module BABYLON {
    /**
     * This is a list of all the different input types that are available in the application.
     * Fo instance: ArcRotateCameraGamepadInput...
     */
    export var CameraInputTypes = {};

    /**
     * This is the contract to implement in order to create a new input class.
     * Inputs are dealing with listening to user actions and moving the camera accordingly.
     */
    export interface ICameraInput<TCamera extends Camera> {
        /**
         * Defines the camera the input is attached to.
         */
        camera: Nullable<TCamera>;
        /**
         * Gets the class name of the current intput.
         * @returns the class name
         */
        getClassName(): string;
        /**
         * Get the friendly name associated with the input class.
         * @returns the input friendly name
         */
        getSimpleName(): string;
        /**
         * Attach the input controls to a specific dom element to get the input from.
         * @param element Defines the element the controls should be listened from
         * @param noPreventDefault Defines whether event caught by the controls should call preventdefault() (https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault)
         */
        attachControl(element: HTMLElement, noPreventDefault?: boolean): void;
        /**
         * Detach the current controls from the specified dom element.
         * @param element Defines the element to stop listening the inputs from
         */
        detachControl(element: Nullable<HTMLElement>): void;
        /**
         * Update the current camera state depending on the inputs that have been used this frame.
         * This is a dynamically created lambda to avoid the performance penalty of looping for inputs in the render loop.
         */
        checkInputs?: () => void;
    }

    /**
     * Represents a map of input types to input instance or input index to input instance.
     */
    export interface CameraInputsMap<TCamera extends Camera> {
        /**
         * Accessor to the input by input type.
         */
        [name: string]: ICameraInput<TCamera>;
        /**
         * Accessor to the input by input index.
         */
        [idx: number]: ICameraInput<TCamera>;
    }

    /**
     * This represents the input manager used within a camera.
     * It helps dealing with all the different kind of input attached to a camera.
     * @see http://doc.babylonjs.com/how_to/customizing_camera_inputs
     */
    export class CameraInputsManager<TCamera extends Camera> {
        /**
         * Defines the list of inputs attahed to the camera.
         */
        public attached: CameraInputsMap<TCamera>;

        /**
         * Defines the dom element the camera is collecting inputs from.
         * This is null if the controls have not been attached.
         */
        public attachedElement: Nullable<HTMLElement>;

        /**
         * Defines whether event caught by the controls should call preventdefault() (https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault)
         */
        public noPreventDefault: boolean;

        /**
         * Defined the camera the input manager belongs to.
         */
        public camera: TCamera;

        /**
         * Update the current camera state depending on the inputs that have been used this frame.
         * This is a dynamically created lambda to avoid the performance penalty of looping for inputs in the render loop.
         */
        public checkInputs: () => void;

        /**
         * Instantiate a new Camera Input Manager.
         * @param camera Defines the camera the input manager blongs to
         */
        constructor(camera: TCamera) {
            this.attached = {};
            this.camera = camera;
            this.checkInputs = () => { };
        }

        /**
         * Add an input method to a camera
         * @see http://doc.babylonjs.com/how_to/customizing_camera_inputs
         * @param input camera input method
         */
        public add(input: ICameraInput<TCamera>): void {
            var type = input.getSimpleName();
            if (this.attached[type]) {
                Tools.Warn("camera input of type " + type + " already exists on camera");
                return;
            }

            this.attached[type] = input;

            input.camera = this.camera;

            //for checkInputs, we are dynamically creating a function
            //the goal is to avoid the performance penalty of looping for inputs in the render loop
            if (input.checkInputs) {
                this.checkInputs = this._addCheckInputs(input.checkInputs.bind(input));
            }

            if (this.attachedElement) {
                input.attachControl(this.attachedElement);
            }
        }

        /**
         * Remove a specific input method from a camera
         * example: camera.inputs.remove(camera.inputs.attached.mouse);
         * @param inputToRemove camera input method
         */
        public remove(inputToRemove: ICameraInput<TCamera>): void {
            for (var cam in this.attached) {
                var input = this.attached[cam];
                if (input === inputToRemove) {
                    input.detachControl(this.attachedElement);
                    input.camera = null;
                    delete this.attached[cam];
                    this.rebuildInputCheck();
                }
            }
        }

        /**
         * Remove a specific input type from a camera
         * example: camera.inputs.remove("ArcRotateCameraGamepadInput");
         * @param inputType the type of the input to remove
         */
        public removeByType(inputType: string): void {
            for (var cam in this.attached) {
                var input = this.attached[cam];
                if (input.getClassName() === inputType) {
                    input.detachControl(this.attachedElement);
                    input.camera = null;
                    delete this.attached[cam];
                    this.rebuildInputCheck();
                }
            }
        }

        private _addCheckInputs(fn: () => void) {
            var current = this.checkInputs;
            return () => {
                current();
                fn();
            }
        }

        /**
         * Attach the input controls to the currently attached dom element to listen the events from.
         * @param input Defines the input to attach
         */
        public attachInput(input: ICameraInput<TCamera>): void {
            if (this.attachedElement) {
                input.attachControl(this.attachedElement, this.noPreventDefault);
            }
        }

        /**
         * Attach the current manager inputs controls to a specific dom element to listen the events from.
         * @param element Defines the dom element to collect the events from
         * @param noPreventDefault Defines whether event caught by the controls should call preventdefault() (https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault)
         */
        public attachElement(element: HTMLElement, noPreventDefault: boolean = false): void {
            if (this.attachedElement) {
                return;
            }

            noPreventDefault = Camera.ForceAttachControlToAlwaysPreventDefault ? false : noPreventDefault;
            this.attachedElement = element;
            this.noPreventDefault = noPreventDefault;

            for (var cam in this.attached) {
                this.attached[cam].attachControl(element, noPreventDefault);
            }
        }

        /**
         * Detach the current manager inputs controls from a specific dom element.
         * @param element Defines the dom element to collect the events from
         * @param disconnect Defines whether the input should be removed from the current list of attached inputs
         */
        public detachElement(element: HTMLElement, disconnect = false): void {
            if (this.attachedElement !== element) {
                return;
            }

            for (var cam in this.attached) {
                this.attached[cam].detachControl(element);

                if (disconnect) {
                    this.attached[cam].camera = null;
                }
            }

            this.attachedElement = null;
        }

        /**
         * Rebuild the dynamic inputCheck function from the current list of 
         * defined inputs in the manager.
         */
        public rebuildInputCheck(): void {
            this.checkInputs = () => { };

            for (var cam in this.attached) {
                var input = this.attached[cam];
                if (input.checkInputs) {
                    this.checkInputs = this._addCheckInputs(input.checkInputs.bind(input));
                }
            }
        }

        /**
         * Remove all attached input methods from a camera
         */
        public clear(): void {
            if (this.attachedElement) {
                this.detachElement(this.attachedElement, true);
            }
            this.attached = {};
            this.attachedElement = null;
            this.checkInputs = () => { };
        }

        /**
         * Serialize the current input manager attached to a camera.
         * This ensures than once parsed, 
         * the input associated to the camera will be identical to the current ones
         * @param serializedCamera Defines the camera serialization JSON the input serialization should write to
         */
        public serialize(serializedCamera: any): void {
            var inputs: { [key: string]: any } = {};
            for (var cam in this.attached) {
                var input = this.attached[cam];
                var res = SerializationHelper.Serialize(input);
                inputs[input.getClassName()] = res;
            }

            serializedCamera.inputsmgr = inputs;
        }

        /**
         * Parses an input manager serialized JSON to restore the previous list of inputs
         * and states associated to a camera.
         * @param parsedCamera Defines the JSON to parse
         */
        public parse(parsedCamera: any): void {
            var parsedInputs = parsedCamera.inputsmgr;
            if (parsedInputs) {
                this.clear();

                for (var n in parsedInputs) {
                    var construct = (<any>CameraInputTypes)[n];
                    if (construct) {
                        var parsedinput = parsedInputs[n];
                        var input = SerializationHelper.Parse(() => { return new construct() }, parsedinput, null);
                        this.add(input as any);
                    }
                }
            } else {
                //2016-03-08 this part is for managing backward compatibility
                for (var n in this.attached) {
                    var construct = (<any>CameraInputTypes)[this.attached[n].getClassName()];
                    if (construct) {
                        var input = SerializationHelper.Parse(() => { return new construct() }, parsedCamera, null);
                        this.remove(this.attached[n]);
                        this.add(input as any);
                    }
                }
            }
        }
    }
}