// ==UserScript==
// @name       ASW-Plan
// @namespace  http://use.i.E.your.homepage/
// @version    0.1
// @description  enter something useful
// @match      http://www.asw-berufsakademie.de/fileadmin/download/download/Sked%20Stundenplan/*.html
// @copyright  2012+, You
// ==/UserScript==

var weekNum = 1;
var weekTable = document.getElementsByTagName('table')[weekNum];

// Create a map to link each date (from header row) with its horizontal position
var days  = weekTable.getElementsByClassName('t');
var dayMap = {};
for(var i=0; i<days.length; i++) {
    var pos = findPos(days[i]);
    dayMap[days[i].innerHTML] = pos.x;
    //alert(pos.x + ' -> ' + days[i].innerHTML);
}

// Find the closest horizontal position for each course
var courses = weekTable.getElementsByClassName('v');
var out = '';
for(var i=0; i<courses.length; i++) {
    var pos = findPos(courses[i]);
    var date = findClosest(pos.x, dayMap);
    out += courses[i].innerHTML + '\n   ==> ' + date + '\n';
}
alert(out);

function findPos(obj) {
    var curleft = 0, curtop = 0;
    if (obj.offsetParent) {
        do {
            curleft += obj.offsetLeft;
            curtop += obj.offsetTop;
        } while (obj = obj.offsetParent);
        return { x: curleft, y: curtop };
    }
    return undefined;
}

function findClosest(horiPos, dayMap) {
    var xDiff = -1;
    var winner;
    for(var date in dayMap) {
        var tmpDiff = Math.abs(dayMap[date] - horiPos);
        if(xDiff == -1 || tmpDiff < xDiff) {
            xDiff = tmpDiff;
            winner = date;
        }
    }
    return winner;
}