import { Observable } from "Tools/observable";
import { Scene } from "scene";
import { AbstractMesh } from "Mesh/abstractMesh";
import { _TimeToken } from "Instrumentation/timeToken";
import { _DepthCullingState, _StencilState, _AlphaState } from "States";
import { PoseEnabledController, ExtendedGamepadButton, MutableGamepadButton } from "./poseEnabledController";
import { StickValues, GamepadButtonChanges } from "Gamepad/gamepad";
    /**
     * Defines the WebVRController object that represents controllers tracked in 3D space
     */
    export abstract class WebVRController extends PoseEnabledController {
        /**
         * Internal, the default controller model for the controller
         */
        protected _defaultModel: AbstractMesh;

        // Observables
        /**
         * Fired when the trigger state has changed
         */
        public onTriggerStateChangedObservable = new Observable<ExtendedGamepadButton>();
        /**
         * Fired when the main button state has changed
         */
        public onMainButtonStateChangedObservable = new Observable<ExtendedGamepadButton>();
        /**
         * Fired when the secondary button state has changed
         */
        public onSecondaryButtonStateChangedObservable = new Observable<ExtendedGamepadButton>();
        /**
         * Fired when the pad state has changed
         */
        public onPadStateChangedObservable = new Observable<ExtendedGamepadButton>();
        /**
         * Fired when controllers stick values have changed
         */
        public onPadValuesChangedObservable = new Observable<StickValues>();

        /**
         * Array of button availible on the controller
         */
        protected _buttons: Array<MutableGamepadButton>;

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

        /**
         * Fired when a controller button's state has changed
         * @param callback the callback containing the button that was modified
         */
        public onButtonStateChange(callback: (controlledIndex: number, buttonIndex: number, state: ExtendedGamepadButton) => void) {
            this._onButtonStateChange = callback;
        }

        /**
         * X and Y axis corrisponding to the controllers joystick
         */
        public pad: StickValues = { x: 0, y: 0 };

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

        /**
         * The default controller model for the controller
         */
        public get defaultModel(): AbstractMesh {
            return this._defaultModel;
        }

        /**
         * Creates a new WebVRController from a gamepad
         * @param vrGamepad the gamepad that the WebVRController should be created from
         */
        constructor(vrGamepad: any) {
            super(vrGamepad);
            this._buttons = new Array<ExtendedGamepadButton>(vrGamepad.buttons.length);
            this.hand = vrGamepad.hand;
        }

        /**
         * Updates the state of the controller and mesh based on the current position and rotation of the controller
         */
        public update() {
            super.update();
            for (var index = 0; index < this._buttons.length; index++) {
                this._setButtonValue(this.browserGamepad.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);
            }
        }

        /**
         * Function to be called when a button is modified
         */
        protected abstract _handleButtonChange(buttonIdx: number, value: ExtendedGamepadButton, changes: GamepadButtonChanges): void;

        /**
         * Loads a mesh and attaches it to the controller
         * @param scene the scene the mesh should be added to
         * @param meshLoaded callback for when the mesh has been loaded
         */
        public abstract initControllerMesh(scene: Scene, meshLoaded?: (mesh: AbstractMesh) => void): 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;
        }

        /**
         * Disposes of th webVRCOntroller
         */
        public dispose(): void {
            super.dispose();

            this.onTriggerStateChangedObservable.clear();
            this.onMainButtonStateChangedObservable.clear();
            this.onSecondaryButtonStateChangedObservable.clear();
            this.onPadStateChangedObservable.clear();
            this.onPadValuesChangedObservable.clear();
        }
    }