// Version: 1.20
// Date: 2007-01-25
// Author: CrazyDave
// Website: http://www.clanccc.co.uk/moo/nested.html
var Nested = new Class({
	getOptions: function() {
		return {
			childTag: 'LI',
			ghost: true,
			childStep: 60, // attempts to become a child if the mouse is moved this number of pixels right
			handleClass: null, 
			onStart: Class.empty,
			onComplete: Class.empty,
			collapse: false, // true/false
			collapseClass: 'nCollapse', // Class added to collapsed items
			expandKey: 'shift', // control | shift
			lock: null, // parent || depth || class
			lockClass: 'unlocked'
		};
	},

	initialize: function(list, options) {
		this.setOptions(this.getOptions(), options);
		if (!this.options.expandKey.match(/^(control|shift)$/)) {
			this.options.expandKey = 'shift';
		}
		this.list = $(list);
		this.options.parentTag = this.list.nodeName;
		this.bound = {};
		this.bound.start = this.start.bindWithEvent(this);
		this.list.addEvent('mousedown', this.bound.start);
		if (this.options.collapse) {
			this.bound.collapse = this.collapse.bindWithEvent(this);
			//this.list.addEvent('click', this.bound.collapse);
		}
		if (this.options.initialize) this.options.initialize.call(this);
	},

	start: function(event) {
		var el = $(event.target);
		if (this.options.handleClass) {
			while (el.nodeName != this.options.childTag && !el.hasClass(this.options.handleClass) && el != this.list) {
				el = el.getParent();
			}
			if (!el.hasClass(this.options.handleClass)) return true;
		} 
		while (el.nodeName != this.options.childTag && el != this.list) {
			el = el.parentNode;
		}
		if (el.nodeName != this.options.childTag) return true;
		el = $(el);
		if (this.options.lock == 'class' && !el.hasClass(this.options.lockClass)) return;
		if (this.options.ghost) { // Create the ghost
			this.ghost = el.clone().setStyles({
				'list-style-type': 'none',
				'opacity': 0.5,
				'position': 'absolute',
				'visibility': 'hidden',
				'top': event.page.y+'px',
				'left': (event.page.x+10)+'px'
			}).injectInside(document.body);
		}
		el.depth = this.getDepth(el);
		el.moved = false;
		this.bound.movement = this.movement.bindWithEvent(this, el);
		this.bound.end = this.end.bind(this, el);
		this.list.removeEvent('mousedown', this.bound.start);
		this.list.addEvent('mousedown', this.bound.end);
		this.list.addEvent('mousemove', this.bound.movement);
		document.addEvent('mouseup', this.bound.end);
		if (window.ie) { // IE fix to stop selection of text when dragging
			this.bound.stop = this.stop.bindWithEvent(this);
			$(document.body).addEvent('drag', this.bound.stop).addEvent('selectstart', this.bound.stop);
		}
		this.fireEvent('onStart', el);
		event.stop();
	},

	collapse: function(event) {
		var el = $(event.target);
		if (this.options.handleClass) {
			while (el.nodeName != this.options.childTag && !el.hasClass(this.options.handleClass) && el != this.list) {
				el = el.getParent();
			}
			if (!el.hasClass(this.options.handleClass)) return true;
		} 
		while (el.nodeName != this.options.childTag && el != this.list) {
			el = el.parentNode;
		}
		if (el == this.list) return;
		el = $(el);
		if (!el.moved) {
			var sub = $E(this.options.parentTag, el);
			if (sub) {
				if (sub.getStyle('display') == 'none') {
					sub.setStyle('display', 'block');
					el.removeClass(this.options.collapseClass);
				} else {
					sub.setStyle('display', 'none');
					el.addClass(this.options.collapseClass);
				}
			}
		}
		event.stop();
	},
	
	stop: function(event) {
		event.stop();
		return false;
	},
	
	getDepth: function(el, add) {
		var counter = (add) ? 1 : 0;
		while (el != this.list) {
			if (el.nodeName == this.options.parentTag) counter += 1;
			el = el.parentNode;
		}
		return counter;
	},
	
	movement: function(event, el) {
		var dir, over, check, items;
		var dest, move, prev, prevParent;
		var abort = false;
		if (this.options.ghost && el.moved) { // Position the ghost
			this.ghost.setStyles({
				'position': 'absolute',
				'visibility': 'visible',
				'top': event.page.y+'px',
				'left': (event.page.x+10)+'px'
			});
		}
		over = event.target;
		while (over.nodeName != this.options.childTag && over != this.list) {
			over = over.parentNode;
		}
		if (over == this.list) return;
		if (event[this.options.expandKey] && over != el && over.hasClass(this.options.collapseClass)) {
			check = $E(this.options.parentTag, over);
			over.removeClass(this.options.collapseClass);
			check.setStyle('display', 'block');
		}
		// Check if it's actually inline with a child element of the event firer
		orig = over;
		if (el != over) {
			items = $ES(this.options.childTag, over);
			items.each(function(item) {
				if (event.page.y > item.getTop() && item.offsetHeight > 0) over = item;
			});
		}
		// Make sure we end up with a childTag element
		if (over.nodeName != this.options.childTag) return;
			
		// store the previous parent 'ol' to remove it if a move makes it empty
		prevParent = el.getParent();
		dir = (event.page.y < el.getTop()) ? 'up' : 'down';
		move = 'before';
		dest = el;

		if (el != over) {
			check = over;
			while (check != null && check != el) {
				check = check.parentNode;
			} // Make sure we're not trying to move something below itself
			if (check == el) return;
			if (dir == 'up') {
				move = 'before'; dest = over;
			} else {
				sub = $E(this.options.childTag, over);
				if (sub && sub.offsetHeight > 0) {
					move = 'before'; dest = sub;
				} else {
					move = 'after'; dest = over;
				}
			}
		}

		// Check if we're trying to go deeper -->>
		prev = (move == 'before') ? dest.getPrevious() : dest;
		if (prev) {
			move = 'after';
			dest = prev;
			check = $E(this.options.parentTag, dest);
			while (check && event.page.x > check.getLeft() && check.offsetHeight > 0) {
				dest = check.getLast();
				check = $E(this.options.parentTag, dest);
			}
			if (!check && event.page.x > dest.getLeft()+this.options.childStep) {
				move = 'inside';
			}
		}

		last = dest.getParent().getLast();
		while (((move == 'after' && last == dest) || last == el) && dest.getParent() != this.list && event.page.x < dest.getLeft()) {
			move = 'after';
			dest = $(dest.parentNode.parentNode);
			last = dest.getParent().getLast();
		}
		
		abort = false;
		if (move != '') {
			abort += (dest == el);
			abort += (move == 'after' && dest.getNext() == el);
			abort += (move == 'before' && dest.getPrevious() == el);
			abort += (this.options.lock == 'depth' && el.depth != this.getDepth(dest, (move == 'inside')));
			abort += (this.options.lock == 'parent' && (move == 'inside' || dest.parentNode != el.parentNode));
			abort += (dest.offsetHeight == 0);
			sub = $E(this.options.parentTag, over);
			sub = (sub) ? sub.getTop() : 0;
			sub = (sub > 0) ? sub-over.getTop() : over.offsetHeight;
			abort += (event.page.y < (sub-el.offsetHeight)+over.getTop());
			if (!abort) {
				if (move == 'inside') dest = new Element(this.options.parentTag).injectInside(dest);
				$(el).inject(dest, move);
				el.moved = true;
				if (!prevParent.getFirst()) prevParent.remove();
			}
		}
		event.stop();
	},

	detach: function() {
		this.list.removeEvent('mousedown', this.start.bindWithEvent(this));
		if (this.options.collapse) this.list.removeEvent('click', this.bound.collapse);
	},

	serialize: function(listEl) {
		var serial = [];
		var kids;
		if (!listEl) listEl = this.list;
		$$(listEl.childNodes).each(function(node, i) {
			kids = $E('ul', node); /* set 'this.options.parentTag' straight to 'ul' to avoid safari bug */
			serial[i] = {
				id: node.id,
				hide: (node.hasClass('remove')) ? 'exclude' : "",
				children: (kids) ? this.serialize(kids) : []
			};
		}.bind(this));
		return serial;
	},

	end: function(el) {
		if (this.options.ghost) this.ghost.remove();
		this.list.removeEvent('mousemove', this.bound.movement);
		document.removeEvent('mouseup', this.bound.end);
		this.list.removeEvent('mousedown', this.bound.end);
		this.list.addEvent('mousedown', this.bound.start);
		this.fireEvent('onComplete', el);
		if (window.ie) $(document.body).removeEvent('drag', this.bound.stop).removeEvent('selectstart', this.bound.stop);
	}
});

Nested.implement(new Events);
Nested.implement(new Options);