<?php
namespace WPGraphQL\Mutation;

use Exception;
use GraphQL\Error\UserError;
use GraphQL\Type\Definition\ResolveInfo;
use GraphQLRelay\Relay;
use WP_Post_Type;
use WPGraphQL\AppContext;
use WPGraphQL\Data\PostObjectMutation;

class PostObjectUpdate {
	/**
	 * Registers the PostObjectUpdate mutation.
	 *
	 * @param WP_Post_Type $post_type_object The post type of the mutation.
	 *
	 * @return void
	 * @throws Exception
	 */
	public static function register_mutation( WP_Post_Type $post_type_object ) {
		$mutation_name = 'update' . ucwords( $post_type_object->graphql_single_name );

		register_graphql_mutation(
			$mutation_name,
			[
				'inputFields'         => self::get_input_fields( $post_type_object ),
				'outputFields'        => self::get_output_fields( $post_type_object ),
				'mutateAndGetPayload' => self::mutate_and_get_payload( $post_type_object, $mutation_name ),
			]
		);
	}

	/**
	 * Defines the mutation input field configuration.
	 *
	 * @param WP_Post_Type $post_type_object   The post type of the mutation.
	 *
	 * @return array
	 */
	public static function get_input_fields( $post_type_object ) {
		return array_merge(
			PostObjectCreate::get_input_fields( $post_type_object ),
			[
				'id' => [
					'type'        => [
						'non_null' => 'ID',
					],
					// translators: the placeholder is the name of the type of post object being updated
					'description' => sprintf( __( 'The ID of the %1$s object', 'wp-graphql' ), $post_type_object->graphql_single_name ),
				],
			]
		);
	}

	/**
	 * Defines the mutation output field configuration.
	 *
	 * @param WP_Post_Type $post_type_object   The post type of the mutation.
	 *
	 * @return array
	 */
	public static function get_output_fields( $post_type_object ) {
		return PostObjectCreate::get_output_fields( $post_type_object );
	}

	/**
	 * Defines the mutation data modification closure.
	 *
	 * @param WP_Post_Type $post_type_object   The post type of the mutation.
	 * @param string        $mutation_name      The mutation name.
	 *
	 * @return callable
	 */
	public static function mutate_and_get_payload( $post_type_object, $mutation_name ) {
		return function ( $input, AppContext $context, ResolveInfo $info ) use ( $post_type_object, $mutation_name ) {

			$id_parts      = ! empty( $input['id'] ) ? Relay::fromGlobalId( $input['id'] ) : null;
			$existing_post = isset( $id_parts['id'] ) && absint( $id_parts['id'] ) ? get_post( absint( $id_parts['id'] ) ) : null;

			/**
			 * If there's no existing post, throw an exception
			 */
			if ( ! isset( $id_parts['id'] ) || empty( $existing_post ) ) {
				// translators: the placeholder is the name of the type of post being updated
				throw new UserError( sprintf( __( 'No %1$s could be found to update', 'wp-graphql' ), $post_type_object->graphql_single_name ) );
			}

			if ( $post_type_object->name !== $existing_post->post_type ) {
				// translators: The first placeholder is an ID and the second placeholder is the name of the post type being edited
				throw new UserError( sprintf( __( 'The id %1$d is not of the type "%2$s"', 'wp-graphql' ), $id_parts['id'], $post_type_object->name ) );
			}

			/**
			 * Stop now if a user isn't allowed to edit posts
			 */
			if ( ! isset( $post_type_object->cap->edit_posts ) || ! current_user_can( $post_type_object->cap->edit_posts ) ) {
				// translators: the $post_type_object->graphql_single_name placeholder is the name of the object being mutated
				throw new UserError( sprintf( __( 'Sorry, you are not allowed to update a %1$s', 'wp-graphql' ), $post_type_object->graphql_single_name ) );
			}

			/**
			 * If the existing post was authored by another author, ensure the requesting user has permission to edit it
			 */
			if ( get_current_user_id() !== (int) $existing_post->post_author && ( ! isset( $post_type_object->cap->edit_others_posts ) || true !== current_user_can( $post_type_object->cap->edit_others_posts ) ) ) {
				// translators: the $post_type_object->graphql_single_name placeholder is the name of the object being mutated
				throw new UserError( sprintf( __( 'Sorry, you are not allowed to update another author\'s %1$s', 'wp-graphql' ), $post_type_object->graphql_single_name ) );
			}

			/**
			 * If the mutation is setting the author to be someone other than the user making the request
			 * make sure they have permission to edit others posts
			 */
			$author_id_parts = ! empty( $input['authorId'] ) ? Relay::fromGlobalId( $input['authorId'] ) : null;
			if ( ! empty( $author_id_parts['id'] ) && get_current_user_id() !== $author_id_parts['id'] && ( ! isset( $post_type_object->cap->edit_others_posts ) || ! current_user_can( $post_type_object->cap->edit_others_posts ) ) ) {
				// translators: the $post_type_object->graphql_single_name placeholder is the name of the object being mutated
				throw new UserError( sprintf( __( 'Sorry, you are not allowed to update %1$s as this user.', 'wp-graphql' ), $post_type_object->graphql_plural_name ) );
			}

			/**
			 * @todo: when we add support for making posts sticky, we should check permissions to make sure users can make posts sticky
			 * @see : https://github.com/WordPress/WordPress/blob/e357195ce303017d517aff944644a7a1232926f7/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php#L640-L642
			 */

			/**
			 * @todo: when we add support for assigning terms to posts, we should check permissions to make sure they can assign terms
			 * @see : https://github.com/WordPress/WordPress/blob/e357195ce303017d517aff944644a7a1232926f7/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php#L644-L646
			 */

			/**
			 * Insert the post object and get the ID
			 */
			$post_args       = PostObjectMutation::prepare_post_object( $input, $post_type_object, $mutation_name );
			$post_args['ID'] = absint( $id_parts['id'] );

			$clean_args = wp_slash( (array) $post_args );

			if ( ! is_array( $clean_args ) || empty( $clean_args ) ) {
				throw new UserError( __( 'The object failed to update.', 'wp-graphql' ) );
			}

			/**
			 * Insert the post and retrieve the ID
			 */
			$post_id = wp_update_post( $clean_args, true );

			/**
			 * Throw an exception if the post failed to update
			 */
			if ( is_wp_error( $post_id ) ) {
				throw new UserError( __( 'The object failed to update', 'wp-graphql' ) );
			}

			/**
			 * Fires after a single term is created or updated via a GraphQL mutation
			 *
			 * The dynamic portion of the hook name, `$taxonomy->name` refers to the taxonomy of the term being mutated
			 *
			 * @param int    $post_id       Inserted post ID
			 * @param WP_Post_Type $post_type_object The Post Type object for the post being mutated
			 * @param array  $args          The args used to insert the term
			 * @param string $mutation_name The name of the mutation being performed
			 */
			do_action( 'graphql_insert_post_object', $post_id, $post_type_object, $post_args, $mutation_name );

			/**
			 * Fires after a single term is created or updated via a GraphQL mutation
			 *
			 * The dynamic portion of the hook name, `$taxonomy->name` refers to the taxonomy of the term being mutated
			 *
			 * @param int    $post_id       Inserted post ID
			 * @param array  $args          The args used to insert the term
			 * @param string $mutation_name The name of the mutation being performed
			 */
			do_action( "graphql_insert_{$post_type_object->name}", $post_id, $post_args, $mutation_name );

			/**
			 * This updates additional data not part of the posts table (postmeta, terms, other relations, etc)
			 *
			 * The input for the postObjectMutation will be passed, along with the $new_post_id for the
			 * postObject that was updated so that relations can be set, meta can be updated, etc.
			 */
			PostObjectMutation::update_additional_post_object_data( $post_id, $input, $post_type_object, $mutation_name, $context, $info );

			/**
			 * Return the payload
			 */
			return [
				'postObjectId' => $post_id,
			];
		};
	}
}