/* external_date_functions.js
*
* Purpose: Sample external date functions for JavaScript calendar
* Author: Richard Pike)
* Website: http://calendar.pikesys.com
*
* my_date returns an alternate date string corresponding to the given Gregorian date
* my_holiday returns an appropriate holiday text string for the given Gregorian date
* my_alt_holiday returns an appropriate alternate holiday string for the given Gregorian date
*
*/

function makeArray() {
  this[0] = makeArray.arguments.length;
  for (i = 0; i < makeArray.arguments.length; i = i + 1)
    this[i+1] = makeArray.arguments[i];
}

var altMonthNames = new makeArray("Red", "Yellow", "Blue","Green","Purple","Orange","Cyan","Magenta","Goldenrod","Brown","Black","White");
var altMonths = new Array;

// altMonths constructor
function altMonth(startdate, monthnumber) {
  this.startdate = startdate;
  this.month = monthnumber;
}

function DefineAltMonth(startdate, monthnumber) {
  altMonths[altMonths.length] = new altMonth(startdate, monthnumber);
}

// these could be defined in external JavaScript such as altdates.js (the last altMonth defined will not show because endate is unknown!)
DefineAltMonth(20040404, 1);
DefineAltMonth(20040505, 2);
DefineAltMonth(20040606, 3);
DefineAltMonth(20040707, 4);
DefineAltMonth(20040808, 5);
DefineAltMonth(20040909, 6);
DefineAltMonth(20041010, 7);
DefineAltMonth(20041111, 8);
DefineAltMonth(20041212, 9);
DefineAltMonth(20050113, 10);
DefineAltMonth(20050214, 11);
DefineAltMonth(20050315, 12);
DefineAltMonth(20050416, 1);

function my_date(day, month, year, style) {
  if (!style) style = 0;
  var mo = 0;
  var dy, yr;
  var dateString = "";

  ymd = day + month*100 + year*10000;
  for (i=1; i<altMonths.length-1; i++) {
    if (ymd >= altMonths[i-1].startdate && ymd < altMonths[i].startdate) {
      mo = altMonths[i-1].month;
      startDay = altMonths[i-1].startdate%100;
      startMonth = ((altMonths[i-1].startdate-startDay)/100)%100;
      if (month == startMonth) {
        dy = day - startDay +1;
      } else {
        ym = month + year*100;
        prevYM = PrevYearMonth(ym);
        prevM = prevYM%100;
        prevY = (prevYM - prevM)/100;
        eom = NumDaysIn(prevM, prevY);
        dy = day + (eom - startDay +1);
      }
      yr = year - 1970;
      break;
    }
  }
  if (mo > 0) {
    if (style == 0) {     // day monthnum year
      dateString = dy + ' ' + mo + ' ' + yr;
    } else if (style == 1) {   // monthname year
      dateString = altMonthNames[mo] + ' ' + yr;
    } else if (style == 2) {   // day monthname
      dateString = dy + ' ' + altMonthNames[mo];
    } else if (style == 3) {   // monthname day
      dateString = altMonthNames[mo] + ' ' + dy;
    } else if (style == 4) {   // day monthname year
      dateString = dy + ' ' + altMonthNames[mo] + ' ' + yr;
    }
  }
  return dateString;
}

  function my_holiday(day, month, year) {

  var holString = "";

  if (month == 1 && day == 1) {
    holString = "New Year's Day";
  }
  //else if (month == 12 && day == 31) {
  //  holString = "New Year's Eve";
  //}
  else if (month == 7 && day == 4) {
    holString = "Independence Day";
  }
  else if (month == 12 && day == 25) {
    holString = "Christmas";
  }
  
  return holString;
}

function my_alt_holiday(day, month, year) {
  var aday, amonth;
  var holString = "";

  // calculate alternate date from given Gregorian date
  var altDate = my_date(day, month, year);
  var altMonthYear = altDate.substring(altDate.indexOf(' ')+1, altDate.length);
  aday = eval(altDate.substring(0, altDate.indexOf(' ')));
  amonth = eval(altMonthYear.substring(0, altMonthYear.indexOf(' ')));

  if (aday == 1 ) {
    holString = "Happy " + altMonthNames[amonth];
  }
  return holString;
}