// WARNING: this file must be kept in sync with tasktracker/lib/pretty_date.py

// Copyright (C) 2006 The Open Planning Project

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the 
// Free Software Foundation, Inc., 
// 51 Franklin Street, Fifth Floor, 
// Boston, MA  02110-1301
// USA

// See http://www.gnu.org/licenses/gpl-faq.html#WMS for the explanation for this:

// As a special exception to GPL, any HTML file which merely makes
// function calls to this code, and for that purpose includes it by
// reference shall be deemed a separate work for copyright law
// purposes. In addition, the copyright holders of this code give you
// permission to combine this code with free software libraries that
// are released under the GNU LGPL. You may copy and distribute such a
// system following the terms of the GNU GPL for this code and the
// LGPL for the libraries. If you modify this code, you may extend
// this exception to your version of the code, but you are not
// obligated to do so. If you do not wish to do so, delete this
// exception statement from your version.


function utc(d) {
    return Date.UTC(d.getFullYear(), d.getMonth(), d.getDate());
}

function date_diff(date1, date2) {
    var date1_UTC = utc(date1);
    var date2_UTC = utc(date2);
    return (date1_UTC - date2_UTC) / 86400000;
}

function dayOfWeek(day) {
    return "SunMonTueWedThuFriSatSun".substr(day * 3, 3);
}

function monthName(month) {
    var months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
    return months[month];
}


function pretty_date_engine(now, date) {
    var diff = date_diff(date, now);
    if (diff == -1) {
	return "Yesterday";
    }
    if (diff == 0) {
	return "Today";
    }
    if (diff == 1) {
	return "Tomorrow";
    }
    if (diff < 7 && diff > 0) {
	return dayOfWeek(date.getDay());
    }
    if (diff < 90 && date.getYear() == now.getYear()) {
	return monthName(date.getMonth()) + " " + date.getDate()
    }
    return monthName(date.getMonth()) + " " + date.getDate() + ", " + date.getFullYear();
}

function pretty_date_from_text(text, now) {
    if (text == "No deadline")
	return text;
    console.log(text);
    parts = text.split("/");
    return pretty_date(new Date(parseInt(parts[2], 10), parseInt(parts[0], 10)-1, parseInt(parts[1], 10)), now);
}

function pretty_date(date, now) {
    if (!now) 
	now = new Date();
    return pretty_date_engine(now, date);
}


function test_pretty_date() {
    var now = new Date(2006, 0, 1);
    var dates = [
		 ['Today', new Date(2006, 0, 1)],
		 ['Tomorrow', new Date(2006, 0, 2)],
		 ['Yesterday', new Date(2005, 11, 31)],
		 ['December 30, 2005', new Date(2005, 11, 30)],
		 ['Tue', new Date(2006, 0, 3)],
		 ['Sat', new Date(2006, 0, 7)],
		 ['January 8', new Date(2006, 0, 8)],
		 ['December 8, 2006', new Date(2006, 11, 8)],
		 ['January 8, 2007', new Date(2007, 0, 8)]
		 ];
    var i;
    for (i = 0; i < dates.length; i++ ) {
	var date = dates[i][1];
	var pd = pretty_date_engine(now, date);
	if (pd != dates[i][0]) {
	    alert("failure mapping " + date + " to " + dates[i][0] + ", got " + pd);
	}
    }

    now = new Date(2006, 0, 1);
    dates = [
	     ['Today', "01/01/2006"],
	     ['Tomorrow', "01/02/2006"],
	     ['Yesterday', "12/31/2005"],
	     ['December 30, 2005', "12/30/2005"],
	     ['Tue', "01/03/2006"],
	     ['Sat', "01/07/2006"],
	     ['January 8', "01/08/2006"],
	     ['December 8, 2006', "12/08/2006"],
	     ['January 8, 2007', "01/08/2007"]
	     ];
    var i;
    for (i = 0; i < dates.length; i++ ) {
	var date = dates[i][1];
	var pd = pretty_date_from_text(date, now);
	if (pd != dates[i][0]) {
	    alert("failure mapping " + date + " to " + dates[i][0] + ", got " + pd);
	}
    }
}