module BABYLON {

    export enum PoseEnabledControllerType {
        VIVE,
        OCULUS,
        WINDOWS,
        GENERIC
    }

    export interface MutableGamepadButton {
        value: number;
        touched: boolean;
        pressed: boolean;
    }

    export class PoseEnabledControllerHelper {
        public static InitiateController(vrGamepad: any) {
            // Oculus Touch
            if (vrGamepad.id.indexOf('Oculus Touch') !== -1) {
                return new OculusTouchController(vrGamepad);
            }
            // Windows Mixed Reality controllers 
            // else if (vrGamepad.id.indexOf('Spatial Control') === 0) {
            //     //return new WindowsMixedRealityController(vrGamepad);
            // }
            // HTC Vive
            else if (vrGamepad.id.toLowerCase().indexOf('openvr') !== -1) {
                return new ViveController(vrGamepad);
            }
            // Generic 
            else {
                return new GenericController(vrGamepad);
            }
        }
    }

    export class PoseEnabledController extends Gamepad implements PoseControlled {
        devicePosition: Vector3;
        deviceRotationQuaternion: Quaternion;
        deviceScaleFactor: number = 1;

        public position: Vector3;
        public rotationQuaternion: Quaternion;
        public controllerType: PoseEnabledControllerType;

        private _calculatedPosition: Vector3;
        private _calculatedRotation: Quaternion;

        public rawPose: DevicePose; //GamepadPose;

        public _mesh: AbstractMesh; // a node that will be attached to this Gamepad
        private _poseControlledCamera: TargetCamera;

        private _leftHandSystemQuaternion: Quaternion = new Quaternion();

        constructor(public vrGamepad) {
            super(vrGamepad.id, vrGamepad.index, vrGamepad);
            this.type = Gamepad.POSE_ENABLED;
            this.controllerType = PoseEnabledControllerType.GENERIC;
            this.position = Vector3.Zero();
            this.rotationQuaternion = new Quaternion();
            this.devicePosition = Vector3.Zero();
            this.deviceRotationQuaternion = new Quaternion();

            this._calculatedPosition = Vector3.Zero();
            this._calculatedRotation = new Quaternion();
            Quaternion.RotationYawPitchRollToRef(Math.PI, 0, 0, this._leftHandSystemQuaternion);
        }

        public update() {
            super.update();
            var pose: GamepadPose = this.vrGamepad.pose;
            this.updateFromDevice(pose);

            if (this._mesh) {
                this._mesh.position.copyFrom(this._calculatedPosition);
                this._mesh.rotationQuaternion.copyFrom(this._calculatedRotation);
            }
        }

        updateFromDevice(poseData: DevicePose) {
            if (poseData) {
                this.rawPose = poseData;
                if (poseData.position) {
                    this.devicePosition.copyFromFloats(poseData.position[0], poseData.position[1], -poseData.position[2]);
                    if (this._mesh && this._mesh.getScene().useRightHandedSystem) {
                        this.devicePosition.z *= -1;
                    }

                    this.devicePosition.scaleToRef(this.deviceScaleFactor, this._calculatedPosition);
                    this._calculatedPosition.addInPlace(this.position);
                }
                if (poseData.orientation) {
                    this.deviceRotationQuaternion.copyFromFloats(this.rawPose.orientation[0], this.rawPose.orientation[1], -this.rawPose.orientation[2], -this.rawPose.orientation[3]);
                    if (this._mesh) {
                        if (this._mesh.getScene().useRightHandedSystem) {
                            this.deviceRotationQuaternion.z *= -1;
                            this.deviceRotationQuaternion.w *= -1;
                        } else {
                            this.deviceRotationQuaternion.multiplyToRef(this._leftHandSystemQuaternion, this.deviceRotationQuaternion);
                        }
                    }

                    // if the camera is set, rotate to the camera's rotation
                    this.deviceRotationQuaternion.multiplyToRef(this.rotationQuaternion, this._calculatedRotation);
                }
            }
        }


        public attachToMesh(mesh: AbstractMesh) {
            if (this._mesh) {
                this._mesh.parent = undefined;
            }
            this._mesh = mesh;
            if (this._poseControlledCamera) {
                this._mesh.parent = this._poseControlledCamera;
            }
            if (!this._mesh.rotationQuaternion) {
                this._mesh.rotationQuaternion = new Quaternion();
            }
        }

        public attachToPoseControlledCamera(camera: TargetCamera) {
            this._poseControlledCamera = camera;
            if (this._mesh) {
                this._mesh.parent = this._poseControlledCamera;
            }
        }

        public dispose() {
            if (this._mesh) {
                this._mesh.dispose();
            }
            this._mesh = undefined;
        }

        public get mesh(): AbstractMesh {
            return this._mesh;
        }

        public getForwardRay(length = 100): Ray {
            if (!this.mesh) {
                return new Ray(Vector3.Zero(), new BABYLON.Vector3(0, 0, 1), length);
            }

            var m = this.mesh.getWorldMatrix();
            var origin = m.getTranslation();

            var forward = new BABYLON.Vector3(0, 0, -1);
            var forwardWorld = BABYLON.Vector3.TransformNormal(forward, m);

            var direction = BABYLON.Vector3.Normalize(forwardWorld);            

            return new Ray(origin, direction, length);
        } 
    }

    export interface GamepadButtonChanges {
        changed: boolean;
        pressChanged: boolean;
        touchChanged: boolean;
        valueChanged: boolean;
    }

    export abstract class WebVRController extends PoseEnabledController {

        //public onTriggerStateChangedObservable = new Observable<{ state: ExtendedGamepadButton, changes: GamepadButtonChanges }>();

        public onTriggerStateChangedObservable = new Observable<ExtendedGamepadButton>();

        public onMainButtonStateChangedObservable = new Observable<ExtendedGamepadButton>();

        public onSecondaryButtonStateChangedObservable = new Observable<ExtendedGamepadButton>();

        public onPadStateChangedObservable = new Observable<ExtendedGamepadButton>();
        public onPadValuesChangedObservable = new Observable<StickValues>();

        protected _buttons: Array<MutableGamepadButton>;

        private _onButtonStateChange: (controlledIndex: number, buttonIndex: number, state: ExtendedGamepadButton) => void;

        public onButtonStateChange(callback: (controlledIndex: number, buttonIndex: number, state: ExtendedGamepadButton) => void) {
            this._onButtonStateChange = callback;
        }

        public pad: StickValues = { x: 0, y: 0 };

        public hand: string; // 'left' or 'right', see https://w3c.github.io/gamepad/extensions.html#gamepadhand-enum

        constructor(vrGamepad) {
            super(vrGamepad);
            this._buttons = new Array<ExtendedGamepadButton>(vrGamepad.buttons.length);
            this.hand = vrGamepad.hand;
        }

        public update() {
            super.update();
            for (var index = 0; index < this._buttons.length; index++) {
                this._setButtonValue(this.vrGamepad.buttons[index], this._buttons[index], index);
            };
            if (this.leftStick.x !== this.pad.x || this.leftStick.y !== this.pad.y) {
                this.pad.x = this.leftStick.x;
                this.pad.y = this.leftStick.y;
                this.onPadValuesChangedObservable.notifyObservers(this.pad);
            }
        }

        protected abstract handleButtonChange(buttonIdx: number, value: ExtendedGamepadButton, changes: GamepadButtonChanges);

        public abstract initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void);

        private _setButtonValue(newState: ExtendedGamepadButton, currentState: ExtendedGamepadButton, buttonIndex: number) {
            if (!newState) {
                newState = {
                    pressed: false,
                    touched: false,
                    value: 0
                };
            }  
            if (!currentState) {
                this._buttons[buttonIndex] = {
                    pressed: newState.pressed,
                    touched: newState.touched,
                    value: newState.value
                }
                return;
            }
            this._checkChanges(newState, currentState);
            if (this._changes.changed) {
                this._onButtonStateChange && this._onButtonStateChange(this.index, buttonIndex, newState);

                this.handleButtonChange(buttonIndex, newState, this._changes);
            }
            this._buttons[buttonIndex].pressed = newState.pressed;
            this._buttons[buttonIndex].touched = newState.touched;
            // oculus triggers are never 0, thou not touched.
            this._buttons[buttonIndex].value = newState.value < 0.00000001 ? 0 : newState.value;
        }

        // avoid GC, store state in a tmp object
        private _changes: GamepadButtonChanges = {
            pressChanged: false,
            touchChanged: false,
            valueChanged: false,
            changed: false
        };

        private _checkChanges(newState: ExtendedGamepadButton, currentState: ExtendedGamepadButton) {
            this._changes.pressChanged = newState.pressed !== currentState.pressed;
            this._changes.touchChanged = newState.touched !== currentState.touched;
            this._changes.valueChanged = newState.value !== currentState.value;
            this._changes.changed = this._changes.pressChanged || this._changes.touchChanged || this._changes.valueChanged;
            return this._changes;
        }
    }

    export class OculusTouchController extends WebVRController {
        private _defaultModel: BABYLON.AbstractMesh;

        public onSecondaryTriggerStateChangedObservable = new Observable<ExtendedGamepadButton>();

        public onThumbRestChangedObservable = new Observable<ExtendedGamepadButton>();

        constructor(vrGamepad) {
            super(vrGamepad);
            this.controllerType = PoseEnabledControllerType.OCULUS;
        }

        public initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void) {
            let meshName = this.hand === 'right' ? 'RightTouch.babylon' : 'LeftTouch.babylon';
            SceneLoader.ImportMesh("", "http://yoda.blob.core.windows.net/models/", meshName, scene, (newMeshes) => {
                /*
                Parent Mesh name: oculus_touch_left
                - body
                - trigger
                - thumbstick
                - grip
                - button_y 
                - button_x
                - button_enter
                */

                this._defaultModel = newMeshes[1];
                if (meshLoaded) {
                    meshLoaded(this._defaultModel);
                }
                this.attachToMesh(this._defaultModel);
            });
        }


        // helper getters for left and right hand.
        public get onAButtonStateChangedObservable() {
            if (this.hand === 'right') {
                return this.onMainButtonStateChangedObservable;
            } else {
                throw new Error('No A button on left hand');
            }
        }

        public get onBButtonStateChangedObservable() {
            if (this.hand === 'right') {
                return this.onSecondaryButtonStateChangedObservable;
            } else {
                throw new Error('No B button on left hand');
            }
        }

        public get onXButtonStateChangedObservable() {
            if (this.hand === 'left') {
                return this.onMainButtonStateChangedObservable;
            } else {
                throw new Error('No X button on right hand');
            }
        }

        public get onYButtonStateChangedObservable() {
            if (this.hand === 'left') {
                return this.onSecondaryButtonStateChangedObservable;
            } else {
                throw new Error('No Y button on right hand');
            }
        }

        /*
         0) thumb stick (touch, press, value = pressed (0,1)). value is in this.leftStick
         1) index trigger (touch (?), press (only when value > 0.1), value 0 to 1)
         2) secondary trigger (same)
         3) A (right) X (left), touch, pressed = value
         4) B / Y 
         5) thumb rest
        */
        protected handleButtonChange(buttonIdx: number, state: ExtendedGamepadButton, changes: GamepadButtonChanges) {
            let notifyObject = state; //{ state: state, changes: changes };
            let triggerDirection = this.hand === 'right' ? -1 : 1;
            switch (buttonIdx) {
                case 0:
                    this.onPadStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 1: // index trigger
                    if (this._defaultModel) {
                        (<AbstractMesh>(this._defaultModel.getChildren()[3])).rotation.x = -notifyObject.value * 0.20;
                        (<AbstractMesh>(this._defaultModel.getChildren()[3])).position.y = -notifyObject.value * 0.005;
                        (<AbstractMesh>(this._defaultModel.getChildren()[3])).position.z = -notifyObject.value * 0.005;
                    }
                    this.onTriggerStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 2:  // secondary trigger
                    if (this._defaultModel) {
                        (<AbstractMesh>(this._defaultModel.getChildren()[4])).position.x = triggerDirection * notifyObject.value * 0.0035;
                    }
                    this.onSecondaryTriggerStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 3:
                    if (this._defaultModel) {
                        if (notifyObject.pressed) {
                            (<AbstractMesh>(this._defaultModel.getChildren()[1])).position.y = -0.001;
                        }
                        else {
                            (<AbstractMesh>(this._defaultModel.getChildren()[1])).position.y = 0;
                        }
                    }
                    this.onMainButtonStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 4:
                    if (this._defaultModel) {
                        if (notifyObject.pressed) {
                            (<AbstractMesh>(this._defaultModel.getChildren()[2])).position.y = -0.001;
                        }
                        else {
                            (<AbstractMesh>(this._defaultModel.getChildren()[2])).position.y = 0;
                        }
                    }
                    this.onSecondaryButtonStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 5:
                    this.onThumbRestChangedObservable.notifyObservers(notifyObject);
                    return;
            }
        }

    }

    export class ViveController extends WebVRController {
        private _defaultModel: BABYLON.AbstractMesh;

        constructor(vrGamepad) {
            super(vrGamepad);
            this.controllerType = PoseEnabledControllerType.VIVE;
        }

        public initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void) {
            SceneLoader.ImportMesh("", "http://yoda.blob.core.windows.net/models/", "ViveWand.babylon", scene, (newMeshes) => {
                /*
                Parent Mesh name: ViveWand
                - body
                - r_gripper
                - l_gripper
                - menu_button
                - system_button
                - trackpad
                - trigger
                - LED
                */
                this._defaultModel = newMeshes[1];
                if (meshLoaded) {
                    meshLoaded(this._defaultModel);
                }
                this.attachToMesh(this._defaultModel);
            });
        }


        public get onLeftButtonStateChangedObservable() {
            return this.onMainButtonStateChangedObservable;
        }

        public get onRightButtonStateChangedObservable() {
            return this.onMainButtonStateChangedObservable;
        }

        public get onMenuButtonStateChangedObservable() {
            return this.onSecondaryButtonStateChangedObservable;
        }

        /**
         * Vive mapping:
         * 0: touchpad
         * 1: trigger
         * 2: left AND right buttons
         * 3: menu button
         */
        protected handleButtonChange(buttonIdx: number, state: ExtendedGamepadButton, changes: GamepadButtonChanges) {
            let notifyObject = state; //{ state: state, changes: changes };
            switch (buttonIdx) {
                case 0:
                    this.onPadStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 1: // index trigger
                    if (this._defaultModel) {
                        (<AbstractMesh>(this._defaultModel.getChildren()[6])).rotation.x = -notifyObject.value * 0.15;
                    }
                    this.onTriggerStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 2:  // left AND right button
                    this.onMainButtonStateChangedObservable.notifyObservers(notifyObject);
                    return;
                case 3:
                    if (this._defaultModel) {
                        if (notifyObject.pressed) {
                            (<AbstractMesh>(this._defaultModel.getChildren()[2])).position.y = -0.001;
                        }
                        else {
                            (<AbstractMesh>(this._defaultModel.getChildren()[2])).position.y = 0;
                        }
                    }
                    this.onSecondaryButtonStateChangedObservable.notifyObservers(notifyObject);
                    return;
            }
        }
    }

    export class GenericController extends WebVRController {
        private _defaultModel: BABYLON.AbstractMesh;

        constructor(vrGamepad) {
            super(vrGamepad);
        }

        public initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void) {
            SceneLoader.ImportMesh("", "http://yoda.blob.core.windows.net/models/", "genericvrcontroller.babylon", scene, (newMeshes) => {
                this._defaultModel = newMeshes[1];
                if (meshLoaded) {
                    meshLoaded(this._defaultModel);
                }
                this.attachToMesh(this._defaultModel);
            });
        }

        protected handleButtonChange(buttonIdx: number, state: ExtendedGamepadButton, changes: GamepadButtonChanges) {
            console.log("Button id: " + buttonIdx + "state: ");
            console.dir(state);
        }
    }
}

interface ExtendedGamepadButton extends GamepadButton {
    readonly pressed: boolean;
    readonly touched: boolean;
    readonly value: number;
}