// class FixedHeadTable
// requires: prototype.js

var FixedHeadTable = Class.create();

/*
 * The algorithm to adjust the widths of the columns is cited from
 * the message by "ween" on Feb 5, 2003 in the following page:
 * http://chaichan.hp.infoseek.co.jp/qa3500/qa3637.htm
 */

FixedHeadTable.prototype = {
    initialize: function(tableId, headContainerId, bodyContainerId, heightRatio) {
	this.tableId = tableId;
	this.headContainerId = headContainerId;
	this.bodyContainerId = bodyContainerId;
	this.heightRatio = heightRatio;
    },
    setup: function() {
	if (navigator.appVersion.match(/MSIE|KHTML/) &&
	    !navigator.userAgent.match(/MSIE.*Mac_PowerPC/)) {
	    $(this.bodyContainerId).style.overflow = "auto";
	    this.setupElements();
	    this.setupHeight($(this.bodyContainerId));
	    this.setupWidth();
	}
	else {
	    this.setupForMozilla();
	}
    },
    setupForMozilla: function() {
	var tbody = $(this.tableId).getElementsByTagName("tbody")[0];
	tbody.style.overflow = "auto";
        var trs = tbody.getElementsByTagName("tr");
	for (var i = 0; i < trs.length; i++) {
	    var tds = trs[i].getElementsByTagName("td");
	    tds[tds.length - 1].style.paddingRight = "20px";
	}
	this.setupHeight(tbody);
    },
    reset: function() {
	if (navigator.appVersion.match(/MSIE|KHTML/) &&
	    !navigator.userAgent.match(/MSIE.*Mac_PowerPC/)) {
	    this.body.rows[0].style.display = "";
	    var nCols = this.body.rows[0].cells.length;
	    for (var i = 0; i < nCols; i++) {
		this.body.rows[0].cells[i].style.width = "";
		this.body.rows[1].cells[i].style.width = "";
	    }
	    this.bodyContainer.style.width = "auto";
	    this.head.style.tableLayout = "auto";
	    this.body.style.tableLayout = "auto";
	    this.setupHeight(this.bodyContainer);
	    this.setupWidth();
	}
	else {
	    this.resetForMozilla();
	}
    },
    resetForMozilla: function() {
	this.setupHeight($(this.tableId).getElementsByTagName("tbody")[0]);
    },
    setupElements: function() {
	this.body = $(this.tableId);
	this.headContainer = $(this.headContainerId);
	this.bodyContainer = $(this.bodyContainerId);

	this.head = this.makeHead(this.body);
	this.headContainer.appendChild(this.head);
    },
    setupHeight: function(elem) {
	var windowHeight = window.innerHeight || document.body.offsetHeight;
	elem.style.height = Math.round(windowHeight * this.heightRatio) + "px";
    },
    setupWidth: function() {
	var diff = this.bodyContainer.offsetWidth - this.bodyContainer.scrollWidth;
	var nCols = this.head.rows[0].cells.length;
	var tempWidths = new Array();

	if (navigator.appVersion.match(/KHTML/)) {
	    this.head.style.width = "98%";
	}

	for (var i = 0; i < nCols; i++) {
	    tempWidths.push(this.body.rows[1].cells[i].offsetWidth);
	}

	if (!navigator.appVersion.match(/KHTML/)) {
	    this.head.style.tableLayout = "fixed";
	    this.body.style.tableLayout = "fixed";
	}

	for (var i = 0; i < nCols; i++) {
	    this.head.rows[0].cells[i].style.width = tempWidths[i];
	    this.body.rows[0].cells[i].style.width = tempWidths[i];
	    this.body.rows[1].cells[i].style.width = tempWidths[i];
	}

	this.body.rows[0].style.display = "none";

	this.head.rows[0].cells[nCols - 1].width = tempWidths[nCols - 1];
	this.bodyContainer.style.width = this.body.offsetWidth + diff;
    },
    makeHead: function(body) {
	var head = document.createElement("table");
	head.id = this.tableId + "Head";
	var theads = body.getElementsByTagName("thead");
	head.appendChild(theads[0].cloneNode(true));
	return head;
    }
};
var fixedHeadTable = new FixedHeadTable("tableBody", "tableHeadContainer", "tableBodyContainer", 0.6);


window.onload = function() {
    fixedHeadTable.setup();
};

window.onresize = function() {
    fixedHeadTable.reset();
};