var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');

var ship = new Ship();
var bullets = [];
function allUpdate(){
    drawBackground();
    ship.update();
    //for loop to draw all bullets
    for(var i =0;i < bullets.length;i++){
        var bullet = bullets[i];
        bullet.update();
    }

    window.requestAnimationFrame(allUpdate);
}
window.requestAnimationFrame(allUpdate);

window.onkeydown = function(event){
    var left = 37;
    var up = 38;
    var right = 39;
    var down = 40;

    if(event.keyCode == up)
        ship.dY = -1;
    if(event.keyCode == down)
        ship.dY = 1;
    if(event.keyCode ==  left){
        ship.isRotating = true;
        ship.theta = -5;
    }
    if(event.keyCode == right){
        ship.isRotating = true;
        ship.theta = 5;
    }
    if(event.key == " "){
        var x = ship.x + ship.width;
        var y = ship.y + ship.height/2;
        var bullet = new Bullet(x,y);
        bullets.push(bullet);
    }

}
window.onkeyup = function(event){
        var left = 37;
        var up = 38;
        var right = 39;
        var down = 40;
        if(event.keyCode == left || event.keyCode == right){
            ship.isRotating = false;
            ship.theta = 0;
        }

    }

var Bullet = function(x,y){
    this.x = x;
    this.y = y;
    this.r = 5;
    this.dX = 2;
    this.dY = 2;

    this.update = function(){
        ctx.fillStyle = "blue";
        ctx.beginPath();
        ctx.arc(this.x+=this.dX,this.y,this.r,0,Math.PI *2,false);
        ctx.closePath();
        ctx.fill();
    }

}


function Ship(){
    this.isRotating = false;
    this.theta = 0; //in degrees
    this.width = 30;
    this.height = 10;
    this.x = 0;
    this.y = canvas.height/2;
    this.dX = 1;
    this.dY = 0;
    this.fillStyle = "white";
    this.update = function() {
        ctx.fillStyle = "white";
        ctx.fillRect(this.x+=this.dX,this.y+=this.dY,this.width,this.height);
        ctx.translate(this.x,this.y+(this.height/2));
        ctx.rotate((this.theta) * Math.PI/180);
        ctx.translate(-this.x,-(this.y +this.height/2));
    }

}

function drawBackground(){
    ctx.fillStyle = "black";
    ctx.fillRect(0,0,canvas.width,canvas.height);
}