<?php
/**
 * Tab library: reusable tabs stored as a post type, so that WPML and Polylang translate them like any other content.
 *
 * @package Prodtabs
 */

namespace Prodtabs;

defined( 'ABSPATH' ) || exit;

/**
 * Post type prodtabs_tab and its data.
 */
final class Library {

	const POST_TYPE = 'prodtabs_tab';

	/** Title shown in the shop, when it differs from the internal title of the library. */
	const META_SHOP_TITLE = '_prodtabs_shop_title';

	/** Products the tab is added to on its own: empty for the products where it is added by hand, "all" for every product. */
	const META_SCOPE = '_prodtabs_scope';

	/** Registers the post type and its meta. */
	public static function register(): void {
		register_post_type(
			self::POST_TYPE,
			array(
				'labels'                => array(
					'name'                     => __( 'Shared tabs', 'prodtabs' ),
					'singular_name'            => __( 'Shared tab', 'prodtabs' ),
					'menu_name'                => __( 'Shared tabs', 'prodtabs' ),
					'all_items'                => __( 'Shared tabs', 'prodtabs' ),
					'add_new'                  => __( 'Add shared tab', 'prodtabs' ),
					'add_new_item'             => _x( 'Add shared tab', 'page title', 'prodtabs' ),
					'edit_item'                => __( 'Edit shared tab', 'prodtabs' ),
					'new_item'                 => __( 'New shared tab', 'prodtabs' ),
					'search_items'             => __( 'Search shared tabs', 'prodtabs' ),
					'not_found'                => __( 'No shared tabs found.', 'prodtabs' ),
					'not_found_in_trash'       => __( 'No shared tabs found in Trash.', 'prodtabs' ),
					'filter_items_list'        => __( 'Filter shared tabs list', 'prodtabs' ),
					'items_list_navigation'    => __( 'Shared tabs list navigation', 'prodtabs' ),
					'items_list'               => __( 'Shared tabs list', 'prodtabs' ),
					'item_published'           => __( 'Shared tab published.', 'prodtabs' ),
					'item_published_privately' => __( 'Shared tab published privately.', 'prodtabs' ),
					'item_reverted_to_draft'   => __( 'Shared tab reverted to draft.', 'prodtabs' ),
					'item_scheduled'           => __( 'Shared tab scheduled.', 'prodtabs' ),
					'item_updated'             => __( 'Shared tab updated.', 'prodtabs' ),
				),
				'description'           => __( 'Product tabs shared between products.', 'prodtabs' ),
				'public'                => false,
				'show_ui'               => true,
				'show_in_menu'          => Admin_Hub::parent_slug(),
				'show_in_admin_bar'     => false,
				'show_in_nav_menus'     => false,
				'show_in_rest'          => true,
				'rest_base'             => 'prodtabs_tabs',
				'rest_controller_class' => Library_Rest_Controller::class,
				'supports'              => array( 'title', 'editor', 'revisions', 'custom-fields' ),
				'capability_type'       => 'product',
				'map_meta_cap'          => true,
				'rewrite'               => false,
				'query_var'             => false,
				'delete_with_user'      => false,
			)
		);

		register_post_meta(
			self::POST_TYPE,
			self::META_SHOP_TITLE,
			array(
				'type'              => 'string',
				'single'            => true,
				'default'           => '',
				'show_in_rest'      => true,
				'sanitize_callback' => 'sanitize_text_field',
				'auth_callback'     => static function ( $allowed, $meta_key, $post_id ) {
					return current_user_can( 'edit_post', $post_id );
				},
			)
		);

		register_post_meta(
			self::POST_TYPE,
			self::META_SCOPE,
			array(
				'type'              => 'string',
				'single'            => true,
				'default'           => '',
				'show_in_rest'      => true,
				// Any choice is kept, also one of an extension that is not running (Premium's "terms"), which then adds
				// the tab nowhere: saving the tab meanwhile would otherwise lose it.
				'sanitize_callback' => static function ( $value ) {
					return is_scalar( $value ) ? sanitize_key( (string) $value ) : '';
				},
				'auth_callback'     => static function ( $allowed, $meta_key, $post_id ) {
					return current_user_can( 'edit_post', $post_id );
				},
			)
		);
	}

	/**
	 * Choices of the "Show on" setting of a shared tab.
	 *
	 * @return string[] Label by value; the empty value is the default.
	 */
	public static function scopes(): array {
		/**
		 * Choices of the "Show on" setting of a shared tab. An extension that adds one decides where it applies with the
		 * prodtabs_shared_tab_applies filter.
		 *
		 * @param string[] $scopes Label by value.
		 */
		$scopes = (array) apply_filters(
			'prodtabs_shared_tab_scopes',
			array(
				''    => __( 'Products where it is added', 'prodtabs' ),
				'all' => __( 'All products', 'prodtabs' ),
			)
		);
		return array( '' => $scopes[''] ?? __( 'Products where it is added', 'prodtabs' ) ) + $scopes;
	}

	/**
	 * Shared tabs added on their own to a product by their "Show on" setting, one per group of translations.
	 *
	 * @param \WC_Product $product Product.
	 * @return array[] id (the tab in the default language when it is published), anchor (title it was created with), family (ids of the tab and its translations).
	 */
	public static function auto_tabs( \WC_Product $product ): array {
		$args = array(
			'post_type'              => self::POST_TYPE,
			'post_status'            => 'publish',
			'fields'                 => 'ids',
			'posts_per_page'         => 100,
			'orderby'                => array(
				'menu_order' => 'ASC',
				'ID'         => 'ASC',
			),
			'no_found_rows'          => true,
			'update_post_term_cache' => false,
			'lang'                   => '', // Polylang: every language.
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- small post type, one key.
			'meta_query'             => array(
				array(
					'key'     => self::META_SCOPE,
					'value'   => '',
					'compare' => '!=',
				),
			),
		);
		$default = Multilingual::default_language();
		$seen    = array();
		$groups  = 0;
		$tabs    = array();
		// Every translation is a row: the limit counts groups of translations, read page after page.
		for ( $page = 1; $groups < 100; ++$page ) {
			$ids = get_posts( $args + array( 'paged' => $page ) );
			foreach ( array_map( 'intval', $ids ) as $id ) {
				if ( isset( $seen[ $id ] ) ) {
					continue;
				}
				++$groups;
				$family = Multilingual::translation_ids( $id, self::POST_TYPE );
				$seen  += array_fill_keys( $family, true );
				// The tab in the default language when it is published; otherwise the first published one of the group.
				$main  = '' !== $default ? Multilingual::translation( $id, self::POST_TYPE, $default ) : 0;
				$main  = $main && in_array( $main, $family, true ) && 'publish' === get_post_status( $main ) ? $main : $id;
				$post  = get_post( $main );
				$scope = $post ? (string) get_post_meta( $main, self::META_SCOPE, true ) : '';
				/**
				 * Whether a shared tab is added on its own to a product.
				 *
				 * @param bool        $applies True for the "All products" setting.
				 * @param int         $id      Shared tab (in the default language when it has one).
				 * @param \WC_Product $product Product.
				 * @param string      $scope   Value of the "Show on" setting.
				 */
				if ( '' === $scope || ! apply_filters( 'prodtabs_shared_tab_applies', 'all' === $scope, $main, $product, $scope ) ) {
					continue;
				}
				$tabs[] = array(
					'id'     => $main,
					'anchor' => self::shop_title( $post ),
					'family' => $family,
				);
			}
			if ( count( $ids ) < 100 ) {
				break;
			}
		}
		return $tabs;
	}

	/**
	 * A published library tab, ready for the shop.
	 *
	 * @param int $id Post id.
	 * @return array|null id, title (shop title), content (raw), anchor; null when missing or not published.
	 */
	public static function get_tab( int $id ): ?array {
		$post = get_post( $id );
		if ( ! $post || self::POST_TYPE !== $post->post_type || 'publish' !== $post->post_status ) {
			return null;
		}
		return array(
			'id'      => $post->ID,
			'title'   => self::shop_title( $post ),
			'content' => $post->post_content,
			'anchor'  => Tabs::anchor( self::shop_title( $post ), 'tab-' . $post->ID ),
		);
	}

	/**
	 * Library tab to show for a stored id, in the language of the page: its published translation, or the tab as it
	 * was chosen while the translation is missing or not published yet (unless prodtabs_untranslated_library_tab
	 * says otherwise). When the id is itself that translation (WPML points the ids of the shortcode to the language of
	 * the page), the original of its group shows instead.
	 *
	 * @param int $id Library tab id stored in the product.
	 * @return array|null Tab (see get_tab()), null when nothing can be shown.
	 */
	public static function resolve( int $id ): ?array {
		$translated = Multilingual::translate_post_id( $id, self::POST_TYPE );
		$tab        = $translated ? self::get_tab( $translated ) : null;
		if ( $tab || ! $translated ) {
			return $tab;
		}
		$fallback = $translated !== $id ? $id : Multilingual::original( $id, self::POST_TYPE );
		if ( ! $fallback || $fallback === $translated ) {
			return null;
		}
		/** This filter is documented in includes/class-multilingual.php */
		return apply_filters( 'prodtabs_untranslated_library_tab', ! Settings::get( 'hide_untranslated' ), $fallback, self::POST_TYPE ) ? self::get_tab( $fallback ) : null;
	}

	/**
	 * Title shown in the shop: the shop title when set, the post title otherwise.
	 *
	 * @param \WP_Post $post Library tab.
	 */
	public static function shop_title( \WP_Post $post ): string {
		$title = (string) get_post_meta( $post->ID, self::META_SHOP_TITLE, true );
		return '' !== trim( $title ) ? $title : $post->post_title;
	}

	/**
	 * Meta query matching the products whose tabs use a library tab or one of its translations. A product stores the
	 * library tab as it was chosen, whatever its language: the structure is the same in every language.
	 *
	 * @param int $id Library tab id.
	 */
	public static function usage_meta_query( int $id ): array {
		$query = array( 'relation' => 'OR' );
		foreach ( Multilingual::translation_ids( $id, self::POST_TYPE ) as $translation ) {
			$query[] = array(
				'key'     => Tabs::META_LAYOUT,
				'value'   => '"library_id";i:' . $translation . ';',
				'compare' => 'LIKE',
			);
		}
		return $query;
	}

	/**
	 * Number of products that use each library tab (or one of its translations), every language counted.
	 *
	 * @param int[] $ids Library tab ids.
	 * @return int[] Count by id.
	 */
	public static function usage_counts( array $ids ): array {
		$counts = array();
		foreach ( array_filter( array_map( 'absint', $ids ) ) as $id ) {
			$counts[ $id ] = (int) Multilingual::all_languages(
				static function () use ( $id ) {
					return ( new \WP_Query( self::usage_args( $id, 1 ) ) )->found_posts;
				}
			);
		}
		return $counts;
	}

	/**
	 * Products that use a library tab or one of its translations.
	 *
	 * @param int $id    Library tab id.
	 * @param int $limit Maximum number of ids.
	 * @return int[]
	 */
	public static function products_using( int $id, int $limit = 50 ): array {
		$args                  = self::usage_args( $id, $limit );
		$args['no_found_rows'] = true;
		return array_map(
			'intval',
			Multilingual::all_languages(
				static function () use ( $args ) {
					return ( new \WP_Query( $args ) )->posts;
				}
			)
		);
	}

	/**
	 * Query of the products that use a library tab.
	 *
	 * @param int $id    Library tab id.
	 * @param int $limit Products per page.
	 */
	private static function usage_args( int $id, int $limit ): array {
		return array(
			'post_type'              => 'product',
			'post_status'            => array( 'publish', 'draft', 'pending', 'private', 'future' ),
			'fields'                 => 'ids',
			'posts_per_page'         => $limit,
			'update_post_term_cache' => false,
			'update_post_meta_cache' => false,
			'lang'                   => '',
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- one meta key, admin screens only.
			'meta_query'             => self::usage_meta_query( $id ),
		);
	}
}