import browser.document;
import browser.window;
import jslang.math;

pragma(no_js_output) {
	enum PI = 3.14159265358979323846;
	float degreesToRadians(float x) {
		return (x * PI / 180);

	}
	template degrees(float x) {
		enum degrees = degreesToRadians(x);
	}
}

struct Player {
	float x = 640/2;
	float y = 480/2;
	float angle = 0;
	float dx = 0;
	float dy = 0;
	float da = 0;
	bool rotatingLeft;
	bool rotatingRight;
	bool thrusting;
	bool shooting;

	void advanceFrame() {
		if(rotatingLeft)
			da -= degrees!1;
		if(rotatingRight)
			da += degrees!1;

		angle += da;

		if(thrusting) {
			dx += Math.cos(angle);
			dy += Math.sin(angle);
		}

		x += dx;
		y += dy;

		if(x < 0)
			x += 640;
		if(y < 0)
			y += 480;
		if(x > 640)
			x -= 640;
		if(y > 480)
			y -= 480;
	}

	void draw(JSCanvasContext painter) {
		float size = 15;

		painter.strokeStyle = "#ffffff";

		painter.beginPath();

		painter.moveTo(x, y);

		foreach(a; [degrees!(180-30), degrees!0, degrees!(180+30)]) {
			painter.lineTo( x + size * Math.cos(a + angle), y + size * Math.sin(a + angle));
		}

		painter.lineTo(x, y);

		painter.closePath();
		painter.stroke();
	}
}


JSElement canvas;
Player player; // FIXME: this should have been initialized

void frame() {
	player.advanceFrame();

	auto painter = canvas.getContext("2d");
	painter.fillStyle = "#000000";
	painter.fillRect(0, 0, 640, 480); // clear the screen

	player.draw(painter);
}

void main() {
	player = Player.init; // FIXME: this shouldn't be necessary

	canvas = document.getElementById("game");
	auto interval = window.setInterval(&frame, 50);

	document.mainBody.addEventListener("click", {
		// play/pause on click
		if(interval) {
			window.clearInterval(interval);
			interval = 0;
		} else {
			interval = window.setInterval(&frame, 50);
		}
	}, false);

	void keyEventHandler(JSEvent event) {
		auto down = event.type == "keydown";
		switch(event.which) {
			case 'A', 'a':
				player.rotatingLeft = down;
			break;
			case 'D', 'd':
				player.rotatingRight = down;
			break;
			case 'W', 'w':
				player.thrusting = down;
			break;
			case ' ':
				player.shooting = down;
			break;
			default: {}
		}

		event.preventDefault();
	}

	document.mainBody.addEventListener("keydown", &keyEventHandler, false);
	document.mainBody.addEventListener("keyup", &keyEventHandler, false);
}