import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:focusflow_shared/focusflow_shared.dart';
import 'package:go_router/go_router.dart';

import '../../../../core/theme/app_colors.dart';
import '../../../../core/widgets/streak_ring.dart';
import '../bloc/streak_bloc.dart';

/// Streak overview screen.
///
///  - Active streaks as cards with [StreakRing] widget.
///  - "Frozen" indicator for paused streaks.
///  - Tap to see history.
///  - "New Streak" FAB.
///  - Grace day info shown positively.
class StreaksScreen extends StatefulWidget {
  const StreaksScreen({super.key});

  @override
  State<StreaksScreen> createState() => _StreaksScreenState();
}

class _StreaksScreenState extends State<StreaksScreen> {
  late final StreakBloc _bloc;

  @override
  void initState() {
    super.initState();
    _bloc = StreakBloc()..add(const StreaksLoaded());
  }

  @override
  void dispose() {
    _bloc.close();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return BlocProvider.value(
      value: _bloc,
      child: Scaffold(
        appBar: AppBar(
          leading: IconButton(
            icon: const Icon(Icons.arrow_back_rounded),
            onPressed: () => context.go('/'),
          ),
          title: const Text('Your Streaks'),
        ),
        body: BlocBuilder<StreakBloc, StreakState>(
          builder: (context, state) {
            if (state is StreakLoading) {
              return const Center(child: CircularProgressIndicator());
            }

            if (state is StreakError) {
              return Center(
                child: Padding(
                  padding: const EdgeInsets.all(32),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      const Icon(Icons.cloud_off_rounded, size: 48, color: AppColors.skipped),
                      const SizedBox(height: 12),
                      Text(state.message, style: theme.textTheme.bodyLarge, textAlign: TextAlign.center),
                      const SizedBox(height: 16),
                      FilledButton(
                        onPressed: () => _bloc.add(const StreaksLoaded()),
                        child: const Text('Retry'),
                      ),
                    ],
                  ),
                ),
              );
            }

            if (state is StreakLoaded) {
              if (state.streaks.isEmpty) {
                return Center(
                  child: Padding(
                    padding: const EdgeInsets.all(32),
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        const Icon(Icons.local_fire_department_rounded,
                            size: 56, color: AppColors.tertiary),
                        const SizedBox(height: 12),
                        Text('No streaks yet',
                            style: theme.textTheme.titleMedium),
                        const SizedBox(height: 4),
                        Text(
                          'Start a streak to build consistency — with grace days built in.',
                          style: theme.textTheme.bodyMedium,
                          textAlign: TextAlign.center,
                        ),
                      ],
                    ),
                  ),
                );
              }

              return ListView.builder(
                padding: const EdgeInsets.only(top: 8, bottom: 100),
                itemCount: state.streaks.length,
                itemBuilder: (context, index) {
                  final streak = state.streaks[index];
                  return _StreakCard(
                    streak: streak,
                    onComplete: () => _bloc.add(StreakCompleted(streak.id)),
                  );
                },
              );
            }

            return const SizedBox.shrink();
          },
        ),
        floatingActionButton: FloatingActionButton.extended(
          onPressed: () {
            // TODO: navigate to create streak screen.
          },
          icon: const Icon(Icons.add_rounded),
          label: const Text('New Streak'),
        ),
      ),
    );
  }
}

class _StreakCard extends StatelessWidget {
  final Streak streak;
  final VoidCallback onComplete;

  const _StreakCard({required this.streak, required this.onComplete});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final isFrozen = streak.frozenUntil != null &&
        streak.frozenUntil!.isAfter(DateTime.now());
    final graceDaysRemaining = streak.graceDays - streak.graceUsed;

    return Card(
      child: InkWell(
        borderRadius: BorderRadius.circular(16),
        onTap: () {
          // TODO: navigate to streak history.
        },
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Row(
            children: [
              StreakRing(
                currentCount: streak.currentCount,
                graceDaysRemaining: graceDaysRemaining,
                totalGraceDays: streak.graceDays,
                isFrozen: isFrozen,
                size: 72,
              ),
              const SizedBox(width: 16),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      children: [
                        Expanded(
                          child: Text(
                            streak.name,
                            style: theme.textTheme.titleMedium?.copyWith(
                              fontWeight: FontWeight.w600,
                            ),
                          ),
                        ),
                        if (isFrozen)
                          Container(
                            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
                            decoration: BoxDecoration(
                              color: AppColors.primaryLight.withAlpha(40),
                              borderRadius: BorderRadius.circular(12),
                            ),
                            child: const Row(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                Icon(Icons.ac_unit_rounded, size: 14, color: AppColors.primaryLight),
                                SizedBox(width: 4),
                                Text('Frozen',
                                    style: TextStyle(fontSize: 12, color: AppColors.primaryLight)),
                              ],
                            ),
                          ),
                      ],
                    ),
                    const SizedBox(height: 4),
                    Text(
                      'Current: ${streak.currentCount} days  |  Best: ${streak.longestCount}',
                      style: theme.textTheme.bodySmall,
                    ),
                    if (graceDaysRemaining > 0 && !isFrozen)
                      Padding(
                        padding: const EdgeInsets.only(top: 4),
                        child: Text(
                          '$graceDaysRemaining grace days remaining',
                          style: theme.textTheme.bodySmall?.copyWith(
                            color: AppColors.primary,
                            fontWeight: FontWeight.w500,
                          ),
                        ),
                      ),
                  ],
                ),
              ),
              if (!isFrozen)
                IconButton(
                  icon: const Icon(Icons.check_circle_outline_rounded,
                      color: AppColors.completed),
                  onPressed: onComplete,
                  tooltip: 'Complete today',
                ),
            ],
          ),
        ),
      ),
    );
  }
}