<?php
/**
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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.
 */

namespace Google\Service;

use Google\Model;
use Google\Http\MediaFileUpload;
use Google\Exception as GoogleException;
use Google\Utils\UriTemplate;
use GuzzleHttp\Psr7\Request;

/**
 * Implements the actual methods/resources of the discovered Google API using magic function
 * calling overloading (__call()), which on call will see if the method name (plus.activities.list)
 * is available in this service, and if so construct an apiHttpRequest representing it.
 *
 */
class Resource
{
  // Valid query parameters that work, but don't appear in discovery.
  private $stackParameters = array(
      'alt' => array('type' => 'string', 'location' => 'query'),
      'fields' => array('type' => 'string', 'location' => 'query'),
      'trace' => array('type' => 'string', 'location' => 'query'),
      'userIp' => array('type' => 'string', 'location' => 'query'),
      'quotaUser' => array('type' => 'string', 'location' => 'query'),
      'data' => array('type' => 'string', 'location' => 'body'),
      'mimeType' => array('type' => 'string', 'location' => 'header'),
      'uploadType' => array('type' => 'string', 'location' => 'query'),
      'mediaUpload' => array('type' => 'complex', 'location' => 'query'),
      'prettyPrint' => array('type' => 'string', 'location' => 'query'),
  );

  /** @var string $rootUrl */
  private $rootUrl;

  /** @var \Google\Client $client */
  private $client;

  /** @var string $serviceName */
  private $serviceName;

  /** @var string $servicePath */
  private $servicePath;

  /** @var string $resourceName */
  private $resourceName;

  /** @var array $methods */
  private $methods;

  public function __construct($service, $serviceName, $resourceName, $resource)
  {
    $this->rootUrl = $service->rootUrl;
    $this->client = $service->getClient();
    $this->servicePath = $service->servicePath;
    $this->serviceName = $serviceName;
    $this->resourceName = $resourceName;
    $this->methods = is_array($resource) && isset($resource['methods']) ?
        $resource['methods'] :
        array($resourceName => $resource);
  }

  /**
   * TODO: This function needs simplifying.
   * @param $name
   * @param $arguments
   * @param $expectedClass - optional, the expected class name
   * @return mixed|$expectedClass|ResponseInterface|RequestInterface
   * @throws \Google\Exception
   */
  public function call($name, $arguments, $expectedClass = null)
  {
    if (! isset($this->methods[$name])) {
      $this->client->getLogger()->error(
          'Service method unknown',
          array(
              'service' => $this->serviceName,
              'resource' => $this->resourceName,
              'method' => $name
          )
      );

      throw new GoogleException(
          "Unknown function: " .
          "{$this->serviceName}->{$this->resourceName}->{$name}()"
      );
    }
    $method = $this->methods[$name];
    $parameters = $arguments[0];

    // postBody is a special case since it's not defined in the discovery
    // document as parameter, but we abuse the param entry for storing it.
    $postBody = null;
    if (isset($parameters['postBody'])) {
      if ($parameters['postBody'] instanceof Model) {
        // In the cases the post body is an existing object, we want
        // to use the smart method to create a simple object for
        // for JSONification.
        $parameters['postBody'] = $parameters['postBody']->toSimpleObject();
      } else if (is_object($parameters['postBody'])) {
        // If the post body is another kind of object, we will try and
        // wrangle it into a sensible format.
        $parameters['postBody'] =
            $this->convertToArrayAndStripNulls($parameters['postBody']);
      }
      $postBody = (array) $parameters['postBody'];
      unset($parameters['postBody']);
    }

    // TODO: optParams here probably should have been
    // handled already - this may well be redundant code.
    if (isset($parameters['optParams'])) {
      $optParams = $parameters['optParams'];
      unset($parameters['optParams']);
      $parameters = array_merge($parameters, $optParams);
    }

    if (!isset($method['parameters'])) {
      $method['parameters'] = array();
    }

    $method['parameters'] = array_merge(
        $this->stackParameters,
        $method['parameters']
    );

    foreach ($parameters as $key => $val) {
      if ($key != 'postBody' && ! isset($method['parameters'][$key])) {
        $this->client->getLogger()->error(
            'Service parameter unknown',
            array(
                'service' => $this->serviceName,
                'resource' => $this->resourceName,
                'method' => $name,
                'parameter' => $key
            )
        );
        throw new GoogleException("($name) unknown parameter: '$key'");
      }
    }

    foreach ($method['parameters'] as $paramName => $paramSpec) {
      if (isset($paramSpec['required']) &&
          $paramSpec['required'] &&
          ! isset($parameters[$paramName])
      ) {
        $this->client->getLogger()->error(
            'Service parameter missing',
            array(
                'service' => $this->serviceName,
                'resource' => $this->resourceName,
                'method' => $name,
                'parameter' => $paramName
            )
        );
        throw new GoogleException("($name) missing required param: '$paramName'");
      }
      if (isset($parameters[$paramName])) {
        $value = $parameters[$paramName];
        $parameters[$paramName] = $paramSpec;
        $parameters[$paramName]['value'] = $value;
        unset($parameters[$paramName]['required']);
      } else {
        // Ensure we don't pass nulls.
        unset($parameters[$paramName]);
      }
    }

    $this->client->getLogger()->info(
        'Service Call',
        array(
            'service' => $this->serviceName,
            'resource' => $this->resourceName,
            'method' => $name,
            'arguments' => $parameters,
        )
    );

    // build the service uri
    $url = $this->createRequestUri(
        $method['path'],
        $parameters
    );

    // NOTE: because we're creating the request by hand,
    // and because the service has a rootUrl property
    // the "base_uri" of the Http Client is not accounted for
    $request = new Request(
        $method['httpMethod'],
        $url,
        ['content-type' => 'application/json'],
        $postBody ? json_encode($postBody) : ''
    );

    // support uploads
    if (isset($parameters['data'])) {
      $mimeType = isset($parameters['mimeType'])
        ? $parameters['mimeType']['value']
        : 'application/octet-stream';
      $data = $parameters['data']['value'];
      $upload = new MediaFileUpload($this->client, $request, $mimeType, $data);

      // pull down the modified request
      $request = $upload->getRequest();
    }

    // if this is a media type, we will return the raw response
    // rather than using an expected class
    if (isset($parameters['alt']) && $parameters['alt']['value'] == 'media') {
      $expectedClass = null;
    }

    // if the client is marked for deferring, rather than
    // execute the request, return the response
    if ($this->client->shouldDefer()) {
      // @TODO find a better way to do this
      $request = $request
        ->withHeader('X-Php-Expected-Class', $expectedClass);

      return $request;
    }

    return $this->client->execute($request, $expectedClass);
  }

  protected function convertToArrayAndStripNulls($o)
  {
    $o = (array) $o;
    foreach ($o as $k => $v) {
      if ($v === null) {
        unset($o[$k]);
      } elseif (is_object($v) || is_array($v)) {
        $o[$k] = $this->convertToArrayAndStripNulls($o[$k]);
      }
    }
    return $o;
  }

  /**
   * Parse/expand request parameters and create a fully qualified
   * request uri.
   * @static
   * @param string $restPath
   * @param array $params
   * @return string $requestUrl
   */
  public function createRequestUri($restPath, $params)
  {
    // Override the default servicePath address if the $restPath use a /
    if ('/' == substr($restPath, 0, 1)) {
      $requestUrl = substr($restPath, 1);
    } else {
      $requestUrl = $this->servicePath . $restPath;
    }

    // code for leading slash
    if ($this->rootUrl) {
      if ('/' !== substr($this->rootUrl, -1) && '/' !== substr($requestUrl, 0, 1)) {
        $requestUrl = '/' . $requestUrl;
      }
      $requestUrl = $this->rootUrl . $requestUrl;
    }
    $uriTemplateVars = array();
    $queryVars = array();
    foreach ($params as $paramName => $paramSpec) {
      if ($paramSpec['type'] == 'boolean') {
        $paramSpec['value'] = $paramSpec['value'] ? 'true' : 'false';
      }
      if ($paramSpec['location'] == 'path') {
        $uriTemplateVars[$paramName] = $paramSpec['value'];
      } else if ($paramSpec['location'] == 'query') {
        if (is_array($paramSpec['value'])) {
          foreach ($paramSpec['value'] as $value) {
            $queryVars[] = $paramName . '=' . rawurlencode(rawurldecode($value));
          }
        } else {
          $queryVars[] = $paramName . '=' . rawurlencode(rawurldecode($paramSpec['value']));
        }
      }
    }

    if (count($uriTemplateVars)) {
      $uriTemplateParser = new UriTemplate();
      $requestUrl = $uriTemplateParser->parse($requestUrl, $uriTemplateVars);
    }

    if (count($queryVars)) {
      $requestUrl .= '?' . implode('&', $queryVars);
    }

    return $requestUrl;
  }
}