import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:provider/provider.dart';

import '../services/app_state.dart';
import 'drive_folder_browser_screen.dart';

class SettingsScreen extends StatefulWidget {
  const SettingsScreen({super.key});

  @override
  State<SettingsScreen> createState() => _SettingsScreenState();
}

class _SettingsScreenState extends State<SettingsScreen> {
  bool _busy = false;
  String? _error;

  Future<void> _connect() async {
    setState(() {
      _busy = true;
      _error = null;
    });
    try {
      await context.read<AppState>().connectDrive();
    } catch (e) {
      setState(() => _error = 'Could not sign in: $e');
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  Future<void> _disconnect() async {
    setState(() => _busy = true);
    try {
      await context.read<AppState>().disconnectDrive();
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  void _chooseFolder() {
    Navigator.of(context).push(
      MaterialPageRoute(builder: (_) => const DriveFolderBrowserScreen()),
    );
  }

  Future<void> _syncNow() async {
    setState(() => _busy = true);
    try {
      await context.read<AppState>().syncNow();
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    final appState = context.watch<AppState>();

    return Scaffold(
      appBar: AppBar(title: const Text('Settings')),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Card(
            child: Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text('Google Drive', style: Theme.of(context).textTheme.titleMedium),
                  const SizedBox(height: 8),
                  if (!appState.isDriveConnected) ...[
                    Text(
                      'Connect Google Drive to share vehicles and fuel receipts with '
                      'other people, and to keep a backup off this device.',
                      style: Theme.of(context).textTheme.bodyMedium,
                    ),
                    const SizedBox(height: 12),
                    if (_error != null) ...[
                      Text(_error!, style: TextStyle(color: Theme.of(context).colorScheme.error)),
                      const SizedBox(height: 8),
                    ],
                    FilledButton.icon(
                      onPressed: _busy ? null : _connect,
                      icon: const Icon(Icons.login),
                      label: const Text('Connect Google Drive'),
                    ),
                  ] else ...[
                    Text('Signed in as ${appState.driveAccountEmail}'),
                    const SizedBox(height: 4),
                    Text(
                      appState.driveFolderPath == null
                          ? 'No folder selected yet.'
                          : 'Folder: ${appState.driveFolderPath}',
                      style: Theme.of(context).textTheme.bodySmall,
                    ),
                    const SizedBox(height: 12),
                    Wrap(
                      spacing: 8,
                      runSpacing: 8,
                      children: [
                        OutlinedButton.icon(
                          onPressed: _busy ? null : _chooseFolder,
                          icon: const Icon(Icons.folder_open),
                          label: Text(appState.driveFolderPath == null
                              ? 'Choose Folder'
                              : 'Change Folder'),
                        ),
                        OutlinedButton.icon(
                          onPressed: (_busy || appState.driveFolderPath == null)
                              ? null
                              : _syncNow,
                          icon: appState.isSyncing
                              ? const SizedBox(
                                  height: 16,
                                  width: 16,
                                  child: CircularProgressIndicator(strokeWidth: 2))
                              : const Icon(Icons.sync),
                          label: const Text('Sync Now'),
                        ),
                        TextButton.icon(
                          onPressed: _busy ? null : _disconnect,
                          icon: const Icon(Icons.logout),
                          label: const Text('Disconnect'),
                        ),
                      ],
                    ),
                    const SizedBox(height: 8),
                    if (appState.lastSyncedAt != null)
                      Text(
                        'Last synced ${DateFormat.yMMMd().add_jm().format(appState.lastSyncedAt!)}',
                        style: Theme.of(context).textTheme.bodySmall,
                      ),
                    if (appState.lastSyncError != null)
                      Padding(
                        padding: const EdgeInsets.only(top: 4),
                        child: Text(
                          'Last sync failed: ${appState.lastSyncError}',
                          style: TextStyle(color: Theme.of(context).colorScheme.error),
                        ),
                      ),
                  ],
                ],
              ),
            ),
          ),
          const SizedBox(height: 16),
          Card(
            child: Padding(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text('Summary', style: Theme.of(context).textTheme.titleMedium),
                  const SizedBox(height: 8),
                  Text('${appState.vehicles.length} vehicle(s)'),
                  Text('${appState.fuelEntries.length} fuel entries'),
                  Text('${appState.totalGallonsAllVehicles.toStringAsFixed(3)} total gallons logged'),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}