W = 800;
H = 600;

fps = 60;

newFrame = (new Date).getTime()

let enemies = [];
enemyLimit = 15;

function setup() {
    frameRate(fps);
    createCanvas(W, H);

    windowResized();



    angleMode(DEGREES);

    startGame();
}

function draw() {
    strokeWeight(0);
    background(bg);

    lastFrame = newFrame
    newFrame = (new Date).getTime()

    if (alive) {
        translate(W / 2 - player.x, H / 2 - player.y);

        c = 0;
        for (e of enemies) {
            e.update();
            e.display();
            distance = (((e.x - player.x) ** 2) + ((e.y - player.y) ** 2)) ** 0.5
            if (distance >= (((W * 2) ** 2) + ((H * 2) ** 2)) ** 0.5) {
                enemies.splice(c, 1);
                enemies.push(new enemy);
            }
            c++;
        }

        player.trailCounter = 0;
        for (t of player.trail) {
            t.display();
            if (t.ttl <= 0) {
                player.trail.splice(this.trailCounter, 1);
            }
            player.trailCounter++;
        }

        for (b of player.bullets) {
            b.update();
            b.display();
        }

        translate(-(W / 2 - player.x), -(H / 2 - player.y))

        player.update();
        player.display();

        fill(255)
        fps = round(1000 / (newFrame - lastFrame))
        text(fps, 10, 20)
        text(((player.xSpeed ** 2) + (player.ySpeed ** 2)) ** 0.5, 10, 40)

        if (player.health <= 0) {
            alive = false;
            enemies = [];
            score = player.score;
            player = null;
        }
    } else {
        textSize(72);
        textAlign(CENTER);
        fill(200, 200, 0);
        text("Score: ".concat(score), W / 2, H / 4);
        fill(255)
        textSize(16)
    }
}

function startGame() {
    bg = [48, 48, 48];
    player = new character
    c = 0;
    while (c < enemyLimit) {
        enemies.push(new enemy);
        c++;
    }
    score = 0;
    alive = true;
    textSize(16)
}

function windowResized() {
    resizeCanvas(windowWidth, windowHeight);
    W = windowWidth, H = windowHeight;
}

class particle {
    constructor() {
        this.x = player.x + round(random(-10, 10)), this.y = player.y + round(random(-10, 10));
        this.radius = round(random(2, 20));
        this.Initialttl = fps;
        this.ttl = this.Initialttl;
        this.color = round(random(48, 200));

        this.xSpeed = -0.01 * player.xSpeed + round(random(-30, 30) / fps);
        this.ySpeed = -0.01 * player.ySpeed + round(random(-30, 30) / fps);
    }

    display() {
        this.x += this.xSpeed;
        this.y += this.ySpeed;

        fill(this.color, 10, 10);
        ellipse(this.x, this.y, 10, 10)
        ellipse(this.x, this.y, this.radius * (this.tll / this.Initialttl), this.radius * (this.tll / this.Initialttl));
        fill(255, 255, 255);
        this.ttl -= 1;
    }
}

function mouseReleased() {
    if (alive) {
        player.shooting = true;
    }
}

function mousePressed() {
    if (alive) {
        player.shooting = false;
    }
}

class character {
    constructor() {
        this.x = 0;
        this.y = 0;

        this.health = 100;
        this.score = 0;

        this.xSpeed = 0;
        this.ySpeed = 0;

        this.speed = 500;

        this.drag = 0.9;

        this.orientation = 45;

        this.width = 40, this.height = 40;

        this.trail = [];
        this.bullets = [];

        this.bulletSpeed = 2000;
        this.fireRate = 30;
        this.damage = 20;

        this.shotCounter = 0;
    }

    update() {
        this.shotCounter += 1;

        if(this.shotCounter >= (fps/this.fireRate) && this.shooting){
            this.shoot();
        }

        if (keyIsDown(87)) {
            this.xSpeed += sin(this.orientation) * this.speed / fps
            this.ySpeed += sin(this.orientation - 90) * this.speed / fps
            this.trail.push(new particle)
        }

        if (keyIsDown(83)) {
            this.xSpeed -= sin(this.orientation) * this.speed / fps
            this.ySpeed -= sin(this.orientation - 90) * this.speed / fps
            this.trail.push(new particle)
        }

        this.x += this.xSpeed / fps;
        this.y += this.ySpeed / fps;

        this.xSpeed = this.xSpeed * (1 - (this.drag / fps));
        this.ySpeed = this.ySpeed * (1 - (this.drag / fps));

        this.orientation = aimToMouse(mouseX, mouseY, W / 2, H / 2);
    }

    shoot() {
        this.bullets.push(new bullet(this.x, this.y, (sin(this.orientation) * this.bulletSpeed) + this.xSpeed, (sin(this.orientation - 90) * this.bulletSpeed) + this.ySpeed), this.damage)
    }

    display() {
        fill(48, 255, 48);
        translate(W / 2, H / 2)
        rotate(this.orientation)
        triangle(-this.width / 2, this.height / 2, 0, -this.height / 2, this.width / 2, this.height / 2);
        rotate(-this.orientation)
        translate(-W / 2, -H / 2)
    }
}

class bullet {
    constructor(x, y, xSpeed, ySpeed, damage) {
        this.x = x;
        this.y = y;

        this.xSpeed = xSpeed;
        this.ySpeed = ySpeed;

        this.damage = damage;

        this.radius = 8;
    }

    update() {
        this.x += this.xSpeed / fps;
        this.y += this.ySpeed / fps;

        this.c = 0

        for (this.e of enemies) {
            if (((((this.x - this.e.x) ** 2) + ((this.y - this.e.y) ** 2)) ** 0.5) < (this.radius + this.e.radius) * 0.75) {
                this.e.health -= this.damage;
                player.bullets.splice(player.bullets.indexOf(this), 1);
            }
            this.c++;
        }
    }

    display() {
        ellipse(this.x, this.y, this.radius, this.radius);
    }
}

class enemy {
    constructor() {
        this.x = round(random(-W * 2, -W)) * ((round(random(0, 1)) * 2) - 1) + player.x
        this.y = round(random(-H * 2, -H)) * ((round(random(0, 1)) * 2) - 1) + player.y

        this.radius = round(random(50, 250));

        this.xSpeed = 0;
        this.ySpeed = 0;

        this.health = 100;
        this.speed = round(random(400, 500));

        this.drag = 0.9;
        this.playerDist = W;
    }

    update() {

        if(this.health <= 0){
            enemies.splice(enemies.indexOf(this), 1);
        }

        this.playerDist = ((this.x - player.x) ** 2 + (this.y - player.y) ** 2) ** 0.5

        if (this.radius >= this.playerDist) {
            bg = [128, 48, 48]
            player.health = 0;
        }

        if (this.x < player.x) {
            this.xSpeed += this.speed / fps;
        } else {
            this.xSpeed -= this.speed / fps;
        }

        if (this.y < player.y) {
            this.ySpeed += this.speed / fps;
        } else {
            this.ySpeed -= this.speed / fps;
        }

        this.x += this.xSpeed / fps;
        this.y += this.ySpeed / fps;

        this.xSpeed = this.xSpeed * (1 - (this.drag / fps));
        this.ySpeed = this.ySpeed * (1 - (this.drag / fps));
    }

    display() {
        ellipse(this.x, this.y, this.radius, this.radius)
    }
}

function aimToMouse(x1, y1, x2, y2) {
    xDif = x1 - x2
    yDif = y1 - y2
    angle = 0
    if (xDif > 0 && yDif < 0) {
        angle = atan(xDif / -yDif)
    }
    if (xDif >= 0 && yDif >= 0) {
        angle = atan(yDif / xDif) + 90
    }
    if (xDif <= 0 && yDif >= 0) {
        angle = atan(-xDif / yDif) + 180
    }
    if (xDif <= 0 && yDif <= 0) {
        angle = atan(yDif / xDif) + 270
    }

    if (xDif == 0 && yDif <= 0) {
        angle = 0
    }

    return angle;
}