/**
 * Filename    : Date.js
 * Author      : Robert Cerny
 * Created     : 2006-07-02
 * Last Change : 2006-11-26
 *
 * Description:
 *   Some useful methods for the Date prototype providing date
 *   formatting and parsing.
 *
 * History:
 *   2006-07-02 Created.
 *
 * License:
 */

CERNY.js.Date = {};

CERNY.require("CERNY.js.Date");

/**
 * Format this date according to format.
 *
 * format - the format in which to format this date
 * return - a string containing the date formatted in format
 */
Date.prototype.format = function(format) {
    var dateStr = "<1>" + format.separator + "<2>" + format.separator + "<3>";
    var year = this.getFullYear();
    var month = this.getMonth() + 1;
    var day = this.getDate();

    dateStr = dateStr.replace("<" + format.positions.year + ">", format.formatters.year(year));
    dateStr = dateStr.replace("<" + format.positions.month + ">", format.formatters.month(month));
    dateStr = dateStr.replace("<" + format.positions.day + ">", format.formatters.day(day));
    return dateStr;
}

/**
 * Parse a date out of a dateStr based on the the formats provided.
 * If there there is more than one matches the first format is applied
 * to parse the dateStr.
 *
 * dateStr - the dateStr to parse
 * formats - a DateFormat or an array of DateFormats
 * return - if the dateStr can be parsed, a date is returned
 *          otherwise null is returned
 */
Date._parse = function(dateStr, formats) {
    if (!isArray(formats) && isObject(formats) && formats.regexp) {
        formats = [formats];
    }

    var match = null;

    var i = 0;
    while (i < formats.length && !match) {
        match = dateStr.match(formats[i].regexp);
        if (match === null) {
            i += 1;
        }
    }

    if (match) {
        var format = formats[i];

        var year = match[format.positions.year];
        var month = match[format.positions.month];
        var day = match[format.positions.day];

        year = (year >= 100) ? year : "" + format.century + year;

        var date = new Date(year, month - 1, day);

        var aYear = date.getFullYear();
        var aMonth = date.getMonth();
        var aDay = date.getDay();

        if (year == date.getFullYear() &&
            month == date.getMonth() + 1 &&
            day == date.getDate()) {
            return date;
        }
    }
    return null;
}