db.js

const Database = require('better-sqlite3');
const path = require('path');

const dbPath = path.join(__dirname, 'users.db');
const db = new Database(dbPath);

db.prepare(`
  CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    email TEXT NOT NULL UNIQUE,
    username TEXT NOT NULL UNIQUE,
    password TEXT NOT NULL
  )
`).run();

function registerUser({ name, email, username, password }) {
  try {
    db.prepare('INSERT INTO users (name, email, username, password) VALUES (?, ?, ?, ?)')
      .run(name, email, username, password);
    return { success: true };
  } catch (e) {
    if (e.code === 'SQLITE_CONSTRAINT_UNIQUE') {
      return { success: false, error: 'Email ou usuário já cadastrado.' };
    }
    return { success: false, error: e.message };
  }
}

function loginUser({ usernameOrEmail, password }) {
  const user = db.prepare('SELECT * FROM users WHERE (username = ? OR email = ?) AND password = ?')
    .get(usernameOrEmail, usernameOrEmail, password);
  if (user) {
    return { success: true, user };
  }
  return { success: false, error: 'Usuário ou senha incorretos.' };
}

function getAllUsers() {
  return db.prepare('SELECT id, name, email, username FROM users').all();
}

module.exports = { registerUser, loginUser, getAllUsers };