<?

namespace DetectLanguage;

class Client
{
  /**
   * Request engine.
   *
   * @var string Request engine (curl or stream).
   */
  public static $requestEngine = 'curl';

  /**
   * Request timeout.
   *
   * @var int
   */
  public static $requestTimeout = 60;

  /**
   * Connect timeout.
   *
   * @var int
   */
  public static $connectTimeout = 10;

  /**
   * Perform a request
   *
   * @param string $method Method name
   * @param array $params The parameters to use for the POST body
   *
   * @return array
   */
  public static function request($method, $params) {
    $url = self::getUrl($method);

    $params['key'] = DetectLanguage::$apiKey;

    $request_method = self::getRequestMethodName();

    $response_body = self::$request_method($url, $params);

    $response = json_decode($response_body);

    if (isset($response->error))
      throw new Error($response->error->message);

    return $response;
  }

  /**
   * Get request method name.
   *
   * @return string
   */
  protected static function getRequestMethodName() {
  	$request_engine = self::$requestEngine;

  	if ($request_engine == 'curl' && !function_exists('curl_init')) {
  		trigger_error("DetectLanguage::Client - CURL not found, switching to stream");
  		$request_engine = self::$requestEngine = 'stream';
  	}

    switch ($request_engine) {
      case 'curl':
        return 'requestCurl';
      
      case 'stream':
        return 'requestStream';

      default:
        throw new Error("Invalid request engine: " . $request_engine);
    }
  }

  /**
   * Perform request using native PHP streams
   *
   * @param string $url Request URL
   * @param array $params The parameters to use for the POST body
   *
   * @return string Response body
   */
  protected static function requestStream($url, $params) {
    $postdata = http_build_query($params);

    $opts = array('http' =>
      array(
        'method'            => 'POST',
        'header'            => implode("\n", self::getHeaders()),
        'content'           => $postdata,
        'timeout'           => self::$requestTimeout
      )
    );

    $context = stream_context_create($opts);

    return file_get_contents($url, false, $context);
  }

  /**
   * Perform request using CURL extension.
   *
   * @param string $url Request URL
   * @param array $params The parameters to use for the POST body
   *
   * @return string Response body
   */
  protected static function requestCurl($url, $params) {
    $ch = curl_init();

    $options = array(
      CURLOPT_URL             => $url,
      CURLOPT_HTTPHEADER      => self::getHeaders(),
      CURLOPT_POSTFIELDS      => http_build_query($params),
      CURLOPT_CONNECTTIMEOUT  => self::$connectTimeout,
      CURLOPT_TIMEOUT         => self::$requestTimeout,
      CURLOPT_USERAGENT       => self::getUserAgent(),
      CURLOPT_RETURNTRANSFER  => true
      );

    curl_setopt_array($ch, $options);

    $result = curl_exec($ch);

    if ($result === false) {
      $e = new Error(curl_error($ch));
      curl_close($ch);
      throw $e;
    }

    curl_close($ch);

    return $result;
  }

  /**
   * Build URL for given method
   *
   * @param string $method Method name
   * @return string
   */
  protected static function getUrl($method) {
    return self::getProtocol() . '://' . DetectLanguage::$host . '/' . DetectLanguage::$apiVersion . '/' . $method;
  }

  protected static function getProtocol() {
    return DetectLanguage::$secure ? 'https' : 'http';
  }

  /**
   * Build request headers.
   *
   * @return string
   */
  protected static function getHeaders() {
    return array(
      "Content-Type: application/x-www-form-urlencoded",
      "Accept-Encoding: gzip, deflate",
      "User-Agent: " . self::getUserAgent()
    );
  }

  protected static function getUserAgent() {
	  return 'detectlanguage-php-' . DetectLanguage::VERSION;
  }
}