// byteMyCode.com
// ©1998-2006 BlueCrestStudios, LLC. All Rights Reserved.

// install window.onload handler
installEventHandler(window, "load", loadResizables);

function loadResizables()
{
	textareas = document.getElementsByTagName('textarea');
	var textarea;
	for (var i = 0; textarea = textareas[i]; ++i) 
	{
		if (hasClass(textarea, 'resizable'))
	 	{
			if (typeof dimensions(textarea).width != 'undefined' && dimensions(textarea).width != 0)
			{
		  		new textArea(textarea);
			}
		}
	}
	
}

function stopEvent(event) 
{
	if (event.preventDefault) 
	{
		event.preventDefault();
		event.stopPropagation();
	}
	else 
	{
		event.returnValue = false;
		event.cancelBubble = true;
	}
}

function dimensions(el) 
{
 	return { width: el.offsetWidth, height: el.offsetHeight };
}
	
function textArea(element) 
{
	var ta = this;
	this.element = element;
	this.parent = this.element.parentNode;
	this.dimensions = dimensions(element);
	
	// Prepare wrapper
	this.wrapper = document.createElement('div');
	this.wrapper.className = 'resizable-textarea';
	this.parent.insertBefore(this.wrapper, this.element);
	
	// Add grippie and measure it
	this.grippie = document.createElement('div');
	this.grippie.className = 'grippie';
	this.wrapper.appendChild(this.grippie);
	this.grippie.dimensions = dimensions(this.grippie);
	this.grippie.onmousedown = function (e) { ta.beginDrag(e); };
	
	// Set wrapper and textarea dimensions
	this.wrapper.style.height = this.dimensions.height + this.grippie.dimensions.height + 1 +'px';
	this.element.style.marginBottom = '0px';
	this.element.style.width = '100%';
	this.element.style.height = this.dimensions.height +'px';
	
	// Wrap textarea
	removeNode(this.element);
	this.wrapper.insertBefore(this.element, this.grippie);

  	// Measure difference between desired and actual textarea dimensions to account for padding/borders
  	this.widthOffset = dimensions(this.wrapper).width - this.dimensions.width;

 	 // Make the grippie line up in various browsers
 	 if (window.opera) 
 	 {
    		// Opera
    		this.grippie.style.marginRight = this.widthOffset +'px';
  	}
  	
  	if (document.all && !window.opera) 
  	{
    		// IE
    		this.grippie.style.width = '100%';
    		this.grippie.style.paddingLeft = '2px';
  	}

  	// Mozilla
  	this.element.style.MozBoxSizing = 'border-box';

  	this.heightOffset = absolutePosition(this.grippie).y - absolutePosition(this.element).y - this.dimensions.height;
}

textArea.prototype.beginDrag = function (event) 
{
	if (document.isDragging) 
	{
		return;
	}
	document.isDragging = true;

  	event = event || window.event;
  	
  	// Capture mouse
	var cp = this;
  	this.oldMoveHandler = document.onmousemove;
 	document.onmousemove = function(e) { cp.handleDrag(e); };
 	this.oldUpHandler = document.onmouseup;
  	document.onmouseup = function(e) { cp.endDrag(e); };

	// Store drag offset from grippie top
	var pos = absolutePosition(this.grippie);
	this.dragOffset = event.clientY - pos.y;
	
	// Make transparent
	this.element.style.opacity = 0.5;
	
	// Process
	this.handleDrag(event);
}

textArea.prototype.handleDrag = function (event) 
{
	event = event || window.event;
	// Get coordinates relative to text area
	var pos = absolutePosition(this.element);
	var y = event.clientY - pos.y;
	
	// Set new height
	var height = Math.max(32, y - this.dragOffset - this.heightOffset);
	this.wrapper.style.height = height + this.grippie.dimensions.height + 1 + 'px';
	this.element.style.height = height + 'px';
	
	// Avoid text selection
	stopEvent(event);
}

textArea.prototype.endDrag = function (event) 
{
	// Uncapture mouse
	document.onmousemove = this.oldMoveHandler;
	document.onmouseup = this.oldUpHandler;
	
	// Restore opacity
	this.element.style.opacity = 1.0;
	document.isDragging = false;
}