<?php

namespace WPGraphQL\Server;

use GraphQL\Server\Helper;

/**
 * Extends GraphQL\Server\Helper to apply filters and parse query extensions.
 *
 * @package WPGraphQL\Server
 */
class WPHelper extends Helper {

	/**
	 * {@inheritDoc}
	 * Parses normalized request params and returns instance of OperationParams
	 * or array of OperationParams in case of batch operation.
	 *
	 * @param string  $method The method of the request (GET, POST, etc).
	 * @param mixed[] $bodyParams The params passed to the body of the request.
	 * @param mixed[] $queryParams The query params passed to the request.
	 *
	 * @return \GraphQL\Server\OperationParams|\GraphQL\Server\OperationParams[]
	 * @throws \GraphQL\Server\RequestError Throws RequestError.
	 */
	public function parseRequestParams( $method, array $bodyParams, array $queryParams ) {
		// Apply wp_unslash to query (GET) variables to undo wp_magic_quotes. We
		// don't need to do this for POST variables because graphql-php reads the
		// HTTP body directly.
		$parsed_body_params = $this->parse_params( $bodyParams );

		$parsed_query_params = $this->parse_extensions( wp_unslash( $queryParams ) );

		$request_context = [
			'method'       => $method,
			'query_params' => ! empty( $parsed_query_params ) ? $parsed_query_params : null,
			'body_params'  => ! empty( $parsed_body_params ) ? $parsed_body_params : null,
		];

		/**
		 * Allow the request data to be filtered. Previously this filter was only
		 * applied to non-HTTP requests. Since 0.2.0, we will apply it to all
		 * requests.
		 *
		 * This is a great place to hook if you are interested in implementing
		 * persisted queries (and ends up being a bit more flexible than
		 * graphql-php's built-in persistentQueryLoader).
		 *
		 * @param mixed[] $data            An array containing the pieces of the data of the GraphQL request
		 * @param array{
		 *  method: string,
		 *  query_params: array<string,mixed>|null,
		 *  body_params: array<string,mixed>|null,
		 * } $request_context An array containing the both body and query params
		 */
		if ( 'GET' === $method ) {
			$parsed_query_params = apply_filters( 'graphql_request_data', $parsed_query_params, $request_context );
			// In GET requests there cannot be any body params so it's empty.
			return parent::parseRequestParams( $method, [], $parsed_query_params );
		}

		// In POST requests the query params are ignored by default but users can
		// merge them into the body params manually using the $request_context if
		// needed.
		$parsed_body_params = apply_filters( 'graphql_request_data', $parsed_body_params, $request_context );
		return parent::parseRequestParams( $method, $parsed_body_params, [] );
	}

	/**
	 * Parse parameters and proxy to parse_extensions.
	 *
	 * @param array<string,mixed>|array<string,mixed>[] $params Request parameters.
	 * @return array<string,mixed>|array<string,mixed>[]
	 */
	private function parse_params( array $params ): array {
		if ( isset( $params[0] ) ) {
			return array_map( [ $this, 'parse_extensions' ], $params );
		}

		return $this->parse_extensions( $params );
	}

	/**
	 * Parse query extensions.
	 *
	 * @param  array<string,mixed> $params Request parameters.
	 * @return array<string,mixed>
	 */
	private function parse_extensions( $params ): array {
		// Bail if no params are passed.
		if ( empty( $params ) || ! is_array( $params ) ) {
			return [];
		}

		if ( isset( $params['extensions'] ) && is_string( $params['extensions'] ) ) {
			$tmp = json_decode( $params['extensions'], true );
			if ( ! json_last_error() ) {
				$params['extensions'] = $tmp;
			}
		}

		// Apollo server/client compatibility: look for the query id in extensions
		if ( isset( $params['extensions']['persistedQuery']['sha256Hash'] ) && ! isset( $params['queryId'] ) ) {
			$params['queryId'] = $params['extensions']['persistedQuery']['sha256Hash'];
			unset( $params['extensions']['persistedQuery'] );
		}

		return $params;
	}
}