import 'dart:async';
import 'package:flutter/material.dart';
import '../l10n/app_localizations.dart';
import '../theme/app_colors.dart';
import '../theme/app_text_styles.dart';
import '../models/distraction_type.dart';
import '../models/focus_session.dart';
import '../services/storage_service.dart';
import '../services/encouragement_service.dart';
import '../services/notification_service.dart';
import 'complete_screen.dart';

/// Focus Screen - Timer and distraction tracking
class FocusScreen extends StatefulWidget {
  final int durationMinutes;
  final EncouragementService encouragementService;

  const FocusScreen({
    super.key,
    required this.durationMinutes,
    required this.encouragementService,
  });

  @override
  State<FocusScreen> createState() => _FocusScreenState();
}

class _FocusScreenState extends State<FocusScreen> with WidgetsBindingObserver {
  late Timer _timer;
  late int _remainingSeconds;
  late DateTime _startTime;
  final List<String> _distractions = [];
  bool _isPaused = false;
  bool _isInBackground = false;
  final NotificationService _notificationService = NotificationService();

  @override
  void initState() {
    super.initState();
    _remainingSeconds = widget.durationMinutes * 60;
    _startTime = DateTime.now();
    WidgetsBinding.instance.addObserver(this);
    _startTimer();
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    _timer.cancel();
    // Cancel ongoing notification when leaving the screen
    _notificationService.cancelOngoingFocusNotification();
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);

    switch (state) {
      case AppLifecycleState.paused:
      case AppLifecycleState.inactive:
      case AppLifecycleState.detached:
        // App went to background
        _isInBackground = true;
        if (!_isPaused && _remainingSeconds > 0) {
          _showBackgroundNotification();
        }
        break;
      case AppLifecycleState.resumed:
        // App came back to foreground
        _isInBackground = false;
        _notificationService.cancelOngoingFocusNotification();
        break;
      case AppLifecycleState.hidden:
        break;
    }
  }

  void _showBackgroundNotification() {
    final l10n = AppLocalizations.of(context)!;
    final minutes = _remainingSeconds ~/ 60;
    final seconds = _remainingSeconds % 60;
    final timeStr = '${minutes.toString().padLeft(2, '0')}:${seconds.toString().padLeft(2, '0')}';
    _notificationService.showOngoingFocusNotification(
      remainingMinutes: minutes,
      remainingSeconds: seconds,
      title: l10n.notificationFocusInProgress,
      timeRemainingText: l10n.notificationRemaining(timeStr),
    );
  }

  void _startTimer() {
    _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      if (!_isPaused && _remainingSeconds > 0) {
        setState(() {
          _remainingSeconds--;
        });

        // Update background notification every 30 seconds when in background
        if (_isInBackground && _remainingSeconds > 0) {
          if (_remainingSeconds % 30 == 0) {
            final l10n = AppLocalizations.of(context)!;
            final minutes = _remainingSeconds ~/ 60;
            final seconds = _remainingSeconds % 60;
            final timeStr = '${minutes.toString().padLeft(2, '0')}:${seconds.toString().padLeft(2, '0')}';
            _notificationService.updateOngoingFocusNotification(
              remainingMinutes: minutes,
              remainingSeconds: seconds,
              title: l10n.notificationFocusInProgress,
              timeRemainingText: l10n.notificationRemaining(timeStr),
            );
          }
        }

        if (_remainingSeconds == 0) {
          _onTimerComplete();
        }
      }
    });
  }

  void _onTimerComplete() async {
    _timer.cancel();

    // Cancel ongoing notification and show completion notification
    await _notificationService.cancelOngoingFocusNotification();

    _saveFocusSession(completed: true);

    if (!mounted) return;

    // Send completion notification with localized text
    final l10n = AppLocalizations.of(context)!;
    final minuteText = l10n.minutes(widget.durationMinutes);
    final notificationBody = _distractions.isEmpty
        ? l10n.notificationFocusCompleteBodyNoDistractions(
            widget.durationMinutes,
            minuteText,
          )
        : l10n.notificationFocusCompleteBody(
            widget.durationMinutes,
            minuteText,
          );

    await _notificationService.showFocusCompletedNotification(
      minutes: widget.durationMinutes,
      distractionCount: _distractions.length,
      title: l10n.notificationFocusCompleteTitle,
      body: notificationBody,
    );

    if (!mounted) return;

    Navigator.pushReplacement(
      context,
      MaterialPageRoute(
        builder: (context) => CompleteScreen(
          focusedMinutes: widget.durationMinutes,
          distractionCount: _distractions.length,
          encouragementService: widget.encouragementService,
        ),
      ),
    );
  }

  void _togglePause() {
    setState(() {
      _isPaused = !_isPaused;
    });

    // Update notification when paused
    if (_isPaused && _isInBackground) {
      _notificationService.cancelOngoingFocusNotification();
    } else if (!_isPaused && _isInBackground) {
      _showBackgroundNotification();
    }
  }

  void _stopEarly() {
    final l10n = AppLocalizations.of(context)!;
    final actualMinutes = ((widget.durationMinutes * 60 - _remainingSeconds) / 60).floor();
    final minuteText = actualMinutes == 1 ? l10n.minutes(1) : l10n.minutes(actualMinutes);

    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(l10n.stopEarly),
        content: Text(
          l10n.stopEarlyMessage(actualMinutes, minuteText),
          style: AppTextStyles.bodyText,
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: Text(l10n.keepGoing),
          ),
          TextButton(
            onPressed: () {
              Navigator.pop(context); // Close dialog
              _timer.cancel();
              _saveFocusSession(completed: false);

              Navigator.pushReplacement(
                context,
                MaterialPageRoute(
                  builder: (context) => CompleteScreen(
                    focusedMinutes: actualMinutes,
                    distractionCount: _distractions.length,
                    encouragementService: widget.encouragementService,
                  ),
                ),
              );
            },
            child: Text(l10n.yesStop),
          ),
        ],
      ),
    );
  }

  Future<void> _saveFocusSession({required bool completed}) async {
    final actualMinutes = completed
        ? widget.durationMinutes
        : ((widget.durationMinutes * 60 - _remainingSeconds) / 60).floor();

    final session = FocusSession(
      startTime: _startTime,
      durationMinutes: widget.durationMinutes,
      actualMinutes: actualMinutes,
      distractionCount: _distractions.length,
      completed: completed,
      distractionTypes: _distractions,
    );

    final storageService = StorageService();
    await storageService.saveFocusSession(session);
  }

  void _showDistractionSheet() {
    final l10n = AppLocalizations.of(context)!;

    // Map distraction types to translations
    final distractionOptions = [
      (type: DistractionType.phoneNotification, label: l10n.distractionPhoneNotification),
      (type: DistractionType.socialMedia, label: l10n.distractionSocialMedia),
      (type: DistractionType.thoughts, label: l10n.distractionThoughts),
      (type: DistractionType.other, label: l10n.distractionOther),
    ];

    showModalBottomSheet(
      context: context,
      backgroundColor: AppColors.white,
      isScrollControlled: true,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(24)),
      ),
      builder: (context) {
        return SafeArea(
          child: SingleChildScrollView(
            child: Padding(
              padding: EdgeInsets.only(
                left: 24.0,
                right: 24.0,
                top: 24.0,
                bottom: 24.0 + MediaQuery.of(context).viewInsets.bottom,
              ),
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  // Drag handle
                  Center(
                    child: Container(
                      width: 32,
                      height: 4,
                      decoration: BoxDecoration(
                        color: AppColors.distractionButton,
                        borderRadius: BorderRadius.circular(2),
                      ),
                    ),
                  ),
                  const SizedBox(height: 24),

                  // Title
                  Text(
                    l10n.whatPulledYouAway,
                    style: const TextStyle(
                      fontFamily: 'Nunito',
                      fontSize: 18,
                      fontWeight: FontWeight.w600,
                      color: AppColors.textPrimary,
                    ),
                  ),
                  const SizedBox(height: 24),

                  // Distraction options
                  ...distractionOptions.map((option) {
                    return Column(
                      children: [
                        ListTile(
                          leading: Text(
                            DistractionType.getEmoji(option.type),
                            style: const TextStyle(fontSize: 24),
                          ),
                          title: Text(
                            option.label,
                            style: AppTextStyles.bodyText,
                          ),
                          onTap: () {
                            Navigator.pop(context);
                            _recordDistraction(option.type);
                          },
                        ),
                        if (option != distractionOptions.last)
                          const Divider(color: AppColors.divider),
                      ],
                    );
                  }),

                  const SizedBox(height: 16),

                  // Skip button
                  Center(
                    child: TextButton(
                      onPressed: () {
                        Navigator.pop(context);
                        _recordDistraction(null);
                      },
                      child: Text(l10n.skipThisTime),
                    ),
                  ),
                ],
              ),
            ),
          ),
        );
      },
    );
  }

  void _recordDistraction(String? type) {
    final l10n = AppLocalizations.of(context)!;

    setState(() {
      if (type != null) {
        _distractions.add(type);
      }
    });

    // Show encouragement toast
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(l10n.distractionEncouragement),
        duration: const Duration(seconds: 2),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  String _formatTime(int seconds) {
    final minutes = seconds ~/ 60;
    final secs = seconds % 60;
    return '${minutes.toString().padLeft(2, '0')}:${secs.toString().padLeft(2, '0')}';
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;

    return Scaffold(
      backgroundColor: AppColors.background,
      body: SafeArea(
        child: Column(
          children: [
            Expanded(
              child: SingleChildScrollView(
                padding: const EdgeInsets.all(24.0),
                child: Column(
                  children: [
                    SizedBox(
                      height: MediaQuery.of(context).size.height * 0.2,
                    ),

                    // Timer Display
                    Text(
                      _formatTime(_remainingSeconds),
                      style: AppTextStyles.timerDisplay,
                    ),

                    const SizedBox(height: 80),

                    // "I got distracted" Button
                    SizedBox(
                      width: double.infinity,
                      child: ElevatedButton(
                        onPressed: _showDistractionSheet,
                        style: ElevatedButton.styleFrom(
                          backgroundColor: AppColors.distractionButton,
                          foregroundColor: AppColors.textPrimary,
                          minimumSize: const Size(double.infinity, 48),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(12),
                          ),
                          elevation: 0,
                        ),
                        child: Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Text(
                              l10n.iGotDistracted,
                              style: const TextStyle(
                                fontFamily: 'Nunito',
                                fontSize: 18,
                                fontWeight: FontWeight.w600,
                              ),
                            ),
                            const SizedBox(width: 8),
                            const Text(
                              '🤚',
                              style: TextStyle(fontSize: 20),
                            ),
                          ],
                        ),
                      ),
                    ),

                    const SizedBox(height: 16),

                    // Pause Button
                    SizedBox(
                      width: double.infinity,
                      child: OutlinedButton(
                        onPressed: _togglePause,
                        style: OutlinedButton.styleFrom(
                          foregroundColor: AppColors.primary,
                          side: const BorderSide(color: AppColors.primary, width: 1),
                          minimumSize: const Size(double.infinity, 48),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(12),
                          ),
                        ),
                        child: Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Icon(_isPaused ? Icons.play_arrow : Icons.pause),
                            const SizedBox(width: 8),
                            Text(_isPaused ? l10n.resume : l10n.pause),
                          ],
                        ),
                      ),
                    ),

                    SizedBox(
                      height: MediaQuery.of(context).size.height * 0.2,
                    ),
                  ],
                ),
              ),
            ),

            // Stop Button (text button at bottom)
            Padding(
              padding: const EdgeInsets.only(bottom: 24.0),
              child: TextButton(
                onPressed: _stopEarly,
                child: Text(
                  l10n.stopSession,
                  style: const TextStyle(
                    color: AppColors.textSecondary,
                    fontSize: 14,
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}