const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");

const ballRadius = 10;
let x = canvas.width / 2;
let y = canvas.height - 30;
let dx, dy;

let intervalID;

let paddleHeight = 10;
let paddleWidth = 500;
let paddleX = (canvas.width - paddleWidth) / 2;

let rightPressed = false;
let leftPressed = false;

document.addEventListener("keydown", keyDownHandler);
document.addEventListener("keyup", keyUpHandler);

function keyDownHandler(e) {
    if (e.key === "Right" || e.key === "ArrowRight") {
        rightPressed = true;
    } else if (e.key === "Left" || e.key === "ArrowLeft") {
        leftPressed = true;
    }
}

function keyUpHandler(e) {
    if (e.key === "Right" || e.key === "ArrowRight") {
        rightPressed = false;
    } else if (e.key === "Left" || e.key === "ArrowLeft") {
        leftPressed = false;
    }
}

function drawPaddle() {
    ctx.beginPath();
    ctx.rect(
        paddleX,
        canvas.height - paddleHeight,
        paddleWidth,
        paddleHeight
    );
    ctx.fillStyle = "red";
    ctx.fill();
    ctx.closePath();
}

function checkCollision() {
    if (x + dx > canvas.width - ballRadius || x + dx < ballRadius) {
        dx = -dx;
    }
    if (y + dy > canvas.height - ballRadius || y + dy < ballRadius) {
        dy = -dy;
    }
    x += dx;
    y += dy;

    checkPaddleWallCollission();
}

function checkPaddleWallCollission() {
    if (paddleX >= canvas.width - paddleWidth) {
        rightPressed = false;
        console.log(paddleX);
    } else if (paddleX <= 0) {
        leftPressed = false;
    }
}

function drawBall() {
    ctx.beginPath();
    ctx.arc(x, y, ballRadius, 0, Math.PI * 2);
    ctx.fillStyle = "black";
    ctx.fill();
    ctx.closePath();
}

function draw() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    drawBall();
    drawPaddle();
    checkCollision();

    if (rightPressed) {
        paddleX += 7;
    } else if (leftPressed) {
        paddleX -= 7;
    }

    console.log("x: " + x + " " + "y: " + y);
}

function startGame() {
    if (intervalID) clearInterval(intervalID);
    intervalID = setInterval(draw, 10);
}

const runButton = document.getElementById("runButton");
runButton.addEventListener("click", () => {
    dx = 2;
    dy = 2;
    startGame();
});

const exit = document.getElementById("exit");
exit.addEventListener("click", () => {
    clearInterval(intervalID);
    dx = 0;
    dy = 0;
});