// ===============================
// AUTH.JS — Login + Token + Redirect + Sessione browser
// ===============================

// 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";


  // -------------------------------
  // TOKEN STORAGE
  // -------------------------------

  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);
      sessionStorage.removeItem("app_open");
    } catch {}
  }



  // -------------------------------
  // 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);


      // segna apertura applicazione
      sessionStorage.setItem(
        "app_open",
        "1"
      );


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


      scheduleAutoLogout();


      return data;


    } catch(err) {

      console.error(
        "Errore login:",
        err
      );

      throw err;

    }

  }



  // -------------------------------
  // CHECK LOGIN
  // -------------------------------

  function isLoggedIn() {


    // nuova apertura browser/tab
    if (
      !sessionStorage.getItem("app_open")
    ) {

      console.log(
        "[AUTH] nuova apertura browser"
      );

      return false;

    }


    const token = getToken();


    if (!token) {

      console.log(
        "[AUTH] token assente"
      );

      return false;

    }


    const payload = parseJwt(token);


    if (!payload?.exp) {

      console.log(
        "[AUTH] token senza exp"
      );

      return false;

    }


    const valid =
      payload.exp * 1000 > Date.now();


    console.log(
      "[AUTH CHECK]",
      {
        valid,
        user: payload.name,
        exp: new Date(
          payload.exp * 1000
        ).toISOString()
      }
    );


    return valid;

  }



  // -------------------------------
  // USER INFO
  // -------------------------------

  function getUser() {

    const token = getToken();

    if (!token) {
      return null;
    }

    return parseJwt(token);

  }



  // -------------------------------
  // REQUIRE AUTH
  // -------------------------------

  function requireAuth(
    redirectUrl = "/login"
  ) {


    if (isLoggedIn()) {
      return true;
    }


    clearToken();


    const currentPath =
      window.location.pathname +
      window.location.search +
      window.location.hash;


    const separator =
      redirectUrl.includes("?")
        ? "&"
        : "?";


    window.location.replace(
      `${redirectUrl}${separator}redirect=${encodeURIComponent(currentPath)}`
    );


    return false;

  }



  // -------------------------------
  // AUTO LOGOUT JWT
  // -------------------------------

  let autoLogoutTimer = null;


  function scheduleAutoLogout() {


    clearTimeout(
      autoLogoutTimer
    );


    const token = getToken();


    if (!token) {
      return;
    }


    const payload =
      parseJwt(token);


    const expSec =
      payload?.exp;


    if (!expSec) {
      return;
    }


    const timeout =
      expSec * 1000 -
      Date.now();



    if (timeout <= 0) {

      window.AppAuth.logout?.({
        redirect:true
      });

      return;

    }


    autoLogoutTimer =
      setTimeout(() => {

        window.AppAuth.logout?.({
          redirect:true
        });

      }, timeout);


  }



  // -------------------------------
  // EXPORT
  // -------------------------------

  window.AppAuth =
    Object.freeze({

      login,

      logout:(opts)=>
        window.AppAuthLogout?.logout(opts),

      isLoggedIn,

      getUser,

      requireAuth,

      scheduleAutoLogout,

    });



  // -------------------------------
  // INIT
  // -------------------------------

  function init() {


    // marca questa apertura browser
    sessionStorage.setItem(
      "app_open",
      "1"
    );


    if (isLoggedIn()) {

      scheduleAutoLogout();

    }

  }



  if (
    document.readyState === "loading"
  ) {

    document.addEventListener(
      "DOMContentLoaded",
      init
    );

  } else {

    init();

  }



  // chiusura pagina/tab
  window.addEventListener(
    "pagehide",
    () => {

      sessionStorage.removeItem(
        "app_open"
      );

    }
  );


})();