import { createSlice, PayloadAction } from '@reduxjs/toolkit';
import { STORAGE_KEY_TOKEN } from '../../constants';

interface AuthUser {
  id: string;
  email: string;
  displayName: string;
  role: 'Dispatcher' | 'Admin' | 'SysAdmin';
  token: string;
}

interface AuthState {
  user: AuthUser | null;
  isAuthenticated: boolean;
  loading: boolean;
  error: string | null;
}

const getUserFromStorage = (): AuthUser | null => {
  try {
    const result = window.localStorage.getItem(STORAGE_KEY_TOKEN);
    return result ? JSON.parse(result) : null;
  } catch {
    return null;
  }
};

const isTokenValid = (token: string): boolean => {
  if (!token) return false;
  try {
    const part = token.split('.')[1];
    if (!part) return false;
    const payload = JSON.parse(atob(part));
    return new Date(payload.exp * 1000) > new Date();
  } catch {
    return false;
  }
};

const storedUser = getUserFromStorage();

const initialState: AuthState = {
  user: storedUser,
  isAuthenticated: storedUser?.token ? isTokenValid(storedUser.token) : false,
  loading: false,
  error: null,
};

const authSlice = createSlice({
  name: 'auth',
  initialState,
  reducers: {
    setUser: (state, action: PayloadAction<AuthUser>) => {
      state.user = action.payload;
      state.isAuthenticated = action.payload.token ? isTokenValid(action.payload.token) : false;
      state.loading = false;
      state.error = null;
      window.localStorage.setItem(STORAGE_KEY_TOKEN, JSON.stringify(action.payload));
    },
    logout: (state) => {
      state.user = null;
      state.isAuthenticated = false;
      state.error = null;
      window.localStorage.removeItem(STORAGE_KEY_TOKEN);
    },
    setLoading: (state, action: PayloadAction<boolean>) => {
      state.loading = action.payload;
    },
    setError: (state, action: PayloadAction<string>) => {
      state.error = action.payload;
      state.loading = false;
    },
    clearError: (state) => {
      state.error = null;
    },
  },
});

export const { setUser, logout, setLoading, setError, clearError } = authSlice.actions;

export const selectUser = (state: { auth: AuthState }) => state.auth.user;
export const selectIsAuthenticated = (state: { auth: AuthState }) => state.auth.isAuthenticated;
export const selectAuthLoading = (state: { auth: AuthState }) => state.auth.loading;
export const selectAuthError = (state: { auth: AuthState }) => state.auth.error;
export const selectToken = (state: { auth: AuthState }) => state.auth.user?.token;

export default authSlice.reducer;