const express = require("express");
const ed = require("@noble/ed25519");
const { sha512 } = require("@noble/hashes/sha2.js");
ed.hashes.sha512 = sha512;
const config = require("./config.json");
const fs = require("node:fs");
const { parse: parseUrl } = require("node:url");
const dns = require("node:dns");
const fetch = require("sync-fetch");
const app = express();
const deasync = require("deasync");
const keysToBase64 = (keys) => {
	return {
		secretKey: new Buffer(keys.secretKey)
			.toString("base64")
			.replace("+", "-")
			.replace("/", "_")
			.replace(/=+$/, ""),
		publicKey: new Buffer(keys.publicKey)
			.toString("base64")
			.replace("+", "-")
			.replace("/", "_")
			.replace(/=+$/, ""),
	};
};
const base64ToKeys = (keys) => {
	const fixBase64 = (str) =>
		str
			.replace("-", "+")
			.replace("_", "/")
			.padEnd(str.length + ((4 - (str.length % 4)) % 4), "=");
	return {
		secretKey: new Uint8Array(Buffer.from(fixBase64(keys.secretKey), "base64")),
		publicKey: new Uint8Array(Buffer.from(fixBase64(keys.publicKey), "base64")),
	};
};

if (!config.secretKey) {
	const keys = ed.keygen();
	config.secretKey = keys.secretKey;
	config.publicKey = keys.publicKey;
	fs.writeFileSync(
		"config.json",
		JSON.stringify({ ...config, ...keysToBase64(config) }),
	);
}
const delegation = (name) => {
	const res = fetch(`https://${name}/.well-known/matrix/server`);
	if (res.status === 200) {
		const json = res.json();
		if (!json["m.server"].includes(":")) {
			return delegation(json["m.server"]);
		}
		return { domain: json["m.server"], host: json["m.server"] };
	} else {
		const resolve = deasync(dns.resolveSrv);
		try {
			const res = resolve(`_matrix-fed._tcp.${name}`)[0];
			return {
				domain: `${res.name}:${res.port}`,
				host: name || res.name,
			};
		} catch (_e) {
			try {
				const res = resolve(`_matrix._tcp.${name}`)[0];
				return { domain: `${res.name}:${res.port}`, host: name || res.name };
			} catch (_e) {
				return {
					domain: `${name}:8448`,
					host: name || res.name,
				};
			}
		}
	}
};
const makeSignedRequest = (origin, method, url) => {
	const parsed = parseUrl(url);
	let payload = {
		method: method,
		uri: parsed.path,
		destination: parsed.hostname,
		origin: origin,
	};
	payload = Object.fromEntries(
		Object.entries(payload).sort(([keyA], [keyB]) => keyA.localeCompare(keyB)),
	);
	const delegate = delegation(parsed.hostname);
	const keys = base64ToKeys(config);
	const signature = ed.sign(
		new TextEncoder().encode(JSON.stringify(payload)),
		keys.secretKey,
	);
	console.log(
		`X-Matrix origin="${origin}",destination="${parsed.hostname}",key="ed25519:${config.publicKey.slice(0, 5)}",sig="${new Buffer(signature).toString("base64").replace("+", "-").replace("/", "_").replace(/=+$/, "")}"`,
	);
	return fetch(
		`https://${delegate.domain}${parsed.path}`,
		{
			headers: {
				Host: delegate.host,
				Authorization: `X-Matrix origin="${origin}",destination="${parsed.hostname}",key="ed25519:${config.publicKey.slice(0, 5)}",sig="${new Buffer(signature).toString("base64").replace("+", "-").replace("/", "_").replace(/=+$/, "")}"`,
			},
		},
	);
};

app.get("/.well-known/matrix/server", (req, res) => {
	return res.json({
		"m.server": req.host.includes(":") ? req.host : `${req.host}:443`,
	});
});
app.get("/_matrix/federation/v1/version", (_req, res) => {
	res.json({
		server: {
			name: "idk",
			version: "0.0.0.0.0.0.0.1",
		},
	});
});
app.get("/_matrix/key/v2/server", (req, res) => {
	const payload = {
		old_verify_keys: {},
		server_name: req.host.replace(":443", ""),
		valid_until_ts: Number.MAX_SAFE_INTEGER,
		verify_keys: {},
	};
	payload.verify_keys[`ed25519:${config.publicKey.slice(0, 5)}`] = {
		key: config.publicKey,
	};
	const keys = base64ToKeys(config);
	const signature = ed.sign(
		new TextEncoder().encode(
			JSON.stringify(
				Object.fromEntries(
					Object.entries(payload).sort(([keyA], [keyB]) =>
						keyA.localeCompare(keyB),
					),
				),
			),
		),
		keys.secretKey,
	);
	payload.signatures = {};
	payload.signatures[req.host.replace(":443", "")] = {};
	payload.signatures[req.host.replace(":443", "")][
		`ed25519:${config.publicKey.slice(0, 5)}`
	] = new Buffer(signature)
		.toString("base64")
		.replace("+", "-")
		.replace("/", "_")
		.replace(/=+$/, "");
	res.json(payload);
});
app.get("/_test/version", (req, res) => {
	const result = delegation(req.query.domain);
	console.log(result);
	res.json(
		fetch(`https://${result.domain}/_matrix/federation/v1/version`, {
			headers: { Host: result.host },
		}).json(),
	);
});
app.get("/_test/alias", (req, res) => {
	res.json(
		makeSignedRequest(
			req.host.replace(":443", ""),
			"GET",
			"https://yjsryd6gyhgl5eyikakf2xe5o4.srv.us/_matrix/federation/v1/query/directory?room_alias=%23ok%3Aorehus.club",
		).json(),
	);
});
app.listen(3000, () => console.log("Listening at 3000"));