/*
* RotationPlugin
* Visit http://createjs.com/ for documentation, updates and examples.
*
* Copyright (c) 2010 gskinner.com, inc.
*
* 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.
*/

/**
 * @module TweenJS
 */

this.createjs = this.createjs||{};

(function() {
	"use strict";

	/**
	 * The RotationPlugin for TweenJS modifies tweens of rotation properties. These properties can be changed when calling
	 * `install`. Install using:
	 * 
	 * 	RotationPlugin.install(props);
	 * 
	 * After installation, by default all rotation tweens will rotate in the shortest direction. For example, if you
	 * tween from `rotation=15` to `rotation=330`, it will rotate counter-clockwise 45 degrees. You can modify this behaviour by
	 * specifying a `rotationDir` tween value. A value of `-1` will force CCW rotation, `1` will force CW, and `0` will
	 * disable the plugin effects for that portion of the tween.
	 * 
	 * Note that the `rotationDir` value will persist until overridden in future `to` calls. Set it to null to re-enable the default behavior.
	 * 
	 * 	// this tween will rotate: CCW, then CCW (because rotationDir persists), then CW.
	 * 	myTween.get(foo).to({rotation:30, rotationDir:-1}).to({rotation:60}).to({rotation:10, rotationDir:1});
	 * 
	 * You can also disable the plugin completely for a tween by setting `tween.pluginData.Rotation_disabled=true`.
	 * 
	 * @class RotationPlugin
	 * @static
	 **/
	function RotationPlugin() {
		throw("Rotation plugin cannot be instantiated.")
	}
	var s = RotationPlugin;
	
	/**
	 * @property _props
	 * @type {Object}
	 * @static
	 * @protected
	 **/
	s._props = {rotation:1, rotationX:1, rotationY:1, rotationZ:1};
	
	/**
	 * READ-ONLY. A unique identifying string for this plugin. Used by TweenJS to ensure duplicate plugins are not installed on a tween.
	 * @property ID
	 * @type {String}
	 * @static
	 * @readonly
	 **/
	s.ID = "Rotation";

	/**
	 * Installs this plugin for use with TweenJS. Call this once after TweenJS is loaded to enable this plugin.
	 * @method install
	 * @param {Object} props An object defining the properties this plugin acts on. For example, passing `{angle:true}`
	 * will cause the plugin to only act on the `angle` property. By default the properties are `rotation`
	 * `rotationX`, `rotationY`, and `rotationZ`.
	 * @static
	 **/
	s.install = function(props) {
		if (props) { s._props = props; }
		createjs.Tween._installPlugin(RotationPlugin);
	};
	
	/**
	 * Called by TweenJS when a new property initializes on a tween.
	 * See {{#crossLink "SamplePlugin/init"}}{{/crossLink}} for more info.
	 * @method init
	 * @param {Tween} tween
	 * @param {String} prop
	 * @param {any} value
	 * @return {any}
	 * @static
	 **/
	s.init = function(tween, prop, value) {
		if (s._props[prop] && !tween.pluginData.Rotation_disabled) {
			var data = tween.pluginData, end = data.Rotation_end || (data.Rotation_end = {});
			end[prop] = value === undefined ? tween.target[prop] : value;
			tween._addPlugin(s);
		}
	};
	
	/**
	 * Called when a new step is added to a tween (ie. a new "to" action is added to a tween).
	 * See {{#crossLink "SamplePlugin/step"}}{{/crossLink}} for more info.
	 * @method step
	 * @param {Tween} tween
	 * @param {TweenStep} step
	 * @param {Object} props
	 * @static
	 **/
	s.step = function(tween, step, props) {
		for (var n in s._props) {
			if (props[n] === undefined) { continue; }
			
			var dir = step.props.rotationDir, value = props[n];
			var data = tween.pluginData, end = data.Rotation_end;
			var start = step.prev.props[n];
			
			if (dir === 0) {
				step.props[n] = value-end[n]+start;
			} else {
				dir = dir || 0;
				var delta = (value - start) % 360;

				if ((dir === 0 && delta > 180) || (dir === -1 && delta > 0)) { delta -= 360; }
				else if ((dir === 0 && delta < -180) || (dir === 1 && delta < 0)) { delta += 360; }

				step.props[n] = start + delta;
			}
			end[n] = value;
		}
	};

	/**
	 * Called before a property is updated by the tween.
	 * See {{#crossLink "SamplePlugin/change"}}{{/crossLink}} for more info.
	 * @method change
	 * @param {Tween} tween
	 * @param {TweenStep} step
	 * @param {String} prop
	 * @param {any} value
	 * @param {Number} ratio
	 * @param {Boolean} end
	 * @return {any}
	 * @static
	 **/
	s.change = function(tween, step, prop, value, ratio, end) {
		if (prop === "rotationDir") { return createjs.Tween.IGNORE; }
		if (end && s._props[prop]) { return tween.pluginData.Rotation_end; } // so it ends on the actual value.
	};

	createjs.RotationPlugin = s;
}());