/**
 * @author florian.schupp
 */

var datePickerDivID = "datepicker";

var iFrameDivID = "datepickeriframe";



var dayArrayShort = new Array('So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa');

var dayArrayMed = new Array('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');

var dayArrayLong = new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday');

var monthArrayShort = new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez');

var monthArrayMed = new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'June', 'July', 'Aug', 'Sept', 'Okt', 'Nov', 'Dez');

var monthArrayLong = new Array('Jan', 'Feb', 'Mär', 'Apr', 'Mai', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez');

// var monthArrayLong = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');



// these variables define the date formatting we're expecting and outputting.

// If you want to use a different format by default, change the defaultDateSeparator

// and defaultDateFormat variables either here or on your HTML page.

var defaultDateSeparator = ".";		// common values would be "/" or "."

var defaultDateFormat = "dmy"	// valid values are "mdy", "dmy", and "ymd"

var dateSeparator = defaultDateSeparator;

var dateFormat = defaultDateFormat;



function displayDatePicker(dateFieldName, displayBelowThisObject, dtFormat, dtSep)

{

  var targetDateField = document.getElementsByName(dateFieldName).item(0);



  // if we weren't told what node to display the datepicker beneath, just display it

  // beneath the date field we're updating

  if (!displayBelowThisObject)

    displayBelowThisObject = targetDateField;



  // if a date separator character was given, update the dateSeparator variable

  if (dtSep)

    dateSeparator = dtSep;

  else

    dateSeparator = defaultDateSeparator;



  // if a date format was given, update the dateFormat variable

  if (dtFormat)

    dateFormat = dtFormat;

  else

    dateFormat = defaultDateFormat;



  var x = displayBelowThisObject.offsetLeft;

  var y = displayBelowThisObject.offsetTop + displayBelowThisObject.offsetHeight;



  // deal with elements inside tables and such

  var parent = displayBelowThisObject;

  while (parent.offsetParent) {

    parent = parent.offsetParent;

    x += parent.offsetLeft;

    y += parent.offsetTop;

  }



  drawDatePicker(targetDateField, x, y);

}





/**

Draw the datepicker object (which is just a table with calendar elements) at the

specified x and y coordinates, using the targetDateField object as the input tag

that will ultimately be populated with a date.



This function will normally be called by the displayDatePicker function.

*/

function drawDatePicker(targetDateField, x, y)

{

  var dt = getFieldDate(targetDateField.value);



  // the datepicker table will be drawn inside of a <div> with an ID defined by the

  // global datePickerDivID variable. If such a div doesn't yet exist on the HTML

  // document we're working with, add one.

  if (!document.getElementById(datePickerDivID)) {

    // don't use innerHTML to update the body, because it can cause global variables

    // that are currently pointing to objects on the page to have bad references

    //document.body.innerHTML += "<div id='" + datePickerDivID + "' class='dpDiv'></div>";

    var newNode = document.createElement("div");

    newNode.setAttribute("id", datePickerDivID);

    newNode.setAttribute("class", "dpDiv");

    newNode.setAttribute("style", "visibility: hidden;");

    document.body.appendChild(newNode);

  }



  // move the datepicker div to the proper x,y coordinate and toggle the visiblity

  var pickerDiv = document.getElementById(datePickerDivID);

  pickerDiv.style.position = "absolute";

  pickerDiv.style.left = x + "px";

  pickerDiv.style.top = y + "px";

  pickerDiv.style.visibility = (pickerDiv.style.visibility == "visible" ? "hidden" : "visible");

  pickerDiv.style.zIndex = 10000;



  // draw the datepicker table

  refreshDatePicker(targetDateField.name, dt.getFullYear(), dt.getMonth(), dt.getDate());

}





/**

This is the function that actually draws the datepicker calendar.

*/

function refreshDatePicker(dateFieldName, year, month, day)

{

  // if no arguments are passed, use today's date; otherwise, month and year

  // are required (if a day is passed, it will be highlighted later)

  var thisDay = new Date();



  if ((month >= 0) && (year > 0)) {

    thisDay = new Date(year, month, 1);

  } else {

    day = thisDay.getDate();

    thisDay.setDate(1);

  }



  // the calendar will be drawn as a table

  // you can customize the table elements with a global CSS style sheet,

  // or by hardcoding style and formatting elements below

  var crlf = "\r\n";

  var TABLE = "<table cols=7 class='dpTable'>" + crlf;

  var xTABLE = "</table>" + crlf;

  var TR = "<tr class='dpTR'>";

  var TR_title = "<tr class='dpTitleTR'>";

  var TR_days = "<tr class='dpDayTR'>";

  var TR_todaybutton = "<tr class='dpTodayButtonTR'>";

  var xTR = "</tr>" + crlf;

  var TD = "<td class='dpTD'";	// leave this tag open, because we'll be adding an onClick event

  var TD_title = "<td colspan=5 class='dpTitleTD'>";

  var TD_buttons = "<td class='dpButtonTD'>";

  var TD_todaybutton = "<td colspan=7 class='dpTodayButtonTD'>";

  var TD_days = "<td class='dpDayTD'>";

  var TD_selected = "<td class='dpDayHighlightTD'";	// leave this tag open, because we'll be adding an onClick event

  var xTD = "</td>" + crlf;

  var DIV_title = "<div class='dpTitleText'>";

  var DIV_selected = "<div class='dpDayHighlight'>";

  var xDIV = "</div>";



  // start generating the code for the calendar table

  var html = TABLE;



  // this is the title bar, which displays the month and the buttons to

  // go back to a previous month or forward to the next month

  html += TR_title;

  html += TD_buttons + getButtonCode(dateFieldName, thisDay, -1, "&lt;") + xTD;

  html += TD_title + DIV_title + monthArrayLong[thisDay.getMonth()] + " " + thisDay.getFullYear() + xDIV + xTD;

  html += TD_buttons + getButtonCode(dateFieldName, thisDay, 1, "&gt;") + xTD;

  html += xTR;



  // this is the row that indicates which day of the week we're on

  html += TR_days;

  for(i = 0; i < dayArrayShort.length; i++)

    html += TD_days + dayArrayShort[i] + xTD;

  html += xTR;



  // now we'll start populating the table with days of the month

  html += TR;



  // first, the leading blanks

  for (i = 0; i < thisDay.getDay(); i++)

    html += TD + "&nbsp;" + xTD;



  // now, the days of the month

  do {

    dayNum = thisDay.getDate();

    TD_onclick = " onclick=\"updateDateField('" + dateFieldName + "', '" + getDateString(thisDay) + "');\">";



    if (dayNum == day)

      html += TD_selected + TD_onclick + DIV_selected + dayNum + xDIV + xTD;

    else

      html += TD + TD_onclick + dayNum + xTD;



    // if this is a Saturday, start a new row

    if (thisDay.getDay() == 6)

      html += xTR + TR;



    // increment the day

    thisDay.setDate(thisDay.getDate() + 1);

  } while (thisDay.getDate() > 1)



  // fill in any trailing blanks

  if (thisDay.getDay() > 0) {

    for (i = 6; i > thisDay.getDay(); i--)

      html += TD + "&nbsp;" + xTD;

  }

  html += xTR;



  // add a button to allow the user to easily return to today, or close the calendar

  var today = new Date();

  var todayString = "Today is " + dayArrayMed[today.getDay()] + ", " + monthArrayMed[today.getMonth()] + " " + today.getDate();

  html += TR_todaybutton + TD_todaybutton;

  html += "<button class='dpTodayButton' onClick='refreshDatePicker(\"" + dateFieldName + "\");'>Akt. Monat</button> ";

  html += "<button class='dpTodayButton' onClick='updateDateField(\"" + dateFieldName + "\");'>x</button>";

  html += xTD + xTR;



  // and finally, close the table

  html += xTABLE;



  document.getElementById(datePickerDivID).innerHTML = html;

  // add an "iFrame shim" to allow the datepicker to display above selection lists

  adjustiFrame();

}





/**

Convenience function for writing the code for the buttons that bring us back or forward

a month.

*/

function getButtonCode(dateFieldName, dateVal, adjust, label)

{

  var newMonth = (dateVal.getMonth() + adjust) % 12;

  var newYear = dateVal.getFullYear() + parseInt((dateVal.getMonth() + adjust) / 12);

  if (newMonth < 0) {

    newMonth += 12;

    newYear += -1;

  }



  return "<button class='dpButton' onClick='refreshDatePicker(\"" + dateFieldName + "\", " + newYear + ", " + newMonth + ");'>" + label + "</button>";

}





/**

Convert a JavaScript Date object to a string, based on the dateFormat and dateSeparator

variables at the beginning of this script library.

*/

function getDateString(dateVal)

{

  var dayString = "00" + dateVal.getDate();

  var monthString = "00" + (dateVal.getMonth()+1);

  dayString = dayString.substring(dayString.length - 2);

  monthString = monthString.substring(monthString.length - 2);



  switch (dateFormat) {

    case "dmy" :

      return dayString + dateSeparator + monthString + dateSeparator + dateVal.getFullYear();

    case "ymd" :

      return dateVal.getFullYear() + dateSeparator + monthString + dateSeparator + dayString;

    case "mdy" :

    default :

      return monthString + dateSeparator + dayString + dateSeparator + dateVal.getFullYear();

  }

}





/**

Convert a string to a JavaScript Date object.

*/

function getFieldDate(dateString)

{

  var dateVal;

  var dArray;

  var d, m, y;



  try {

    dArray = splitDateString(dateString);

    if (dArray) {

      switch (dateFormat) {

        case "dmy" :

          d = parseInt(dArray[0], 10);

          m = parseInt(dArray[1], 10) - 1;

          y = parseInt(dArray[2], 10);

          break;

        case "ymd" :

          d = parseInt(dArray[2], 10);

          m = parseInt(dArray[1], 10) - 1;

          y = parseInt(dArray[0], 10);

          break;

        case "mdy" :

        default :

          d = parseInt(dArray[1], 10);

          m = parseInt(dArray[0], 10) - 1;

          y = parseInt(dArray[2], 10);

          break;

      }

      dateVal = new Date(y, m, d);

    } else {

      dateVal = new Date(dateString);

    }

  } catch(e) {

    dateVal = new Date();

  }



  return dateVal;

}





/**

Try to split a date string into an array of elements, using common date separators.

If the date is split, an array is returned; otherwise, we just return false.

*/

function splitDateString(dateString)

{

  var dArray;

  if (dateString.indexOf("/") >= 0)

    dArray = dateString.split("/");

  else if (dateString.indexOf(".") >= 0)

    dArray = dateString.split(".");

  else if (dateString.indexOf("-") >= 0)

    dArray = dateString.split("-");

  else if (dateString.indexOf("\\") >= 0)

    dArray = dateString.split("\\");

  else

    dArray = false;



  return dArray;

}



function updateDateField(dateFieldName, dateString)

{

  var targetDateField = document.getElementsByName(dateFieldName).item(0);

  if (dateString)

    targetDateField.value = dateString;

  document.getElementById(datePickerDivID).style.visibility = "hidden";

  adjustiFrame();

  targetDateField.focus();



  // after the datepicker has closed, optionally run a user-defined function called

  // datePickerClosed, passing the field that was just updated as a parameter

  // (note that this will only run if the user actually selected a date from the datepicker)

  if ((dateString) && (typeof(datePickerClosed) == "function"))

    datePickerClosed(targetDateField);

}





/**

Use an "iFrame shim" to deal with problems where the datepicker shows up behind

selection list elements, if they're below the datepicker. The problem and solution are

described at:



http://dotnetjunkies.com/WebLog/jking/archive/2003/07/21/488.aspx

http://dotnetjunkies.com/WebLog/jking/archive/2003/10/30/2975.aspx

*/

function adjustiFrame(pickerDiv, iFrameDiv)

{

  if (!document.getElementById(iFrameDivID)) {

    // don't use innerHTML to update the body, because it can cause global variables

    // that are currently pointing to objects on the page to have bad references

    //document.body.innerHTML += "<iframe id='" + iFrameDivID + "' src='javascript:false;' scrolling='no' frameborder='0'>";

    var newNode = document.createElement("iFrame");

    newNode.setAttribute("id", iFrameDivID);

    newNode.setAttribute("src", "javascript:false;");

    newNode.setAttribute("scrolling", "no");

    newNode.setAttribute("frameborder", "0");

    document.body.appendChild(newNode);

  }



  if (!pickerDiv)

    pickerDiv = document.getElementById(datePickerDivID);

  if (!iFrameDiv)

    iFrameDiv = document.getElementById(iFrameDivID);



  try {

    iFrameDiv.style.position = "absolute";

    iFrameDiv.style.width = pickerDiv.offsetWidth;

    iFrameDiv.style.height = pickerDiv.offsetHeight;

    iFrameDiv.style.top = pickerDiv.style.top;

    iFrameDiv.style.left = pickerDiv.style.left;

    iFrameDiv.style.zIndex = pickerDiv.style.zIndex - 1;

    iFrameDiv.style.visibility = pickerDiv.style.visibility;

  } catch(e) {

  }

}