backend/index.ts

import express, { Request, Response } from "express";
import { Database } from "sqlite3";
import bcrypt from "bcrypt";
import session from "express-session";

const db = new Database("db.sqlite");

declare module "express-session" {
  // noinspection JSUnusedGlobalSymbols
  interface SessionData {
    user?: number;
  }
}

(async () => {
  await dbRun("CREATE TABLE IF NOT EXISTS version ( version INT );");
  const dbVersion: { version: number } | undefined
      = await dbGet("SELECT version FROM version;");

  if (dbVersion && dbVersion.version === 1) {
    console.log("skip db setup")
    return;
  }

  await dbRun(`CREATE TABLE IF NOT EXISTS users (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      name TEXT NOT NULL,
      pass TEXT NOT NULL
    )`);
  await dbRun("CREATE UNIQUE INDEX IF NOT EXISTS idx_users_name ON users (name);");

  await dbRun(`CREATE TABLE IF NOT EXISTS highScores (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      user INTEGER,
      score BIGINT NOT NULL,
      FOREIGN KEY (user) REFERENCES users(id)
    )`);
  await dbRun("INSERT INTO version VALUES (1)");
})();

const app = express();
app.use(express.json());
app.use(session({
  secret: "your mom",
  resave: true,
}));

app.get("/", (_req: Request, res: Response) => {
  res.send("Hello World!");
});

app.get("/leaderboard", async (req: Request, res: Response) => {
  const { limit = 100, offset = 0 } = req.query;

  const leaders = await dbAll(`
select h.score, u.name
from highScores h
    join main.users u on u.id = h.user
order by score desc
limit ? offset ?`, limit, offset);

  res.json(leaders);
});
app.put("/leaderboard", async (req: Request, res: Response) => {
  const { score } = req.body;

  if (!req.session.user) {
    res.status(403).json({ success: false, message: "unauthorised" });
    return;
  }

  if (!score) {
    res.status(400).json({ success: false, message: "provide score" });
    return;
  }

  await dbRun("insert into highScores (user, score) VALUES (?, ?)", req.session.user, score);

  res.status(200).json({ success: true });
});

app.post("/login", async (req: Request, res: Response) => {
  await sleep(Math.random() * 50 + 50);

  const { username, password } = req.body;

  const user: {
    name: string,
    pass: string,
    id: number,
  } = await dbGet("SELECT * FROM users WHERE name = ?", username);

  if (!user) {
    res.status(403).json({ success: false, message: "invalid credentials" });
    return;
  }

  if (!await bcrypt.compare(password, user.pass)) {
    res.status(403).json({ success: false, message: "invalid credentials" });
    return;
  }

  await new Promise(res => req.session.regenerate(res));

  req.session.user = user.id;

  res.status(200).json({ success: true });
});

app.post("/register", async (req: Request, res: Response) => {
  await sleep(Math.random() * 50 + 50);

  const { username, password } = req.body;

  if (!username || !password) {
    res.status(400).json({ success: false, message: "invalid credentials" });
    return;
  }

  const pass = await bcrypt.hash(password, 12);

  const success = await dbRun("INSERT INTO users (name, pass) VALUES (?, ?)", [ username, pass ])
      .then(() => true, () => false);

  if (!success) {
    res.status(400).json({ success: false, message: "invalid credentials" });
  } else {
    res.status(200).json({ success: true });
  }
});

app.post("/logout", async (req: Request, res: Response) => {
  await new Promise(res => req.session.destroy(res));
  res.send(200).json({ success: true });
});

app.listen(3000, () => {
  console.log("Server running on port 3000");
});

function dbGet<T>(query: string, ...args: any[]): Promise<T> {
  return new Promise((res, rej) => {
    db.get(query, ...args, (err: unknown, result: T) => {
      if (err) rej(err);
      else res(result);
    });
  });
}

function dbAll<T>(query: string, ...args: any[]): Promise<T[]> {
  return new Promise((res, rej) => {
    db.all(query, ...args, (err: unknown, result: T[]) => {
      if (err) rej(err);
      else res(result);
    });
  });
}

function dbRun(query: string, ...args: any[]): Promise<void> {
  return new Promise((res, rej) => {
    db.run(query, ...args, (err: unknown) => {
      if (err) rej(err);
      else res();
    });
  })
}

function sleep(ms: number) {
  return new Promise(resolve => setTimeout(resolve, ms));
}