/**
 * @author mikael emtinger / http://gomo.se/
 * @author mrdoob / http://mrdoob.com/
 * @author alteredq / http://alteredqualia.com/
 * @author khang duong
 * @author erik kitson
 */

THREE.KeyFrameAnimation = function ( data ) {

	this.root = data.node;
	this.data = THREE.AnimationHandler.init( data );
	this.hierarchy = THREE.AnimationHandler.parse( this.root );
	this.currentTime = 0;
	this.timeScale = 0.001;
	this.isPlaying = false;
	this.isPaused = true;
	this.loop = true;

	// initialize to first keyframes

	for ( var h = 0, hl = this.hierarchy.length; h < hl; h ++ ) {

		var keys = this.data.hierarchy[ h ].keys,
			sids = this.data.hierarchy[ h ].sids,
			obj = this.hierarchy[ h ];

		if ( keys.length && sids ) {

			for ( var s = 0; s < sids.length; s ++ ) {

				var sid = sids[ s ],
					next = this.getNextKeyWith( sid, h, 0 );

				if ( next ) {

					next.apply( sid );

				}

			}

			obj.matrixAutoUpdate = false;
			this.data.hierarchy[ h ].node.updateMatrix();
			obj.matrixWorldNeedsUpdate = true;

		}

	}

};

THREE.KeyFrameAnimation.prototype = {

	constructor: THREE.KeyFrameAnimation,

	play: function ( startTime ) {

		this.currentTime = startTime !== undefined ? startTime : 0;

		if ( this.isPlaying === false ) {

			this.isPlaying = true;

			// reset key cache

			var h, hl = this.hierarchy.length,
				object,
				node;

			for ( h = 0; h < hl; h ++ ) {

				object = this.hierarchy[ h ];
				node = this.data.hierarchy[ h ];

				if ( node.animationCache === undefined ) {

					node.animationCache = {};
					node.animationCache.prevKey = null;
					node.animationCache.nextKey = null;
					node.animationCache.originalMatrix = object.matrix;

				}

				var keys = this.data.hierarchy[ h ].keys;

				if ( keys.length > 1 ) {

					node.animationCache.prevKey = keys[ 0 ];
					node.animationCache.nextKey = keys[ 1 ];

					this.startTime = Math.min( keys[ 0 ].time, this.startTime );
					this.endTime = Math.max( keys[ keys.length - 1 ].time, this.endTime );

				}

			}

			this.update( 0 );

		}

		this.isPaused = false;
	},

	stop: function () {

		this.isPlaying = false;
		this.isPaused  = false;

		// reset JIT matrix and remove cache

		for ( var h = 0; h < this.data.hierarchy.length; h ++ ) {

			var obj = this.hierarchy[ h ];
			var node = this.data.hierarchy[ h ];

			if ( node.animationCache !== undefined ) {

				var original = node.animationCache.originalMatrix;

				original.copy( obj.matrix );
				obj.matrix = original;

				delete node.animationCache;

			}

		}

	},

	update: function ( delta ) {

		if ( this.isPlaying === false ) return;

		this.currentTime += delta * this.timeScale;

		//

		var duration = this.data.length;

		if ( this.loop === true && this.currentTime > duration ) {

			this.currentTime %= duration;

		}

		this.currentTime = Math.min( this.currentTime, duration );

		for ( var h = 0, hl = this.hierarchy.length; h < hl; h ++ ) {

			var object = this.hierarchy[ h ];
			var node = this.data.hierarchy[ h ];

			var keys = node.keys,
				animationCache = node.animationCache;


			if ( keys.length ) {

				var prevKey = animationCache.prevKey;
				var nextKey = animationCache.nextKey;

				if ( nextKey.time <= this.currentTime ) {

					while ( nextKey.time < this.currentTime && nextKey.index > prevKey.index ) {

						prevKey = nextKey;
						nextKey = keys[ prevKey.index + 1 ];

					}

					animationCache.prevKey = prevKey;
					animationCache.nextKey = nextKey;

				}

				if ( nextKey.time >= this.currentTime ) {

					prevKey.interpolate( nextKey, this.currentTime );

				} else {

					prevKey.interpolate( nextKey, nextKey.time );

				}

				this.data.hierarchy[ h ].node.updateMatrix();
				object.matrixWorldNeedsUpdate = true;

			}

		}

	},

	getNextKeyWith: function ( sid, h, key ) {

		var keys = this.data.hierarchy[ h ].keys;
		key = key % keys.length;

		for ( ; key < keys.length; key ++ ) {

			if ( keys[ key ].hasTarget( sid ) ) {

				return keys[ key ];

			}

		}

		return keys[ 0 ];

	},

	getPrevKeyWith: function ( sid, h, key ) {

		var keys = this.data.hierarchy[ h ].keys;
		key = key >= 0 ? key : key + keys.length;

		for ( ; key >= 0; key -- ) {

			if ( keys[ key ].hasTarget( sid ) ) {

				return keys[ key ];

			}

		}

		return keys[ keys.length - 1 ];

	}

};