module BABYLON {
    export interface Scene {
        /** @hidden */
        _pointerOverSprite: Nullable<Sprite>;

        /** @hidden */
        _pickedDownSprite: Nullable<Sprite>;

        /** @hidden */
        _tempSpritePickingRay: Nullable<Ray>;

        /**
         * All of the sprite managers added to this scene
         * @see http://doc.babylonjs.com/babylon101/sprites
         */
        spriteManagers: Array<ISpriteManager>;

        /**
         * An event triggered when sprites rendering is about to start
         * Note: This event can be trigger more than once per frame (because sprites can be rendered by render target textures as well)
         */
        onBeforeSpritesRenderingObservable: Observable<Scene>;

        /**
         * An event triggered when sprites rendering is done
         * Note: This event can be trigger more than once per frame (because sprites can be rendered by render target textures as well)
         */
        onAfterSpritesRenderingObservable: Observable<Scene>;

        /** @hidden */
        _internalPickSprites(ray: Ray, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo>;

        /** Launch a ray to try to pick a sprite in the scene
         * @param x position on screen
         * @param y position on screen
         * @param predicate Predicate function used to determine eligible sprites. Can be set to null. In this case, a sprite must have isPickable set to true
         * @param fastCheck Launch a fast check only using the bounding boxes. Can be set to null.
         * @param camera camera to use for computing the picking ray. Can be set to null. In this case, the scene.activeCamera will be used
         * @returns a PickingInfo
         */
        pickSprite(x: number, y: number, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo>;

        /** Use the given ray to pick a sprite in the scene
         * @param ray The ray (in world space) to use to pick meshes
         * @param predicate Predicate function used to determine eligible sprites. Can be set to null. In this case, a sprite must have isPickable set to true
         * @param fastCheck Launch a fast check only using the bounding boxes. Can be set to null.
         * @param camera camera to use. Can be set to null. In this case, the scene.activeCamera will be used
         * @returns a PickingInfo
         */
        pickSpriteWithRay(ray: Ray, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo>;

        /** 
         * Force the sprite under the pointer
         * @param sprite defines the sprite to use
         */
        setPointerOverSprite(sprite: Nullable<Sprite>): void;

        /** 
         * Gets the sprite under the pointer
         * @returns a Sprite or null if no sprite is under the pointer
         */
        getPointerOverSprite(): Nullable<Sprite>;
    }

    Scene.prototype._internalPickSprites = function(ray: Ray, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo> {
        if (!PickingInfo) {
            return null;
        }

        var pickingInfo = null;

        if (!camera) {
            if (!this.activeCamera) {
                return null;
            }
            camera = this.activeCamera;
        }

        if (this.spriteManagers.length > 0) {
            for (var spriteIndex = 0; spriteIndex < this.spriteManagers.length; spriteIndex++) {
                var spriteManager = this.spriteManagers[spriteIndex];

                if (!spriteManager.isPickable) {
                    continue;
                }

                var result = spriteManager.intersects(ray, camera, predicate, fastCheck);
                if (!result || !result.hit)
                    continue;

                if (!fastCheck && pickingInfo != null && result.distance >= pickingInfo.distance)
                    continue;

                pickingInfo = result;

                if (fastCheck) {
                    break;
                }
            }
        }

        return pickingInfo || new PickingInfo();
    }

    Scene.prototype.pickSprite = function(x: number, y: number, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo> {
        this.createPickingRayInCameraSpaceToRef(x, y, this._tempSpritePickingRay!, camera);

        return this._internalPickSprites(this._tempSpritePickingRay!, predicate, fastCheck, camera);
    }

    Scene.prototype.pickSpriteWithRay = function(ray: Ray, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo> {
        if (!this._tempSpritePickingRay) {
            return null;
        }

        if (!camera) {
            if (!this.activeCamera) {
                return null;
            }
            camera = this.activeCamera;
        }

        Ray.TransformToRef(ray, camera.getViewMatrix(), this._tempSpritePickingRay);

        return this._internalPickSprites(this._tempSpritePickingRay, predicate, fastCheck, camera);
    }

    Scene.prototype.setPointerOverSprite = function(sprite: Nullable<Sprite>): void {
        if (this._pointerOverSprite === sprite) {
            return;
        }

        if (this._pointerOverSprite && this._pointerOverSprite.actionManager) {
            this._pointerOverSprite.actionManager.processTrigger(ActionManager.OnPointerOutTrigger, ActionEvent.CreateNewFromSprite(this._pointerOverSprite, this));
        }

        this._pointerOverSprite = sprite;
        if (this._pointerOverSprite && this._pointerOverSprite.actionManager) {
            this._pointerOverSprite.actionManager.processTrigger(ActionManager.OnPointerOverTrigger, ActionEvent.CreateNewFromSprite(this._pointerOverSprite, this));
        }
    }

    Scene.prototype.getPointerOverSprite = function(): Nullable<Sprite> {
        return this._pointerOverSprite;
    }

    /**
     * Defines the sprite scene component responsible to manage sprites
     * in a given scene.
     */
    export class SpriteSceneComponent implements ISceneComponent {
        /**
         * The component name helpfull to identify the component in the list of scene components.
         */
        public readonly name = SceneComponentConstants.NAME_SPRITE;

        /**
         * The scene the component belongs to.
         */
        public scene: Scene;

        /** @hidden */
        private _spritePredicate: (sprite: Sprite) => boolean;

        /**
         * Creates a new instance of the component for the given scene
         * @param scene Defines the scene to register the component in
         */
        constructor(scene: Scene) {
            this.scene = scene;
            this.scene.spriteManagers = new Array<ISpriteManager>();
            this.scene._tempSpritePickingRay = Ray ? Ray.Zero() : null;
            this.scene.onBeforeSpritesRenderingObservable = new Observable<Scene>();
            this.scene.onAfterSpritesRenderingObservable = new Observable<Scene>();
            this._spritePredicate = (sprite: Sprite): boolean => {
                return sprite.isPickable && sprite.actionManager && sprite.actionManager.hasPointerTriggers;
            };
        }

        /**
         * Registers the component in a given scene
         */
        public register(): void {
            this.scene._pointerMoveStage.registerStep(SceneComponentConstants.STEP_POINTERMOVE_SPRITE, this, this._pointerMove);
            this.scene._pointerDownStage.registerStep(SceneComponentConstants.STEP_POINTERDOWN_SPRITE, this, this._pointerDown);
            this.scene._pointerUpStage.registerStep(SceneComponentConstants.STEP_POINTERUP_SPRITE, this, this._pointerUp);
        }

        /**
         * Rebuilds the elements related to this component in case of
         * context lost for instance.
         */
        public rebuild(): void {
            /** Nothing to do for sprites */
        }

        /**
         * Disposes the component and the associated ressources.
         */
        public dispose(): void {
            this.scene.onBeforeSpritesRenderingObservable.clear();
            this.scene.onAfterSpritesRenderingObservable.clear();

            let spriteManagers = this.scene.spriteManagers;
            while (spriteManagers.length) {
                spriteManagers[0].dispose();
            }
        }

        private _pickSpriteButKeepRay(originalPointerInfo: Nullable<PickingInfo>, x: number, y: number, fastCheck?: boolean, camera?: Camera): Nullable<PickingInfo> {
            var result = this.scene.pickSprite(x, y, this._spritePredicate, fastCheck, camera);
            if (result) {
                result.ray = originalPointerInfo ? originalPointerInfo.ray : null;
            }
            return result;
        }

        private _pointerMove(unTranslatedPointerX: number, unTranslatedPointerY: number, pickResult: Nullable<PickingInfo>, isMeshPicked: boolean, canvas: HTMLCanvasElement): Nullable<PickingInfo> {
            var scene = this.scene;
            if (isMeshPicked) {
                scene.setPointerOverSprite(null);
            } else {
                pickResult = this._pickSpriteButKeepRay(pickResult, unTranslatedPointerX, unTranslatedPointerY, false, scene.cameraToUseForPointers || undefined);

                if (pickResult && pickResult.hit && pickResult.pickedSprite) {
                    scene.setPointerOverSprite(pickResult.pickedSprite);
                    if (scene._pointerOverSprite && scene._pointerOverSprite.actionManager && scene._pointerOverSprite.actionManager.hoverCursor) {
                        canvas.style.cursor = scene._pointerOverSprite.actionManager.hoverCursor;
                    } else {
                        canvas.style.cursor = scene.hoverCursor;
                    }
                } else {
                    scene.setPointerOverSprite(null);
                }
            }

            return pickResult;
        }

        private _pointerDown(unTranslatedPointerX: number, unTranslatedPointerY: number, pickResult: Nullable<PickingInfo>, evt: PointerEvent): Nullable<PickingInfo> {
            var scene = this.scene;
            scene._pickedDownSprite = null;
            if (scene.spriteManagers.length > 0) {
                pickResult = scene.pickSprite(unTranslatedPointerX, unTranslatedPointerY, this._spritePredicate, false, scene.cameraToUseForPointers || undefined);

                if (pickResult && pickResult.hit && pickResult.pickedSprite) {
                    if (pickResult.pickedSprite.actionManager) {
                        scene._pickedDownSprite = pickResult.pickedSprite;
                        switch (evt.button) {
                            case 0:
                                pickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnLeftPickTrigger, ActionEvent.CreateNewFromSprite(pickResult.pickedSprite, scene, evt));
                                break;
                            case 1:
                                pickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnCenterPickTrigger, ActionEvent.CreateNewFromSprite(pickResult.pickedSprite, scene, evt));
                                break;
                            case 2:
                                pickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnRightPickTrigger, ActionEvent.CreateNewFromSprite(pickResult.pickedSprite, scene, evt));
                                break;
                        }
                        if (pickResult.pickedSprite.actionManager) {
                            pickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnPickDownTrigger, ActionEvent.CreateNewFromSprite(pickResult.pickedSprite, scene, evt));
                        }
                    }
                }
            }

            return pickResult;
        }

        private _pointerUp(unTranslatedPointerX: number, unTranslatedPointerY: number, pickResult: Nullable<PickingInfo>, evt: PointerEvent): Nullable<PickingInfo> {
            var scene = this.scene;
            if (scene.spriteManagers.length > 0) {
                let spritePickResult = scene.pickSprite(unTranslatedPointerX, unTranslatedPointerY, this._spritePredicate, false, scene.cameraToUseForPointers || undefined);

                if (spritePickResult) {
                    if (spritePickResult.hit && spritePickResult.pickedSprite) {
                        if (spritePickResult.pickedSprite.actionManager) {
                            spritePickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnPickUpTrigger, ActionEvent.CreateNewFromSprite(spritePickResult.pickedSprite, scene, evt));
                            if (spritePickResult.pickedSprite.actionManager) {
                                if (!this.scene._isPointerSwiping()) {
                                    spritePickResult.pickedSprite.actionManager.processTrigger(ActionManager.OnPickTrigger, ActionEvent.CreateNewFromSprite(spritePickResult.pickedSprite, scene, evt));
                                }
                            }
                        }
                    }
                    if (scene._pickedDownSprite && scene._pickedDownSprite.actionManager && scene._pickedDownSprite !== spritePickResult.pickedSprite) {
                        scene._pickedDownSprite.actionManager.processTrigger(ActionManager.OnPickOutTrigger, ActionEvent.CreateNewFromSprite(scene._pickedDownSprite, scene, evt));
                    }
                }
            }

            return pickResult;
        }
    }
}