import { writable, get } from 'svelte/store';

function safeParse(jsonString) {
  if (!jsonString || jsonString === 'undefined' || jsonString === 'null') return null;
  try { return JSON.parse(jsonString); } catch (e) { return null; }
}

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

const normalizeUser = (u) => {
  if (!u) return null;
  return { ...u, isAdmin: !!(u.isAdmin || u.is_admin) };
};

const storedToken = localStorage.getItem('token');
let initialUser = normalizeUser(safeParse(localStorage.getItem('user')));
let initialAuth = false;

if (storedToken) {
    const decoded = decodeJwt(storedToken);
    const currentTime = Date.now() / 1000;
    
    if (decoded && decoded.exp && decoded.exp < currentTime) {
        console.warn("Token im Storage ist abgelaufen. Auto-Logout.");
        localStorage.removeItem('token');
        localStorage.removeItem('user');
        initialUser = null;
    } else {
        initialAuth = !!initialUser;
    }
}

export const auth = writable({
  token: initialAuth ? storedToken : null,
  user: initialUser,
  isAuthenticated: initialAuth
});

auth.subscribe(value => {
  if (value.token && value.user) {
    localStorage.setItem('token', value.token);
    localStorage.setItem('user', JSON.stringify(value.user));
  } else {
    localStorage.removeItem('token');
    localStorage.removeItem('user');
  }
});

export const loading = writable(false);

export const toasts = writable([]);

export function addToast(message, type = 'info') {
  const id = Date.now() + Math.random(); 
  const newToast = { id, message, type }; 
  toasts.update(all => [newToast, ...all]);
  setTimeout(() => removeToast(id), 5000); 
}

export function removeToast(id) {
  toasts.update(all => all.filter(t => t.id !== id));
}