#!/usr/bin/env node
/**
 * A test NeoPass server! This is a very lean, hacky implementation, designed
 * to just see the basic OAuth interactions Work At All.
 *
 * First, we have a "backing server", which is a `oauth2-mock-server` instance
 * that's easy to spin up and have perform OAuth for us. We give it a hardcoded
 * development-only key, and it just auto-grants permissions!
 *
 * We also have a "main server", which obeys the actual NeoPass API: the
 * backing server isn't configurable with stuff like paths, so we use the main
 * server to proxy from the paths in the NeoPass spec to the paths the backing
 * server uses.
 */

const fs = require("node:fs/promises");
const pathLib = require("node:path");
const { spawn } = require("node:child_process");
const urlLib = require("node:url");

const { OAuth2Server } = require("oauth2-mock-server");
const express = require("express");

const certPath = pathLib.join(__dirname, "..", "tmp", "localhost.pem");
const keyPath = pathLib.join(__dirname, "..", "tmp", "localhost-key.pem");

async function fileExists(path) {
	try {
		await fs.stat(path);
	} catch (error) {
		if (error.code === "ENOENT") {
			return false;
		}
		throw error;
	}
	return true;
}

async function ensureCertsExist() {
	if (!(await fileExists(certPath)) || !(await fileExists(keyPath))) {
		console.log(
			"Using mkcert to create localhost.pem and localhost-key.pem in " +
				"the Rails tmp dir, to serve over HTTPS.",
		);

		const mkcertProc = spawn("mkcert", [
			"-cert-file",
			certPath,
			"-key-file",
			keyPath,
			"localhost",
		], {stdio: ["ignore", process.stdout, process.stderr]});

		// Wait for the process to finish, raising an error if it fails.
		await new Promise((resolve, reject) => {
			mkcertProc.on("close", (code) => {
				if (code === 0) {
					resolve();
				} else {
					reject(new Error(`mkcert returned status ${code}`));
				}
			});
			mkcertProc.on("error", (error) => {
				reject(error);
			});
		});
	}
}

async function startBackingServer(port) {
	const server = new OAuth2Server(
		keyPath,
		certPath,
	);
	await server.issuer.keys.add({
		// A key we generated for the NeoPass test server. It's okay for its
		// "secret" info to be here, because it's for development only!
		kid: "neopass-server-DEVLOPMENT-ONLY-NOT-FOR-PRODUCTION",
		p: "50btwsJlPbGLUFnCSBZzddyMX_oRQ8nz4lMrpAd4umPLqMUmS0NbBZNf6DI7s8PkRUxtV8KdvZh3OYWavFnbk55GDG4Y_J_wA4XlHU3d5KIfSNaIdbtVp4CFOq1lovho4sYX_26vcGgYb2Azeg7nz_gDpqNmIdJdKuZxzsrboK8",
		kty: "RSA",
		q: "xha0i9_lbOMQhmmni02Dtpocil26GI7W8xbOFyOvceBCRNf-XOA_-W_Xk9ItJRHnAWM1TML36PN0l864d4QAXbBo64FHu2cjdFKnXJNliJaPcOPAMQB_D8GSylU1gTwSpP_vVe8t232LeF1oBwbOoBIS-6NsOpLmL8Sezv6Fpac",
		d: "WSUNeEd_EyaELK7wqT6GJJK_RfYjaE5h6USe9rD9cd_tQE2PaZWXMyZ4OCk5Z5hdG2ryZY7NYsOI2CPs8HCFBqMoKd0z0A0EgB8Dq2fe_-t5Rm0Zq1ZnI5tnBcZeQmw0hDT98Wg00FA53SSUqfnOgI_VuLvquM6f18_XQOKRRfTcwh1a4teDAH0g0s8FVOS5DANtg71mTdq5fEkWmQMD3qKC6SNrx3WXXHezDs0MWdeFqn9Dg7gssSqB7PnqB-hlC_fHnu4gm9nDqPTMzsJC2i8d3adm0AeORRCulGLe7hU-_TgTbZzgIYCgOK_asaewW-6Qk9qFj-J4djBaKIee-Q",
		e: "AQAB",
		use: "sig",
		qi: "WNiwCcAk2x7e0KvuupL2DNU-JUjLEF9Onee5T9u9ihbgGSDIyP04_96TzCIK3wsY6lct64oOo0Er-z5cf_5eOBPD3n0eEL-JuKIgn0mEKrazJOnGQzlyeZPzk4dUO2J7D42ObopfYsoBIcJx-Y_43a6WORDMGSVCiURmKavTHUU",
		dp: "p1_wj-Npq3VDElpzPQJqeuCrAoaSWhHcm21_hs0VdSbl6_UJ2qwbQnS-kudPx7A8El7WPw4MZHrjxdBIBImvXCzOGw7OrHz_ET2ka0nADUe7BlakGTgDLB7ZzHZSuNe36G5eTbCH7PyYunnPp0UERMEDu2RDdLSuUm7F7FdpDOc",
		alg: "RS256",
		dq: "purLCHKKKM7NRfYRsFiI_H2wPwfroHX8uqokz2rKk_Kc5NX9CNYOEmokBfO9BtenCIxIhX5k2G8NeD5BQrSAenIEdy5g-5FVVtevH1s023vDMyU29hOs_eHnh4d1poiwTUk8q_T3d1S7CZnr5r_drRSN2m1C7biLLwVHrLTceVE",
		n: "svVfGU4NGcfBCmQiIOW5uzg5SAN2CWSIQSstnhqZoCdjy5OoKpKVR8O9TbDvxixrvkFyAav90Q0Xse8iFTcjfCKuqINYiuYMXhCvfBlc_DVVOQca9pMpN03LaDofd5Ll4_BFTtt1nSPahwWU7xDM-Bkkh_TcS2qS4N2xbpEGi0q0ZkrJN4WyiDBC2k9WbK-YHr4Rj4JKypFVSeBIrjxVPmlPzgfqlLGGIB0l92SnJDXDMlkWcCCTyLgqSBM04nkxGDSykq_ei76qCdRd7b10wMBaoS9DeBThAyHpur2LoPdH3gxbcwoWExi-jPlNP1LdKVZD8b95OY3CRyMAAMGdKQ",
	});

	await server.start(port, "localhost");
	console.log(`Started NeoPass backing server at: ${server.issuer.url}`);
}

async function startMainServer(port) {
	const fetch = (await import("node-fetch")).default;

	const app = express();
	app.use(express.text({ type: "*/*" }));

	app.get("/", (req, res) => res.end("NeoPass development server for DTI!"));

	app.get("/oauth2/auth", (req, res) => {
		const query = urlLib.parse(req.url).query;
		res.redirect(`http://localhost:8686/authorize?${query}`);
	});

	app.post("/oauth2/token", async (req, res) => {
		try {
			// For POST requests, the HTTP spec doesn't allow a redirect to a
			// POST, so we proxy the request instead.
			const backingRes = await fetch("http://localhost:8686/token", {
				method: "POST",
				headers: {
					"Content-Type": req.get("Content-Type"),
				},
				body: req.body,
			});
			if (!backingRes.ok) {
				throw new Error(`backing server returned status ${res.status}`);
			}

			res.set("Content-Type", backingRes.headers.get("Content-Type"));
			return res.end(await backingRes.text());
		} catch (error) {
			console.error(error);
			return res.end(error.message);
		}
	});

	await new Promise((resolve) => app.listen(port, resolve));
	console.log(`Started NeoPass main server at: http://localhost:${port}`);
}

async function main() {
	await ensureCertsExist();
	await startBackingServer(8686);
	await startMainServer(8585);
}

main().catch((error) => {
	console.error(error);
});