//% icon="\uf245"
//% color="#9c1355"
//% block="Browser Events"
namespace browserEvents {
    export enum Event {
        //% block="pointer down"
        PointerDown = 6857,
        //% block="pointer up"
        PointerUp = 6858,
        //% block="pointer move"
        PointerMove = 6859,
        //% block="pointer leave"
        PointerLeave = 6860,
        //% block="pointer enter"
        PointerEnter = 6861,
        //% block="pointer cancel"
        PointerCancel = 6862,
        //% block="pointer over"
        PointerOver = 6863,
        //% block="pointer out"
        PointerOut = 6864,
        //% block="wheel"
        Wheel = 6865,
        //% block="key down"
        KeyDown = 6866,
        //% block="key up"
        KeyUp = 6867
    }

    export enum MouseButtonId {
        //% block="left"
        Left = 1,
        //% block="right"
        Right = 3,
        //% block="wheel"
        Wheel = 2,
        //% block="back"
        Back = 4,
        //% block="forward"
        Forward = 5
    }

    export enum MouseButtonEvent {
        //% block="pressed"
        Pressed = Event.PointerDown,
        //% block="released"
        Released = Event.PointerUp,
    }

    //% whenUsed
    const INTERNAL_POINTER_DOWN = 6868;
    //% whenUsed
    const INTERNAL_POINTER_UP = 6869;

    type MouseHandler = (x: number, y: number) => void;

    //% fixedInstances
    export class MouseButton {
        protected _pressed: boolean;

        protected sceneStack: _SceneButtonHandlers<MouseHandler>[];

        protected get state(): _SceneButtonHandlers<MouseHandler> {
            return this.sceneStack[this.sceneStack.length - 1];
        }

        constructor(public id: number) {
            control.internalOnEvent(INTERNAL_POINTER_DOWN, this.id, () => this.setPressed(true), 16);
            control.internalOnEvent(INTERNAL_POINTER_UP, this.id, () => this.setPressed(false), 16);

            this._pressed = false;

            this.sceneStack = [new _SceneButtonHandlers<MouseHandler>(id, invokeMouseHandler)];

            game.addScenePushHandler(() => {
                this.sceneStack.push(new _SceneButtonHandlers<MouseHandler>(id, invokeMouseHandler));
            });
            game.addScenePopHandler(() => {
                this.sceneStack.pop();
                if (this.sceneStack.length === 0) {
                    this.sceneStack = [new _SceneButtonHandlers<MouseHandler>(id, invokeMouseHandler)];
                }
            });
        }

        setPressed(pressed: boolean) {
            this._pressed = pressed;

            if (pressed) {
                control.raiseEvent(MouseButtonEvent.Pressed, this.id);
            }
            else {
                control.raiseEvent(MouseButtonEvent.Released, this.id);
            }
        }

        //% blockId=browserEvents_mouseButton_onEvent
        //% block="on $this mouse button $event $x $y"
        //% draggableParameters="reporter"
        //% group="Mouse"
        //% weight=50
        onEvent(event: MouseButtonEvent, handler: (x: number, y: number) => void) {
            this.state.onEvent(event, handler);
        }

        //% blockId=browserEvents_mouseButton_isPressed
        //% block="is $this mouse button pressed"
        //% group="Mouse"
        //% weight=40
        isPressed() {
            return this._pressed;
        }

        //% blockId=browserEvents_mouseButton_pauseUntil
        //% block="pause until $this mouse button is $event"
        //% group="Mouse"
        //% weight=30
        pauseUntil(event: MouseButtonEvent) {
            control.waitForEvent(event, this.id)
        }

        addEventListener(event: MouseButtonEvent, handler: (x: number, y: number) => void) {
            this.state.addEventListener(event, handler);
        }

        removeEventListener(event: MouseButtonEvent, handler: (x: number, y: number) => void) {
            this.state.removeEventListener(event, handler);
        }
    }

    export class _SceneButtonHandlers<U> {
        protected handlers: ButtonHandler<U>[];

        constructor(public id: number, protected invokeHandler: (handler: U) => void) {
            this.handlers = [];
        }

        onEvent(event: number, handler: U) {
            this.getHandler(event, true).handler = handler;
        }

        addEventListener(event: number, handler: U) {
            this.getHandler(event, true).listeners.push(handler);
        }

        removeEventListener(event: number, handler: U) {
            const eventHandler = this.getHandler(event);

            if (eventHandler) {
                eventHandler.listeners = eventHandler.listeners.filter(h => h !== handler);
            }
        }

        protected getHandler(event: number, createIfMissing?: boolean) {
            for (const handler of this.handlers) {
                if (handler.event === event) return handler;
            }

            if (createIfMissing) {
                const newHandler = new ButtonHandler<U>(event, this.id, this.invokeHandler);
                this.handlers.push(newHandler);
                return newHandler;
            }

            return undefined;
        }
    }

    class ButtonHandler<U> {
        handler: U;
        listeners: U[] = [];

        constructor(public readonly event: number, id: number, invokeHandler: (handler: U) => void) {
            control.onEvent(event, id, () => {
                if (this.handler) {
                    invokeHandler(this.handler);
                }
                for (const listener of this.listeners) {
                    invokeHandler(listener);
                }
            });
        }
    }

    function invokeMouseHandler(handler: MouseHandler) {
        handler(mouseX(), mouseY());
    }

    //% blockId=browserEvents_onEvent
    //% block="on browser event $event"
    //% draggableParameters="reporter"
    //% group="Mouse"
    //% weight=10
    export function onEvent(event: Event, handler: () => void) {
        control.onEvent(event, 0, handler);
    }

    //% blockId=browserEvents_onMouseMove
    //% block="on mouse move $x $y"
    //% draggableParameters="reporter"
    //% group="Mouse"
    //% weight=100
    export function onMouseMove(handler: (x: number, y: number) => void) {
        control.onEvent(Event.PointerMove, 0, () => {
            handler(mouseX(), mouseY());
        });
    }

    //% blockId=browserEvents_onWheel
    //% block="on mouse wheel $dx $dy $dz"
    //% draggableParameters="reporter"
    //% group="Mouse"
    //% weight=20
    export function onWheel(handler: (dx: number, dy: number, dz: number) => void) {
        control.onEvent(Event.Wheel, 0, () => {
            handler(wheelDx(), wheelDy(), wheelDz());
        });
    }

    //% blockId=browserEvents_setCursorVisible
    //% block="set cursor visible $visible"
    //% group="Mouse"
    //% weight=0
    export function setCursorVisible(visible: boolean) {
        _setCursorVisible(visible);
    }

    //% fixedInstance whenUsed block="left"
    export const MouseLeft = new MouseButton(MouseButtonId.Left);

    //% fixedInstance whenUsed block="right"
    export const MouseRight = new MouseButton(MouseButtonId.Right);

    //% fixedInstance whenUsed block="wheel"
    export const MouseWheel = new MouseButton(MouseButtonId.Wheel);

    //% fixedInstance whenUsed block="back"
    export const MouseBack = new MouseButton(MouseButtonId.Back);

    //% fixedInstance whenUsed block="forward"
    export const MouseForward = new MouseButton(MouseButtonId.Forward);

    //% fixedInstance whenUsed block="any"
    export const MouseAny = new MouseButton(0);
}