<?php

/**

 * REST API: WP_REST_Terms_Controller class

 *

 * @package WordPress

 * @subpackage REST_API

 * @since 4.7.0

 */

/**

 * Core class used to managed terms associated with a taxonomy via the REST API.

 *

 * @since 4.7.0

 *

 * @see WP_REST_Controller

 */

class WP_REST_Terms_Controller extends WP_REST_Controller {

	/**

	 * Taxonomy key.

	 *

	 * @since 4.7.0

	 * @var string

	 */

	protected $taxonomy;

	/**

	 * Instance of a term meta fields object.

	 *

	 * @since 4.7.0

	 * @var WP_REST_Term_Meta_Fields

	 */

	protected $meta;

	/**

	 * Column to have the terms be sorted by.

	 *

	 * @since 4.7.0

	 * @var string

	 */

	protected $sort_column;

	/**

	 * Number of terms that were found.

	 *

	 * @since 4.7.0

	 * @var int

	 */

	protected $total_terms;

	/**

	 * Constructor.

	 *

	 * @since 4.7.0

	 *

	 * @param string $taxonomy Taxonomy key.

	 */

	public function __construct( $taxonomy ) {

		$this->taxonomy = $taxonomy;

		$this->namespace = 'wp/v2';

		$tax_obj = get_taxonomy( $taxonomy );

		$this->rest_base = ! empty( $tax_obj->rest_base ) ? $tax_obj->rest_base : $tax_obj->name;

		$this->meta = new WP_REST_Term_Meta_Fields( $taxonomy );

	}

	/**

	 * Registers the routes for the objects of the controller.

	 *

	 * @since 4.7.0

	 *

	 * @see register_rest_route()

	 */

	public function register_routes() {

		register_rest_route( $this->namespace, '/' . $this->rest_base, array(

			array(

				'methods'             => WP_REST_Server::READABLE,

				'callback'            => array( $this, 'get_items' ),

				'permission_callback' => array( $this, 'get_items_permissions_check' ),

				'args'                => $this->get_collection_params(),

			),

			array(

				'methods'             => WP_REST_Server::CREATABLE,

				'callback'            => array( $this, 'create_item' ),

				'permission_callback' => array( $this, 'create_item_permissions_check' ),

				'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::CREATABLE ),

			),

			'schema' => array( $this, 'get_public_item_schema' ),

		) );

		register_rest_route( $this->namespace, '/' . $this->rest_base . '/(?P<id>[\d]+)', array(

			'args' => array(

				'id' => array(

					'description' => __( 'Unique identifier for the term.' ),

					'type'        => 'integer',

				),

			),

			array(

				'methods'             => WP_REST_Server::READABLE,

				'callback'            => array( $this, 'get_item' ),

				'permission_callback' => array( $this, 'get_item_permissions_check' ),

				'args'                => array(

					'context' => $this->get_context_param( array( 'default' => 'view' ) ),

				),

			),

			array(

				'methods'             => WP_REST_Server::EDITABLE,

				'callback'            => array( $this, 'update_item' ),

				'permission_callback' => array( $this, 'update_item_permissions_check' ),

				'args'                => $this->get_endpoint_args_for_item_schema( WP_REST_Server::EDITABLE ),

			),

			array(

				'methods'             => WP_REST_Server::DELETABLE,

				'callback'            => array( $this, 'delete_item' ),

				'permission_callback' => array( $this, 'delete_item_permissions_check' ),

				'args'                => array(

					'force' => array(

						'type'        => 'boolean',

						'default'     => false,

						'description' => __( 'Required to be true, as terms do not support trashing.' ),

					),

				),

			),

			'schema' => array( $this, 'get_public_item_schema' ),

		) );

	}

	/**

	 * Checks if a request has access to read terms in the specified taxonomy.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return bool|WP_Error True if the request has read access, otherwise false or WP_Error object.

	 */

	public function get_items_permissions_check( $request ) {

		$tax_obj = get_taxonomy( $this->taxonomy );

		if ( ! $tax_obj || ! $this->check_is_taxonomy_allowed( $this->taxonomy ) ) {

			return false;

		}

		if ( 'edit' === $request['context'] && ! current_user_can( $tax_obj->cap->edit_terms ) ) {

			return new WP_Error( 'rest_forbidden_context', __( 'Sorry, you are not allowed to edit terms in this taxonomy.' ), array( 'status' => rest_authorization_required_code() ) );

		}

		return true;

	}

	/**

	 * Retrieves terms associated with a taxonomy.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.

	 */

	public function get_items( $request ) {

		// Retrieve the list of registered collection query parameters.

		$registered = $this->get_collection_params();

		/*

		 * This array defines mappings between public API query parameters whose

		 * values are accepted as-passed, and their internal WP_Query parameter

		 * name equivalents (some are the same). Only values which are also

		 * present in $registered will be set.

		 */

		$parameter_mappings = array(

			'exclude'    => 'exclude',

			'include'    => 'include',

			'order'      => 'order',

			'orderby'    => 'orderby',

			'post'       => 'post',

			'hide_empty' => 'hide_empty',

			'per_page'   => 'number',

			'search'     => 'search',

			'slug'       => 'slug',

		);

		$prepared_args = array();

		/*

		 * For each known parameter which is both registered and present in the request,

		 * set the parameter's value on the query $prepared_args.

		 */

		foreach ( $parameter_mappings as $api_param => $wp_param ) {

			if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {

				$prepared_args[ $wp_param ] = $request[ $api_param ];

			}

		}

		if ( isset( $prepared_args['orderby'] ) && isset( $request['orderby'] ) ) {

			$orderby_mappings = array(

				'include_slugs' => 'slug__in',

			);

			if ( isset( $orderby_mappings[ $request['orderby'] ] ) ) {

				$prepared_args['orderby'] = $orderby_mappings[ $request['orderby'] ];

			}

		}

		if ( isset( $registered['offset'] ) && ! empty( $request['offset'] ) ) {

			$prepared_args['offset'] = $request['offset'];

		} else {

			$prepared_args['offset'] = ( $request['page'] - 1 ) * $prepared_args['number'];

		}

		$taxonomy_obj = get_taxonomy( $this->taxonomy );

		if ( $taxonomy_obj->hierarchical && isset( $registered['parent'], $request['parent'] ) ) {

			if ( 0 === $request['parent'] ) {

				// Only query top-level terms.

				$prepared_args['parent'] = 0;

			} else {

				if ( $request['parent'] ) {

					$prepared_args['parent'] = $request['parent'];

				}

			}

		}

		/**

		 * Filters the query arguments before passing them to get_terms().

		 *

		 * The dynamic portion of the hook name, `$this->taxonomy`, refers to the taxonomy slug.

		 *

		 * Enables adding extra arguments or setting defaults for a terms

		 * collection request.

		 *

		 * @since 4.7.0

		 *

		 * @link https://developer.wordpress.org/reference/functions/get_terms/

		 *

		 * @param array           $prepared_args Array of arguments to be

		 *                                       passed to get_terms().

		 * @param WP_REST_Request $request       The current request.

		 */

		$prepared_args = apply_filters( "rest_{$this->taxonomy}_query", $prepared_args, $request );

		if ( ! empty( $prepared_args['post'] )  ) {

			$query_result = wp_get_object_terms( $prepared_args['post'], $this->taxonomy, $prepared_args );

			// Used when calling wp_count_terms() below.

			$prepared_args['object_ids'] = $prepared_args['post'];

		} else {

			$query_result = get_terms( $this->taxonomy, $prepared_args );

		}

		$count_args = $prepared_args;

		unset( $count_args['number'], $count_args['offset'] );

		$total_terms = wp_count_terms( $this->taxonomy, $count_args );

		// wp_count_terms can return a falsy value when the term has no children.

		if ( ! $total_terms ) {

			$total_terms = 0;

		}

		$response = array();

		foreach ( $query_result as $term ) {

			$data = $this->prepare_item_for_response( $term, $request );

			$response[] = $this->prepare_response_for_collection( $data );

		}

		$response = rest_ensure_response( $response );

		// Store pagination values for headers.

		$per_page = (int) $prepared_args['number'];

		$page     = ceil( ( ( (int) $prepared_args['offset'] ) / $per_page ) + 1 );

		$response->header( 'X-WP-Total', (int) $total_terms );

		$max_pages = ceil( $total_terms / $per_page );

		$response->header( 'X-WP-TotalPages', (int) $max_pages );

		$base = add_query_arg( $request->get_query_params(), rest_url( $this->namespace . '/' . $this->rest_base ) );

		if ( $page > 1 ) {

			$prev_page = $page - 1;

			if ( $prev_page > $max_pages ) {

				$prev_page = $max_pages;

			}

			$prev_link = add_query_arg( 'page', $prev_page, $base );

			$response->link_header( 'prev', $prev_link );

		}

		if ( $max_pages > $page ) {

			$next_page = $page + 1;

			$next_link = add_query_arg( 'page', $next_page, $base );

			$response->link_header( 'next', $next_link );

		}

		return $response;

	}

	/**

	 * Get the term, if the ID is valid.

	 *

	 * @since 4.7.2

	 *

	 * @param int $id Supplied ID.

	 * @return WP_Term|WP_Error Term object if ID is valid, WP_Error otherwise.

	 */

	protected function get_term( $id ) {

		$error = new WP_Error( 'rest_term_invalid', __( 'Term does not exist.' ), array( 'status' => 404 ) );

		if ( ! $this->check_is_taxonomy_allowed( $this->taxonomy ) ) {

			return $error;

		}

		if ( (int) $id <= 0 ) {

			return $error;

		}

		$term = get_term( (int) $id, $this->taxonomy );

		if ( empty( $term ) || $term->taxonomy !== $this->taxonomy ) {

			return $error;

		}

		return $term;

	}

	/**

	 * Checks if a request has access to read or edit the specified term.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return bool|WP_Error True if the request has read access for the item, otherwise false or WP_Error object.

	 */

	public function get_item_permissions_check( $request ) {

		$term = $this->get_term( $request['id'] );

		if ( is_wp_error( $term ) ) {

			return $term;

		}

		if ( 'edit' === $request['context'] && ! current_user_can( 'edit_term', $term->term_id ) ) {

			return new WP_Error( 'rest_forbidden_context', __( 'Sorry, you are not allowed to edit this term.' ), array( 'status' => rest_authorization_required_code() ) );

		}

		return true;

	}

	/**

	 * Gets a single term from a taxonomy.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.

	 */

	public function get_item( $request ) {

		$term = $this->get_term( $request['id'] );

		if ( is_wp_error( $term ) ) {

			return $term;

		}

		$response = $this->prepare_item_for_response( $term, $request );

		return rest_ensure_response( $response );

	}

	/**

	 * Checks if a request has access to create a term.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return bool|WP_Error True if the request has access to create items, false or WP_Error object otherwise.

	 */

	public function create_item_permissions_check( $request ) {

		if ( ! $this->check_is_taxonomy_allowed( $this->taxonomy ) ) {

			return false;

		}

		$taxonomy_obj = get_taxonomy( $this->taxonomy );

		if ( ( is_taxonomy_hierarchical( $this->taxonomy )

				&& ! current_user_can( $taxonomy_obj->cap->edit_terms ) )

			|| ( ! is_taxonomy_hierarchical( $this->taxonomy )

				&& ! current_user_can( $taxonomy_obj->cap->assign_terms ) ) ) {

			return new WP_Error( 'rest_cannot_create', __( 'Sorry, you are not allowed to create new terms.' ), array( 'status' => rest_authorization_required_code() ) );

		}

		return true;

	}

	/**

	 * Creates a single term in a taxonomy.

	 *

	 * @since 4.7.0

	 *

	 * @param WP_REST_Request $request Full details about the request.

	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.

	 */

	public function create_item( $request ) {

		if ( isset( $request['parent'] ) ) {

			if ( ! is_taxonomy_hierarchical( $this->taxonomy ) ) {

				return new WP_Error( 'rest_taxonomy_not_hierarchical', __( 'Cannot set parent term, taxonomy is not hierarchical.' ), array( 'status' => 400 ) );

			}

			$parent = get_term( (int) $request['parent'], $this->taxonomy );

			if ( ! $parent ) {

				return new WP_Error( 'rest_term_invalid', __( 'Parent term does not exist.' ), array( 'status' => 400 ) );

			}

		}

		$prepared_term = $this->prepare_item_for_database( $request );

		$term = wp_insert_term( wp_slash( $prepared_term->name ), $this->taxonomy, wp_slash( (array) $prepared_term ) );

		if ( is_wp_error( $term ) ) {

			/*

			 * If we're going to inform the client that the term already exists,

			 * give them the identifier for future use.

			 */

			if ( $term_id = $term->get_error_data( 'term_exists' ) ) {

				$existing_term = get_term( $term_id, $this->taxonomy );

				$term->add_data( $existing_term->term_id, 'term_exists' );

				$term->add_data( array( 'status' => 409, 'term_id' => $term_id ) );