<?php

/**
 * LICENSE: The MIT License (the "License")
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * https://github.com/azure/azure-storage-php/LICENSE
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * PHP version 5
 *
 * @category  Microsoft
 * @package   MicrosoftAzure\Storage\Common\Middlewares
 * @author    Azure Storage PHP SDK <dmsh@microsoft.com>
 * @copyright 2017 Microsoft Corporation
 * @license   https://github.com/azure/azure-storage-php/LICENSE
 * @link      https://github.com/azure/azure-storage-php
 */

namespace MicrosoftAzure\Storage\Common\Middlewares;

use MicrosoftAzure\Storage\Common\LocationMode;
use MicrosoftAzure\Storage\Common\Internal\Resources;
use MicrosoftAzure\Storage\Common\Internal\Utilities;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Psr7\Uri;
use GuzzleHttp\Promise\RejectedPromise;

/**
 * This class provides the functionality of a middleware that handles all the
 * retry logic for the request.
 *
 * @category  Microsoft
 * @package   MicrosoftAzure\Storage\Common\Middlewares
 * @author    Azure Storage PHP SDK <dmsh@microsoft.com>
 * @copyright 2017 Microsoft Corporation
 * @license   https://github.com/azure/azure-storage-php/LICENSE
 * @link      https://github.com/azure/azure-storage-php
 */
class RetryMiddleware extends MiddlewareBase
{
    private $intervalCalculator;
    private $decider;

    public function __construct(
        callable $intervalCalculator,
        callable $decider
    ) {
        $this->intervalCalculator = $intervalCalculator;
        $this->decider            = $decider;
    }

    /**
     * This function will be invoked after the request is sent, if
     * the promise is fulfilled.
     *
     * @param  RequestInterface $request the request sent.
     * @param  array            $options the options that the request sent with.
     *
     * @return callable
     */
    protected function onFulfilled(RequestInterface $request, array $options)
    {
        return function (ResponseInterface $response) use ($request, $options) {
            $isSecondary = Utilities::requestSentToSecondary($request, $options);
            if (!isset($options['retries'])) {
                $options['retries'] = 0;
            }
            if (call_user_func(
                $this->decider,
                $options['retries'],
                $request,
                $response,
                null,
                $isSecondary
            )) {
                return $this->retry($request, $options, $response);
            }
            //Add the header that indicates the endpoint to be used if
            //continuation token is used for subsequent request.
            if ($isSecondary) {
                $response = $response->withHeader(
                    Resources::X_MS_CONTINUATION_LOCATION_MODE,
                    LocationMode::SECONDARY_ONLY
                );
            } else {
                $response = $response->withHeader(
                    Resources::X_MS_CONTINUATION_LOCATION_MODE,
                    LocationMode::PRIMARY_ONLY
                );
            }
            return $response;
        };
    }

    /**
     * This function will be executed after the request is sent, if
     * the promise is rejected.
     *
     * @param  RequestInterface $request the request sent.
     * @param  array            $options the options that the request sent with.
     *
     * @return callable
     */
    protected function onRejected(RequestInterface $request, array $options)
    {
        return function ($reason) use ($request, $options) {
            $isSecondary = Utilities::requestSentToSecondary($request, $options);
            if (!isset($options['retries'])) {
                $options['retries'] = 0;
            }

            if (call_user_func(
                $this->decider,
                $options['retries'],
                $request,
                null,
                $reason,
                $isSecondary
            )) {
                return $this->retry($request, $options);
            }
            return new RejectedPromise($reason);
        };
    }

    /**
     * This function does the real retry job.
     *
     * @param  RequestInterface  $request  the request sent.
     * @param  array             $options  the options that the request sent with.
     * @param  ResponseInterface $response the response of the request
     *
     * @return callable
     */
    private function retry(
        RequestInterface $request,
        array $options,
        ResponseInterface $response = null
    ) {
        $options['delay'] = call_user_func(
            $this->intervalCalculator,
            ++$options['retries']
        );

        //Change the request URI according to the location mode.
        if (array_key_exists(Resources::ROS_LOCATION_MODE, $options)) {
            $locationMode = $options[Resources::ROS_LOCATION_MODE];
            //If have RA-GRS enabled for the request, switch between
            //primary and secondary.
            if ($locationMode == LocationMode::PRIMARY_THEN_SECONDARY ||
                $locationMode == LocationMode::SECONDARY_THEN_PRIMARY) {
                $primaryUri = $options[Resources::ROS_PRIMARY_URI];
                $secondaryUri = $options[Resources::ROS_SECONDARY_URI];

                $target = $request->getRequestTarget();
                if (Utilities::startsWith($target, '/')) {
                    $target = substr($target, 1);
                    $primaryUri = new Uri($primaryUri . $target);
                    $secondaryUri = new Uri($secondaryUri . $target);
                }

                //substitute the uri.
                if ((string)$request->getUri() == (string)$primaryUri) {
                    $request = $request->withUri($secondaryUri);
                } elseif ((string)$request->getUri() == (string)$secondaryUri) {
                    $request = $request->withUri($primaryUri);
                }
            }
        }
        $handler = $options[Resources::ROS_HANDLER];

        return \call_user_func($handler, $request, $options);
    }
}