/**
 *
 * $Id$
 *
 * This script waits for the document to be loaded,
 * then seeks the right table cell for today's date
 * and changes it's background color.
 *
 * Fading is just an additional effect.
 *
 **/

set_hilight_timer();

function set_hilight_timer()
{
    window.setTimeout(hilight_today, 50);
}

function hilight_today()
{
    /* Has document fetching completed enough? */
    if (document.getElementById("upcoming"))
    {
        var now = new Date();
        var today_id = "calendar-" +
            now.getFullYear() + "-" +
            (now.getMonth() + 1) + "-" +
            now.getDate();

        var today = document.getElementById(today_id);

        var td = today.parentNode;
        if (td)
        {
            td.style.backgroundColor = "#ebc63c";
            td.style.backgroundColor = "black";
            fade_td(td, 0, 100);
        }
    }
    else
    {
        /* No calendar, continue waiting */
        window.setTimeout(hilight_today, 300);
    }
}

function fade_td(td, step, interval)
{
    var colors = new Array(
        "#edece5",
        "#edece7",
        "#edebe1",
        "#ede9db",
        "#ede8d5",
        "#ede7cf",
        "#ede5c9",
        "#ede4c3",
        "#ede2bc",
        "#ede1b6",
        "#ece0b0",
        "#ecdeaa",
        "#ecdda4",
        "#ecdc9e",
        "#ecda98",
        "#ecd991",
        "#ecd78b",
        "#ecd685",
        "#ecd57f",
        "#ecd379",
        "#ebd273",
        "#ebd16d");

    td.style.backgroundColor = colors[step];
    var next_step = step + 1;
    if (next_step < colors.length)
    {
        /* These three lines feature two techniques:
         * * lambda
         * * tail-recursive
         */
        window.setTimeout(function() {
	    fade_td(td, next_step, interval);
        },(next_step == 1) ? interval * 10 : interval); /* Delay the first step */
    }
}