source: Dev/trunk/src/client/dojox/calendar/time.js

define(["dojo/_base/lang", "dojo/date", "dojo/cldr/supplemental","dojo/date/stamp"], function(lang, date, cldr, stamp) {

// summary: Advanced date manipulation utilities.

var time = {};


time.newDate = function(obj, dateClassObj){
        // summary:
        //              Creates a new Date object.
        // obj: Object
        //              This object can have several values:
        //              - the time in milliseconds since gregorian epoch.
        //              - a Date instance
        //              - a String instance that can be decoded by the dojo/date/stamp class.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.

        // returns: Date
        dateClassObj = dateClassObj || Date;  
        var d;
        
        if(typeof(obj) == "number"){
                return new dateClassObj(time);
        }else if(obj.getTime){
                return new dateClassObj(obj.getTime());
        }else if(obj.toGregorian){
                d = obj.toGregorian();
                if(dateClassObj !== Date){
                        d = new dateClassObj(d.getTime());
                }
                return d;
        }else if(typeof obj == "string"){
                d = stamp.fromISOString(obj);
                if(d === null){
                        throw new Error("Cannot parse date string ("+obj+"), specify a \"decodeDate\" function that translates this string into a Date object"); // cannot build date
                }else if(dateClassObj !== Date){ // from Date to dateClassObj
                        d = new dateClassObj(d.getTime());
                }
                return d;
        }

};

time.floorToDay = function(d, reuse, dateClassObj){
        // summary:
        //              Floors the specified date to the start of day.
        // date: Date
        //              The date to floor.
        // reuse: Boolean
        //              Whether use the specified instance or create a new one. Default is false.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.        
        // returns: Date
        dateClassObj = dateClassObj || Date;  
        
        if(!reuse){
                d = time.newDate(d, dateClassObj);
        }
        
        d.setHours(0, 0, 0, 0);
                
        return d;
};

time.floorToMonth = function(d, reuse, dateClassObj){
        // summary:
        //              Floors the specified date to the start of the date's month.
        // date: Date
        //              The date to floor.
        // reuse: Boolean
        //              Whether use the specified instance or create a new one. Default is false.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.        
        // returns: Date
        dateClassObj = dateClassObj || Date;  
        
        if(!reuse){
                d = time.newDate(d, dateClassObj);
        }
        
        d.setDate(1);
        d.setHours(0, 0, 0, 0);
        
        return d;
};


time.floorToWeek = function(d, dateClassObj, dateModule, firstDayOfWeek, locale){
        // summary:
        //              Floors the specified date to the beginning of week.
        // d: Date
        //              Date to floor.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.        
        // dateModule: Object?
        //              Object that contains the "add" method. By default dojo.date is used.
        // firstDayOfWeek: Integer?
        //              Optional day of week that overrides the one provided by the CLDR.       
        // locale: String?
        //              Optional locale used to determine first day of week.
        dateClassObj = dateClassObj || Date; 
        dateModule = dateModule || date;        
        
        var fd = firstDayOfWeek == undefined || firstDayOfWeek < 0 ? cldr.getFirstDayOfWeek(locale) : firstDayOfWeek;
        var day = d.getDay();
        if(day == fd){
                return d;
        }
        return time.floorToDay(
                dateModule.add(d, "day", day > fd ? -day+fd : -day+fd-7),
                true, dateClassObj);
};

time.floor = function(date, unit, steps, reuse, dateClassObj){
        // summary:
        //              floors the date to the unit.
        // date: Date
        //              The date/time to floor.
        // unit: String
        //              The unit. Valid values are "minute", "hour", "day".
        // steps: Integer
        //              Valid for "minute" or "hour" units.
        // reuse: Boolean
        //              Whether use the specified instance or create a new one. Default is false.       
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.
        // returns: Date

        var d = time.floorToDay(date, reuse, dateClassObj);
        
        switch(unit){
                case "week":
                        return time.floorToWeek(d, firstDayOfWeek, dateModule, locale);
                case "minute":
                        d.setHours(date.getHours());
                        d.setMinutes(Math.floor(date.getMinutes() /steps) * steps);
                        break;
                case "hour":
                        d.setHours(Math.floor(date.getHours() /steps) * steps);
                        break;
        }
        return d;
};

time.isStartOfDay = function(d, dateClassObj, dateModule){
        // summary:
        //              Tests if the specified date represents the starts of day. 
        // d: Date
        //              The date to test.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.        
        // dateModule: Object?
        //              Object that contains the "add" method. By default dojo.date is used.
        // returns: Boolean
        dateModule = dateModule || date;
        return dateModule.compare(this.floorToDay(d, false, dateClassObj), d) == 0;
};

time.isToday = function(d, dateClassObj){
        // summary:
        //              Returns whether the specified date is in the current day.
        // d: Date
        //              The date to test.
        // dateClassObj: Object?
        //              The Date class used, by default the native Date.
        // returns: Boolean
        dateClassObj = dateClassObj || Date;
        var today = new dateClassObj();
        return d.getFullYear() == today.getFullYear() &&
                                 d.getMonth() == today.getMonth() && 
                                 d.getDate() == today.getDate();
};

return time;
});