import React from 'react';
import { ActivityIndicator, View, StyleSheet } from 'react-native';
import { NavigationContainer } from '@react-navigation/native';
import { createNativeStackNavigator } from '@react-navigation/native-stack';
import { createBottomTabNavigator } from '@react-navigation/bottom-tabs';
import Icon from 'react-native-vector-icons/MaterialCommunityIcons';
import { useSelector } from 'react-redux';
import {
  selectIsAuthenticated,
  selectAuthLoading,
  selectUser,
} from '../store/slices/authSlice';
import type {
  RootStackParamList,
  MainTabParamList,
  ProposalsStackParamList,
} from './types';

import { LoginScreen } from '../screens/auth/LoginScreen';
import { DashboardScreen } from '../screens/dispatcher/DashboardScreen';
import { AdminDashboardScreen } from '../screens/admin/AdminDashboardScreen';
import { NewProposalScreen } from '../screens/dispatcher/NewProposalScreen';
import { ProposalDetailScreen } from '../screens/dispatcher/ProposalDetailScreen';
import { ProposalQueueScreen } from '../screens/admin/ProposalQueueScreen';
import { ProposalWorkspaceScreen } from '../screens/admin/ProposalWorkspaceScreen';
import { LineItemEditScreen } from '../screens/admin/LineItemEditScreen';
import { SettingsScreen } from '../screens/SettingsScreen';

const RootStack = createNativeStackNavigator<RootStackParamList>();
const Tab = createBottomTabNavigator<MainTabParamList>();
const ProposalsStack = createNativeStackNavigator<ProposalsStackParamList>();

function ProposalsNavigator() {
  const user = useSelector(selectUser);
  const isAdmin = user?.role === 'Admin' || user?.role === 'SysAdmin';

  return (
    <ProposalsStack.Navigator screenOptions={{ headerShown: true }}>
      <ProposalsStack.Screen
        name="ProposalList"
        component={ProposalQueueScreen}
        options={{ title: isAdmin ? 'Proposal Queue' : 'My Proposals' }}
      />
      <ProposalsStack.Screen
        name="NewProposal"
        component={NewProposalScreen}
        options={{ title: 'New Proposal' }}
      />
      <ProposalsStack.Screen
        name="ProposalDetail"
        component={ProposalDetailScreen}
        options={{ title: 'Proposal' }}
      />
      <ProposalsStack.Screen
        name="ProposalWorkspace"
        component={ProposalWorkspaceScreen}
        options={{ title: 'Proposal' }}
      />
      <ProposalsStack.Screen
        name="LineItemEdit"
        component={LineItemEditScreen}
        options={{ title: 'Edit Line Item' }}
      />
    </ProposalsStack.Navigator>
  );
}

function DashboardRouter() {
  const user = useSelector(selectUser);
  const isAdmin = user?.role === 'Admin' || user?.role === 'SysAdmin';
  return isAdmin ? <AdminDashboardScreen /> : <DashboardScreen />;
}

function MainTabs() {
  return (
    <Tab.Navigator
      screenOptions={({ route }) => ({
        headerShown: route.name === 'DashboardTab',
        tabBarIcon: ({ color, size }) => {
          const icons: Record<string, string> = {
            DashboardTab: 'view-dashboard',
            ProposalsTab: 'file-document-outline',
            SettingsTab: 'cog-outline',
          };
          return (
            <Icon
              name={icons[route.name] || 'circle'}
              size={size}
              color={color}
            />
          );
        },
        tabBarActiveTintColor: '#1565C0',
        tabBarInactiveTintColor: '#757575',
      })}
    >
      <Tab.Screen
        name="DashboardTab"
        component={DashboardRouter}
        options={{ title: 'Dashboard' }}
      />
      <Tab.Screen
        name="ProposalsTab"
        component={ProposalsNavigator}
        options={{ headerShown: false, title: 'Proposals' }}
      />
      <Tab.Screen
        name="SettingsTab"
        component={SettingsScreen}
        options={{ title: 'Settings' }}
      />
    </Tab.Navigator>
  );
}

export function RootNavigator() {
  const isAuthenticated = useSelector(selectIsAuthenticated);
  const loading = useSelector(selectAuthLoading);

  if (loading) {
    return (
      <View style={styles.loading}>
        <ActivityIndicator size="large" color="#1565C0" />
      </View>
    );
  }

  return (
    <NavigationContainer>
      <RootStack.Navigator screenOptions={{ headerShown: false }}>
        {isAuthenticated ? (
          <RootStack.Screen name="Main" component={MainTabs} />
        ) : (
          <RootStack.Screen name="Auth" component={LoginScreen} />
        )}
      </RootStack.Navigator>
    </NavigationContainer>
  );
}

const styles = StyleSheet.create({
  loading: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#FAFAFA',
  },
});