/// <reference lib="deno.worker" />

// runs the game in a worker without any permissions, the host does files and networking
import type { GameServer } from "./game_server.ts";
import { GameLoop } from "./game_loop.ts";
import { GameToHost, HostToGame } from "./host_protocol.ts";
import { data_url, start_game } from "./load_mods.ts";

const SAVE_INTERVAL_MS = 30_000;

let game: GameServer | undefined;
let starting: Promise<void> | undefined;

function post(message: GameToHost) {
	self.postMessage(message);
}

self.onmessage = async (event: MessageEvent<HostToGame>) => {
	const message = event.data;

	if (message.type === "init") {
		starting = init(message);
		return;
	}

	// players can connect while mods are still loading
	await starting;
	if (!game) {
		return;
	}

	switch (message.type) {
		case "connect":
			game.on_connect(message.conn);
			break;
		case "message":
			game.on_message(message.conn, message.data);
			break;
		case "disconnect":
			game.on_disconnect(message.conn);
			break;
		case "shutdown":
			post({ type: "save", data: game.save(), final: true });
			break;
	}
};

async function init(message: Extract<HostToGame, { type: "init" }>) {
	try {
		game = await start_game(
			{
				send: (conn, data) => post({ type: "send", conn, data }),
				close: (conn) => post({ type: "close", conn }),
			},
			message.save,
			message.default_seed,
			message.atlas,
			message.mods.map((mod) => ({
				listing: mod.listing,
				data: mod.data,
				// the worker has no file access, so the host sends the code and it's imported from memory
				server_url: mod.server_code ? data_url(mod.server_code) : undefined,
				worldgen_url: mod.worldgen_code ? data_url(mod.worldgen_code) : undefined,
			})),
		);
	} catch (e) {
		post({ type: "failed", error: e instanceof Error ? e.message : String(e) });
		return;
	}

	const loop = new GameLoop(() => game!.tick());
	game.loop = loop;
	loop.start();

	setInterval(() => {
		if (game!.world.dirty) {
			post({ type: "save", data: game!.save(), final: false });
		}
	}, SAVE_INTERVAL_MS);

	post({ type: "ready", seed: game.world.seed });
}