import { join } from "jsr:@std/path";
import { serveDir } from "jsr:@std/http/file-server";

const root = import.meta.dirname ?? ".";
const port = Number(Deno.env.get("PORT") ?? "8080");

function trimPathLine(line: string): string {
	let s = line.trim();
	if (!s || s.startsWith("#")) return "";
	if ((s.startsWith('"') && s.endsWith('"')) || (s.startsWith("'") && s.endsWith("'"))) {
		s = s.slice(1, -1);
	}
	return s.trim();
}

/** Optional one-line file next to this script: absolute path to `ChatRequest/Database.json`. */
function readOptionalPathFile(): string | undefined {
	try {
		const pathFile = join(root, "chat-request-database.path");
		const raw = Deno.readTextFileSync(pathFile);
		for (const line of raw.split(/\r?\n/)) {
			const p = trimPathLine(line);
			if (p) return p;
		}
	} catch {
		// missing or unreadable
	}
	return undefined;
}

const chatRequestDatabase =
	Deno.env.get("CHAT_REQUEST_DATABASE")?.trim() || readOptionalPathFile();

function isChatRequestFilename(pathname: string): boolean {
	const base = pathname.split("/").pop() ?? "";
	return base === "ChatRequest.json" || base === "database.json";
}

Deno.serve({ port, hostname: "127.0.0.1" }, async (req) => {
	const url = new URL(req.url);
	if (req.method === "GET" && chatRequestDatabase && isChatRequestFilename(url.pathname)) {
		try {
			let text = await Deno.readTextFile(chatRequestDatabase);
			if (text.charCodeAt(0) === 0xfeff) text = text.slice(1);
			return new Response(text, {
				headers: {
					"Content-Type": "application/json; charset=utf-8",
					"Cache-Control": "no-store",
				},
			});
		} catch (e) {
			if (e instanceof Deno.errors.NotFound) {
				console.error(`CHAT_REQUEST_DATABASE not found: ${chatRequestDatabase}`);
				return new Response(null, { status: 404 });
			}
			const msg = e instanceof Error ? e.message : String(e);
			console.error(`CHAT_REQUEST_DATABASE read error (${chatRequestDatabase}): ${msg}`);
			return new Response(`Failed to read CHAT_REQUEST_DATABASE: ${msg}\n`, { status: 500 });
		}
	}
	return serveDir(req, { fsRoot: root, showDirListing: false });
});

console.log(`Overlay: http://127.0.0.1:${port}/index.html`);
if (chatRequestDatabase) {
	console.log(`Chat request database file: ${chatRequestDatabase}`);
} else {
	console.warn(
		"No database path: set CHAT_REQUEST_DATABASE or create chat-request-database.path (see README). " +
			"Otherwise /ChatRequest.json is only served from this folder if the file exists.",
	);
}