import { IEasingFunction, EasingFunction } from "./easing";
import { Vector3, Quaternion, Vector2, Color3, Size, Matrix } from "../Maths/math";
import { Scalar } from "../Maths/math.scalar";

import { Nullable } from "../types";
import { Scene } from "../scene";
import { IAnimatable } from "../Misc/tools";
import { SerializationHelper } from "../Misc/decorators";
import { _TypeStore } from '../Misc/typeStore';
import { IAnimationKey, AnimationKeyInterpolation } from './animationKey';
import { AnimationRange } from './animationRange';
import { AnimationEvent } from './animationEvent';
import { Node } from "../node";

declare type Animatable = import("./animatable").Animatable;
declare type RuntimeAnimation = import("./runtimeAnimation").RuntimeAnimation;

/**
 * Class used to store any kind of animation
 */
export class Animation {
    /**
     * Use matrix interpolation instead of using direct key value when animating matrices
     */
    public static AllowMatricesInterpolation = false;

    /**
     * When matrix interpolation is enabled, this boolean forces the system to use Matrix.DecomposeLerp instead of Matrix.Lerp. Interpolation is more precise but slower
     */
    public static AllowMatrixDecomposeForInterpolation = true;

    /**
     * Stores the key frames of the animation
     */
    private _keys: Array<IAnimationKey>;

    /**
     * Stores the easing function of the animation
     */
    private _easingFunction: IEasingFunction;

    /**
     * @hidden Internal use only
     */
    public _runtimeAnimations = new Array<RuntimeAnimation>();

    /**
     * The set of event that will be linked to this animation
     */
    private _events = new Array<AnimationEvent>();

    /**
     * Stores an array of target property paths
     */
    public targetPropertyPath: string[];

    /**
     * Stores the blending speed of the animation
     */
    public blendingSpeed = 0.01;

    /**
     * Stores the animation ranges for the animation
     */
    private _ranges: { [name: string]: Nullable<AnimationRange> } = {};

    /**
     * @hidden Internal use
     */
    public static _PrepareAnimation(name: string, targetProperty: string, framePerSecond: number, totalFrame: number,
        from: any, to: any, loopMode?: number, easingFunction?: EasingFunction): Nullable<Animation> {
        var dataType = undefined;

        if (!isNaN(parseFloat(from)) && isFinite(from)) {
            dataType = Animation.ANIMATIONTYPE_FLOAT;
        } else if (from instanceof Quaternion) {
            dataType = Animation.ANIMATIONTYPE_QUATERNION;
        } else if (from instanceof Vector3) {
            dataType = Animation.ANIMATIONTYPE_VECTOR3;
        } else if (from instanceof Vector2) {
            dataType = Animation.ANIMATIONTYPE_VECTOR2;
        } else if (from instanceof Color3) {
            dataType = Animation.ANIMATIONTYPE_COLOR3;
        } else if (from instanceof Size) {
            dataType = Animation.ANIMATIONTYPE_SIZE;
        }

        if (dataType == undefined) {
            return null;
        }

        var animation = new Animation(name, targetProperty, framePerSecond, dataType, loopMode);

        var keys: Array<IAnimationKey> = [{ frame: 0, value: from }, { frame: totalFrame, value: to }];
        animation.setKeys(keys);

        if (easingFunction !== undefined) {
            animation.setEasingFunction(easingFunction);
        }

        return animation;
    }

    /**
     * Sets up an animation
     * @param property The property to animate
     * @param animationType The animation type to apply
     * @param framePerSecond The frames per second of the animation
     * @param easingFunction The easing function used in the animation
     * @returns The created animation
     */
    public static CreateAnimation(property: string, animationType: number, framePerSecond: number, easingFunction: EasingFunction): Animation {
        var animation: Animation = new Animation(property + "Animation",
            property,
            framePerSecond,
            animationType,
            Animation.ANIMATIONLOOPMODE_CONSTANT);

        animation.setEasingFunction(easingFunction);

        return animation;
    }

    /**
     * Create and start an animation on a node
     * @param name defines the name of the global animation that will be run on all nodes
     * @param node defines the root node where the animation will take place
     * @param targetProperty defines property to animate
     * @param framePerSecond defines the number of frame per second yo use
     * @param totalFrame defines the number of frames in total
     * @param from defines the initial value
     * @param to defines the final value
     * @param loopMode defines which loop mode you want to use (off by default)
     * @param easingFunction defines the easing function to use (linear by default)
     * @param onAnimationEnd defines the callback to call when animation end
     * @returns the animatable created for this animation
     */
    public static CreateAndStartAnimation(name: string, node: Node, targetProperty: string,
        framePerSecond: number, totalFrame: number,
        from: any, to: any, loopMode?: number, easingFunction?: EasingFunction, onAnimationEnd?: () => void): Nullable<Animatable> {

        var animation = Animation._PrepareAnimation(name, targetProperty, framePerSecond, totalFrame, from, to, loopMode, easingFunction);

        if (!animation) {
            return null;
        }

        return node.getScene().beginDirectAnimation(node, [animation], 0, totalFrame, (animation.loopMode === 1), 1.0, onAnimationEnd);
    }

    /**
     * Create and start an animation on a node and its descendants
     * @param name defines the name of the global animation that will be run on all nodes
     * @param node defines the root node where the animation will take place
     * @param directDescendantsOnly if true only direct descendants will be used, if false direct and also indirect (children of children, an so on in a recursive manner) descendants will be used
     * @param targetProperty defines property to animate
     * @param framePerSecond defines the number of frame per second to use
     * @param totalFrame defines the number of frames in total
     * @param from defines the initial value
     * @param to defines the final value
     * @param loopMode defines which loop mode you want to use (off by default)
     * @param easingFunction defines the easing function to use (linear by default)
     * @param onAnimationEnd defines the callback to call when an animation ends (will be called once per node)
     * @returns the list of animatables created for all nodes
     * @example https://www.babylonjs-playground.com/#MH0VLI
     */
    public static CreateAndStartHierarchyAnimation(name: string, node: Node, directDescendantsOnly: boolean, targetProperty: string,
        framePerSecond: number, totalFrame: number,
        from: any, to: any, loopMode?: number, easingFunction?: EasingFunction, onAnimationEnd?: () => void): Nullable<Animatable[]> {

        var animation = Animation._PrepareAnimation(name, targetProperty, framePerSecond, totalFrame, from, to, loopMode, easingFunction);

        if (!animation) {
            return null;
        }

        let scene = node.getScene();
        return scene.beginDirectHierarchyAnimation(node, directDescendantsOnly, [animation], 0, totalFrame, (animation.loopMode === 1), 1.0, onAnimationEnd);
    }

    /**
     * Creates a new animation, merges it with the existing animations and starts it
     * @param name Name of the animation
     * @param node Node which contains the scene that begins the animations
     * @param targetProperty Specifies which property to animate
     * @param framePerSecond The frames per second of the animation
     * @param totalFrame The total number of frames
     * @param from The frame at the beginning of the animation
     * @param to The frame at the end of the animation
     * @param loopMode Specifies the loop mode of the animation
     * @param easingFunction (Optional) The easing function of the animation, which allow custom mathematical formulas for animations
     * @param onAnimationEnd Callback to run once the animation is complete
     * @returns Nullable animation
     */
    public static CreateMergeAndStartAnimation(name: string, node: Node, targetProperty: string,
        framePerSecond: number, totalFrame: number,
        from: any, to: any, loopMode?: number, easingFunction?: EasingFunction, onAnimationEnd?: () => void): Nullable<Animatable> {

        var animation = Animation._PrepareAnimation(name, targetProperty, framePerSecond, totalFrame, from, to, loopMode, easingFunction);

        if (!animation) {
            return null;
        }

        node.animations.push(animation);

        return node.getScene().beginAnimation(node, 0, totalFrame, (animation.loopMode === 1), 1.0, onAnimationEnd);
    }

    /**
     * Transition property of an host to the target Value
     * @param property The property to transition
     * @param targetValue The target Value of the property
     * @param host The object where the property to animate belongs
     * @param scene Scene used to run the animation
     * @param frameRate Framerate (in frame/s) to use
     * @param transition The transition type we want to use
     * @param duration The duration of the animation, in milliseconds
     * @param onAnimationEnd Callback trigger at the end of the animation
     * @returns Nullable animation
     */
    public static TransitionTo(property: string, targetValue: any, host: any, scene: Scene, frameRate: number, transition: Animation, duration: number, onAnimationEnd: Nullable<() => void> = null): Nullable<Animatable> {
        if (duration <= 0) {
            host[property] = targetValue;
            if (onAnimationEnd) {
                onAnimationEnd();
            }
            return null;
        }

        var endFrame: number = frameRate * (duration / 1000);

        transition.setKeys([{
            frame: 0,
            value: host[property].clone ? host[property].clone() : host[property]
        },
        {
            frame: endFrame,
            value: targetValue
        }]);

        if (!host.animations) {
            host.animations = [];
        }

        host.animations.push(transition);

        var animation: Animatable = scene.beginAnimation(host, 0, endFrame, false);
        animation.onAnimationEnd = onAnimationEnd;
        return animation;
    }

    /**
     * Return the array of runtime animations currently using this animation
     */
    public get runtimeAnimations(): RuntimeAnimation[] {
        return this._runtimeAnimations;
    }

    /**
     * Specifies if any of the runtime animations are currently running
     */
    public get hasRunningRuntimeAnimations(): boolean {
        for (var runtimeAnimation of this._runtimeAnimations) {
            if (!runtimeAnimation.isStopped) {
                return true;
            }
        }

        return false;
    }

    /**
     * Initializes the animation
     * @param name Name of the animation
     * @param targetProperty Property to animate
     * @param framePerSecond The frames per second of the animation
     * @param dataType The data type of the animation
     * @param loopMode The loop mode of the animation
     * @param enableBlending Specifies if blending should be enabled
     */
    constructor(
        /**Name of the animation */
        public name: string,
        /**Property to animate */
        public targetProperty: string,
        /**The frames per second of the animation */
        public framePerSecond: number,
        /**The data type of the animation */
        public dataType: number,
        /**The loop mode of the animation */
        public loopMode?: number,
        /**Specifies if blending should be enabled */
        public enableBlending?: boolean) {
        this.targetPropertyPath = targetProperty.split(".");
        this.dataType = dataType;
        this.loopMode = loopMode === undefined ? Animation.ANIMATIONLOOPMODE_CYCLE : loopMode;
    }

    // Methods
    /**
     * Converts the animation to a string
     * @param fullDetails support for multiple levels of logging within scene loading
     * @returns String form of the animation
     */
    public toString(fullDetails?: boolean): string {
        var ret = "Name: " + this.name + ", property: " + this.targetProperty;
        ret += ", datatype: " + (["Float", "Vector3", "Quaternion", "Matrix", "Color3", "Vector2"])[this.dataType];
        ret += ", nKeys: " + (this._keys ? this._keys.length : "none");
        ret += ", nRanges: " + (this._ranges ? Object.keys(this._ranges).length : "none");
        if (fullDetails) {
            ret += ", Ranges: {";
            var first = true;
            for (var name in this._ranges) {
                if (first) {
                    ret += ", ";
                    first = false;
                }
                ret += name;
            }
            ret += "}";
        }
        return ret;
    }

    /**
     * Add an event to this animation
     * @param event Event to add
     */
    public addEvent(event: AnimationEvent): void {
        this._events.push(event);
    }

    /**
     * Remove all events found at the given frame
     * @param frame The frame to remove events from
     */
    public removeEvents(frame: number): void {
        for (var index = 0; index < this._events.length; index++) {
            if (this._events[index].frame === frame) {
                this._events.splice(index, 1);
                index--;
            }
        }
    }

    /**
     * Retrieves all the events from the animation
     * @returns Events from the animation
     */
    public getEvents(): AnimationEvent[] {
        return this._events;
    }

    /**
     * Creates an animation range
     * @param name Name of the animation range
     * @param from Starting frame of the animation range
     * @param to Ending frame of the animation
     */
    public createRange(name: string, from: number, to: number): void {
        // check name not already in use; could happen for bones after serialized
        if (!this._ranges[name]) {
            this._ranges[name] = new AnimationRange(name, from, to);
        }
    }

    /**
     * Deletes an animation range by name
     * @param name Name of the animation range to delete
     * @param deleteFrames Specifies if the key frames for the range should also be deleted (true) or not (false)
     */
    public deleteRange(name: string, deleteFrames = true): void {
        let range = this._ranges[name];
        if (!range) {
            return;

        }
        if (deleteFrames) {
            var from = range.from;
            var to = range.to;

            // this loop MUST go high to low for multiple splices to work
            for (var key = this._keys.length - 1; key >= 0; key--) {
                if (this._keys[key].frame >= from && this._keys[key].frame <= to) {
                    this._keys.splice(key, 1);
                }
            }
        }
        this._ranges[name] = null; // said much faster than 'delete this._range[name]'

    }

    /**
     * Gets the animation range by name, or null if not defined
     * @param name Name of the animation range
     * @returns Nullable animation range
     */
    public getRange(name: string): Nullable<AnimationRange> {
        return this._ranges[name];
    }

    /**
     * Gets the key frames from the animation
     * @returns The key frames of the animation
     */
    public getKeys(): Array<IAnimationKey> {
        return this._keys;
    }

    /**
     * Gets the highest frame rate of the animation
     * @returns Highest frame rate of the animation
     */
    public getHighestFrame(): number {
        var ret = 0;

        for (var key = 0, nKeys = this._keys.length; key < nKeys; key++) {
            if (ret < this._keys[key].frame) {
                ret = this._keys[key].frame;
            }
        }
        return ret;
    }

    /**
     * Gets the easing function of the animation
     * @returns Easing function of the animation
     */
    public getEasingFunction(): IEasingFunction {
        return this._easingFunction;
    }

    /**
     * Sets the easing function of the animation
     * @param easingFunction A custom mathematical formula for animation
     */
    public setEasingFunction(easingFunction: EasingFunction): void {
        this._easingFunction = easingFunction;
    }

    /**
     * Interpolates a scalar linearly
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated scalar value
     */
    public floatInterpolateFunction(startValue: number, endValue: number, gradient: number): number {
        return Scalar.Lerp(startValue, endValue, gradient);
    }

    /**
     * Interpolates a scalar cubically
     * @param startValue Start value of the animation curve
     * @param outTangent End tangent of the animation
     * @param endValue End value of the animation curve
     * @param inTangent Start tangent of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated scalar value
     */
    public floatInterpolateFunctionWithTangents(startValue: number, outTangent: number, endValue: number, inTangent: number, gradient: number): number {
        return Scalar.Hermite(startValue, outTangent, endValue, inTangent, gradient);
    }

    /**
     * Interpolates a quaternion using a spherical linear interpolation
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated quaternion value
     */
    public quaternionInterpolateFunction(startValue: Quaternion, endValue: Quaternion, gradient: number): Quaternion {
        return Quaternion.Slerp(startValue, endValue, gradient);
    }

    /**
     * Interpolates a quaternion cubically
     * @param startValue Start value of the animation curve
     * @param outTangent End tangent of the animation curve
     * @param endValue End value of the animation curve
     * @param inTangent Start tangent of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated quaternion value
     */
    public quaternionInterpolateFunctionWithTangents(startValue: Quaternion, outTangent: Quaternion, endValue: Quaternion, inTangent: Quaternion, gradient: number): Quaternion {
        return Quaternion.Hermite(startValue, outTangent, endValue, inTangent, gradient).normalize();
    }

    /**
     * Interpolates a Vector3 linearl
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated scalar value
     */
    public vector3InterpolateFunction(startValue: Vector3, endValue: Vector3, gradient: number): Vector3 {
        return Vector3.Lerp(startValue, endValue, gradient);
    }

    /**
     * Interpolates a Vector3 cubically
     * @param startValue Start value of the animation curve
     * @param outTangent End tangent of the animation
     * @param endValue End value of the animation curve
     * @param inTangent Start tangent of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns InterpolatedVector3 value
     */
    public vector3InterpolateFunctionWithTangents(startValue: Vector3, outTangent: Vector3, endValue: Vector3, inTangent: Vector3, gradient: number): Vector3 {
        return Vector3.Hermite(startValue, outTangent, endValue, inTangent, gradient);
    }

    /**
     * Interpolates a Vector2 linearly
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated Vector2 value
     */
    public vector2InterpolateFunction(startValue: Vector2, endValue: Vector2, gradient: number): Vector2 {
        return Vector2.Lerp(startValue, endValue, gradient);
    }

    /**
     * Interpolates a Vector2 cubically
     * @param startValue Start value of the animation curve
     * @param outTangent End tangent of the animation
     * @param endValue End value of the animation curve
     * @param inTangent Start tangent of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated Vector2 value
     */
    public vector2InterpolateFunctionWithTangents(startValue: Vector2, outTangent: Vector2, endValue: Vector2, inTangent: Vector2, gradient: number): Vector2 {
        return Vector2.Hermite(startValue, outTangent, endValue, inTangent, gradient);
    }

    /**
     * Interpolates a size linearly
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated Size value
     */
    public sizeInterpolateFunction(startValue: Size, endValue: Size, gradient: number): Size {
        return Size.Lerp(startValue, endValue, gradient);
    }

    /**
     * Interpolates a Color3 linearly
     * @param startValue Start value of the animation curve
     * @param endValue End value of the animation curve
     * @param gradient Scalar amount to interpolate
     * @returns Interpolated Color3 value
     */
    public color3InterpolateFunction(startValue: Color3, endValue: Color3, gradient: number): Color3 {
        return Color3.Lerp(startValue, endValue, gradient);
    }

    /**
     * @hidden Internal use only
     */
    public _getKeyValue(value: any): any {
        if (typeof value === "function") {
            return value();
        }

        return value;
    }

    /**
     * @hidden Internal use only
     */
    public _interpolate(currentFrame: number, repeatCount: number, workValue?: any, loopMode?: number, offsetValue?: any, highLimitValue?: any): any {
        if (loopMode === Animation.ANIMATIONLOOPMODE_CONSTANT && repeatCount > 0) {
            return highLimitValue.clone ? highLimitValue.clone() : highLimitValue;
        }

        const keys = this._keys;
        if (keys.length === 1) {
            return this._getKeyValue(keys[0].value);
        }

        // Try to get a hash to find the right key
        var startKeyIndex = Math.max(0, Math.min(keys.length - 1, Math.floor(keys.length * (currentFrame - keys[0].frame) / (keys[keys.length - 1].frame - keys[0].frame)) - 1));

        if (keys[startKeyIndex].frame >= currentFrame) {
            while (startKeyIndex - 1 >= 0 && keys[startKeyIndex].frame >= currentFrame) {
                startKeyIndex--;
            }
        }

        for (var key = startKeyIndex; key < keys.length; key++) {
            var endKey = keys[key + 1];

            if (endKey.frame >= currentFrame) {
                var startKey = keys[key];
                var startValue = this._getKeyValue(startKey.value);
                if (startKey.interpolation === AnimationKeyInterpolation.STEP) {
                    return startValue;
                }

                var endValue = this._getKeyValue(endKey.value);

                var useTangent = startKey.outTangent !== undefined && endKey.inTangent !== undefined;
                var frameDelta = endKey.frame - startKey.frame;

                // gradient : percent of currentFrame between the frame inf and the frame sup
                var gradient = (currentFrame - startKey.frame) / frameDelta;

                // check for easingFunction and correction of gradient
                let easingFunction = this.getEasingFunction();
                if (easingFunction != null) {
                    gradient = easingFunction.ease(gradient);
                }

                switch (this.dataType) {
                    // Float
                    case Animation.ANIMATIONTYPE_FLOAT:
                        var floatValue = useTangent ? this.floatInterpolateFunctionWithTangents(startValue, startKey.outTangent * frameDelta, endValue, endKey.inTangent * frameDelta, gradient) : this.floatInterpolateFunction(startValue, endValue, gradient);
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return floatValue;
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return offsetValue * repeatCount + floatValue;
                        }
                        break;
                    // Quaternion
                    case Animation.ANIMATIONTYPE_QUATERNION:
                        var quatValue = useTangent ? this.quaternionInterpolateFunctionWithTangents(startValue, startKey.outTangent.scale(frameDelta), endValue, endKey.inTangent.scale(frameDelta), gradient) : this.quaternionInterpolateFunction(startValue, endValue, gradient);
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return quatValue;
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return quatValue.addInPlace(offsetValue.scale(repeatCount));
                        }

                        return quatValue;
                    // Vector3
                    case Animation.ANIMATIONTYPE_VECTOR3:
                        var vec3Value = useTangent ? this.vector3InterpolateFunctionWithTangents(startValue, startKey.outTangent.scale(frameDelta), endValue, endKey.inTangent.scale(frameDelta), gradient) : this.vector3InterpolateFunction(startValue, endValue, gradient);
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return vec3Value;
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return vec3Value.add(offsetValue.scale(repeatCount));
                        }
                    // Vector2
                    case Animation.ANIMATIONTYPE_VECTOR2:
                        var vec2Value = useTangent ? this.vector2InterpolateFunctionWithTangents(startValue, startKey.outTangent.scale(frameDelta), endValue, endKey.inTangent.scale(frameDelta), gradient) : this.vector2InterpolateFunction(startValue, endValue, gradient);
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return vec2Value;
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return vec2Value.add(offsetValue.scale(repeatCount));
                        }
                    // Size
                    case Animation.ANIMATIONTYPE_SIZE:
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return this.sizeInterpolateFunction(startValue, endValue, gradient);
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return this.sizeInterpolateFunction(startValue, endValue, gradient).add(offsetValue.scale(repeatCount));
                        }
                    // Color3
                    case Animation.ANIMATIONTYPE_COLOR3:
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                return this.color3InterpolateFunction(startValue, endValue, gradient);
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return this.color3InterpolateFunction(startValue, endValue, gradient).add(offsetValue.scale(repeatCount));
                        }
                    // Matrix
                    case Animation.ANIMATIONTYPE_MATRIX:
                        switch (loopMode) {
                            case Animation.ANIMATIONLOOPMODE_CYCLE:
                            case Animation.ANIMATIONLOOPMODE_CONSTANT:
                                if (Animation.AllowMatricesInterpolation) {
                                    return this.matrixInterpolateFunction(startValue, endValue, gradient, workValue);
                                }
                            case Animation.ANIMATIONLOOPMODE_RELATIVE:
                                return startValue;
                        }
                    default:
                        break;
                }
                break;
            }
        }

        return this._getKeyValue(keys[keys.length - 1].value);
    }

    /**
     * Defines the function to use to interpolate matrices
     * @param startValue defines the start matrix
     * @param endValue defines the end matrix
     * @param gradient defines the gradient between both matrices
     * @param result defines an optional target matrix where to store the interpolation
     * @returns the interpolated matrix
     */
    public matrixInterpolateFunction(startValue: Matrix, endValue: Matrix, gradient: number, result?: Matrix): Matrix {
        if (Animation.AllowMatrixDecomposeForInterpolation) {
            if (result) {
                Matrix.DecomposeLerpToRef(startValue, endValue, gradient, result);
                return result;
            }
            return Matrix.DecomposeLerp(startValue, endValue, gradient);
        }

        if (result) {
            Matrix.LerpToRef(startValue, endValue, gradient, result);
            return result;
        }
        return Matrix.Lerp(startValue, endValue, gradient);
    }

    /**
     * Makes a copy of the animation
     * @returns Cloned animation
     */
    public clone(): Animation {
        var clone = new Animation(this.name, this.targetPropertyPath.join("."), this.framePerSecond, this.dataType, this.loopMode);

        clone.enableBlending = this.enableBlending;
        clone.blendingSpeed = this.blendingSpeed;

        if (this._keys) {
            clone.setKeys(this._keys);
        }

        if (this._ranges) {
            clone._ranges = {};
            for (var name in this._ranges) {
                let range = this._ranges[name];
                if (!range) {
                    continue;
                }
                clone._ranges[name] = range.clone();
            }
        }

        return clone;
    }

    /**
     * Sets the key frames of the animation
     * @param values The animation key frames to set
     */
    public setKeys(values: Array<IAnimationKey>): void {
        this._keys = values.slice(0);
    }

    /**
     * Serializes the animation to an object
     * @returns Serialized object
     */
    public serialize(): any {
        var serializationObject: any = {};

        serializationObject.name = this.name;
        serializationObject.property = this.targetProperty;
        serializationObject.framePerSecond = this.framePerSecond;
        serializationObject.dataType = this.dataType;
        serializationObject.loopBehavior = this.loopMode;
        serializationObject.enableBlending = this.enableBlending;
        serializationObject.blendingSpeed = this.blendingSpeed;

        var dataType = this.dataType;
        serializationObject.keys = [];
        var keys = this.getKeys();
        for (var index = 0; index < keys.length; index++) {
            var animationKey = keys[index];

            var key: any = {};
            key.frame = animationKey.frame;

            switch (dataType) {
                case Animation.ANIMATIONTYPE_FLOAT:
                    key.values = [animationKey.value];
                    break;
                case Animation.ANIMATIONTYPE_QUATERNION:
                case Animation.ANIMATIONTYPE_MATRIX:
                case Animation.ANIMATIONTYPE_VECTOR3:
                case Animation.ANIMATIONTYPE_COLOR3:
                    key.values = animationKey.value.asArray();
                    break;
            }

            serializationObject.keys.push(key);
        }

        serializationObject.ranges = [];
        for (var name in this._ranges) {
            let source = this._ranges[name];

            if (!source) {
                continue;
            }
            var range: any = {};
            range.name = name;
            range.from = source.from;
            range.to = source.to;
            serializationObject.ranges.push(range);
        }

        return serializationObject;
    }

    // Statics
    /**
     * Float animation type
     */
    private static _ANIMATIONTYPE_FLOAT = 0;
    /**
     * Vector3 animation type
     */
    private static _ANIMATIONTYPE_VECTOR3 = 1;
    /**
     * Quaternion animation type
     */
    private static _ANIMATIONTYPE_QUATERNION = 2;
    /**
     * Matrix animation type
     */
    private static _ANIMATIONTYPE_MATRIX = 3;
    /**
     * Color3 animation type
     */
    private static _ANIMATIONTYPE_COLOR3 = 4;
    /**
     * Vector2 animation type
     */
    private static _ANIMATIONTYPE_VECTOR2 = 5;
    /**
     * Size animation type
     */
    private static _ANIMATIONTYPE_SIZE = 6;
    /**
     * Relative Loop Mode
     */
    private static _ANIMATIONLOOPMODE_RELATIVE = 0;
    /**
     * Cycle Loop Mode
     */
    private static _ANIMATIONLOOPMODE_CYCLE = 1;
    /**
     * Constant Loop Mode
     */
    private static _ANIMATIONLOOPMODE_CONSTANT = 2;

    /**
     * Get the float animation type
     */
    public static get ANIMATIONTYPE_FLOAT(): number {
        return Animation._ANIMATIONTYPE_FLOAT;
    }

    /**
     * Get the Vector3 animation type
     */
    public static get ANIMATIONTYPE_VECTOR3(): number {
        return Animation._ANIMATIONTYPE_VECTOR3;
    }

    /**
     * Get the Vector2 animation type
     */
    public static get ANIMATIONTYPE_VECTOR2(): number {
        return Animation._ANIMATIONTYPE_VECTOR2;
    }

    /**
     * Get the Size animation type
     */
    public static get ANIMATIONTYPE_SIZE(): number {
        return Animation._ANIMATIONTYPE_SIZE;
    }

    /**
     * Get the Quaternion animation type
     */
    public static get ANIMATIONTYPE_QUATERNION(): number {
        return Animation._ANIMATIONTYPE_QUATERNION;
    }

    /**
     * Get the Matrix animation type
     */
    public static get ANIMATIONTYPE_MATRIX(): number {
        return Animation._ANIMATIONTYPE_MATRIX;
    }

    /**
     * Get the Color3 animation type
     */
    public static get ANIMATIONTYPE_COLOR3(): number {
        return Animation._ANIMATIONTYPE_COLOR3;
    }

    /**
     * Get the Relative Loop Mode
     */
    public static get ANIMATIONLOOPMODE_RELATIVE(): number {
        return Animation._ANIMATIONLOOPMODE_RELATIVE;
    }

    /**
     * Get the Cycle Loop Mode
     */
    public static get ANIMATIONLOOPMODE_CYCLE(): number {
        return Animation._ANIMATIONLOOPMODE_CYCLE;
    }

    /**
     * Get the Constant Loop Mode
     */
    public static get ANIMATIONLOOPMODE_CONSTANT(): number {
        return Animation._ANIMATIONLOOPMODE_CONSTANT;
    }

    /** @hidden */
    public static _UniversalLerp(left: any, right: any, amount: number): any {
        let constructor = left.constructor;
        if (constructor.Lerp) { // Lerp supported
            return constructor.Lerp(left, right, amount);
        } else if (constructor.Slerp) { // Slerp supported
            return constructor.Slerp(left, right, amount);
        } else if (left.toFixed) { // Number
            return left * (1.0 - amount) + amount * right;
        } else { // Blending not supported
            return right;
        }
    }

    /**
     * Parses an animation object and creates an animation
     * @param parsedAnimation Parsed animation object
     * @returns Animation object
     */
    public static Parse(parsedAnimation: any): Animation {
        var animation = new Animation(parsedAnimation.name, parsedAnimation.property, parsedAnimation.framePerSecond, parsedAnimation.dataType, parsedAnimation.loopBehavior);

        var dataType = parsedAnimation.dataType;
        var keys: Array<IAnimationKey> = [];
        var data;
        var index: number;

        if (parsedAnimation.enableBlending) {
            animation.enableBlending = parsedAnimation.enableBlending;
        }

        if (parsedAnimation.blendingSpeed) {
            animation.blendingSpeed = parsedAnimation.blendingSpeed;
        }

        for (index = 0; index < parsedAnimation.keys.length; index++) {
            var key = parsedAnimation.keys[index];
            var inTangent: any;
            var outTangent: any;

            switch (dataType) {
                case Animation.ANIMATIONTYPE_FLOAT:
                    data = key.values[0];
                    if (key.values.length >= 1) {
                        inTangent = key.values[1];
                    }
                    if (key.values.length >= 2) {
                        outTangent = key.values[2];
                    }
                    break;
                case Animation.ANIMATIONTYPE_QUATERNION:
                    data = Quaternion.FromArray(key.values);
                    if (key.values.length >= 8) {
                        var _inTangent = Quaternion.FromArray(key.values.slice(4, 8));
                        if (!_inTangent.equals(Quaternion.Zero())) {
                            inTangent = _inTangent;
                        }
                    }
                    if (key.values.length >= 12) {
                        var _outTangent = Quaternion.FromArray(key.values.slice(8, 12));
                        if (!_outTangent.equals(Quaternion.Zero())) {
                            outTangent = _outTangent;
                        }
                    }
                    break;
                case Animation.ANIMATIONTYPE_MATRIX:
                    data = Matrix.FromArray(key.values);
                    break;
                case Animation.ANIMATIONTYPE_COLOR3:
                    data = Color3.FromArray(key.values);
                    break;
                case Animation.ANIMATIONTYPE_VECTOR3:
                default:
                    data = Vector3.FromArray(key.values);
                    break;
            }

            var keyData: any = {};
            keyData.frame = key.frame;
            keyData.value = data;

            if (inTangent != undefined) {
                keyData.inTangent = inTangent;
            }
            if (outTangent != undefined) {
                keyData.outTangent = outTangent;
            }
            keys.push(keyData);
        }

        animation.setKeys(keys);

        if (parsedAnimation.ranges) {
            for (index = 0; index < parsedAnimation.ranges.length; index++) {
                data = parsedAnimation.ranges[index];
                animation.createRange(data.name, data.from, data.to);
            }
        }

        return animation;
    }

    /**
     * Appends the serialized animations from the source animations
     * @param source Source containing the animations
     * @param destination Target to store the animations
     */
    public static AppendSerializedAnimations(source: IAnimatable, destination: any): void {
        SerializationHelper.AppendSerializedAnimations(source, destination);
    }
}

_TypeStore.RegisteredTypes["BABYLON.Animation"] = Animation;
Node._AnimationRangeFactory = (name: string, from: number, to: number) => new AnimationRange(name, from, to);