<?php
/*
 * auto translates the posts and terms ids
 * useful for example for themes querying a specific cat
 *
 * @since 1.1
 */
class PLL_Frontend_Auto_Translate {
	public $model, $curlang;

	/*
	 * constructor
	 *
	 * @since 1.1
	 *
	 * @param object $polylang
	 */
	public function __construct( &$polylang ) {
		$this->model = &$polylang->model;
		$this->curlang = &$polylang->curlang;

		add_action( 'pre_get_posts', array( &$this, 'pre_get_posts' ) ); // after main Polylang filter
		add_filter( 'get_terms_args', array( &$this, 'get_terms_args' ), 10, 2 );
	}

	/*
	 * helper function to get the translated post in the current language
	 *
	 * since 1.8
	 *
	 * @param int $post_id
	 * @return int
	 */
	protected function get_post( $post_id ) {
		return $this->model->post->get( $post_id, $this->curlang );
	}

	/*
	 * helper function to get the translated term in the current language
	 *
	 * since 1.8
	 *
	 * @param int $term_id
	 * @return int
	 */
	protected function get_term( $term_id ) {
		return $this->model->term->get( $term_id, $this->curlang );
	}

	/*
	 * filters posts query to automatically translate included ids
	 *
	 * @since 1.1
	 *
	 * @param object $query WP_Query object
	 */
	public function pre_get_posts( $query ) {
		global $wpdb;
		$qv = &$query->query_vars;

		if ( $query->is_main_query() || ! empty( $qv['lang'] ) || ( ! empty( $qv['post_type'] ) && ! $this->model->is_translated_post_type( $qv['post_type'] ) ) ) {
			return;
		}

		// /!\ always keep untranslated as is

		// term ids separated by a comma
		$arr = array();
		if ( ! empty( $qv['cat'] ) ) {
			foreach ( explode( ',', $qv['cat'] ) as $cat ) {
				$tr = $this->get_term( abs( $cat ) );
				$arr[] = $cat < 0 ? -$tr : $tr;
			}

			$qv['cat'] = implode( ',', $arr );
		}

		// category_name
		$arr = array();
		if ( ! empty( $qv['category_name'] ) ) {
			foreach ( explode( ',', $qv['category_name'] ) as $slug ) {
				$arr[] = ( ( $cat = get_category_by_slug( $slug ) ) && ( $tr_id = $this->get_term( $cat->term_id ) ) && ! is_wp_error( $tr = get_category( $tr_id ) ) ) ? $tr->slug : $slug;
			}

			$qv['category_name'] = implode( ',', $arr );
		}

		// array of term ids
		foreach ( array( 'category__and', 'category__in', 'category__not_in', 'tag__and', 'tag__in', 'tag__not_in' ) as $key ) {
			$arr = array();
			if ( ! empty( $qv[ $key ] ) ) {
				foreach ( $qv[ $key ] as $cat ) {
					$arr[] = ( $tr = $this->get_term( $cat ) ) ? $tr : $cat;
				}
				$qv[ $key ] = $arr;
			}
		}

		// tag
		$arr = array();
		if ( ! empty( $qv['tag'] ) ) {
			$sep = strpos( $qv['tag'], ',' ) !== false ? ',' : '+'; // two possible separators for tag slugs
			foreach ( explode( $sep, $qv['tag'] ) as $slug ) {
				$arr[] = ( ( $tag = get_term_by( 'slug', $slug, 'post_tag' ) ) && ( $tr_id = $this->get_term( $tag->term_id ) ) && ! is_wp_error( $tr = get_tag( $tr_id ) ) ) ? $tr->slug : $slug;
			}

			$qv['tag'] = implode( $sep, $arr );
		}

		// tag_id can only take one id
		if ( ! empty( $qv['tag_id'] ) && $tr_id = $this->get_term( $qv['tag_id'] ) ) {
			$qv['tag_id'] = $tr_id;
		}

		// array of tag slugs
		foreach ( array( 'tag_slug__and', 'tag_slug__in' ) as $key ) {
			$arr = array();
			if ( ! empty( $qv[ $key ] ) ) {
				foreach ( $qv[ $key ] as $slug ) {
					$arr[] = ( ( $tag = get_term_by( 'slug', $slug, 'post_tag' ) ) && ( $tr_id = $this->get_term( $tag->term_id ) ) && ! is_wp_error( $tr = get_tag( $tr_id ) ) ) ? $tr->slug : $slug;
				}

				$qv[ $key ] = $arr;
			}
		}

		// custom taxonomies
		// according to codex, this type of query is deprecated as of WP 3.1 but it does not appear in WP 3.5 source code
		foreach ( array_intersect( $this->model->get_translated_taxonomies(), get_taxonomies( array( '_builtin' => false ) ) ) as $taxonomy ) {
			$tax = get_taxonomy( $taxonomy );
			$arr = array();
			if ( ! empty( $qv[ $tax->query_var ] ) ) {
				$sep = strpos( $qv[ $tax->query_var ], ',' ) !== false ? ',' : '+'; // two possible separators
				foreach ( explode( $sep, $qv[ $tax->query_var ] ) as $slug ) {
					$arr[] = ( ( $tag = get_term_by( 'slug', $slug, $taxonomy ) ) && ( $tr_id = $this->get_term( $tag->term_id ) ) && ! is_wp_error( $tr = get_term( $tr_id, $taxonomy ) ) ) ? $tr->slug : $slug;
				}

				$qv[ $tax->query_var ] = implode( $sep, $arr );
			}
		}

		// tax_query since WP 3.1
		if ( ! empty( $qv['tax_query'] ) && is_array( $qv['tax_query'] ) ) {
			$qv['tax_query'] = $this->translate_tax_query_recursive( $qv['tax_query'] );
		}

		// p, page_id, post_parent can only take one id
		foreach ( array( 'p', 'page_id', 'post_parent' ) as $key ) {
			if ( ! empty( $qv[ $key ] ) && $tr_id = $this->get_post( $qv[ $key ] ) ) {
				$qv[ $key ] = $tr_id;
			}
		}

		// name, pagename can only take one slug
		foreach ( array( 'name', 'pagename' ) as $key ) {
			if ( ! empty( $qv[ $key ] ) ) {
				// no function to get post by name except get_posts itself
				$post_type = empty( $qv['post_type'] ) ? 'post' : $qv['post_type'];
				$id = $wpdb->get_var( $wpdb->prepare( "SELECT ID from $wpdb->posts WHERE post_type=%s AND post_name=%s", $post_type, $qv[ $key ] ) );
				$qv[ $key ] = ( $id && ( $tr_id = $this->get_post( $id ) ) && $tr = get_post( $tr_id ) ) ? $tr->post_name : $qv[ $key ];
			}
		}

		// array of post ids
		// post_parent__in & post_parent__not_in since WP 3.6
		foreach ( array( 'post__in', 'post__not_in', 'post_parent__in', 'post_parent__not_in' ) as $key ) {
			$arr = array();
			if ( ! empty( $qv[ $key ] ) ) {
				// post__in used by the 2 functions below
				// useless to filter them as output is already in the right language and would result in performance loss
				foreach ( debug_backtrace() as $trace ) {
					if ( in_array( $trace['function'], array( 'wp_nav_menu', 'gallery_shortcode' ) ) ) {
						return;
					}
				}

				foreach ( $qv[ $key ] as $p ) {
					$arr[] = ( $tr = $this->get_post( $p ) ) ? $tr : $p;
				}

				$qv[ $key ] = $arr;
			}
		}
	}

	/*
	 * filters terms query to automatically translate included ids
	 *
	 * @since 1.1.1
	 *
	 * @param array $args
	 * @param array $taxonomies
	 * @return array modified $args
	 */
	public function get_terms_args( $args, $taxonomies ) {
		if ( ! empty( $args['include'] ) && $this->model->is_translated_taxonomy( $taxonomies ) ) {
			foreach ( wp_parse_id_list( $args['include'] ) as $id ) {
				$arr[] = ( $tr = $this->get_term( $id ) ) ? $tr : $id;
			}

			$args['include'] = $arr;
		}
		return $args;
	}

	/*
	 * translates tax queries
	 * compatible with nested tax queries introduced in WP 4.1
	 *
	 * @since 1.7
	 *
	 * @param array $tax_queries
	 * @return array translated tax queries
	 */
	protected function translate_tax_query_recursive( $tax_queries ) {
		foreach ( $tax_queries as $key => $q ) {
			if ( isset( $q['taxonomy'] ) && $this->model->is_translated_taxonomy( $q['taxonomy'] ) ) {
				$arr = array();
				$field = isset( $q['field'] ) && in_array( $q['field'], array( 'slug', 'name' ) ) ? $q['field'] : 'term_id';
				foreach ( (array) $q['terms'] as $t ) {
					$arr[] = ( ( $tag = get_term_by( $field, $t, $q['taxonomy'] ) ) && ( $tr_id = $this->get_term( $tag->term_id ) ) && ! is_wp_error( $tr = get_term( $tr_id, $q['taxonomy'] ) ) ) ? $tr->$field : $t;
				}

				$tax_queries[ $key ]['terms'] = $arr;
			}

			// nested queries
			elseif ( is_array( $q ) ) {
				$tax_queries[ $key ] = $this->translate_tax_query_recursive( $q );
			}
		}

		return $tax_queries;
	}
}
