) {
        return new WP_Error( 'not-found', __( 'پلی لیست پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    $user_id = get_current_user_id();
    $guest_token = aiofilm_playlists_get_guest_token();
    
    // Verify ownership or guest token
    if ( $user_id > 0 ) {
        if ( (int) $playlist->user_id !== $user_id ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه ویرایش این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    } else {
        if ( $playlist->guest_token !== $guest_token ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه ویرایش این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    }

    // Validate name if provided
    if ( ! empty( $new_name ) && strlen( $new_name ) > 255 ) {
        return new WP_Error( 'name-too-long', __( 'نام پلی لیست نباید بیش از 255 کاراکتر باشد.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    // Prepare update data
    $update_data = array();
    if ( ! empty( $new_name ) ) {
        $update_data['name'] = $new_name;
    }
    if ( isset( $request['description'] ) ) {
        $update_data['description'] = $new_description;
    }

    // Update playlist
    $result = $wpdb->update(
        $playlists_table,
        $update_data,
        array( 'playlist_id' => $playlist_id ),
        array_fill( 0, count( $update_data ), '%s' ),
        array( '%d' )
    );

    if ( false === $result ) {
        aiofilm_playlists_log( 'Error updating playlist: ' . $wpdb->last_error );
        return new WP_Error( 'db-error', __( 'خطایی در بروزرسانی پلی لیست رخ داد.', 'aiofilm-playlists' ), array( 'status' => 500 ) );
    }

    // Fetch updated playlist
    $updated_playlist = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    aiofilm_playlists_log( "Playlist $playlist_id updated by user $user_id" );

    return new WP_REST_Response( array(
        'success' => true,
        'message' => __( 'پلی لیست با موفقیت بروزرسانی شد.', 'aiofilm-playlists' ),
        'playlist' => array(
            'id' => (int) $updated_playlist->playlist_id,
            'name' => $updated_playlist->name,
            'description' => $updated_playlist->description,
        ),
    ), 200 );
}

// ===== PHASE 1: ENDPOINT - Update Visibility =====
function aiofilm_update_playlist_visibility( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['id'];
    $visibility = sanitize_key( $request['visibility'] );

    // Validate inputs
    if ( empty( $playlist_id ) ) {
        return new WP_Error( 'invalid-id', __( 'شناسه پلی لیست معتبر نیست.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $valid_visibilities = array( 'public', 'private', 'unlisted' );
    if ( ! in_array( $visibility, $valid_visibilities, true ) ) {
        return new WP_Error( 'invalid-visibility', __( 'مقدار مرئی‌بودن معتبر نیست. مقادیر معتبر: public, private, unlisted', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    
    // Get playlist and verify ownership
    $playlist = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    if ( ! $playlist ) {
        return new WP_Error( 'not-found', __( 'پلی لیست پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    $user_id = get_current_user_id();
    $guest_token = aiofilm_playlists_get_guest_token();
    
    // Verify ownership
    if ( $user_id > 0 ) {
        if ( (int) $playlist->user_id !== $user_id ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه تغییر مرئی‌بودن این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    } else {
        if ( $playlist->guest_token !== $guest_token ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه تغییر مرئی‌بودن این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    }

    // Update visibility
    $result = $wpdb->update(
        $playlists_table,
        array( 'visibility' => $visibility ),
        array( 'playlist_id' => $playlist_id ),
        array( '%s' ),
        array( '%d' )
    );

    if ( false === $result ) {
        aiofilm_playlists_log( 'Error updating visibility: ' . $wpdb->last_error );
        return new WP_Error( 'db-error', __( 'خطایی در بروزرسانی مرئی‌بودن رخ داد.', 'aiofilm-playlists' ), array( 'status' => 500 ) );
    }

    aiofilm_playlists_log( "Playlist $playlist_id visibility changed to $visibility by user $user_id" );

    return new WP_REST_Response( array(
        'success' => true,
        'message' => __( 'مرئی‌بودن پلی لیست با موفقیت تغییر کرد.', 'aiofilm-playlists' ),
        'visibility' => $visibility,
    ), 200 );
}



// ===== PHASE 1: ENDPOINT - Reorder Playlist Items =====
function aiofilm_reorder_items( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['playlist_id'];
    $items = $request['items']; // Array of {id, position} objects

    // Validate inputs
    if ( empty( $playlist_id ) || ! is_array( $items ) || empty( $items ) ) {
        return new WP_Error( 'invalid-data', __( 'شناسه پلی لیست و آیتم‌ها الزامی است.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    $items_table = $wpdb->prefix . 'aiofilm_playlist_items';

    // Verify playlist exists and user owns it
    $playlist = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    if ( ! $playlist ) {
        return new WP_Error( 'not-found', __( 'پلی لیست پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    $user_id = get_current_user_id();
    $guest_token = aiofilm_playlists_get_guest_token();
    
    // Verify ownership
    if ( $user_id > 0 ) {
        if ( (int) $playlist->user_id !== $user_id ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه تغییر ترتیب این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    } else {
        if ( $playlist->guest_token !== $guest_token ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه تغییر ترتیب این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    }

    // Update positions
    $updated_count = 0;
    foreach ( $items as $item ) {
        $item_id = (int) $item['id'];
        $position = (int) $item['position'];

        // Verify item belongs to this playlist
        $item_check = $wpdb->get_var( $wpdb->prepare(
            "SELECT item_id FROM {$items_table} WHERE item_id = %d AND playlist_id = %d",
            $item_id, $playlist_id
        ) );

        if ( ! $item_check ) {
            continue; // Skip items that don't belong to this playlist
        }

        $result = $wpdb->update(
            $items_table,
            array( 'position' => $position ),
            array( 'item_id' => $item_id ),
            array( '%d' ),
            array( '%d' )
        );

        if ( $result !== false ) {
            $updated_count++;
        }
    }

    aiofilm_playlists_log( "Playlist $playlist_id reordered: $updated_count items updated by user $user_id" );

    return new WP_REST_Response( array(
        'success' => true,
        'message' => sprintf( __( '%d آیتم با موفقیت مرتب شد.', 'aiofilm-playlists' ), $updated_count ),
        'updated_count' => $updated_count,
    ), 200 );
}

// ===== PHASE 1: ENDPOINT - Bulk Delete Items =====
function aiofilm_bulk_delete_items( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['playlist_id'];
    $item_ids = $request['item_ids']; // Array of item IDs

    // Validate inputs
    if ( empty( $playlist_id ) || ! is_array( $item_ids ) || empty( $item_ids ) ) {
        return new WP_Error( 'invalid-data', __( 'شناسه پلی لیست و آیتم‌ها الزامی است.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    // Sanitize item IDs
    $item_ids = array_map( 'absint', $item_ids );
    $item_ids = array_filter( $item_ids );

    if ( empty( $item_ids ) ) {
        return new WP_Error( 'invalid-items', __( 'شناسه آیتم‌های نامعتبر.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    $items_table = $wpdb->prefix . 'aiofilm_playlist_items';

    // Verify playlist exists and user owns it
    $playlist = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    if ( ! $playlist ) {
        return new WP_Error( 'not-found', __( 'پلی لیست پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    $user_id = get_current_user_id();
    $guest_token = aiofilm_playlists_get_guest_token();
    
    // Verify ownership
    if ( $user_id > 0 ) {
        if ( (int) $playlist->user_id !== $user_id ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه حذف از این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    } else {
        if ( $playlist->guest_token !== $guest_token ) {
            return new WP_Error( 'forbidden', __( 'شما اجازه حذف از این پلی لیست را ندارید.', 'aiofilm-playlists' ), array( 'status' => 403 ) );
        }
    }

    // Verify all items belong to this playlist
    $placeholders = implode( ',', array_fill( 0, count( $item_ids ), '%d' ) );
    $items_check = $wpdb->get_var(
        $wpdb->prepare(
            "SELECT COUNT(*) FROM {$items_table} WHERE playlist_id = %d AND item_id NOT IN ($placeholders)",
            array_merge( array( $playlist_id ), $item_ids )
        )
    );

    // Get count of items that belong to this playlist
    $valid_items = $wpdb->get_var(
        $wpdb->prepare(
            "SELECT COUNT(*) FROM {$items_table} WHERE playlist_id = %d AND item_id IN ($placeholders)",
            array_merge( array( $playlist_id ), $item_ids )
        )
    );

    if ( empty( $valid_items ) ) {
        return new WP_Error( 'no-items', __( 'هیچ آیتم معتبری برای حذف پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    // Delete items
    $delete_query = $wpdb->prepare(
        "DELETE FROM {$items_table} WHERE playlist_id = %d AND item_id IN ($placeholders)",
        array_merge( array( $playlist_id ), $item_ids )
    );
    
    $result = $wpdb->query( $delete_query );

    if ( false === $result ) {
        aiofilm_playlists_log( 'Error deleting items: ' . $wpdb->last_error );
        return new WP_Error( 'db-error', __( 'خطایی در حذف آیتم‌ها رخ داد.', 'aiofilm-playlists' ), array( 'status' => 500 ) );
    }

    aiofilm_playlists_log( "Deleted $result items from playlist $playlist_id by user $user_id" );

    return new WP_REST_Response( array(
        'success' => true,
        'message' => sprintf( __( '%d آیتم با موفقیت حذف شد.', 'aiofilm-playlists' ), $result ),
        'deleted_count' => (int) $result,
    ), 200 );
}



// ===== PHASE 1: ENDPOINT - Duplicate Playlist =====
function aiofilm_duplicate_playlist( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['id'];
    $new_name = isset( $request['name'] ) ? sanitize_text_field( $request['name'] ) : '';

    // Validate inputs
    if ( empty( $playlist_id ) ) {
        return new WP_Error( 'invalid-id', __( 'شناسه پلی لیست معتبر نیست.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    $items_table = $wpdb->prefix . 'aiofilm_playlist_items';

    // Get original playlist
    $original = $wpdb->get_row( $wpdb->prepare( 
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d", 
        $playlist_id 
    ) );

    if ( ! $original ) {
        return new WP_Error( 'not-found', __( 'پلی لیست اصلی پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    $user_id = get_current_user_id();
    
    // Set default name if not provided
    if ( empty( $new_name ) ) {
        $new_name = $original->name . ' (' . __( 'کپی', 'aiofilm-playlists' ) . ')';
    }

    // Create new playlist (owned by current user, private visibility)
    $insert_result = $wpdb->insert(
        $playlists_table,
        array(
            'user_id' => $user_id > 0 ? $user_id : 0,
            'guest_token' => $user_id > 0 ? '' : aiofilm_playlists_get_guest_token(),
            'name' => $new_name,
            'description' => $original->description,
            'visibility' => 'private', // New playlists are private by default
            'created_at' => current_time( 'mysql' ),
        ),
        array( '%d', '%s', '%s', '%s', '%s', '%s' )
    );

    if ( ! $insert_result ) {
        aiofilm_playlists_log( 'Error duplicating playlist: ' . $wpdb->last_error );
        return new WP_Error( 'db-error', __( 'خطایی در کپی کردن پلی لیست رخ داد.', 'aiofilm-playlists' ), array( 'status' => 500 ) );
    }

    $new_playlist_id = $wpdb->insert_id;

    // Copy all items from original playlist
    $items = $wpdb->get_results( $wpdb->prepare(
        "SELECT post_id, position FROM {$items_table} WHERE playlist_id = %d ORDER BY position ASC",
        $playlist_id
    ) );

    foreach ( $items as $item ) {
        $wpdb->insert(
            $items_table,
            array(
                'playlist_id' => $new_playlist_id,
                'post_id' => $item->post_id,
                'position' => $item->position,
                'added_at' => current_time( 'mysql' ),
            ),
            array( '%d', '%d', '%d', '%s' )
        );
    }

    aiofilm_playlists_log( "Playlist $playlist_id duplicated to $new_playlist_id by user $user_id" );

    return new WP_REST_Response( array(
        'success' => true,
        'message' => __( 'پلی لیست با موفقیت کپی شد.', 'aiofilm-playlists' ),
        'new_playlist_id' => (int) $new_playlist_id,
        'new_playlist_name' => $new_name,
    ), 201 );
}

// ===== PHASE 1: ENDPOINT - Get Playlist Statistics =====
function aiofilm_get_playlist_stats( WP_REST_Request $request ) {
    global $wpdb;
    $playlist_id = (int) $request['id'];

    // Validate input
    if ( empty( $playlist_id ) ) {
        return new WP_Error( 'invalid-id', __( 'شناسه پلی لیست معتبر نیست.', 'aiofilm-playlists' ), array( 'status' => 400 ) );
    }

    // Check cache first
    $cache_key = "playlist_stats_$playlist_id";
    $cached_stats = get_transient( $cache_key );
    if ( $cached_stats !== false ) {
        return new WP_REST_Response( $cached_stats, 200 );
    }

    $playlists_table = $wpdb->prefix . 'aiofilm_playlists';
    $items_table = $wpdb->prefix . 'aiofilm_playlist_items';
    $likes_table = $wpdb->prefix . 'aiofilm_playlist_likes';

    // Check playlist exists
    $playlist = $wpdb->get_row( $wpdb->prepare(
        "SELECT * FROM {$playlists_table} WHERE playlist_id = %d",
        $playlist_id
    ) );

    if ( ! $playlist ) {
        return new WP_Error( 'not-found', __( 'پلی لیست پیدا نشد.', 'aiofilm-playlists' ), array( 'status' => 404 ) );
    }

    // Calculate statistics
    $stats = array(
        'playlist_id' => (int) $playlist_id,
        'name' => $playlist->name,
        'description' => $playlist->description,
    );

    // Items count
    $stats['items_count'] = (int) $wpdb->get_var( $wpdb->prepare(
        "SELECT COUNT(*) FROM {$items_table} WHERE playlist_id = %d",
        $playlist_id
    ) );

    // Likes count
    $stats['likes_count'] = (int) $wpdb->get_var( $wpdb->prepare(
        "SELECT COUNT(*) FROM {$likes_table} WHERE playlist_id = %d",
        $playlist_id
    ) );

    // Duration (sum of post meta if available)
    $stats['total_duration'] = 0;
    $stats['total_duration_formatted'] = '0 ساعت';

    // Average rating (if rating system exists)
    $stats['average_rating'] = 0;

    // Cache for 1 hour
    set_transient( $cache_key, $stats, HOUR_IN_SECONDS );

    aiofilm_playlists_log( "Statistics retrieved for playlist $playlist_id" );

    return new WP_REST_Response( $stats, 200 );
}

?>