SUFFIX_DAY = 'Day';
SUFFIX_MONTH = 'Month';
SUFFIX_YEAR = 'Year';
DATE_DELIMITER = '-';
END_OF_MONTH = 'end';

SHORT_MONTH = ['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

function endOfMonth(m, y)
{
    eom = [0,31,28,31,30,31,30,31,31,30,31,30,31];
//    if ((m < 1) && (m > 12)) { alertError(ERROR_TYPE_DESIGN, 'invalid month value. (Should be validated before calling.)'); return -1; }
    leapyear = (((y % 4) == 0) && (((y % 100) != 0) || ((y % 400) == 0)));
    if ((m == 2) && leapyear)
        return 29;
    else
        return eom[m];
}

function daysAfter(day1, day2)
{
    day2_arr = day2.split(DATE_DELIMITER, 3);
    day1_arr = day1.split(DATE_DELIMITER, 3);
    return (Date.UTC(day2_arr[0], day2_arr[1] - 1, day2_arr[2]) - Date.UTC(day1_arr[0], day1_arr[1] - 1, day1_arr[2])) / 86400000;
}

// date returned from today() is not UTC date
function today()
{
    day_date = new Date();
    m = day_date.getMonth() + 1;
    if (m < 10) m = '0' + m;
    d = day_date.getDate();
    if (d < 10) d = '0' + d;
    return day_date.getFullYear() + '-' + m + '-' + d;
}

function relativeDate(day_str, offset)
{
    day_arr = day_str.split(DATE_DELIMITER, 3);
    day_date = new Date(day_arr[0], day_arr[1] - 1, day_arr[2]);
    day_date.setDate(day_date.getDate() + offset);
    m = day_date.getMonth() + 1;
    if (m < 10) m = '0' + m;
    d = day_date.getDate();
    if (d < 10) d = '0' + d;
    return day_date.getFullYear() + DATE_DELIMITER + m + DATE_DELIMITER + d;
}

function getDateStringFromSelect(aform, vname)
{
    if (vname.indexOf('_') != -1) {
        name_suffix = vname.substring(vname.indexOf('_'));
        vname = vname.substring(0, vname.indexOf('_'));
    } else
        name_suffix = '';
    day = getValue(aform, vname + SUFFIX_DAY + name_suffix, STRING);
    month = getValue(aform, vname + SUFFIX_MONTH + name_suffix, STRING);
    year = getValue(aform, vname + SUFFIX_YEAR + name_suffix, STRING);
    if ((month == false) || (year == false))
        return false;
    else {
        if ((day == false) || (day == END_OF_MONTH))
            day = endOfMonth(month, year);
        return year + DATE_DELIMITER + month + DATE_DELIMITER + day;
    }
}

function getFormattedDate(adate)
{
    arr_date = adate.split(DATE_DELIMITER, 3);
    return arr_date[2] + DATE_DELIMITER + SHORT_MONTH[parseInt(arr_date[1])] + DATE_DELIMITER + arr_date[0];
}