function listEvents(e) {

  var calendar_name = e.parameter.calendar;

  var startDate = new Date(e.parameter.year, e.parameter.month - 1, e.parameter.day);

  var endDate = new Date();

  var Calendar = CalendarApp.getCalendarsByName(calendar_name);

  var sheetName = calendar_name + "-" + e.parameter.year + "-" + e.parameter.month;

  var events = Calendar[0].getEvents(startDate , endDate);

  if (events[0]) {

    var eventarray = new Array();

    var line = new Array();

    line.push('Datum');

    line.push('Ukon');

    line.push('Zaciatok');

    line.push('Koniec');

    line.push('Cas');

    eventarray.push(line);

    

    var i = 0;

    for (i = 0; i < events.length; i++) {

      line = new Array();

      var st = events[i].getStartTime();

      var et = events[i].getEndTime();

      line.push(st.getDate() + "." + (st.getMonth()+1) + "." + st.getYear());

      line.push(events[i].getTitle());

      line.push(st.getHours() + ":" + st.getMinutes());

      line.push(et.getHours() + ":" + et.getMinutes());

      line.push((events[i].getEndTime() - events[i].getStartTime()) / 3600000);

      eventarray.push(line);

    }

    line = new Array();

    line.push('');

    line.push('');

    line.push('');

    line.push('Spolu');

    line.push('');

    eventarray.push(line);

    var sheet = SpreadsheetApp.getActiveSpreadsheet().insertSheet(sheetName);

    sheet.getRange('A1:E' + (i+2)).setValues(eventarray);

    sheet.getRange('E' + (i+3)).setFormula('=SUM(E2:E' + (i+2)+ ')');

  } else {

    Browser.msgBox('nothing between ' + startDate + ' till ' + endDate);

  }

  

  var app = UiApp.getActiveApplication();

  app.close();

  return app;  

}

function workingHoursTool() {

  var doc = SpreadsheetApp.getActiveSpreadsheet();

  var app = UiApp.createApplication().setTitle('Export working hours');

  // Create a grid with 3 text boxes and corresponding labels

  var grid = app.createGrid(4, 2);

  grid.setWidget(0, 0, app.createLabel('Calendar name:'));

  

  var list = app.createListBox();

  list.setName('calendar');

  grid.setWidget(0, 1, list);

  var calendars = CalendarApp.getAllCalendars();

  for (var i = 0; i < calendars .length; i++) {

    list.a

    list.addItem(calendars[i].getName());

  }

        

  grid.setWidget(1, 0, app.createLabel('Year:'));

  grid.setWidget(1, 1, app.createTextBox().setName('year'));

  grid.setWidget(2, 0, app.createLabel('Month'));

  grid.setWidget(2, 1, app.createTextBox().setName('month'));

  grid.setWidget(3, 0, app.createLabel('Day'));

  grid.setWidget(3, 1, app.createTextBox().setName('day'));

  

  // Create a vertical panel..

  var panel = app.createVerticalPanel();

  

  // ...and add the grid to the panel

  panel.add(grid);

  

  // Create a button and click handler; pass in the grid object as a callback element and the handler as a click handler

  // Identify the function b as the server click handler

  var button = app.createButton('submit');

  var handler = app.createServerClickHandler('listEvents');

  handler.addCallbackElement(grid);

  button.addClickHandler(handler);

  

  // Add the button to the panel and the panel to the application, then display the application app in the Spreadsheet doc

  panel.add(button);

  app.add(panel);

  doc.show(app);

}

function onOpen() {   setMenus();   }

function setMenus() {

 var ss = SpreadsheetApp.getActiveSpreadsheet();

  var menuEntries = [{name: "Export from calendar", functionName: "workingHoursTool"}];  

  ss.addMenu("Working Hours", menuEntries);  }