module BABYLON {
    export class SpriteManager {
        public sprites = new Array<Sprite>();
        public renderingGroupId = 0;
        public layerMask: number = 0x0FFFFFFF;
        public fogEnabled = true;
        public isPickable = false;
        public cellWidth: number;
        public cellHeight: number;

        /**
        * An event triggered when the manager is disposed.
        */
        public onDisposeObservable = new Observable<SpriteManager>();

        private _onDisposeObserver: Nullable<Observer<SpriteManager>>;
        public set onDispose(callback: () => void) {
            if (this._onDisposeObserver) {
                this.onDisposeObservable.remove(this._onDisposeObserver);
            }
            this._onDisposeObserver = this.onDisposeObservable.add(callback);
        }

        private _capacity: number;
        private _spriteTexture: Texture;
        private _epsilon: number;

        private _scene: Scene;

        private _vertexData: Float32Array;
        private _buffer: Buffer;
        private _vertexBuffers: { [key: string]: VertexBuffer } = {};
        private _indexBuffer: WebGLBuffer;
        private _effectBase: Effect;
        private _effectFog: Effect;

        public get texture(): Texture {
            return this._spriteTexture;
        }

        public set texture(value: Texture) {
            this._spriteTexture = value;
        }

        constructor(public name: string, imgUrl: string, capacity: number, cellSize: any, scene: Scene, epsilon: number = 0.01, samplingMode: number = Texture.TRILINEAR_SAMPLINGMODE) {
            this._capacity = capacity;
            this._spriteTexture = new Texture(imgUrl, scene, true, false, samplingMode);
            this._spriteTexture.wrapU = Texture.CLAMP_ADDRESSMODE;
            this._spriteTexture.wrapV = Texture.CLAMP_ADDRESSMODE;

            if (cellSize.width && cellSize.height) {
                this.cellWidth = cellSize.width;
                this.cellHeight = cellSize.height;
            } else if(cellSize !== undefined) {
                this.cellWidth = cellSize;
                this.cellHeight = cellSize;
            } else {
               return;   
            }

            this._epsilon = epsilon;
            this._scene = scene;
            this._scene.spriteManagers.push(this);

            var indices = [];
            var index = 0;
            for (var count = 0; count < capacity; count++) {
                indices.push(index);
                indices.push(index + 1);
                indices.push(index + 2);
                indices.push(index);
                indices.push(index + 2);
                indices.push(index + 3);
                index += 4;
            }

            this._indexBuffer = scene.getEngine().createIndexBuffer(indices);

            // VBO
            // 16 floats per sprite (x, y, z, angle, sizeX, sizeY, offsetX, offsetY, invertU, invertV, cellIndexX, cellIndexY, color r, color g, color b, color a)
            this._vertexData = new Float32Array(capacity * 16 * 4);
            this._buffer = new Buffer(scene.getEngine(), this._vertexData, true, 16);

            var positions = this._buffer.createVertexBuffer(VertexBuffer.PositionKind, 0, 4);
            var options = this._buffer.createVertexBuffer("options", 4, 4);
            var cellInfo = this._buffer.createVertexBuffer("cellInfo", 8, 4);
            var colors = this._buffer.createVertexBuffer(VertexBuffer.ColorKind, 12, 4);

            this._vertexBuffers[VertexBuffer.PositionKind] = positions;
            this._vertexBuffers["options"] = options;
            this._vertexBuffers["cellInfo"] = cellInfo;
            this._vertexBuffers[VertexBuffer.ColorKind] = colors;

            // Effects
            this._effectBase = this._scene.getEngine().createEffect("sprites",
                [VertexBuffer.PositionKind, "options", "cellInfo", VertexBuffer.ColorKind],
                ["view", "projection", "textureInfos", "alphaTest"],
                ["diffuseSampler"], "");

            this._effectFog = this._scene.getEngine().createEffect("sprites",
                [VertexBuffer.PositionKind, "options", "cellInfo", VertexBuffer.ColorKind],
                ["view", "projection", "textureInfos", "alphaTest", "vFogInfos", "vFogColor"],
                ["diffuseSampler"], "#define FOG");
        }

        private _appendSpriteVertex(index: number, sprite: Sprite, offsetX: number, offsetY: number, rowSize: number): void {
            var arrayOffset = index * 16;

            if (offsetX === 0)
                offsetX = this._epsilon;
            else if (offsetX === 1)
                offsetX = 1 - this._epsilon;

            if (offsetY === 0)
                offsetY = this._epsilon;
            else if (offsetY === 1)
                offsetY = 1 - this._epsilon;

            this._vertexData[arrayOffset] = sprite.position.x;
            this._vertexData[arrayOffset + 1] = sprite.position.y;
            this._vertexData[arrayOffset + 2] = sprite.position.z;
            this._vertexData[arrayOffset + 3] = sprite.angle;
            this._vertexData[arrayOffset + 4] = sprite.width;
            this._vertexData[arrayOffset + 5] = sprite.height;
            this._vertexData[arrayOffset + 6] = offsetX;
            this._vertexData[arrayOffset + 7] = offsetY;
            this._vertexData[arrayOffset + 8] = sprite.invertU ? 1 : 0;
            this._vertexData[arrayOffset + 9] = sprite.invertV ? 1 : 0;
            var offset = (sprite.cellIndex / rowSize) >> 0;
            this._vertexData[arrayOffset + 10] = sprite.cellIndex - offset * rowSize;
            this._vertexData[arrayOffset + 11] = offset;
            // Color
            this._vertexData[arrayOffset + 12] = sprite.color.r;
            this._vertexData[arrayOffset + 13] = sprite.color.g;
            this._vertexData[arrayOffset + 14] = sprite.color.b;
            this._vertexData[arrayOffset + 15] = sprite.color.a;
        }

        public intersects(ray: Ray, camera:Camera, predicate?: (sprite: Sprite) => boolean, fastCheck?: boolean): Nullable<PickingInfo> {
            var count = Math.min(this._capacity, this.sprites.length);
            var min = Vector3.Zero();
            var max = Vector3.Zero();
            var distance = Number.MAX_VALUE;
            var currentSprite: Nullable<Sprite> = null;
            var cameraSpacePosition = Vector3.Zero();
            var cameraView = camera.getViewMatrix();

            for (var index = 0; index < count; index++) {
                var sprite = this.sprites[index];
                if (!sprite) {
                    continue;
                }

                if (predicate) {
                    if (!predicate(sprite)) {
                        continue;
                    }
                } else if (!sprite.isPickable) {
                    continue;
                }

                Vector3.TransformCoordinatesToRef(sprite.position, cameraView, cameraSpacePosition);

                min.copyFromFloats(cameraSpacePosition.x - sprite.width / 2, cameraSpacePosition.y - sprite.height / 2, cameraSpacePosition.z);
                max.copyFromFloats(cameraSpacePosition.x + sprite.width / 2, cameraSpacePosition.y + sprite.height / 2, cameraSpacePosition.z);

                if (ray.intersectsBoxMinMax(min, max)) {
                    var currentDistance = Vector3.Distance(cameraSpacePosition, ray.origin);

                    if (distance > currentDistance) {
                        distance = currentDistance;
                        currentSprite = sprite;

                        if (fastCheck) {
                            break;
                        }
                    }
                }
            }

            if (currentSprite) {
                var result = new PickingInfo();

                result.hit = true;
                result.pickedSprite = currentSprite;
                result.distance = distance;

                return result;
            }

            return null;
        } 

        public render(): void {
            // Check
            if (!this._effectBase.isReady() || !this._effectFog.isReady() || !this._spriteTexture || !this._spriteTexture.isReady())
                return;

            var engine = this._scene.getEngine();
            var baseSize = this._spriteTexture.getBaseSize();

            // Sprites
            var deltaTime = engine.getDeltaTime();
            var max = Math.min(this._capacity, this.sprites.length);
            var rowSize = baseSize.width / this.cellWidth;

            var offset = 0;
            for (var index = 0; index < max; index++) {
                var sprite = this.sprites[index];
                if (!sprite || !sprite.isVisible) {
                    continue;
                }

                sprite._animate(deltaTime);

                this._appendSpriteVertex(offset++, sprite, 0, 0, rowSize);
                this._appendSpriteVertex(offset++, sprite, 1, 0, rowSize);
                this._appendSpriteVertex(offset++, sprite, 1, 1, rowSize);
                this._appendSpriteVertex(offset++, sprite, 0, 1, rowSize);
            }
            this._buffer.update(this._vertexData);

            // Render
            var effect = this._effectBase;

            if (this._scene.fogEnabled && this._scene.fogMode !== Scene.FOGMODE_NONE && this.fogEnabled) {
                effect = this._effectFog;
            }

            engine.enableEffect(effect);

            var viewMatrix = this._scene.getViewMatrix();
            effect.setTexture("diffuseSampler", this._spriteTexture);
            effect.setMatrix("view", viewMatrix);
            effect.setMatrix("projection", this._scene.getProjectionMatrix());

            effect.setFloat2("textureInfos", this.cellWidth / baseSize.width, this.cellHeight / baseSize.height);

            // Fog
            if (this._scene.fogEnabled && this._scene.fogMode !== Scene.FOGMODE_NONE && this.fogEnabled) {
                effect.setFloat4("vFogInfos", this._scene.fogMode, this._scene.fogStart, this._scene.fogEnd, this._scene.fogDensity);
                effect.setColor3("vFogColor", this._scene.fogColor);
            }

            // VBOs
            engine.bindBuffers(this._vertexBuffers, this._indexBuffer, effect);

            // Draw order
            engine.setDepthFunctionToLessOrEqual();
            effect.setBool("alphaTest", true);
            engine.setColorWrite(false);
            engine.drawElementsType(Material.TriangleFillMode, 0, max * 6);
            engine.setColorWrite(true);
            effect.setBool("alphaTest", false);

            engine.setAlphaMode(Engine.ALPHA_COMBINE);
            engine.drawElementsType(Material.TriangleFillMode, 0, max * 6);
            engine.setAlphaMode(Engine.ALPHA_DISABLE);
        }

        public dispose(): void {
            if (this._buffer) {
                this._buffer.dispose();
                (<any>this._buffer) = null;
            }

            if (this._indexBuffer) {
                this._scene.getEngine()._releaseBuffer(this._indexBuffer);
                (<any>this._indexBuffer) = null;
            }

            if (this._spriteTexture) {
                this._spriteTexture.dispose();
                (<any>this._spriteTexture) = null;
            }

            // Remove from scene
            var index = this._scene.spriteManagers.indexOf(this);
            this._scene.spriteManagers.splice(index, 1);

            // Callback
            this.onDisposeObservable.notifyObservers(this);
            this.onDisposeObservable.clear();
        }
    }
}