aowow/template/js/Draggable.js

var Draggable = new function () {
	var
        start = {},
        mouse = {},
        clickObj,
        dragObj;

    function onMouseDown(e) {
		e = $E(e);

		if (this._handle) {
			var _ = e._target,
			found = false,
			i = 0;

			while (_ && i <= 3) {
				if (_ == this._handle) {
					found = true;
					break;
				}

				_ = _.parentNode;
                ++i;
			}

			if (!found) {
				return false;
			}
		}

		clickObj = this;

		start = g_getCursorPos(e);

		aE(document, 'mousemove', onMouseMove);
		aE(document, 'mouseup', onMouseUp);

		if (clickObj.onClick) {
			clickObj.onClick(e, clickObj);
		}

		return false;
	}

	function onMouseMove(e) {
		e = $E(e);

		var pos = g_getCursorPos(e);

		if (clickObj) {
			if (Math.abs(pos.x - start.x) > 5 || Math.abs(pos.y - start.y) > 5) {
				onDragStart(e, clickObj);
				clickObj = null;
			}
		}

        if (!dragObj || !dragObj._bounds) {
			return false;
		}

        var
            bounds = getBounds(dragObj),
            dX     = pos.x - start.x,
            dY     = pos.y - start.y;

        dX = Math.max(dragObj._bounds.x1 - mouse.x, Math.min(dragObj._bounds.x2 - mouse.x - (bounds.x2 - bounds.x1), dX));
		dY = Math.max(dragObj._bounds.y1 - mouse.y, Math.min(dragObj._bounds.y2 - mouse.y - (bounds.y2 - bounds.y1), dY));

		setPosition(dX, dY);

		return false;
	}

	function onMouseUp(e) {
		e = $E(e);

		clickObj = null;

		if (dragObj) {
			onDragEnd(e);
		}
	}

	function onDragStart(e, obj) {
		if (dragObj) {
			onDragEnd(e);
		}

		var foo = ac(obj);
		mouse.x = foo[0];
		mouse.y = foo[1];

		if (obj._targets.length) {
			dragObj = obj.cloneNode(true);
			dragObj._orig = obj;

			ae(ge('layers'), dragObj);
			// ae(document.body, dragObj); // 5.0.. why does it do that?
			setPosition(-2323, -2323);
		}
        else {
			dragObj = obj;
		}

		Tooltip.disabled = true;
		Tooltip.hide();

		if (obj.onDrag) {
			obj.onDrag(e, dragObj, obj);
		}

		dragObj._bounds = getBounds(obj._container);
		dragObj.className += ' dragged';
	}

	function onDragEnd(e) {
		var
            found = false,
            cursor = g_getCursorPos(e);

        if (dragObj._orig && dragObj._orig._targets.length) {
			clearPosition();

			var pos = {
				x1: dragObj._x,
				x2: dragObj._x + parseInt(dragObj.offsetWidth),
				y1: dragObj._y,
				y2: dragObj._y + parseInt(dragObj.offsetHeight)
			};

			de(dragObj);
			dragObj = dragObj._orig;

			for (var i = 0, len = dragObj._targets.length; i < len; ++i) {
				var targObj = dragObj._targets[i],
				bounds = getBounds(targObj);

				if (pos.x2 >= bounds.x1 && pos.x1 < bounds.x2 && pos.y2 >= bounds.y1 && pos.y1 < bounds.y2) {
					found = true;
					if (dragObj.onDrop) {
						dragObj.onDrop(e, dragObj, targObj, (cursor.x >= bounds.x1 && cursor.x <= bounds.x2 && cursor.y >= bounds.y1 && cursor.y <= bounds.y2));
					}
                    else {
						ae(targObj, dragObj);
					}
				}
			}
		}

		if (!found && dragObj.onDrop) {
			dragObj.onDrop(e, dragObj, null);
		}

		dE(document, 'mousemove', onMouseMove);
		dE(document, 'mouseup', onMouseUp);

		Tooltip.disabled = false;

		dragObj.className = dragObj.className.replace(/dragged/, '');
		dragObj = null;
	}

	function setPosition(dX, dY) {
		dragObj.style.position = 'absolute';
		dragObj.style.left = mouse.x + dX + 'px';
		dragObj.style.top = mouse.y + dY + 'px';

		dragObj._x = mouse.x + dX;
		dragObj._y = mouse.y + dY;
	}

	function clearPosition() {
		dragObj.style.left = '-2323px';
		dragObj.style.top = '-2323px';
	}

	function getBounds(obj) {
		var pos = ac(obj);

		return {
			x1: pos[0],
			x2: pos[0] + parseInt(obj.offsetWidth),
			y1: pos[1],
			y2: pos[1] + parseInt(obj.offsetHeight)
		};
	}

	this.init = function (obj, opt) {
		obj.onmousedown = onMouseDown;

		var a = obj.getElementsByTagName('a');
		for (var i = 0, len = a.length; i < len; ++i) {
			ns(a[i]);
		}

		if (!obj._targets) {
			obj._targets = [];
		}

		if (!obj._container) {
			obj._container = document.body;
		}

		if (opt != null) {
			if (opt.targets) {
				for (var i = 0, len = opt.targets.length; i < len; ++i) {
					obj._targets.push(ge(opt.targets[i]));
				}
			}

			if (opt.container) {
				obj._container = $(opt.container);
			}

			// Functions
			if (opt.onClick) {
				obj.onClick = opt.onClick;
			}

			if (opt.onDrop) {
				obj.onDrop = opt.onDrop;
			}

			if (opt.onDrag) {
				obj.onDrag = opt.onDrag;
			}
		}
	}
};