document.getElementById("loginForm").addEventListener("submit", function(e) {
  e.preventDefault();

  const username = document.getElementById("username").value.trim();
  const password = document.getElementById("password").value.trim();
  const errorBox = document.getElementById("errorBox");

  errorBox.style.display = "none";
  errorBox.innerText = "";

  if (!username || !password) {
    showError("Username dan password harus diisi");
    return;
  }

  if (password.length < 6) {
    showError("Password minimal 6 karakter");
    return;
  }

  const usersData = localStorage.getItem("users");
  const users = usersData ? JSON.parse(usersData) : [];

  const user = users.find(u => u.username === username);

  if (!user) {
    showError("Username tidak ditemukan");
    return;
  }

  if (user.password !== password) {
    showError("Password salah");
    return;
  }

  // Login success
  localStorage.setItem("loggedInUser", JSON.stringify(user));
  window.location.href = "mainboard.html";
});

function showError(msg) {
  const errorBox = document.getElementById("errorBox");
  errorBox.innerText = msg;
  errorBox.style.display = "block";
}