module BABYLON {
    // We're mainly based on the logic defined into the FreeCamera code
    export class DeviceOrientationCamera extends FreeCamera {
        private _offsetX: number = null;
        private _offsetY: number = null;
        private _orientationGamma: number = 0;
        private _orientationBeta: number = 0;
        private _initialOrientationGamma: number = 0;
        private _initialOrientationBeta: number = 0;
        private _attachedCanvas: HTMLCanvasElement;
        private _orientationChanged: (e: DeviceOrientationEvent) => any;

        public angularSensibility: number = 10000.0;
        public moveSensibility: number = 50.0;

        constructor(name: string, position: Vector3, scene: Scene) {
            super(name, position, scene);

            window.addEventListener("resize", () => {
                this._initialOrientationGamma = null;
            }, false);
        }

        public attachControl(canvas: HTMLCanvasElement, noPreventDefault: boolean): void {
            if (this._attachedCanvas) {
                return;
            }
            this._attachedCanvas = canvas;

            if (!this._orientationChanged) {
                this._orientationChanged = (evt) => {

                    if (!this._initialOrientationGamma) {
                            this._initialOrientationGamma = evt.gamma;
                            this._initialOrientationBeta = evt.beta;
                    }

                    this._orientationGamma = evt.gamma;
                    this._orientationBeta = evt.beta;
 
                    this._offsetY = (this._initialOrientationBeta - this._orientationBeta);
                    this._offsetX = (this._initialOrientationGamma - this._orientationGamma);
                };
            }

            window.addEventListener("deviceorientation", this._orientationChanged);
        }

        public detachControl(canvas: HTMLCanvasElement): void {
            if (this._attachedCanvas != canvas) {
                return;
            }

            window.removeEventListener("deviceorientation", this._orientationChanged);

            this._attachedCanvas = null;
            this._orientationGamma = 0;
            this._orientationBeta = 0;
            this._initialOrientationGamma = 0;
            this._initialOrientationBeta = 0;
        }

        public _checkInputs(): void {
            if (!this._offsetX) {
                return;
            }
            this.cameraRotation.y -= this._offsetX / this.angularSensibility;

            var speed = this._computeLocalCameraSpeed();
            var direction = new BABYLON.Vector3(0, 0, speed * this._offsetY / this.moveSensibility);

            BABYLON.Matrix.RotationYawPitchRollToRef(this.rotation.y, this.rotation.x, 0, this._cameraRotationMatrix);
            this.cameraDirection.addInPlace(BABYLON.Vector3.TransformCoordinates(direction, this._cameraRotationMatrix));

            super._checkInputs();
        }
    }
}