"use strict";
const assert = require("assert").strict;
const fs = require("node:fs/promises");
const http = require("http");
const https = require("https");
const util = require("util");
const events = require("node:events");

const HttpCloser = require("@clusterio/controller/dist/node/src/HttpCloser").default;

// Time to wait during async operations to ensure they happened in order.
const tick = 20;

// Register a rejection handler to the promise so that Node.js doesn't panic.
function catched(promise) {
	promise.catch(() => {});
	return promise;
}

function stageWaiter() {
	let stage;
	let waitForStage = new Promise(resolve => { stage = resolve; });
	return [stage, waitForStage];
}

function serverSuite(proto) {
	let api = proto === "http" ? http : https;
	let server;
	let serverOptions = {};
	let clientOptions = {};
	let closer;
	let isClosed;
	let addr;

	function setClosed() {
		isClosed = true;
	}

	async function get(url, options = {}) {
		const request = api.request(url, { ...clientOptions, ...options });
		request.end();
		const [response] = await events.once(request, "response");
		response.body = await new Promise((resolve, reject) => {
			const chunks = [];
			response.on("data", chunk => { chunks.push(chunk); });
			response.on("error", err => { reject(err); });
			response.on("end", () => { resolve(Buffer.concat(chunks)); });
		});
		return response;
	}

	before(async function() {
		if (proto === "https") {
			serverOptions.key = await fs.readFile("test/file/tls/key.pem");
			serverOptions.cert = await fs.readFile("test/file/tls/cert.pem");
			clientOptions.ca = serverOptions.cert;
		}
	});
	beforeEach(async function() {
		isClosed = false;
		server = api.createServer(serverOptions);
		server.unref();
		server.on("close", setClosed);
		closer = new HttpCloser(server);
		await util.promisify(server.listen.bind(server))();
		addr = `${proto}://localhost:${server.address().port}/`;
	});

	afterEach(function() {
		server.off("close", setClosed);
	});

	it("should close the server", async function() {
		await closer.close();
		assert(isClosed, "Server was not closed");
	});

	it("should reject with error if the close fails", async function() {
		await closer.close();
		await assert.rejects(closer.close(), { code: "ERR_SERVER_NOT_RUNNING" });
	});

	it("should gracefully let pending requests finish", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			waitForStage2.then(() => { response.end("ok-1"); });
		});

		let request = catched(get(addr));
		await waitForStage1;
		stage2();
		await closer.close();

		let response = await request;
		assert.equal(response.statusCode, 200, "non-200 response status code");
		assert.equal(response.body.toString(), "ok-1", "response content does not match expected");
	});

	it("should set Connection header to close for pending requests", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			waitForStage2.then(() => { response.end("ok-2"); });
			assert.equal(request.headers.connection, "keep-alive", "Connection not kept alive");
		});

		let agent = new api.Agent({ keepAlive: true });
		let request = catched(get(addr, { agent }));
		await waitForStage1;
		stage2();
		await closer.close();

		let response = await request;
		assert.equal(response.statusCode, 200, "non-200 response status code");
		assert.equal(response.body.toString(), "ok-2", "response content does not match expected");
		assert.equal(response.headers.connection, "close", "response Connection header not set to close");
	});

	it("should gracefully close open connections", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		server.on("request", (request, response) => {
			response.end("ok-3");
			assert.equal(request.headers.connection, "keep-alive", "Connection not kept alive");
			stage1();
		});

		let agent = new api.Agent({ keepAlive: true });
		let request = catched(get(addr, { agent }));
		await waitForStage1;
		await closer.close();

		let response = await request;
		assert.equal(response.statusCode, 200, "Request replied with non-200 status code");
		assert.equal(response.body.toString(), "ok-3", "Request content does not match expected");
	});

	it("should refuse connection if request sent after starting closure", async function() {
		this.timeout(4000); // On Windows this test takes 2 seconds for some reason.
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			waitForStage2.then(() => { response.end("ok-4"); });
		});

		let request = catched(get(addr));
		await waitForStage1;
		stage2();
		let close = catched(closer.close());

		let agent = new api.Agent({ keepAlive: true });
		await assert.rejects(get(addr, { agent }), { code: "ECONNREFUSED" });

		let response = await request;
		assert.equal(response.statusCode, 200, "non-200 response status code");
		assert.equal(response.body.toString(), "ok-4", "response content does not match expected");

		await close;
	});

	it("should close connection after in-flight request is over", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			response.write("ok");
			waitForStage2.then(() => { response.end("-5"); });
			assert.equal(request.headers.connection, "keep-alive", "Connection not kept alive");
		});

		let agent = new api.Agent({ keepAlive: true });
		let request = catched(get(addr, { agent }));
		await waitForStage1;
		stage2();
		await closer.close();

		let response = await request;
		assert.equal(response.statusCode, 200, "non-200 response status code");
		assert.equal(response.body.toString(), "ok-5", "response content does not match expected");
	});

	it("should cause connection reset for qeueud request after in-flight request", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			response.write("ok");
			waitForStage2.then(() => { response.end("-6"); });
			assert.equal(request.headers.connection, "keep-alive", "Connection not kept alive");
		});

		let agent = new api.Agent({ keepAlive: true, maxSockets: 1 });
		let request = catched(get(addr, { agent }));
		let droppedRequest = catched(get(addr, { agent }));
		await waitForStage1;
		stage2();
		await closer.close();

		let response = await request;
		assert.equal(response.statusCode, 200, "non-200 response status code");
		assert.equal(response.body.toString(), "ok-6", "response content does not match expected");
		await assert.rejects(droppedRequest, { code: "ECONNRESET" });
	});

	it("should abort requests that take too long to respond", async function() {
		let [stage1, waitForStage1] = stageWaiter();
		let [stage2, waitForStage2] = stageWaiter();
		server.on("request", (request, response) => {
			stage1();
			response.write("ok");
			waitForStage2.then(() => { response.end("-7"); });
		});

		let request = catched(get(addr));
		await waitForStage1;
		await closer.close(tick*2);
		stage2();

		await assert.rejects(request);
	});
}

describe("controller/src/HttpCloser.js", function() {
	describe("class HttpCloser", function() {
		describe("constructor()", function() {
			it("should throw if not passed a Server instance", function() {
				assert.throws(() => new HttpCloser({}));
			});
		});
		for (let proto of ["http", "https"]) {
			describe(`${proto} server`, function() {
				serverSuite(proto);
			});
		}
	});
});