export class Gamelib {
    keysPressed = new Set();
    keyPressHandlers = new Map();
    keyReleaseHandlers = new Map();

    constructor(console, codeStopper, spriteProvider, canvasElement) {
        this.console = console;
        this.codeStopper = codeStopper;
        this.spriteProvider = spriteProvider;

        this.canvas = canvasElement;
        this.width = 480;
        this.height = 360;
        this.canvas.width = this.width;
        this.canvas.height = this.height;
        this.cx = this.canvas.getContext("2d");
        this.cx.imageSmootingEnabled = false;

        document.body.addEventListener("keydown", (ev) => {
            this.keysPressed.add(ev.key);
            this.keyPressHandlers.get(ev.key)?.();
        });

        document.body.addEventListener("keyup", (ev) => {
            this.keysPressed.delete(ev.key);
            this.keyReleaseHandlers.get(ev.key)?.();
        });
    }

    println(msg) {
        this.console.log(msg);
    }

    startGameLoop(loopFunction) {
        let before = Date.now();
        const loopInterval = setInterval(() => {
            const now = Date.now();
            const deltaT = (now - before) / 1000;
            before = now;
            try {
                loopFunction(deltaT);
            } catch (error) {
                this.console.log(error);
            }
        }, 16);

        if (this.codeStopper.isStopped()) {
            clearInterval(loopInterval);
        }

        this.codeStopper.addListener(() => {
            clearInterval(loopInterval);
        });
    }

    isPressed(key) {
        return this.keysPressed.has(key);
    }

    onPress(key, handlerFunction) {
        this.keyPressHandlers.set(key, handlerFunction);
    }

    onRelease(key, handlerFunction) {
        this.keyReleaseHandlers.set(key, handlerFunction);
    }

    rgb(red, green, blue) {
        return `rgb(${red}, ${green}, ${blue})`;
    }

    clear(color) {
        const cx = this.cx;

        cx.fillStyle = color;
        cx.fillRect(0, 0, this.width, this.height);
    }

    drawSprite(x, y, width, height, name) {
        const cx = this.cx;

        const image = new Image();
        image.src = this.spriteProvider.url(name);
        image.onload = () => {
            cx.drawImage(image, x, y, width, height);
        };
    }

    drawRect(x, y, width, height, color) {
        const cx = this.cx;

        cx.fillStyle = color;
        cx.fillRect(x, y, width, height);
    }
}