import { create } from 'zustand';

interface User {
  id: string;
  username: string;
  email: string;
}

interface AuthState {
  token: string | null;
  user: User | null;
  isLoading: boolean;
  error: string | null;
  login: (email: string, password: string) => Promise<void>;
  register: (username: string, email: string, password: string) => Promise<void>;
  logout: () => void;
  loadFromStorage: () => void;
  clearError: () => void;
}

export const useAuthStore = create<AuthState>((set, get) => ({
  token: null,
  user: null,
  isLoading: false,
  error: null,

  login: async (email: string, password: string) => {
    set({ isLoading: true, error: null });
    try {
      const res = await fetch('/api/auth/login', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ email, password }),
      });

      if (!res.ok) {
        const data = await res.json().catch(() => ({ message: 'Login failed' }));
        throw new Error(data.message || `Login failed (${res.status})`);
      }

      const data = await res.json();
      localStorage.setItem('token', data.token);
      localStorage.setItem('user', JSON.stringify(data.user));
      set({ token: data.token, user: data.user, isLoading: false });
    } catch (err: any) {
      set({ error: err.message, isLoading: false });
    }
  },

  register: async (username: string, email: string, password: string) => {
    set({ isLoading: true, error: null });
    try {
      const res = await fetch('/api/auth/register', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ username, email, password }),
      });

      if (!res.ok) {
        const data = await res.json().catch(() => ({ message: 'Registration failed' }));
        throw new Error(data.message || `Registration failed (${res.status})`);
      }

      const data = await res.json();
      localStorage.setItem('token', data.token);
      localStorage.setItem('user', JSON.stringify(data.user));
      set({ token: data.token, user: data.user, isLoading: false });
    } catch (err: any) {
      set({ error: err.message, isLoading: false });
    }
  },

  logout: () => {
    localStorage.removeItem('token');
    localStorage.removeItem('user');
    set({ token: null, user: null });
  },

  loadFromStorage: () => {
    const token = localStorage.getItem('token');
    const userStr = localStorage.getItem('user');
    if (token && userStr) {
      try {
        const user = JSON.parse(userStr);
        set({ token, user });
      } catch {
        localStorage.removeItem('token');
        localStorage.removeItem('user');
      }
    }
  },

  clearError: () => set({ error: null }),
}));