import {
	createWindow,
	getProcAddress,
	mainloop,
	gl,
} from "./deps.ts";

const window = createWindow({
	title: "Faux",
	width: 1024,
	height: 1024,
	resizable: false,
	glVersion: [3, 2],
	gles: true,
});

gl.load(getProcAddress);

function loadShader(type: number, src: string) {
	const shader = gl.CreateShader(type);
	gl.ShaderSource(
		shader,
		1,
		new Uint8Array(
			new BigUint64Array([
				BigInt(
					Deno.UnsafePointer.value(
						Deno.UnsafePointer.of(new TextEncoder().encode(src)),
					),
				),
			]).buffer,
		),
		new Int32Array([src.length]),
	);
	gl.CompileShader(shader);
	const status = new Int32Array(1);
	gl.GetShaderiv(shader, gl.COMPILE_STATUS, status);
	if (status[0] === gl.FALSE) {
		const logLength = new Int32Array(1);
		gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, logLength);
		const log = new Uint8Array(logLength[0]);
		gl.GetShaderInfoLog(shader, logLength[0], logLength, log);
		console.log(new TextDecoder().decode(log));
		gl.DeleteShader(shader);
		return 0;
	}
	return shader;
}

const vShaderSrc = `
attribute vec4 vPosition;
attribute vec4 vCol;
varying vec4 color;
void main() {
	gl_Position = vPosition;
	color = vCol;
}
`;

const fShaderSrc = `
	precision mediump float;
	varying vec4 color;
	void main() {
		gl_FragColor = color;
	}
 `;

const vShader = loadShader(gl.VERTEX_SHADER, vShaderSrc);
const fShader = loadShader(gl.FRAGMENT_SHADER, fShaderSrc);

const program = gl.CreateProgram();
gl.AttachShader(program, vShader);
gl.AttachShader(program, fShader);

gl.BindAttribLocation(program, 0, new TextEncoder().encode("vPosition\0"));
gl.BindAttribLocation(program, 1, new TextEncoder().encode("vCol\0"));

gl.LinkProgram(program);

const status = new Int32Array(1);
gl.GetProgramiv(program, gl.LINK_STATUS, status);
if (status[0] === gl.FALSE) {
	const logLength = new Int32Array(1);
	gl.GetProgramiv(program, gl.INFO_LOG_LENGTH, logLength);
	const log = new Uint8Array(logLength[0]);
	gl.GetProgramInfoLog(program, logLength[0], logLength, log);
	console.log(new TextDecoder().decode(log));
	gl.DeleteProgram(program);
	Deno.exit(1);
}

gl.ClearColor(0.0, 0.0, 0.0, 1.0);

addEventListener("resize", (event) => {
	gl.Viewport(0, 0, event.width, event.height);
});

const pixelsPerRow = 128;

const top = 1;
const left = -1;
const cell = 2/pixelsPerRow;

const px = (x: number, y: number) => {
	// deno-fmt-ignore
	return [
		left + x*cell, top - y*cell, 0,
		left + (x+1)*cell, top - y*cell, 0,
		left + x*cell, top - (y+1)*cell, 0,
		left + (x+1)*cell, top - y*cell, 0,
		left + x*cell, top - (y+1)*cell, 0,
		left + (x+1)*cell, top - (y+1)*cell, 0,
	];
}

const palette = [
	[0, 0, 0, 0],
	[0, 0, 0, 1],
	[1, 1, 1, 1],
	[1, 0, 0, 1],
	[1, 1, 0, 1],
	[0, 1, 0, 1],
	[0, 0, 1, 1],
]

const c = (n: number) => {
	return [
		...palette[n],
		...palette[n],
		...palette[n],
		...palette[n],
		...palette[n],
		...palette[n],
	];
}

const allPixelTriangles = new Float32Array(
	Array(pixelsPerRow*pixelsPerRow).fill(null).flatMap((_, i) => px(i%pixelsPerRow,Math.floor(i/pixelsPerRow)))
)

const choose = <T>(alts: Array<T>): T => {
	return alts[Math.floor(Math.random()*alts.length)];
}

const allPixelColors = new Float32Array(
	Array(pixelsPerRow*pixelsPerRow).fill(null).flatMap(() => c(choose([1,2,3,4,5,6])))
)

const frame = () => {
	gl.Clear(gl.COLOR_BUFFER_BIT);
	gl.UseProgram(program);
	gl.VertexAttribPointer(0, 3, gl.FLOAT, gl.FALSE, 0, allPixelTriangles);
	gl.VertexAttribPointer(1, 4, gl.FLOAT, gl.FALSE, 0, allPixelColors);
	gl.EnableVertexAttribArray(0);
	gl.EnableVertexAttribArray(1);
	gl.DrawArrays(gl.TRIANGLES, 0, 6*pixelsPerRow*pixelsPerRow);
	window.swapBuffers();
}

await mainloop(() => {
	frame();
});