<?php

/**

 * Taxonomy API: WP_Tax_Query class

 *

 * @package WordPress

 * @subpackage Taxonomy

 * @since 4.4.0

 */

/**

 * Core class used to implement taxonomy queries for the Taxonomy API.

 *

 * Used for generating SQL clauses that filter a primary query according to object

 * taxonomy terms.

 *

 * WP_Tax_Query is a helper that allows primary query classes, such as WP_Query, to filter

 * their results by object metadata, by generating `JOIN` and `WHERE` subclauses to be

 * attached to the primary SQL query string.

 *

 * @since 3.1.0

 */

class WP_Tax_Query {

	/**

	 * Array of taxonomy queries.

	 *

	 * See WP_Tax_Query::__construct() for information on tax query arguments.

	 *

	 * @since 3.1.0

	 * @var array

	 */

	public $queries = array();

	/**

	 * The relation between the queries. Can be one of 'AND' or 'OR'.

	 *

	 * @since 3.1.0

	 * @var string

	 */

	public $relation;

	/**

	 * Standard response when the query should not return any rows.

	 *

	 * @since 3.2.0

	 * @var string

	 */

	private static $no_results = array(

		'join'  => array( '' ),

		'where' => array( '0 = 1' ),

	);

	/**

	 * A flat list of table aliases used in the JOIN clauses.

	 *

	 * @since 4.1.0

	 * @var array

	 */

	protected $table_aliases = array();

	/**

	 * Terms and taxonomies fetched by this query.

	 *

	 * We store this data in a flat array because they are referenced in a

	 * number of places by WP_Query.

	 *

	 * @since 4.1.0

	 * @var array

	 */

	public $queried_terms = array();

	/**

	 * Database table that where the metadata's objects are stored (eg $wpdb->users).

	 *

	 * @since 4.1.0

	 * @var string

	 */

	public $primary_table;

	/**

	 * Column in 'primary_table' that represents the ID of the object.

	 *

	 * @since 4.1.0

	 * @var string

	 */

	public $primary_id_column;

	/**

	 * Constructor.

	 *

	 * @since 3.1.0

	 * @since 4.1.0 Added support for `$operator` 'NOT EXISTS' and 'EXISTS' values.

	 *

	 * @param array $tax_query {

	 *     Array of taxonomy query clauses.

	 *

	 *     @type string $relation Optional. The MySQL keyword used to join

	 *                            the clauses of the query. Accepts 'AND', or 'OR'. Default 'AND'.

	 *

	 *         @type string           $taxonomy         Taxonomy being queried. Optional when field=term_taxonomy_id.

	 *         @type string|int|array $terms            Term or terms to filter by.

	 *         @type string           $field            Field to match $terms against. Accepts 'term_id', 'slug',

	 *                                                 'name', or 'term_taxonomy_id'. Default: 'term_id'.

	 *         @type string           $operator         MySQL operator to be used with $terms in the WHERE clause.

	 *                                                  Accepts 'AND', 'IN', 'NOT IN', 'EXISTS', 'NOT EXISTS'.

	 *                                                  Default: 'IN'.

	 *         @type bool             $include_children Optional. Whether to include child terms.

	 *                                                  Requires a $taxonomy. Default: true.

	 *     }

	 * }

	 */

	public function __construct( $tax_query ) {

		if ( isset( $tax_query['relation'] ) ) {

			$this->relation = $this->sanitize_relation( $tax_query['relation'] );

		} else {

			$this->relation = 'AND';

		}

		$this->queries = $this->sanitize_query( $tax_query );

	}

	/**

	 * Ensure the 'tax_query' argument passed to the class constructor is well-formed.

	 *

	 * Ensures that each query-level clause has a 'relation' key, and that

	 * each first-order clause contains all the necessary keys from `$defaults`.

	 *

	 * @since 4.1.0

	 *

	 * @param array $queries Array of queries clauses.

	 * @return array Sanitized array of query clauses.

	 */

	public function sanitize_query( $queries ) {

		$cleaned_query = array();

		$defaults = array(

			'taxonomy'         => '',

			'terms'            => array(),

			'field'            => 'term_id',

			'operator'         => 'IN',

			'include_children' => true,

		);

		foreach ( $queries as $key => $query ) {

			if ( 'relation' === $key ) {

				$cleaned_query['relation'] = $this->sanitize_relation( $query );

				// First-order clause.

			} elseif ( self::is_first_order_clause( $query ) ) {

				$cleaned_clause          = array_merge( $defaults, $query );

				$cleaned_clause['terms'] = (array) $cleaned_clause['terms'];

				$cleaned_query[]         = $cleaned_clause;

				/*

				 * Keep a copy of the clause in the flate

				 * $queried_terms array, for use in WP_Query.

				 */

				if ( ! empty( $cleaned_clause['taxonomy'] ) && 'NOT IN' !== $cleaned_clause['operator'] ) {

					$taxonomy = $cleaned_clause['taxonomy'];

					if ( ! isset( $this->queried_terms[ $taxonomy ] ) ) {

						$this->queried_terms[ $taxonomy ] = array();

					}

					/*

					 * Backward compatibility: Only store the first

					 * 'terms' and 'field' found for a given taxonomy.

					 */

					if ( ! empty( $cleaned_clause['terms'] ) && ! isset( $this->queried_terms[ $taxonomy ]['terms'] ) ) {

						$this->queried_terms[ $taxonomy ]['terms'] = $cleaned_clause['terms'];

					}

					if ( ! empty( $cleaned_clause['field'] ) && ! isset( $this->queried_terms[ $taxonomy ]['field'] ) ) {

						$this->queried_terms[ $taxonomy ]['field'] = $cleaned_clause['field'];

					}

				}

				// Otherwise, it's a nested query, so we recurse.

			} elseif ( is_array( $query ) ) {

				$cleaned_subquery = $this->sanitize_query( $query );

				if ( ! empty( $cleaned_subquery ) ) {

					// All queries with children must have a relation.

					if ( ! isset( $cleaned_subquery['relation'] ) ) {

						$cleaned_subquery['relation'] = 'AND';

					}

					$cleaned_query[] = $cleaned_subquery;

				}

			}

		}

		return $cleaned_query;

	}

	/**

	 * Sanitize a 'relation' operator.

	 *

	 * @since 4.1.0

	 *

	 * @param string $relation Raw relation key from the query argument.

	 * @return string Sanitized relation ('AND' or 'OR').

	 */

	public function sanitize_relation( $relation ) {

		if ( 'OR' === strtoupper( $relation ) ) {

			return 'OR';

		} else {

			return 'AND';

		}

	}

	/**

	 * Determine whether a clause is first-order.

	 *

	 * A "first-order" clause is one that contains any of the first-order

	 * clause keys ('terms', 'taxonomy', 'include_children', 'field',

	 * 'operator'). An empty clause also counts as a first-order clause,

	 * for backward compatibility. Any clause that doesn't meet this is

	 * determined, by process of elimination, to be a higher-order query.

	 *

	 * @since 4.1.0

	 *

	 * @param array $query Tax query arguments.

	 * @return bool Whether the query clause is a first-order clause.

	 */

	protected static function is_first_order_clause( $query ) {

		return is_array( $query ) && ( empty( $query ) || array_key_exists( 'terms', $query ) || array_key_exists( 'taxonomy', $query ) || array_key_exists( 'include_children', $query ) || array_key_exists( 'field', $query ) || array_key_exists( 'operator', $query ) );

	}

	/**

	 * Generates SQL clauses to be appended to a main query.

	 *

	 * @since 3.1.0

	 *

	 * @param string $primary_table     Database table where the object being filtered is stored (eg wp_users).

	 * @param string $primary_id_column ID column for the filtered object in $primary_table.

	 * @return array {

	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.

	 *

	 *     @type string $join  SQL fragment to append to the main JOIN clause.

	 *     @type string $where SQL fragment to append to the main WHERE clause.

	 * }

	 */

	public function get_sql( $primary_table, $primary_id_column ) {

		$this->primary_table     = $primary_table;

		$this->primary_id_column = $primary_id_column;

		return $this->get_sql_clauses();

	}

	/**

	 * Generate SQL clauses to be appended to a main query.

	 *

	 * Called by the public WP_Tax_Query::get_sql(), this method

	 * is abstracted out to maintain parity with the other Query classes.

	 *

	 * @since 4.1.0

	 *

	 * @return array {

	 *     Array containing JOIN and WHERE SQL clauses to append to the main query.

	 *

	 *     @type string $join  SQL fragment to append to the main JOIN clause.

	 *     @type string $where SQL fragment to append to the main WHERE clause.

	 * }

	 */

	protected function get_sql_clauses() {

		/*

		 * $queries are passed by reference to get_sql_for_query() for recursion.

		 * To keep $this->queries unaltered, pass a copy.

		 */

		$queries = $this->queries;

		$sql     = $this->get_sql_for_query( $queries );

		if ( ! empty( $sql['where'] ) ) {

			$sql['where'] = ' AND ' . $sql['where'];

		}

		return $sql;

	}

	/**

	 * Generate SQL clauses for a single query array.

	 *

	 * If nested subqueries are found, this method recurses the tree to

	 * produce the properly nested SQL.

	 *

	 * @since 4.1.0

	 *

	 * @param array $query Query to parse (passed by reference).

	 * @param int   $depth Optional. Number of tree levels deep we currently are.

	 *                     Used to calculate indentation. Default 0.

	 * @return array {

	 *     Array containing JOIN and WHERE SQL clauses to append to a single query array.

	 *

	 *     @type string $join  SQL fragment to append to the main JOIN clause.

	 *     @type string $where SQL fragment to append to the main WHERE clause.

	 * }

	 */

	protected function get_sql_for_query( &$query, $depth = 0 ) {

		$sql_chunks = array(

			'join'  => array(),

			'where' => array(),

		);

		$sql = array(

			'join'  => '',

			'where' => '',

		);

		$indent = '';

		for ( $i = 0; $i < $depth; $i++ ) {

			$indent .= '  ';

		}

		foreach ( $query as $key => &$clause ) {

			if ( 'relation' === $key ) {

				$relation = $query['relation'];

			} elseif ( is_array( $clause ) ) {

				// This is a first-order clause.

				if ( $this->is_first_order_clause( $clause ) ) {

					$clause_sql = $this->get_sql_for_clause( $clause, $query );

					$where_count = count( $clause_sql['where'] );

					if ( ! $where_count ) {

						$sql_chunks['where'][] = '';

					} elseif ( 1 === $where_count ) {

						$sql_chunks['where'][] = $clause_sql['where'][0];

					} else {

						$sql_chunks['where'][] = '( ' . implode( ' AND ', $clause_sql['where'] ) . ' )';

					}

					$sql_chunks['join'] = array_merge( $sql_chunks['join'], $clause_sql['join'] );

					// This is a subquery, so we recurse.

				} else {

					$clause_sql = $this->get_sql_for_query( $clause, $depth + 1 );

					$sql_chunks['where'][] = $clause_sql['where'];

					$sql_chunks['join'][]  = $clause_sql['join'];

				}

			}

		}

		// Filter to remove empties.

		$sql_chunks['join']  = array_filter( $sql_chunks['join'] );

		$sql_chunks['where'] = array_filter( $sql_chunks['where'] );

		if ( empty( $relation ) ) {

			$relation = 'AND';

		}

		// Filter duplicate JOIN clauses and combine into a single string.

		if ( ! empty( $sql_chunks['join'] ) ) {

			$sql['join'] = implode( ' ', array_unique( $sql_chunks['join'] ) );

		}

		// Generate a single WHERE clause with proper brackets and indentation.

		if ( ! empty( $sql_chunks['where'] ) ) {

			$sql['where'] = '( ' . "\n  " . $indent . implode( ' ' . "\n  " . $indent . $relation . ' ' . "\n  " . $indent, $sql_chunks['where'] ) . "\n" . $indent . ')';

		}

		return $sql;

	}

	/**

	 * Generate SQL JOIN and WHERE clauses for a "first-order" query clause.

	 *

	 * @since 4.1.0

	 *

	 * @global wpdb $wpdb The WordPress database abstraction object.

	 *

	 * @param array $clause       Query clause (passed by reference).

	 * @param array $parent_query Parent query array.

	 * @return array {

	 *     Array containing JOIN and WHERE SQL clauses to append to a first-order query.

	 *

	 *     @type string $join  SQL fragment to append to the main JOIN clause.

	 *     @type string $where SQL fragment to append to the main WHERE clause.

	 * }

	 */

	public function get_sql_for_clause( &$clause, $parent_query ) {

		global $wpdb;

		$sql = array(

			'where' => array(),

			'join'  => array(),

		);

		$this->clean_query( $clause );

		if ( is_wp_error( $clause ) ) {

			return self::$no_results;

		}

		$terms    = $clause['terms'];

		$operator = strtoupper( $clause['operator'] );

			if ( empty( $terms ) ) {

				return self::$no_results;

			}

			$terms = implode( ',', $terms );

			/*

			 * Before creating another table join, see if this clause has a

			 * sibling with an existing join that can be shared.

			 */

			$alias = $this->find_compatible_table_alias( $clause, $parent_query );

			if ( false === $alias ) {

				$i     = count( $this->table_aliases );

				$alias = $i ? 'tt' . $i : $wpdb->term_relationships;

				// Store the alias as part of a flat array to build future iterators.

				$this->table_aliases[] = $alias;

				// Store the alias with this clause, so later siblings can use it.

				$clause['alias'] = $alias;

				$join .= " LEFT JOIN $wpdb->term_relationships";

				$join .= $i ? " AS $alias" : '';

				$join .= " ON ($this->primary_table.$this->primary_id_column = $alias.object_id)";

			}

			$where = "$alias.term_taxonomy_id $operator ($terms)";

			if ( empty( $terms ) ) {

				return $sql;

			}