// lib/screens/settings.dart

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

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

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

class _SettingsScreenState extends State<SettingsScreen> {
  bool _isSyncingData = false;

  Future<void> _manualDataSync() async {
    if (_isSyncingData) return;
    setState(() => _isSyncingData = true);

    final auth = Provider.of<AuthProvider>(context, listen: false);

    // 1. Pre-sync checks
    if (!await auth.isConnected()) {
      _showSnackBar('Sync failed: No internet connection.', isError: true);
      setState(() => _isSyncingData = false);
      return;
    }

    if (auth.isSessionExpired) {
      _showSessionExpiredDialog();
      setState(() => _isSyncingData = false);
      return;
    }

    // 2. Attempt the sync operation
    try {
      await auth.syncAllData(forceRefresh: true);
      // No need to reload settings here, child screens will load on demand
      if (mounted) {
        _showSnackBar('Data synced successfully.', isError: false);
      }
    } catch (e) {
      // 3. Handle failures
      if (mounted) {
        if (auth.isSessionExpired) {
          _showSessionExpiredDialog();
        } else {
          _showSnackBar('Data sync failed: ${e.toString()}', isError: true);
        }
      }
    } finally {
      if (mounted) {
        setState(() => _isSyncingData = false);
      }
    }
  }

  void _showSessionExpiredDialog() {
    if (!mounted) return;
    showDialog(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: const Text("Session Expired"),
        content: const Text("Your session has expired and automatic re-login failed. Please log out and log in again to sync data."),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(dialogContext),
            child: const Text("OK"),
          ),
          ElevatedButton(
            onPressed: () {
              final auth = Provider.of<AuthProvider>(context, listen: false);
              Navigator.pop(dialogContext);
              auth.logout();
              Navigator.pushNamedAndRemoveUntil(context, '/', (route) => false);
            },
            child: const Text("Logout"),
          ),
        ],
      ),
    );
  }

  void _showSnackBar(String message, {bool isError = false}) {
    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(message),
          backgroundColor: isError ? Theme.of(context).colorScheme.error : Colors.green,
        ),
      );
    }
  }

  Widget _buildSectionHeader(BuildContext context, String title) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(8.0, 0, 8.0, 16.0),
      child: Text(
        title,
        style: Theme.of(context).textTheme.headlineSmall?.copyWith(fontWeight: FontWeight.bold),
      ),
    );
  }

  Widget _buildNavTile(BuildContext context, {
    required String title,
    required String subtitle,
    required IconData icon,
    required String routeName,
  }) {
    return Card(
      margin: const EdgeInsets.symmetric(vertical: 6.0),
      child: ListTile(
        leading: Icon(icon, size: 32.0, color: Theme.of(context).colorScheme.primary),
        title: Text(title, style: const TextStyle(fontWeight: FontWeight.bold)),
        subtitle: Text(subtitle),
        trailing: const Icon(Icons.arrow_forward_ios),
        onTap: () {
          Navigator.pushNamed(context, routeName);
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final auth = Provider.of<AuthProvider>(context);
    final lastSync = auth.lastSyncTimestamp;

    return Scaffold(
      appBar: AppBar(
        title: const Text("Settings"),
      ),
      body: SingleChildScrollView(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            _buildSectionHeader(context, "Synchronization"),
            Card(
              margin: const EdgeInsets.symmetric(vertical: 6.0),
              child: Padding(
                padding: const EdgeInsets.all(16.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Text("Last Data Sync:", style: Theme.of(context).textTheme.titleMedium),
                    const SizedBox(height: 4),
                    Text(lastSync != null ? DateFormat('yyyy-MM-dd HH:mm:ss').format(lastSync.toLocal()) : 'Never', style: Theme.of(context).textTheme.bodyLarge),
                    const SizedBox(height: 16),
                    ElevatedButton.icon(
                      onPressed: _isSyncingData ? null : _manualDataSync,
                      icon: _isSyncingData ? const SizedBox(width: 20, height: 20, child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white)) : const Icon(Icons.cloud_sync),
                      label: Text(_isSyncingData ? 'Syncing Data...' : 'Sync App Data'),
                      style: ElevatedButton.styleFrom(minimumSize: const Size(double.infinity, 50)),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 32),

            _buildSectionHeader(context, "App Management"),

            _buildNavTile(
              context,
              title: "Submission Preferences",
              subtitle: "Manage API & FTP submissions for each module.",
              icon: Icons.send_to_mobile,
              routeName: '/settings/submission-prefs',
            ),

            _buildNavTile(
              context,
              title: "Telegram Alert Settings",
              subtitle: "View Telegram chat IDs for alerts.",
              icon: Icons.telegram,
              routeName: '/settings/telegram-alerts',
            ),

            _buildNavTile(
              context,
              title: "API/FTP Configurations",
              subtitle: "View synced server configurations.",
              icon: Icons.dns,
              routeName: '/settings/api-ftp-configs',
            ),

            _buildNavTile(
              context,
              title: "Parameter Limits",
              subtitle: "View parameter limits for all modules.",
              icon: Icons.science_outlined,
              routeName: '/settings/parameter-limits',
            ),

            _buildNavTile(
              context,
              title: "Air Clients",
              subtitle: "View and search for synced Air clients.",
              icon: Icons.air,
              routeName: '/settings/air-clients',
            ),

            _buildNavTile(
              context,
              title: "Station Info",
              subtitle: "View and search all synced stations.",
              icon: Icons.location_on,
              routeName: '/settings/station-info',
            ),

            const SizedBox(height: 32),
            _buildSectionHeader(context, "Other Information"),
            Card(
              margin: const EdgeInsets.symmetric(vertical: 6.0),
              child: Column(
                children: [
                  ListTile(
                    leading: const Icon(Icons.info_outline),
                    title: const Text('App Version'),
                    subtitle: const Text('MMS Version 3.8.01'),
                    dense: true,
                  ),
                  ListTile(
                    leading: const Icon(Icons.privacy_tip_outlined),
                    title: const Text('Privacy Policy'),
                    onTap: () {},
                    dense: true,
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}