import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:health/health.dart';
import '../../providers/user_provider.dart';
import '../../services/health_service.dart';

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

  @override
  ConsumerState<PrivacySettingsScreen> createState() =>
      _PrivacySettingsScreenState();
}

class _PrivacySettingsScreenState extends ConsumerState<PrivacySettingsScreen> {
  bool _hasPermissions = false;
  final HealthService _healthService = HealthService();

  @override
  void initState() {
    super.initState();
    _checkPermissions();
  }

  Future<void> _checkPermissions() async {
    final hasPermissions = await _healthService.hasPermissions(_healthService.menstruationDataTypes);
    setState(() {
      _hasPermissions = hasPermissions;
    });
  }

  Future<void> _requestPermissions() async {
    final authorized = await _healthService.requestAuthorization(_healthService.menstruationDataTypes);
    if (authorized) {
      _hasPermissions = true;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Health app access granted!')),
      );
    } else {
      _hasPermissions = false;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Health app access denied.')),
      );
    }
    setState(() {}); // Rebuild to update UI
  }

  Future<void> _syncPeriodDays(bool sync) async {
    if (sync) {
      if (!_hasPermissions) {
        // Request permissions if not already granted
        final authorized = await _healthService.requestAuthorization(_healthService.menstruationDataTypes);
        if (!authorized) {
          if (mounted) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(content: Text('Cannot sync without health app permissions.')),
            );
          }
          return;
        }
        _hasPermissions = true;
      }

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Syncing period data...')),
        );
      }
      final userProfile = ref.read(userProfileProvider);
      final cycleEntries = ref.read(cycleEntriesProvider);

      if (userProfile != null) {
        final success = await _healthService.writeMenstruationData(cycleEntries);
        if (mounted) {
          if (success) {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(content: Text('Period data synced successfully!')),
            );
          } else {
            ScaffoldMessenger.of(context).showSnackBar(
              const SnackBar(content: Text('Failed to sync period data.')),
            );
          }
        }
      }
    } else {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Period data sync disabled.')),
        );
      }
    }
    setState(() {}); // Rebuild to update UI
  }

  Future<void> _setPin() async {
    final pin = await _showPinDialog(context, title: 'Set New PIN');
    if (pin != null && pin.length >= 4) {
      final user = ref.read(userProfileProvider);
      if (user != null) {
        await ref.read(userProfileProvider.notifier).updateProfile(user.copyWith(privacyPin: pin));
        if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('PIN Set Successfully')));
      }
    }
  }
  
  Future<void> _removePin() async {
    final user = ref.read(userProfileProvider);
    if (user == null) return;
    
    // Require current PIN
    final currentPin = await _showPinDialog(context, title: 'Enter Current PIN');
    if (currentPin == user.privacyPin) {
       await ref.read(userProfileProvider.notifier).updateProfile(
         // To clear fields, copyWith might need to handle nulls explicitly if written that way, 
         // but here we might pass empty string or handle logic. 
         // Actually, copyWith signature usually ignores nulls. 
         // I'll assume updating with empty string or handle it in provider, 
         // but for now let's just use empty string to signify removal if logic supports it.
         // Wait, copyWith `privacyPin: privacyPin ?? this.privacyPin`. 
         // If I pass null, it keeps existing. I can't clear it via standard copyWith unless I change copyWith logic or pass emptiness.
         // I'll update the userProfile object directly and save? No, Hive object.
         // For now, let's treat "empty string" as no PIN if I can pass it.
         user.copyWith(privacyPin: '', isBioProtected: false, isHistoryProtected: false)
       );
       if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('PIN Removed')));
    } else {
      if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Incorrect PIN')));
    }
  }

  Future<String?> _showPinDialog(BuildContext context, {required String title}) {
    final controller = TextEditingController();
    return showDialog<String>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(title),
        content: TextField(
          controller: controller,
          keyboardType: TextInputType.number,
          obscureText: true,
          maxLength: 4,
          decoration: const InputDecoration(hintText: 'Enter 4-digit PIN'),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(context), child: const Text('Cancel')),
          ElevatedButton(
            onPressed: () => Navigator.pop(context, controller.text),
            child: const Text('OK'),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    bool syncPeriodToHealth = _hasPermissions;
    final user = ref.watch(userProfileProvider);
    final hasPin = user?.privacyPin != null && user!.privacyPin!.isNotEmpty;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Privacy Settings'),
      ),
      body: ListView(
        padding: const EdgeInsets.all(16.0),
        children: [
          // Security Section
          Text('App Security', style: Theme.of(context).textTheme.titleMedium?.copyWith(color: Theme.of(context).colorScheme.primary)),
          const SizedBox(height: 8),
          ListTile(
            title: const Text('Privacy PIN'),
            subtitle: Text(hasPin ? 'PIN is set' : 'Protect sensitive data with a PIN'),
            trailing: hasPin ? const Icon(Icons.lock, color: Colors.green) : const Icon(Icons.lock_open),
            onTap: () {
              if (hasPin) {
                showModalBottomSheet(context: context, builder: (context) => Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    ListTile(
                      leading: const Icon(Icons.edit),
                      title: const Text('Change PIN'),
                      onTap: () {
                         Navigator.pop(context);
                        _setPin();
                      }, 
                    ),
                    ListTile(
                      leading: const Icon(Icons.delete, color: Colors.red),
                      title: const Text('Remove PIN'),
                      onTap: () {
                        Navigator.pop(context);
                        _removePin();
                      },
                    ),
                  ],
                ));
              } else {
                _setPin();
              }
            },
          ),
          
          if (hasPin) ...[
            SwitchListTile(
              title: const Text('Use Biometrics'),
              subtitle: const Text('Unlock with FaceID / Fingerprint'),
              value: user?.isBioProtected ?? false,
              onChanged: (val) {
                 ref.read(userProfileProvider.notifier).updateProfile(user!.copyWith(isBioProtected: val));
              },
            ),

            const Divider(),
            const Text('Protected Features', style: TextStyle(fontWeight: FontWeight.bold, color: Colors.grey)),
            SwitchListTile(
              title: const Text('Daily Logs'),
              value: user?.isLogProtected ?? false,
              onChanged: (val) {
                 ref.read(userProfileProvider.notifier).updateProfile(user!.copyWith(isLogProtected: val));
              },
            ),
             SwitchListTile(
              title: const Text('Calendar'),
              value: user?.isCalendarProtected ?? false,
              onChanged: (val) {
                 ref.read(userProfileProvider.notifier).updateProfile(user!.copyWith(isCalendarProtected: val));
              },
            ),
             SwitchListTile(
              title: const Text('Supplies / Pad Tracker'),
              value: user?.isSuppliesProtected ?? false,
              onChanged: (val) {
                 ref.read(userProfileProvider.notifier).updateProfile(user!.copyWith(isSuppliesProtected: val));
              },
            ),
            SwitchListTile(
              title: const Text('Cycle History'),
              value: user?.isHistoryProtected ?? false,
              onChanged: (val) {
                 ref.read(userProfileProvider.notifier).updateProfile(user!.copyWith(isHistoryProtected: val));
              },
            ),
          ],

          const Divider(height: 32),

          // Health Section
          Text('Health App Integration', style: Theme.of(context).textTheme.titleMedium?.copyWith(color: Theme.of(context).colorScheme.primary)),
          const SizedBox(height: 8),
          ListTile(
            title: const Text('Health Source'),
            subtitle: _hasPermissions
                ? const Text('Connected to Health App.')
                : const Text('Not connected. Tap to grant access.'),
            trailing: _hasPermissions ? const Icon(Icons.check_circle, color: Colors.green) : const Icon(Icons.warning, color: Colors.orange),
            onTap: _requestPermissions,
          ),
          SwitchListTile(
            title: const Text('Sync Period Days'),
            subtitle: const Text('Automatically sync period dates.'),
            value: syncPeriodToHealth,
            onChanged: _hasPermissions ? (value) async {
              if (value) {
                await _syncPeriodDays(true);
              } else {
                await _syncPeriodDays(false);
              }
              setState(() {
                syncPeriodToHealth = value; // Update local state for toggle
              });
            } : null,
          ),
        ],
      ),
    );
  }
}