// ===============================
// AUTH.JS — Login + Token + Redirect + Auto-Login
// ===============================

// parseJwt DEVE essere globale
function parseJwt(token) {
  try {
    const base64Url = token.split('.')[1];
    const base64 = base64Url.replace(/-/g, '+').replace(/_/g, '/');
    const jsonPayload = decodeURIComponent(
      atob(base64)
        .split('')
        .map(c => '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2))
        .join('')
    );
    return JSON.parse(jsonPayload);
  } catch (e) {
    console.error("Errore parseJwt:", e);
    return null;
  }
}

(() => {
  const LOGIN_ENDPOINT = "/auth/login";
  const TOKEN_KEY = "token";

  // -------------------------------
  // Helpers token
  // -------------------------------
  function saveToken(token) {
    try {
      localStorage.setItem(TOKEN_KEY, token);
    } catch (err) {
      console.error("Errore salvataggio token:", err);
    }
  }

  function getToken() {
    try {
      return localStorage.getItem(TOKEN_KEY) || "";
    } catch {
      return "";
    }
  }

  function clearToken() {
    try {
      localStorage.removeItem(TOKEN_KEY);
    } catch {}
  }

  // -------------------------------
  // JWT decode
  // -------------------------------
  function decode(token) {
    return parseJwt(token);
  }

  // -------------------------------
  // LOGIN
  // -------------------------------
  async function login(email, password) {
    try {
      const res = await fetch(LOGIN_ENDPOINT, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ email, password })
      });

      if (!res.ok) {
        const msg = await res.text();
        throw new Error(msg || "Credenziali non valide");
      }

      const data = await res.json();
      if (!data?.token) {
        throw new Error("Token mancante nella risposta");
      }

      saveToken(data.token);

      // Notifica globale
      window.dispatchEvent(new CustomEvent("login:success", { detail: data }));

      // Auto-logout programmato
      scheduleAutoLogout();

      return data;
    } catch (err) {
      console.error("Errore login:", err);
      throw err;
    }
  }

  // -------------------------------
  // CHECK LOGIN
  // -------------------------------
  function isLoggedIn() {
    const token = getToken();
    if (!token) return false;

    const payload = decode(token);
    if (!payload?.exp) return false;

    return payload.exp * 1000 > Date.now();
  }

  // -------------------------------
  // USER INFO
  // -------------------------------
  function getUser() {
    const token = getToken();
    if (!token) return null;

    return decode(token);
  }

  // -------------------------------
  // REQUIRE AUTH
  // -------------------------------
  function requireAuth(redirectUrl = "/login") {
    if (!isLoggedIn()) {
      window.location.assign(redirectUrl);
      return false;
    }
    return true;
  }

  // -------------------------------
  // AUTO-LOGOUT
  // -------------------------------
  let autoLogoutTimer = null;

  function scheduleAutoLogout() {
    clearTimeout(autoLogoutTimer);

    const token = getToken();
    if (!token) return;

    const payload = decode(token);
    const expSec = payload?.exp;
    if (!expSec) return;

    const msToExp = expSec * 1000 - Date.now();
    if (msToExp <= 0) {
      window.AppAuth.logout?.({ redirect: true });
      return;
    }

    autoLogoutTimer = setTimeout(() => {
      window.AppAuth.logout?.({ redirect: true });
    }, msToExp);
  }

  // -------------------------------
  // EXPORT API
  // -------------------------------
  window.AppAuth = Object.freeze({
    login,
    logout: (opts) => window.AppAuthLogout?.logout(opts),
    isLoggedIn,
    getUser,
    requireAuth,
    scheduleAutoLogout
  });

  // -------------------------------
  // INIT
  // -------------------------------
  function init() {
    if (isLoggedIn()) {
      scheduleAutoLogout();
    }
  }

  if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", init);
  } else {
    init();
  }
})();