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<?php

namespace GuzzleHttp;

use GuzzleHttp\Cookie\CookieJarInterface;

use GuzzleHttp\Exception\RequestException;

use GuzzleHttp\Promise\RejectedPromise;

use GuzzleHttp\Psr7;

use Psr\Http\Message\ResponseInterface;

use Psr\Log\LoggerInterface;

use Psr\Log\LogLevel;

/**

 * Functions used to create and wrap handlers with handler middleware.

 */

final class Middleware

{

    /**

     * Middleware that adds cookies to requests.

     *

     * The options array must be set to a CookieJarInterface in order to use

     * cookies. This is typically handled for you by a client.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function cookies()

    {

        return function (callable $handler) {

            return function ($request, array $options) use ($handler) {

                if (empty($options['cookies'])) {

                    return $handler($request, $options);

                } elseif (!($options['cookies'] instanceof CookieJarInterface)) {

                    throw new \InvalidArgumentException('cookies must be an instance of GuzzleHttp\Cookie\CookieJarInterface');

                }

                $cookieJar = $options['cookies'];

                $request = $cookieJar->withCookieHeader($request);

                return $handler($request, $options)

                    ->then(function ($response) use ($cookieJar, $request) {

                        $cookieJar->extractCookies($request, $response);

                        return $response;

                    }

                );

            };

        };

    }

    /**

     * Middleware that throws exceptions for 4xx or 5xx responses when the

     * "http_error" request option is set to true.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function httpErrors()

    {

        return function (callable $handler) {

            return function ($request, array $options) use ($handler) {

                if (empty($options['http_errors'])) {

                    return $handler($request, $options);

                }

                return $handler($request, $options)->then(

                    function (ResponseInterface $response) use ($request, $handler) {

                        $code = $response->getStatusCode();

                        if ($code < 400) {

                            return $response;

                        }

                        throw RequestException::create($request, $response);

                    }

                );

            };

        };

    }

    /**

     * Middleware that pushes history data to an ArrayAccess container.

     *

     * @param array $container Container to hold the history (by reference).

     *

     * @return callable Returns a function that accepts the next handler.

     * @throws \InvalidArgumentException if container is not an array or ArrayAccess.

     */

    public static function history(&$container)

    {

        if (!is_array($container) && !$container instanceof \ArrayAccess) {

            throw new \InvalidArgumentException('history container must be an array or object implementing ArrayAccess');

        }

        return function (callable $handler) use (&$container) {

            return function ($request, array $options) use ($handler, &$container) {

                return $handler($request, $options)->then(

                    function ($value) use ($request, &$container, $options) {

                        $container[] = [

                            'request'  => $request,

                            'response' => $value,

                            'error'    => null,

                            'options'  => $options

                        ];

                        return $value;

                    },

                    function ($reason) use ($request, &$container, $options) {

                        $container[] = [

                            'request'  => $request,

                            'response' => null,

                            'error'    => $reason,

                            'options'  => $options

                        ];

                        return new RejectedPromise($reason);

                    }

                );

            };

        };

    }

    /**

     * Middleware that invokes a callback before and after sending a request.

     *

     * The provided listener cannot modify or alter the response. It simply

     * "taps" into the chain to be notified before returning the promise. The

     * before listener accepts a request and options array, and the after

     * listener accepts a request, options array, and response promise.

     *

     * @param callable $before Function to invoke before forwarding the request.

     * @param callable $after  Function invoked after forwarding.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function tap(callable $before = null, callable $after = null)

    {

        return function (callable $handler) use ($before, $after) {

            return function ($request, array $options) use ($handler, $before, $after) {

                if ($before) {

                    $before($request, $options);

                }

                $response = $handler($request, $options);

                if ($after) {

                    $after($request, $options, $response);

                }

                return $response;

            };

        };

    }

    /**

     * Middleware that handles request redirects.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function redirect()

    {

        return function (callable $handler) {

            return new RedirectMiddleware($handler);

        };

    }

    /**

     * Middleware that retries requests based on the boolean result of

     * invoking the provided "decider" function.

     *

     * If no delay function is provided, a simple implementation of exponential

     * backoff will be utilized.

     *

     * @param callable $decider Function that accepts the number of retries,

     *                          a request, [response], and [exception] and

     *                          returns true if the request is to be retried.

     * @param callable $delay   Function that accepts the number of retries and

     *                          returns the number of milliseconds to delay.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function retry(callable $decider, callable $delay = null)

    {

        return function (callable $handler) use ($decider, $delay) {

            return new RetryMiddleware($decider, $handler, $delay);

        };

    }

    /**

     * Middleware that logs requests, responses, and errors using a message

     * formatter.

     *

     * @param LoggerInterface  $logger Logs messages.

     * @param MessageFormatter $formatter Formatter used to create message strings.

     * @param string           $logLevel Level at which to log requests.

     *

     * @return callable Returns a function that accepts the next handler.

     */

    public static function log(LoggerInterface $logger, MessageFormatter $formatter, $logLevel = LogLevel::INFO)

    {

        return function (callable $handler) use ($logger, $formatter, $logLevel) {

            return function ($request, array $options) use ($handler, $logger, $formatter, $logLevel) {

                return $handler($request, $options)->then(

                    function ($response) use ($logger, $request, $formatter, $logLevel) {

                        $message = $formatter->format($request, $response);

                        $logger->log($logLevel, $message);

                        return $response;

                    },

                    function ($reason) use ($logger, $request, $formatter) {

                        $response = $reason instanceof RequestException

                            ? $reason->getResponse()

                            : null;

                        $message = $formatter->format($request, $response, $reason);

                        $logger->notice($message);

                        return \GuzzleHttp\Promise\rejection_for($reason);

                    }

                );

            };

        };

    }

    /**

     * This middleware adds a default content-type if possible, a default

     * content-length or transfer-encoding header, and the expect header.

     *

     * @return callable

     */

    public static function prepareBody()

    {

        return function (callable $handler) {

            return new PrepareBodyMiddleware($handler);

        };

    }

    /**

     * Middleware that applies a map function to the request before passing to

     * the next handler.

     *

     * @param callable $fn Function that accepts a RequestInterface and returns

     *                     a RequestInterface.

     * @return callable

     */

    public static function mapRequest(callable $fn)

    {

        return function (callable $handler) use ($fn) {

            return function ($request, array $options) use ($handler, $fn) {

                return $handler($fn($request), $options);

            };

        };

    }

    /**

     * Middleware that applies a map function to the resolved promise's

     * response.

     *

     * @param callable $fn Function that accepts a ResponseInterface and

     *                     returns a ResponseInterface.

     * @return callable

     */

    public static function mapResponse(callable $fn)

    {

        return function (callable $handler) use ($fn) {

            return function ($request, array $options) use ($handler, $fn) {

                return $handler($request, $options)->then($fn);

            };

        };

    }

}