// Version: 1.0.0 | Created: 2026-04-01
// Main rooms list screen with bottom navigation.

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../profile/presentation/profile_screen.dart';
import '../../spaces/presentation/spaces_screen.dart';
import 'room_tile.dart';
import 'rooms_controller.dart';

class RoomsScreen extends ConsumerStatefulWidget {
  const RoomsScreen({super.key});

  @override
  ConsumerState<RoomsScreen> createState() => _RoomsScreenState();
}

class _RoomsScreenState extends ConsumerState<RoomsScreen> {
  int _selectedIndex = 0;

  static const _destinations = [
    NavigationDestination(
      icon: Icon(Icons.chat_bubble_outline),
      selectedIcon: Icon(Icons.chat_bubble),
      label: 'Rooms',
    ),
    NavigationDestination(
      icon: Icon(Icons.dashboard_outlined),
      selectedIcon: Icon(Icons.dashboard),
      label: 'Spaces',
    ),
    NavigationDestination(
      icon: Icon(Icons.person_outline),
      selectedIcon: Icon(Icons.person),
      label: 'Profile',
    ),
  ];

  Widget _buildBody() {
    return switch (_selectedIndex) {
      0 => const _RoomListBody(),
      1 => const SpacesScreen(embedded: true),
      2 => const ProfileScreen(embedded: true),
      _ => const _RoomListBody(),
    };
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: _selectedIndex == 0
          ? AppBar(
              title: const Text('M8Chat'),
              actions: [
                IconButton(
                  icon: const Icon(Icons.search),
                  tooltip: 'Search rooms',
                  onPressed: () {
                    // Phase 2: room search
                  },
                ),
                IconButton(
                  icon: const Icon(Icons.edit_square),
                  tooltip: 'New message',
                  onPressed: () {
                    // Phase 2: start a new DM or group chat
                  },
                ),
              ],
            )
          : null,
      body: _buildBody(),
      bottomNavigationBar: NavigationBar(
        selectedIndex: _selectedIndex,
        onDestinationSelected: (index) =>
            setState(() => _selectedIndex = index),
        destinations: _destinations,
      ),
    );
  }
}

class _RoomListBody extends ConsumerWidget {
  const _RoomListBody();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final roomsAsync = ref.watch(roomsListProvider);

    return roomsAsync.when(
      loading: () => const Center(child: CircularProgressIndicator()),
      error: (error, _) => Center(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              const Icon(Icons.error_outline, size: 48),
              const SizedBox(height: 16),
              Text(
                'Could not load rooms.',
                style: Theme.of(context).textTheme.titleMedium,
              ),
              const SizedBox(height: 8),
              Text(
                error.toString(),
                textAlign: TextAlign.center,
                style: Theme.of(context).textTheme.bodySmall,
              ),
              const SizedBox(height: 24),
              ElevatedButton(
                onPressed: () => ref.refresh(roomsListProvider),
                child: const Text('Retry'),
              ),
            ],
          ),
        ),
      ),
      data: (rooms) {
        if (rooms.isEmpty) {
          return const _EmptyRoomsState();
        }
        return ListView.separated(
          itemCount: rooms.length,
          separatorBuilder: (_, __) => const Divider(height: 1, indent: 72),
          itemBuilder: (context, index) {
            final room = rooms[index];
            return RoomTile(
              room: room,
              onTap: () =>
                  context.push('/rooms/${Uri.encodeComponent(room.id)}'),
            );
          },
        );
      },
    );
  }
}

class _EmptyRoomsState extends StatelessWidget {
  const _EmptyRoomsState();

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.chat_bubble_outline,
              size: 64,
              color: theme.colorScheme.onSurface.withAlpha(77),
            ),
            const SizedBox(height: 16),
            Text(
              'No rooms yet',
              style: theme.textTheme.titleMedium?.copyWith(
                color: theme.colorScheme.onSurface.withAlpha(153),
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Rooms you join will appear here.',
              style: theme.textTheme.bodySmall?.copyWith(
                color: theme.colorScheme.onSurface.withAlpha(102),
              ),
            ),
          ],
        ),
      ),
    );
  }
}