import * as graphics from "./graphics_core.mjs";
export * from "./graphics_core.mjs";

import { range, iter_2d } from "./utils/range.mjs";
import * as entity from "./entity.mjs";
import * as world from "./world.mjs";



const canvas = document.getElementById("canvas");
const canvas_context = canvas.getContext("2d");
graphics.set_size(canvas.width, canvas.height);

const BASE_SCALE = 81;

export function draw_rect (x, y, size = BASE_SCALE) {
	graphics.fill_rect(x, y, size, size);
}

function checkerboard (x, y) {
	return ((x ^ y) & 1) === 0;
}

function should_be_darker (x, y) {
	const CENTER  = world.CENTER;
	const BOX_SIZE = world.BOX_SIZE;

	return x === CENTER && y === CENTER
		|| (x === 0 || x === BOX_SIZE - 1) && (y === 0 || y === BOX_SIZE - 1)
}

export function draw_floor (start_x, start_y, scale, invert = false) {
	iter_2d(range(0, world.BOX_SIZE - 1), (x, y) => {
		let dark = "#888";
		let bright = "#aaa";
		if (should_be_darker(x, y)) {
			dark = "#555";
			bright = "#666";
		}

		graphics.set_color(dark);
		draw_rect(x * scale + start_x, y * scale + start_y, scale);

		graphics.set_color(bright);
		draw_rect(x * scale + start_x, y * scale + start_y, scale / 2);
		draw_rect((x + 0.5) * scale + start_x, (y + 0.5) * scale + start_y, scale / 2);
	});
}

export function draw_world (box, start_x = 0, start_y = 0, scale = BASE_SCALE) {
	if (scale < 1) return;

	draw_floor(start_x, start_y, scale, !checkerboard(start_x, start_y));

	world.for_each_tile(box, (x, y, tile) => {
		draw_tile(tile, x * scale + start_x, y * scale + start_y, scale);
	});

	entity.for_each((entity, id) => {
		if (entity.box !== box) return;
		graphics.set_color(entity.color);
		const [visual_x, visual_y] = project_pos(entity.x, entity.y, scale);
		draw_rect(start_x + visual_x, start_y + visual_y, scale);
	});
}

function draw_tile (tile, x, y, scale) {
	switch (tile.type) {
		case "box": {
			// recursively draw box contents.
			draw_world(tile.box, x, y, scale / world.BOX_SIZE);
			break;
		}
		case "paint": {
			graphics.set_color(tile.color);
			draw_rect(x, y, scale);
			break;
		}
		// temporary: in the future, textures will exist and tile definitions will exist and keep track of textures for tiles.
		case "grass": {
			graphics.set_color("#2a0");
			draw_rect(x, y, scale);
			graphics.set_color("#4c0");
			draw_rect(x, y, scale * 0.5);
			draw_rect(x + scale / 2, y + scale / 2, scale * 0.5);
			break;
		}
	}
}

function project_pos (x, y, scale) {
	return [x, y].map(a => a * scale);
}

export function render () {
	graphics.render(canvas_context);
}