if (typeof Qt != "undefined") {
  Qt.include("common.js");
  Qt.include("http.js");
  Qt.include("eventemitter.js");
  var md5 = Qt.md5;
} else if (typeof md5 != "function") {
  function md5(str) {
    console.error("MD5 encoding not supported!");
  }
}

var API_HOST = "api.vk.com";
var API_PATH = "/method/";
var API_DELAY = 334;

function Api(options) {
  options = options || {};
  this.accessToken = options.accessToken;
  this.version = options.version;
  this.delay = options.delay || API_DELAY;
}

Api.prototype = {
  request: null,
  _processing: false,
  _requestQueue: [],
  _requestTime: 0,

  // public
  call: function(method, params, options) {
    var request = new ApiRequest(this, method, params, options);
    if (this._processing) {
      //
    }
    if (this._locked) {
      console.log("Add request to queue");
      this._requestQueue.push(request);
    } else {
      // Запоминает запрос, т.к. он может еще понадобиться
      this.request = request;
      request.send();
    }
  },

  execute: function(code, options) {
    this.call('execute', {code: code}, options);
  },

  cancelAllRequests: function() {
    console.log("Cancel all requests");
    this._requestQueue = [];
    this._unlock();
  },

  _processRequestQueue: function() {
    var request = this._requestQueue.shift();
    if (request) {
      request.send();
    } else {
      console.log("Requests queue empty");
      this._unlock();
    }
  },

  _lock: function() {
    this._locked = true;
  },

  _unlock: function() {
    this._locked = false;
  },
};

EventEmitter.mixin(Api);

function ApiRequest(api, method, params, options) {
  this.api = api;
  this.method = method;
  this.params = extend({}, params);
  this.done = options.done;
  this.fail = options.fail;
  this.context = options.context;
  this.delay = options.delay || this.api.delay;
}

ApiRequest.prototype = {
  _processing: true,

  send: function() {
    console.log("Send request");
    this.api._lock();
    var params = extend({}, this.api.extraParams, this.params);
    if (this.api.version) {
      params.v = this.api.version;
    }
    var scheme = "https";
    if (this.api.accessToken) {
      params.access_token = this.api.accessToken.accessToken;
      if (this.api.accessToken.secret) {
        // https://vk.com/dev/api_nohttps
        scheme = "http";
        if (params.sig) {
          delete params.sig;
        }
        var str = formatStr(
          "{0}{1}?{2}{3}",
          API_PATH,
          this.method,
          encodeQueryParams(params),
          this.api.accessToken.secret
        );
        params.sig = md5(str);
      }
    }
    var format = "{0}://{1}{2}{3}";
    var endpoint = formatStr(format, scheme, API_HOST, API_PATH, this.method);
    var nextRequestTime = this.api._requestTime + this.delay;
    var now = Date.now();
    var timeout = nextRequestTime > now ? nextRequestTime - now : 0;
    console.log("timeout = %sms", timeout);
    var self = this;
    setTimeout(function() {
      post(endpoint, params, function(data) {
        self.api._requestTime = Date.now();
        var error = data.error;
        var response = data.response;
        if (error) {
          console.error(self._formatError(error));
          self.api.emit('error', error);
        }
        if (self._processing) {
          if (error && typeof self.fail == "function") {
            self.fail.call(self.context, error);
          }
          if (response && typeof self.done == "function") {
            self.done.call(self.context, response);
          }
          self.next();
        }
      });
    }, timeout);
  },

  // Переходит к следующему запросу в очереди
  next: function() {
    this.api._processRequestQueue();
  },

  // Останавливает обработку всех запросов
  stopProcessing: function() {
    console.log("Stop all requests processing");
    this._processing = false;
  },

  // Повторить запрос через delay миллисекунд
  retry: function(delay) {
    this.processing = true;
    if (delay != null) {
      this.delay = delay;
    }
    this.send();
  },

  _formatError: function(error) {
    var params = {};
    for (var i = 0; i < error.request_params.length; ++i) {
      params[error.request_params[i].key] = error.request_params[i].value;
    }
    var method = params.method;
    delete params.method;
    return template(
      'An error occurred while calling method "{method}"' +
      ' with parameters: {params}' +
      ' (Error Code: {code}, Message: {msg})',
      {
        code: error.error_code,
        msg: error.error_msg,
        method: method,
        params: this._formatParams(params)
      }
    );
  },

  _formatParams: function(params) {
    return JSON.stringify(params, function(k, v) {
      if (k == "access_token") {
        return "**CENSORED**";
      }
      return v;
    });
  },
};