const User = require('../models/User');
const argon2 = require('argon2');

async function usernameTaken(username) {
  return await User.exists({ username });
}

async function getUserByUsername(username) {
  return await User.findOne({ username });
}

async function checkPassword(username, password) {
  const user = await User.findOne({ username });
  if (!user) return false;
  return await argon2.verify(user.passwordHash, password);
}

async function createUser(username, password) {
  if (await usernameTaken(username)) return null;
  const hash = await argon2.hash(password);
  const newUser = new User({ username, passwordHash: hash });
  return await newUser.save();
}

async function updatePassword(userId, newPassword) {
  const hash = await argon2.hash(newPassword);
  return await User.findByIdAndUpdate(userId, { passwordHash: hash });
}

module.exports = {
  usernameTaken,
  getUserByUsername,
  checkPassword,
  createUser,
  updatePassword
};