/**
 * com.deviouswork.display.utils.ScrollBar
 * @version 1.0.0
 * @author Joakim Roos | j  at deviouswork dot com 
 * 
 * Bases on com.jeroenwijering.utils.Scrollbar - but allowing any displayobject
 * to be scrolled and using any graphics as a scroll.
 * (http://developer.longtailvideo.com/trac/browser/trunk/as3/com/jeroenwijering/utils/Scrollbar.as)
 * 
 * Copyright (c) 2009 Deviouswork
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
package com.deviouswork.display.utils {
 
	import flash.display.DisplayObject;
	import flash.display.MovieClip;
	import flash.display.Sprite;
	import flash.events.Event;
	import flash.events.MouseEvent;		
 
	/**
	 * ScrollBar
	 */
	public class ScrollBar {
 
 
 
		private var _scroll : Sprite;
		private var _scrollBar : DisplayObject;
		private var _scrollTrack : DisplayObject;
		private var _scrollTarget : DisplayObject;
		private var _mask : DisplayObject;
		private var _proportions_num : Number;
 
 
		/*
		 * STATIC vars unused at the moment.
		 */
 
		public static var VERTICAL : String = "vertical";
		public static var HORIZONTAL : String = "horizontal";
 
		/**
		 * Constructor
		 * 
		 * @param target	DisplayObject to scroll.
		 * @param mask		DisplayObject that masks the target.
		 * @param bar		DisplayObject used as graphic representation of the scrollbar.
		 * @param track		DisplayObject used to guide the bar.
		 */
		public function ScrollBar(target : DisplayObject, mask : DisplayObject, bar : DisplayObject, track : DisplayObject) : void {
			_scrollTarget = target;
			_mask = mask;
			_scrollBar = bar;
			_scrollTrack = track;
			MovieClip(_scrollTrack.parent).removeChild(_scrollTrack);
			MovieClip(_scrollBar.parent).removeChild(_scrollBar);
			_scroll = new Sprite();
			_scrollTrack.x = 0;
			_scrollTrack.y = 0;
			_scrollBar.x = 0;
			_scrollBar.y = 0;
			_scroll.addChild(_scrollTrack);
			_scroll.addChild(_scrollBar);
			MovieClip(_scrollTarget.parent).addChild(_scroll);
			_scroll.buttonMode = true;
		};
 
		/**
		 * Add events for the scroll and sets the correct proportions.
		 */
		public function draw() : void {
			_scrollTarget.y = _mask.y;
			_scroll.x = _mask.x + _mask.width + _scrollTrack.width/4;
			_scroll.y = _mask.y;
			_proportions_num = _mask.height / _scrollTarget.height;
			if(_proportions_num < 1) {
				_scroll.visible = true;
				_scrollTrack.height = _mask.height;
				_scrollBar.height = _mask.height * _proportions_num;
				var hitShape : Sprite = new Sprite();
				hitShape.graphics.beginFill(0xfff000, 0);
				hitShape.graphics.drawRect(_scrollTrack.x, _scrollTrack.y, _scrollTrack.width * 2, _scrollTrack.height);
				hitShape.graphics.endFill();
				hitShape.x = -_scrollTrack.width/ 4;
				_scroll.addChild(hitShape);
				_scroll.addEventListener(MouseEvent.MOUSE_DOWN, _onMouseDown);
			} else {
				_scroll.visible = false;
				_scroll.removeEventListener(MouseEvent.MOUSE_DOWN, _onMouseDown);
			}
		};
 
		/**
		 * Event Handlers
		 */
 
		private function _onMouseDown(event_m : MouseEvent) : void {
			_scroll.addEventListener(Event.ENTER_FRAME, _onScrollTarget);
			_mask.stage.addEventListener(MouseEvent.MOUSE_UP, _onMouseUp);
		};
 
		private function _onMouseUp(event_m : MouseEvent) : void {
			_scroll.removeEventListener(Event.ENTER_FRAME, _onScrollTarget);
			_mask.stage.removeEventListener(MouseEvent.MOUSE_UP, _onMouseUp);
		};
 
		private function _onScrollTarget(event : Event) : void {
			var mps : Number = _scroll.mouseY;
			if(mps < _scrollBar.height / 2) {
				_scrollBar.y = 0;
				_scrollTarget.y = _mask.y;
			} else if (mps > _scroll.height - _scrollBar.height / 2) {
				_scrollBar.y = _scroll.height - _scrollBar.height;
				_scrollTarget.y = _mask.y + _mask.height - _scrollTarget.height;
			} else {
				_scrollBar.y = mps - _scrollBar.height / 2;
				_scrollTarget.y = _mask.y + _mask.height / 2 - mps / _proportions_num;
			}
		};
	}
}