ajax.dnd = {};

ajax.dnd.DragPopupSource = function(elementId) {
	this.element = document.getElementById(elementId);
	this.dragging = false; // ÇöÀç µå·¡±×ÁßÀÎÁö ¿©ºÎ Ç¥½Ã
	this.selected = false; // ÇöÀç ¸¶¿ì½º´Ù¿î »óÅÂÀÎÁö Ç¥½Ã
	this.diff = null; // ¸¶¿ì½º À§Ä¡¿Í °´Ã¼ À§Ä¡
	
	this.mouseDown = ajax.Event.bindAsListener(this.doMouseDown, this);
	this.mouseMove = ajax.Event.bindAsListener(this.doMouseMove, this);
	this.mouseUp = ajax.Event.bindAsListener(this.doMouseUp, this);
	
	ajax.Event.addListener(
		this.element, "mousedown", this.mouseDown);
}
ajax.dnd.DragPopupSource.prototype = {
	doMouseDown: function(e) {
		var event = window.event || e;
		if (!ajax.Event.isLeftButton(event)) return;
		
		this.selected = true;
		
		var elementXY = ajax.GUI.getXY(this.element);
		var mouseXY = ajax.Event.getMouseXY(event);
		this.diff = {
			x: mouseXY.x - elementXY.x,
			y: mouseXY.y - elementXY.y
		};
		
		ajax.Event.addListener(document, "mousemove", this.mouseMove);
		ajax.Event.addListener(document, "mouseup", this.mouseUp);
		ajax.Event.stopEvent(event);
	},
	doMouseMove: function(e) {
		if (!this.selected) return false;
		
		if (!this.dragging) {
			this.dragging = true;
			ajax.GUI.setOpacity(this.element, 0.60);
		}
		
		var event = window.event || e;
		var mouseXY = ajax.Event.getMouseXY(event);
		var newXY = {
			x: mouseXY.x - this.diff.x,
			y: mouseXY.y - this.diff.y
		}
		ajax.GUI.setXY(this.element, newXY.x, newXY.y);
		
		ajax.Event.stopEvent(event);
	},
	doMouseUp: function(e) {
		if (!this.selected) return;
		
		this.selected = false;
		this.diff = null;
		
		var event = window.event || e;
		if (this.dragging) {
			this.dragging = false;
			ajax.GUI.setOpacity(this.element, 1.0);
		}
		ajax.Event.removeListener(
			document, "mousemove", this.mouseMove);
		ajax.Event.removeListener(
			document, "mouseup", this.mouseUp);
		ajax.Event.stopEvent(event);
	}
}