var categories = {
  UI_ACTION: 'ui_action',
  CLIENT_INFO: 'client_info'
};

var events = {
  'DATE_BUTTON': {
    category: categories.UI_ACTION,
    action: 'date_button'
  },
  'PASSENGERS_BUTTON': {
    category: categories.UI_ACTION,
    action: 'passengers_button'
  },
  'SEARCH_BUTTON': {
    category: categories.UI_ACTION,
    action: 'search_button'
  },
  'SORT_BUTTON': {
    category: categories.UI_ACTION,
    action: 'sort_button',
    label: 'byTime' // byTime || byPrice || byDuration
  },
  'SEARCH_LOADMORE': {
    category: categories.UI_ACTION,
    action: 'search_loadmore'
  },
  'SELECT_ROUTE': {
    category: categories.UI_ACTION,
    action: 'select_route'
  },
  'SELECT_DETAILS_TAB': {
    category: categories.UI_ACTION,
    action: 'select_details_tab',
    label: 'Stations' // Stations || Prices || Map
  },
  'BUY_BUTTON': {
    category: categories.UI_ACTION,
    action: 'buy_button'
  },
  'BUY_CONFIRM': {
    category: categories.UI_ACTION,
    action: 'buy_confirm',
    label: 'one-way' // one-way || return
  },
  'SHARE_BUTTON': {
    category: categories.UI_ACTION,
    action: 'share_button'
  },
  'ANDROID_LINK': {
    category: categories.UI_ACTION,
    action: 'android_link'
  },
  'IOS_LINK': {
    category: categories.UI_ACTION,
    action: 'ios_link'
  },
  'INFO_LINK': {
    category: categories.UI_ACTION,
    action: 'info_link'
  },
  // LOADING
  'BROWSER_NOT_SUPPORTED': {
    category: categories.CLIENT_INFO,
    action: 'browser_not_supported'
  },
  'BROWSER_TYPE': {
    category: categories.CLIENT_INFO
  }
};

function track(eventType,options) {
  var event = events[eventType];
  if (event) {
    options = options || {};
    var category = event.category;
    var action = options.action || event.action;
    var label = options.label || event.label;
    var ga_args_string = "'"+category+"'";
    var ga_args = ['send','event',category];
    if (action) {
      ga_args_string += ",'"+action+"'";
      ga_args.push(action);
    }
    if (label) {
      ga_args_string += ",'"+label+"'";
      ga_args.push(label);
    }
  }
  //console.log("ga('send','event',"+ga_args_string+");");
  if (ga) {
    ga.apply(null,ga_args);
  }
}

function trackSync(eventType,options) {
  if (ga) {
    ga(function(){
      track(eventType,options);
      if (options.cbk) {
        options.cbk ();
      }
    })
  }
}

module.exports = {
  track: track,
  trackSync: trackSync
};