<?php
/**
 * The Connection Client class file.
 *
 * @package automattic/jetpack-connection
 */

namespace Automattic\Jetpack\Connection;

use Automattic\Jetpack\Constants;

/**
 * The Client class that is used to connect to WordPress.com Jetpack API.
 */
class Client {
	const WPCOM_JSON_API_VERSION = '1.1';

	/**
	 * Makes an authorized remote request using Jetpack_Signature
	 *
	 * @param array        $args the arguments for the remote request.
	 * @param array|String $body the request body.
	 * @return array|WP_Error WP HTTP response on success
	 */
	public static function remote_request( $args, $body = null ) {
		if ( isset( $args['url'] ) ) {
			/**
			 * Filters the remote request url.
			 *
			 * @since 1.30.12
			 *
			 * @param string The remote request url.
			 */
			$args['url'] = apply_filters( 'jetpack_remote_request_url', $args['url'] );
		}

		$result = self::build_signed_request( $args, $body );
		if ( ! $result || is_wp_error( $result ) ) {
			return $result;
		}

		$response = self::_wp_remote_request( $result['url'], $result['request'] );

		Error_Handler::get_instance()->check_api_response_for_errors(
			$response,
			$result['auth'],
			empty( $args['url'] ) ? '' : $args['url'],
			empty( $args['method'] ) ? 'POST' : $args['method'],
			'rest'
		);

		/**
		 * Fired when the remote request response has been received.
		 *
		 * @since 1.30.8
		 *
		 * @param array|WP_Error The HTTP response.
		 */
		do_action( 'jetpack_received_remote_request_response', $response );

		return $response;
	}

	/**
	 * Adds authorization signature to a remote request using Jetpack_Signature
	 *
	 * @param array        $args the arguments for the remote request.
	 * @param array|String $body the request body.
	 * @return WP_Error|array {
	 *     An array containing URL and request items.
	 *
	 *     @type String $url     The request URL.
	 *     @type array  $request Request arguments.
	 *     @type array  $auth    Authorization data.
	 * }
	 */
	public static function build_signed_request( $args, $body = null ) {
		add_filter(
			'jetpack_constant_default_value',
			__NAMESPACE__ . '\Utils::jetpack_api_constant_filter',
			10,
			2
		);

		$defaults = array(
			'url'           => '',
			'user_id'       => 0,
			'blog_id'       => 0,
			'auth_location' => Constants::get_constant( 'JETPACK_CLIENT__AUTH_LOCATION' ),
			'method'        => 'POST',
			'timeout'       => 10,
			'redirection'   => 0,
			'headers'       => array(),
			'stream'        => false,
			'filename'      => null,
			'sslverify'     => true,
		);

		$args = wp_parse_args( $args, $defaults );

		$args['blog_id'] = (int) $args['blog_id'];

		if ( 'header' !== $args['auth_location'] ) {
			$args['auth_location'] = 'query_string';
		}

		$token = ( new Tokens() )->get_access_token( $args['user_id'] );
		if ( ! $token ) {
			return new \WP_Error( 'missing_token' );
		}

		$method = strtoupper( $args['method'] );

		$timeout = (int) $args['timeout'];

		$redirection = $args['redirection'];
		$stream      = $args['stream'];
		$filename    = $args['filename'];
		$sslverify   = $args['sslverify'];

		$request = compact( 'method', 'body', 'timeout', 'redirection', 'stream', 'filename', 'sslverify' );

		@list( $token_key, $secret ) = explode( '.', $token->secret ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
		if ( empty( $token ) || empty( $secret ) ) {
			return new \WP_Error( 'malformed_token' );
		}

		$token_key = sprintf(
			'%s:%d:%d',
			$token_key,
			Constants::get_constant( 'JETPACK__API_VERSION' ),
			$token->external_user_id
		);

		$time_diff         = (int) \Jetpack_Options::get_option( 'time_diff' );
		$jetpack_signature = new \Jetpack_Signature( $token->secret, $time_diff );

		$timestamp = time() + $time_diff;

		if ( function_exists( 'wp_generate_password' ) ) {
			$nonce = wp_generate_password( 10, false );
		} else {
			$nonce = substr( sha1( wp_rand( 0, 1000000 ) ), 0, 10 );
		}

		// Kind of annoying.  Maybe refactor Jetpack_Signature to handle body-hashing.
		if ( $body === null ) {
			$body_hash = '';

		} else {
			// Allow arrays to be used in passing data.
			$body_to_hash = $body;

			if ( is_array( $body ) ) {
				// We cast this to a new variable, because the array form of $body needs to be
				// maintained so it can be passed into the request later on in the code.
				if ( array() !== $body ) {
					$body_to_hash = wp_json_encode( self::_stringify_data( $body ) );
				} else {
					$body_to_hash = '';
				}
			}

			if ( ! is_string( $body_to_hash ) ) {
				return new \WP_Error( 'invalid_body', 'Body is malformed.' );
			}

			$body_hash = base64_encode( sha1( $body_to_hash, true ) ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode
		}

		$auth = array(
			'token'     => $token_key,
			'timestamp' => $timestamp,
			'nonce'     => $nonce,
			'body-hash' => $body_hash,
		);

		if ( false !== strpos( $args['url'], 'xmlrpc.php' ) ) {
			$url_args = array(
				'for'           => 'jetpack',
				'wpcom_blog_id' => \Jetpack_Options::get_option( 'id' ),
			);
		} else {
			$url_args = array();
		}

		if ( 'header' !== $args['auth_location'] ) {
			$url_args += $auth;
		}

		$url = add_query_arg( urlencode_deep( $url_args ), $args['url'] );

		$signature = $jetpack_signature->sign_request( $token_key, $timestamp, $nonce, $body_hash, $method, $url, $body, false );

		if ( ! $signature || is_wp_error( $signature ) ) {
			return $signature;
		}

		// Send an Authorization header so various caches/proxies do the right thing.
		$auth['signature'] = $signature;
		$auth['version']   = Constants::get_constant( 'JETPACK__VERSION' );
		$header_pieces     = array();
		foreach ( $auth as $key => $value ) {
			$header_pieces[] = sprintf( '%s="%s"', $key, $value );
		}
		$request['headers'] = array_merge(
			$args['headers'],
			array(
				'Authorization' => 'X_JETPACK ' . implode( ' ', $header_pieces ),
			)
		);

		if ( 'header' !== $args['auth_location'] ) {
			$url = add_query_arg( 'signature', rawurlencode( $signature ), $url );
		}

		return compact( 'url', 'request', 'auth' );
	}

	/**
	 * Wrapper for wp_remote_request().  Turns off SSL verification for certain SSL errors.
	 * This is lame, but many, many, many hosts have misconfigured SSL.
	 *
	 * When Jetpack is registered, the jetpack_fallback_no_verify_ssl_certs option is set to the current time if:
	 * 1. a certificate error is found AND
	 * 2. not verifying the certificate works around the problem.
	 *
	 * The option is checked on each request.
	 *
	 * @internal
	 *
	 * @param String  $url the request URL.
	 * @param array   $args request arguments.
	 * @param Boolean $set_fallback whether to allow flagging this request to use a fallback certficate override.
	 * @return array|WP_Error WP HTTP response on success
	 */
	public static function _wp_remote_request( $url, $args, $set_fallback = false ) { // phpcs:ignore PSR2.Methods.MethodDeclaration.Underscore
		$fallback = \Jetpack_Options::get_option( 'fallback_no_verify_ssl_certs' );
		if ( false === $fallback ) {
			\Jetpack_Options::update_option( 'fallback_no_verify_ssl_certs', 0 );
		}

		/**
		 * SSL verification (`sslverify`) for the JetpackClient remote request
		 * defaults to off, use this filter to force it on.
		 *
		 * Return `true` to ENABLE SSL verification, return `false`
		 * to DISABLE SSL verification.
		 *
		 * @since 1.7.0
		 * @since-jetpack 3.6.0
		 *
		 * @param bool Whether to force `sslverify` or not.
		 */
		if ( apply_filters( 'jetpack_client_verify_ssl_certs', false ) ) {
			return wp_remote_request( $url, $args );
		}

		if ( (int) $fallback ) {
			// We're flagged to fallback.
			$args['sslverify'] = false;
		}

		$response = wp_remote_request( $url, $args );

		if (
			! $set_fallback                                     // We're not allowed to set the flag on this request, so whatever happens happens.
			||
			isset( $args['sslverify'] ) && ! $args['sslverify'] // No verification - no point in doing it again.
			||
			! is_wp_error( $response )                          // Let it ride.
		) {
			self::set_time_diff( $response, $set_fallback );
			return $response;
		}

		// At this point, we're not flagged to fallback and we are allowed to set the flag on this request.

		$message = $response->get_error_message();

		// Is it an SSL Certificate verification error?
		if (
			false === strpos( $message, '14090086' ) // OpenSSL SSL3 certificate error.
			&&
			false === strpos( $message, '1407E086' ) // OpenSSL SSL2 certificate error.
			&&
			false === strpos( $message, 'error setting certificate verify locations' ) // cURL CA bundle not found.
			&&
			false === strpos( $message, 'Peer certificate cannot be authenticated with' ) // cURL CURLE_SSL_CACERT: CA bundle found, but not helpful
			// Different versions of curl have different error messages
			// this string should catch them all.
			&&
			false === strpos( $message, 'Problem with the SSL CA cert' ) // cURL CURLE_SSL_CACERT_BADFILE: probably access rights.
		) {
			// No, it is not.
			return $response;
		}

		// Redo the request without SSL certificate verification.
		$args['sslverify'] = false;
		$response          = wp_remote_request( $url, $args );

		if ( ! is_wp_error( $response ) ) {
			// The request went through this time, flag for future fallbacks.
			\Jetpack_Options::update_option( 'fallback_no_verify_ssl_certs', time() );
			self::set_time_diff( $response, $set_fallback );
		}

		return $response;
	}

	/**
	 * Sets the time difference for correct signature computation.
	 *
	 * @param HTTP_Response $response the response object.
	 * @param Boolean       $force_set whether to force setting the time difference.
	 */
	public static function set_time_diff( &$response, $force_set = false ) {
		$code = wp_remote_retrieve_response_code( $response );

		// Only trust the Date header on some responses.
		if ( 200 != $code && 304 != $code && 400 != $code && 401 != $code ) { // phpcs:ignore  Universal.Operators.StrictComparisons.LooseNotEqual
			return;
		}

		$date = wp_remote_retrieve_header( $response, 'date' );
		if ( ! $date ) {
			return;
		}

		$time = (int) strtotime( $date );
		if ( 0 >= $time ) {
			return;
		}

		$time_diff = $time - time();

		if ( $force_set ) { // During register.
			\Jetpack_Options::update_option( 'time_diff', $time_diff );
		} else { // Otherwise.
			$old_diff = \Jetpack_Options::get_option( 'time_diff' );
			if ( false === $old_diff || abs( $time_diff - (int) $old_diff ) > 10 ) {
				\Jetpack_Options::update_option( 'time_diff', $time_diff );
			}
		}
	}

	/**
	 * Validate and build arguments for a WordPress.com REST API request.
	 *
	 * @param  string $path             REST API path.
	 * @param  string $version          REST API version. Default is `2`.
	 * @param  array  $args             Arguments to {@see WP_Http}. Default is `array()`.
	 * @param  string $base_api_path    REST API root. Default is `wpcom`.
	 *
	 * @return array|WP_Error $response Response data, else {@see WP_Error} on failure.
	 */
	public static function validate_args_for_wpcom_json_api_request(
		$path,
		$version = '2',
		$args = array(),
		$base_api_path = 'wpcom'
	) {
		$base_api_path = trim( $base_api_path, '/' );
		$version       = ltrim( $version, 'v' );
		$path          = ltrim( $path, '/' );

		$filtered_args = array_intersect_key(
			$args,
			array(
				'headers'     => 'array',
				'method'      => 'string',
				'timeout'     => 'int',
				'redirection' => 'int',
				'stream'      => 'boolean',
				'filename'    => 'string',
				'sslverify'   => 'boolean',
			)
		);

		// Use GET by default whereas `remote_request` uses POST.
		$request_method = isset( $filtered_args['method'] ) ? strtoupper( $filtered_args['method'] ) : 'GET';

		$url = sprintf(
			'%s/%s/v%s/%s',
			Constants::get_constant( 'JETPACK__WPCOM_JSON_API_BASE' ),
			$base_api_path,
			$version,
			$path
		);

		$validated_args = array_merge(
			$filtered_args,
			array(
				'url'    => $url,
				'method' => $request_method,
			)
		);

		return $validated_args;
	}

	/**
	 * Queries the WordPress.com REST API with a user token.
	 *
	 * @param  string $path             REST API path.
	 * @param  string $version          REST API version. Default is `2`.
	 * @param  array  $args             Arguments to {@see WP_Http}. Default is `array()`.
	 * @param  string $body             Body passed to {@see WP_Http}. Default is `null`.
	 * @param  string $base_api_path    REST API root. Default is `wpcom`.
	 *
	 * @return array|WP_Error $response Response data, else {@see WP_Error} on failure.
	 */
	public static function wpcom_json_api_request_as_user(
		$path,
		$version = '2',
		$args = array(),
		$body = null,
		$base_api_path = 'wpcom'
	) {
		$args            = self::validate_args_for_wpcom_json_api_request( $path, $version, $args, $base_api_path );
		$args['user_id'] = get_current_user_id();

		if ( isset( $body ) && ! isset( $args['headers'] ) && in_array( $args['method'], array( 'POST', 'PUT', 'PATCH' ), true ) ) {
			$args['headers'] = array( 'Content-Type' => 'application/json' );
		}

		if ( isset( $body ) && ! is_string( $body ) ) {
			$body = wp_json_encode( $body );
		}

		return self::remote_request( $args, $body );
	}

	/**
	 * Query the WordPress.com REST API using the blog token
	 *
	 * @param String $path The API endpoint relative path.
	 * @param String $version The API version.
	 * @param array  $args Request arguments.
	 * @param String $body Request body.
	 * @param String $base_api_path (optional) the API base path override, defaults to 'rest'.
	 * @return array|WP_Error $response Data.
	 */
	public static function wpcom_json_api_request_as_blog(
		$path,
		$version = self::WPCOM_JSON_API_VERSION,
		$args = array(),
		$body = null,
		$base_api_path = 'rest'
	) {
		$validated_args            = self::validate_args_for_wpcom_json_api_request( $path, $version, $args, $base_api_path );
		$validated_args['blog_id'] = (int) \Jetpack_Options::get_option( 'id' );

		// For Simple sites get the response directly without any HTTP requests.
		if ( defined( 'IS_WPCOM' ) && IS_WPCOM ) {
			add_filter( 'is_jetpack_authorized_for_site', '__return_true' );
			require_lib( 'wpcom-api-direct' );
			return \WPCOM_API_Direct::do_request( $validated_args, $body );
		}

		return self::remote_request( $validated_args, $body );
	}

	/**
	 * Takes an array or similar structure and recursively turns all values into strings. This is used to
	 * make sure that body hashes are made ith the string version, which is what will be seen after a
	 * server pulls up the data in the $_POST array.
	 *
	 * @param array|Mixed $data the data that needs to be stringified.
	 *
	 * @return array|string
	 */
	public static function _stringify_data( $data ) { // phpcs:ignore PSR2.Methods.MethodDeclaration.Underscore

		// Booleans are special, lets just makes them and explicit 1/0 instead of the 0 being an empty string.
		if ( is_bool( $data ) ) {
			return $data ? '1' : '0';
		}

		// Cast objects into arrays.
		if ( is_object( $data ) ) {
			$data = (array) $data;
		}

		// Non arrays at this point should be just converted to strings.
		if ( ! is_array( $data ) ) {
			return (string) $data;
		}

		foreach ( $data as &$value ) {
			$value = self::_stringify_data( $value );
		}

		return $data;
	}
}
