
// Global variables
var table;				// Table object
var rowArray = new Array();		// Data row array
var titleRowArray = new Array();	// Contains title texts
var titleRowCellArray = new Array();	// Dynamically constructed title cells
var titleSpanCellArray = new Array();	// Title elelments from row-spanned
var colSpanArray = new Array();		// Rows col-spanned
var colTitleFilled = new Array();	// Indicates whether title is filled
var sortIndex;				// Selected index for sort
var descending = false;			// Descending order
var nRow, actualNRow, maxNCol;		// Various table stats
var origColor;				// Holds original default color
var isIE;				// True if IE
var linkEventString =			// What's insider <a> tag
	'onMouseOver=\'setCursor(this);' +
	'setColor(this,"selected");\' ' +
	'onMouseOut=\'setColor(this,"default");\' ' +
	'onClick=\'sortTable(';

// Configurable constants
var ascChr = ""; // "^"; 		// Symbol for ascending sort
var desChr = ""; // "v";			// Symbol for descending sort
var selectedColor = "blue";		// Color for sort focus
var defaultColor = "black";		// Default color for sort off-focus
var recDelimiter = '|';			// Char used as a record separator
var titleFace = 'b';			// Specifies the HTML tag for titles
var updownColor = 'gray';		// Specified the color for up/downs 

//*****************************************************************************
// Main function. This is to be associated with onLoad event in <BODY>. 
//
// IMPORTANT: This is the only function that needs to be included in the pages
// to be sorted. The rest of the functions are simply called by this
// function.
//*****************************************************************************
function initTable(obj)
{
	// Check whether it's viewed by IE 5.0 or greater
	if (! checkBrowser()) return;

	// Local variables
	var countCol;
	var nChildNodes;
	var innerMostNode;
	var nColSpan, nRowSpannedTitleCol, colPos;
	var cell, cellText;
	var titleFound = false;
	var skipRow = false;
	var rNRowSpan, rNColSpan, parentNodeName;

	// Initializing global table object variable
	if (obj.tagName == "TABLE")
	{
		// Assumes that the obj is THE OBJECT
		table = obj;
	}
	else
	{
		// Assumes that the obj is the id of the object
		table = document.getElementById(obj);
	}

	// Check whether it's an object
	if (table == null) return;

	// Check whether it's a table
	if (table.tagName != "TABLE") return;

	// Initializing the max col number with the size of last data row
	maxNCol = table.rows[table.rows.length-1].cells.length;

	// Initializing arrays
	rowArray = new Array();
	colSpanArray = new Array();
	colTitleFilled = new Array();
	titleRowArray = new Array();
	titleRowCellArray = new Array();
	
	for (var i=0; i<maxNCol; i++)
		colTitleFilled[i] = false;

	// Setting the number of rows
	nRow = table.rows.length;	

	// Should have at least 1 row
	if (nRow < 1) return;

	// Initialization of local variables
	actualNRow = 0;			// Number of actual data rows
	rNRowSpan = 0;			// Remaining rows in the row span
	rNColSpan = 0;			// Remaining cols in the col span
	nRowSpannedTitleCol = 0;	// Number of title cols from row span
		
	// Loop through rows
	for (var i=0; i<nRow; i++)
	{
		skipRow = false;
		// Skip if it's THEAD, TFOOT
		if (table.rows[i].parentNode != null)
		{
			parentNodeName = table.rows[i].parentNode.nodeName;
			parentNodeName.toUpperCase();
			if (parentNodeName == 'THEAD' ||
				parentNodeName == 'TFOOT')
			{
				skipRow = true;
			}
		}
		nColSpan = 1, colPos = 0;
		// Loop through columns
		// Initializing
		for (var j=0; j<table.rows[i].cells.length; j++)
		{
			// Do this iff title has not been found
			if (titleFound == false)
			{
				if (table.rows[i].cells[j].rowSpan > 1)
				{
					if (table.rows[i].cells[j].colSpan < 2)
					{
						titleSpanCellArray[colPos] =
							table.rows[i].cells[j];
						colTitleFilled[colPos] = true;
						nRowSpannedTitleCol++;
					}
					if (table.rows[i].cells[j].rowSpan - 1 
						> rNRowSpan)
					{
						rNRowSpan = 
							table.
							rows[i].cells[j].
							rowSpan - 1;

						if (table.rows[i].
							cells[j].colSpan > 1)
							rNColSpan = 
								rNRowSpan + 1;
					}
				}
			}
			if (table.rows[i].cells[j].colSpan > 1 &&
				rNColSpan == 0)
			{ 
				nColSpan = table.rows[i].cells[j].colSpan;
				colPos += nColSpan;
			}
			else
			{
				colPos++;
			}		
		}
					
		// Setting up the title cells
		if (titleFound == false && nColSpan == 1 && 
			rNRowSpan == 0 && rNColSpan == 0 && titleFound == false)
		{
			colSpanArray[i] = true;
			titleFound = true;

			// Using indivisual cell as an array element
			countCol = 0;
			for (var j=0; 
				j<table.rows[i].cells.length
					+ nRowSpannedTitleCol; j++)
			{
				if (colTitleFilled[j] != true)
				{
					titleRowCellArray[j] =
						table.rows[i].cells[countCol];
					countCol++;
				}
				else
				{
					titleRowCellArray[j] = 
						titleSpanCellArray[j];
				}
			}
		}
		// Setting up the data rows
		else if (titleFound == true && nColSpan == 1 && 
			rNRowSpan == 0 && !skipRow)
		{
			for (var j=0; j<table.rows[i].cells.length; j++)
			{
				// Can't have row span in record rows ...
				if (table.rows[i].cells[j].rowSpan > 1) return;
				nChildNodes =
					table.rows[i].
					cells[j].firstChild.childNodes.
					length;

				innerMostNode = 
					table.rows[i].
					cells[j].firstChild;

				while ( nChildNodes != 0)
				{
					innerMostNode =
						innerMostNode.
						firstChild;
					nChildNodes =
						innerMostNode.
						childNodes.
						length;
				}

				if (j == 0)
				{
					rowArray[actualNRow] = 
						innerMostNode.data;
				}
				else
				{
					rowArray[actualNRow] += recDelimiter +
						innerMostNode.data;
				}
			}
			// Inconsistent col lengh for data rows
			if (table.rows[i].cells.length > maxNCol)
				return;
			actualNRow++;
			colSpanArray[i] = false;
		}
		else if (nColSpan == 1 && rNRowSpan == 0 && 
			rNColSpan == 0 && titleFound == false && !skipRow)
		{
			colSpanArray[i] = false;
		}
		else
		{
			colSpanArray[i] = true;
		}
		
		// Counters for row/column spans
		if (rNRowSpan > 0) rNRowSpan--;
		if (rNColSpan > 0) rNColSpan--;
	}

	// If the row number is < 1, no need to do anything ...
	if (actualNRow < 1) return;

	// Re-drawing the title row
	for (var j=0; j<maxNCol; j++)
	{
		// If for some reason, the rows do NOT have any child, then
		// simply return ...
		if (titleRowCellArray[j].childNodes.length == 0) return;
		if (titleRowCellArray[j].firstChild != null)
		{
			nChildNodes = 
				titleRowCellArray[j].
				firstChild.childNodes.length;
			innerMostNode = 
				titleRowCellArray[j].firstChild;

			while ( nChildNodes != 0)
			{
				innerMostNode =
					innerMostNode.firstChild;
				nChildNodes =
					innerMostNode.
					childNodes.
					length;
			}
			cellText = innerMostNode.data;
		}
		else
		{
			cellText = "column(" + j + ")";
		}
		titleRowArray[j] = cellText;
		titleRowCellArray[j].innerHTML =
			'<a ' +
			linkEventString +
			j + ',' + '"' + table.id + '"' + ');\'>' + 
			'<' + titleFace + '>' + cellText + 
			'</' + titleFace +'></a>';
	}
}

//*****************************************************************************
// Function called when user clicks on a title to sort
//*****************************************************************************
function sortTable(index,obj)
{
	// Re-inializing the table object
	initTable(obj);

	// Local variables
	var nChildNodes;
	var innerMostNode;
	var rowContent;
	var rowCount;
	var cell, cellText;
	var newTitle;
	
	// Can't sort past the max allowed column size
	if (index < 0 || index >= maxNCol) return;
	
	// Assignment of sort index
	sortIndex = index;
	// Doing the sort using JavaScript generic function for an Array
	rowArray.sort(compare);

	// Re-drawing the title row
	for (var j=0; j<maxNCol; j++)
	{
		cellText = titleRowArray[j];
		cellText = '<' + titleFace +'>' +
			cellText + '</' + titleFace + '></a>';
		newTitle = '<a ' +
			linkEventString +
			j + ',' + '"' + table.id + '"' + ');\'>' +
			cellText +
			'</a>';
		if (j == sortIndex)
		{
			//newTitle += '&nbsp;<font color=' + updownColor + '>';
			newTitle += '<font color=' + updownColor + '>';
			if (descending)
				newTitle += desChr;
			else
				newTitle += ascChr;
			newTitle += '</font>';
		}
		titleRowCellArray[j].innerHTML = newTitle;
	}

	// Re-drawing the table
	rowCount = 0;
	for (var i=0; i<nRow; i++)
	{
		if (! colSpanArray[i])
		{
			for (var j=0; j<maxNCol; j++)
			{
				rowContent = rowArray[rowCount].
					split(recDelimiter);
				nChildNodes =
					table.rows[i].cells[j].firstChild.
					childNodes.length;
				innerMostNode = 
					table.rows[i].cells[j].firstChild;

				while ( nChildNodes != 0)
				{
					innerMostNode =
						innerMostNode.firstChild;
					nChildNodes =
						innerMostNode.
						childNodes.
						length;
				}
				innerMostNode.data = rowContent[j];
			}
			rowCount++;
		}
	}

	// Switching btw descending/ascending sort
	if (descending)
		descending = false;
	else
		descending = true;
}

//*****************************************************************************
// Function to be used for Array sorting
//*****************************************************************************
function compare(a, b)
{
	// Getting the element array for inputs (a,b)
	var aRowContent = a.split(recDelimiter);
	var bRowContent = b.split(recDelimiter);
	
	// Needed in case the data conversion is necessary
	var aToBeCompared, bToBeCompared;

	if (isDate(aRowContent[sortIndex]) && isDate(bRowContent[sortIndex]))
	{
		// Compare as dates
		aToBeCompared = new Date(aRowContent[sortIndex]);
		bToBeCompared = new Date(bRowContent[sortIndex]);
	}
	else if (! isNaN(aRowContent[sortIndex]) && 
		! isNaN(bRowContent[sortIndex]))
	{
		aToBeCompared = parseFloat(aRowContent[sortIndex]);
		bToBeCompared = parseFloat(bRowContent[sortIndex]);
	}
	else
	{
		aToBeCompared = aRowContent[sortIndex];
		bToBeCompared = bRowContent[sortIndex];
	}

	if (aToBeCompared < bToBeCompared)
		if (!descending)
		{
			return -1;
		}
		else
		{
			return 1;
		}
	if (aToBeCompared > bToBeCompared)
		if (!descending)
		{
			return 1;
		}
		else
		{
			return -1;
		}
	return 0;
}

//*****************************************************************************
// Function to check whether it's a IETF recognized date string 
//*****************************************************************************
function isDate(x)
{
	var xDate;
	xDate = new Date(x);
	if (xDate.toString() != 'NaN')
		return true;
	else
		return false;
}

//*****************************************************************************
// Function to set the cursor
//*****************************************************************************
function setCursor(obj)
{
	// Show hint text at the browser status bar
	window.status = "Sort by " + obj.firstChild.innerHTML;
	// Change the mouse cursor to hand or pointer
	if (isIE)
		obj.firstChild.style.cursor = "hand";
	else
		obj.firstChild.style.cursor = "pointer";
}

//*****************************************************************************
// Function to set the title color
//*****************************************************************************
function setColor(obj,mode)
{
	if (mode == "selected")
	{
		// Remember the original color
		if (obj.style.color != selectedColor) 
			defaultColor = obj.style.color;
		obj.style.color = selectedColor;
	}
	else
	{	
		// Restoring original color and re-setting the status bar
		obj.style.color = defaultColor;
		window.status = '';
	}
}

//*****************************************************************************
// Function to check browser type/version
//*****************************************************************************
function checkBrowser()
{
	if (navigator.appName == "Microsoft Internet Explorer"
		&& navigator.appVersion.indexOf("5.") >= 0)
	{
		isIE = true;
		return true;
	}
	// For some reason, appVersion returns 5 for Netscape 6.2 ...
	else if (navigator.appName == "Netscape"
		&& navigator.appVersion.indexOf("5.") >= 0)
	{
		isIE = false;
		return true;
	}
	else
		return false;
}
