/**
 * @file This file provides functions for sending AJAX requests to the Ingress API.
 * @module send_request
 */

/**
 * Sends an AJAX POST request to the Ingress API.
 *
 * @function postAjax
 * @param {string} action - The last part of the URL, automatically appended to the Ingress API endpoint.
 * @param {Object} data - JSON data to post. The method is derived automatically from action but may be overridden.
 *                        Expects to be given a Hash. Strings are not supported.
 * @param {Function} successCallback - Function to call on success. See jQuery API docs for available arguments.
 * @param {Function} errorCallback - Function to call on error. Additionally, it is logged if the request failed.
 * @returns {jqXHR} The jQuery wrapped XMLHttpRequest object.
 */
window.postAjax = function(action, data, successCallback, errorCallback) {
  // state management functions... perhaps should be outside of this func?

//  var remove = function(data, textStatus, jqXHR) { window.requests.remove(jqXHR); };
//  var errCnt = function(jqXHR) { window.failedRequestCount++; window.requests.remove(jqXHR); };

  if (window.latestFailedRequestTime && window.latestFailedRequestTime < Date.now()-120*1000) {
    // no errors in the last two minutes - clear the error count
    window.failedRequestCount = 0;
    window.latestFailedRequestTime = undefined;
  }

  var onError = function(jqXHR, textStatus, errorThrown) {
    window.requests.remove(jqXHR);
    window.failedRequestCount++;

    window.latestFailedRequestTime = Date.now();

    // pass through to the user error func, if one exists
    if (errorCallback) {
      errorCallback(jqXHR, textStatus, errorThrown);
    }
  };

  var onSuccess = function(data, textStatus, jqXHR) {
    window.requests.remove(jqXHR);

    // the Niantic server can return a HTTP success, but the JSON response contains an error. handle that sensibly
    if (data && data.error && data.error == 'out of date') {
      window.failedRequestCount++;
      // let's call the error callback in thos case...
      if (errorCallback) {
        errorCallback(jqXHR, textStatus, "data.error == 'out of date'");
      }

      window.outOfDateUserPrompt();
    } else {
      successCallback(data, textStatus, jqXHR);
    }
  };

  // we set this flag when we want to block all requests due to having an out of date CURRENT_VERSION
  if (window.blockOutOfDateRequests) {
    window.failedRequestCount++;
    window.latestFailedRequestTime = Date.now();

    // call the error callback, if one exists
    if (errorCallback) {
      // NOTE: error called on a setTimeout - as it won't be expected to be synchronous
      // ensures no recursion issues if the error handler immediately resends the request
      setTimeout(function(){errorCallback(null, undefined, "window.blockOutOfDateRequests is set");}, 10);
    }
    return;
  }

  var versionStr = niantic_params.CURRENT_VERSION;
  var post_data = JSON.stringify($.extend({}, data, {v: versionStr}));

  var result = $.ajax({
    url: '/r/'+action,
    type: 'POST',
    data: post_data,
    context: data,
    dataType: 'json',
    success: [onSuccess],
    error: [onError],
    contentType: 'application/json; charset=utf-8',
    beforeSend: function(req) {
      req.setRequestHeader('X-CSRFToken', readCookie('csrftoken'));
    }
  });

  requests.add(result);

  return result;
}

/**
 * Displays a dialog prompt to the user when the IITC version is out of date.
 * Blocks all requests while the dialog is open.
 *
 * @function outOfDateUserPrompt
 */
window.outOfDateUserPrompt = function()
{
  // we block all requests while the dialog is open.
  if (!window.blockOutOfDateRequests) {
    window.blockOutOfDateRequests = true;

    dialog({
      title: 'Reload IITC',
      html: '<p>IITC is using an outdated version code. This will happen when Niantic updates the standard intel site.</p>'
           +'<p>You need to reload the page to get the updated changes.</p>'
           +'<p>If you have just reloaded the page, then an old version of the standard site script is cached somewhere.'
           +'In this case, try clearing your cache, or waiting 15-30 minutes for the stale data to expire.</p>',
      buttons: {
        'RELOAD': function() {
          if (window.isApp && app.reloadIITC) {
            app.reloadIITC();
          } else {
            window.location.reload();
          }
        }
      },
      close: function(event, ui) {
        delete window.blockOutOfDateRequests;
      }

    });


  }

}