import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:go_router/go_router.dart';
import '../../../../core/theme/app_colors.dart';
import '../../../../core/widgets/gentle_nudge_card.dart';
import '../../../../core/widgets/streak_ring.dart';
import '../../../../core/widgets/task_card.dart';
import '../../../../features/auth/presentation/bloc/auth_bloc.dart';
import '../bloc/task_list_bloc.dart';

/// Home screen — the task dashboard.
///
/// Layout:
///  - AppBar greeting.
///  - Focus Mode prominent card at the top.
///  - Today's tasks list (limited to preferredTaskLoad).
///  - Streak summary cards (horizontal scroll).
///  - Bottom nav: Tasks, Streaks, Time, Settings.
class TaskDashboardScreen extends StatefulWidget {
  const TaskDashboardScreen({super.key});

  @override
  State<TaskDashboardScreen> createState() => _TaskDashboardScreenState();
}

class _TaskDashboardScreenState extends State<TaskDashboardScreen> {
  late final TaskListBloc _taskListBloc;
  int _currentNavIndex = 0;

  @override
  void initState() {
    super.initState();
    _taskListBloc = TaskListBloc()..add(const TasksLoaded());
  }

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

  String _greeting(AuthState authState) {
    final name = authState is AuthAuthenticated ? authState.user.displayName : 'Friend';
    return 'Hey $name! What shall we tackle?';
  }

  void _onNavTap(int index) {
    switch (index) {
      case 0:
        break; // already here
      case 1:
        context.go('/streaks');
      case 2:
        context.go('/time');
      case 3:
        context.go('/settings');
    }
    setState(() => _currentNavIndex = index);
  }

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

    return BlocProvider.value(
      value: _taskListBloc,
      child: Scaffold(
        // ── AppBar ───────────────────────────────────────────────
        appBar: AppBar(
          title: BlocBuilder<AuthBloc, AuthState>(
            builder: (context, state) => Text(
              _greeting(state),
              style: theme.textTheme.titleMedium,
            ),
          ),
          actions: [
            IconButton(
              icon: const Icon(Icons.notifications_none_rounded),
              onPressed: () {},
              tooltip: 'Notifications',
            ),
          ],
        ),

        // ── Body ─────────────────────────────────────────────────
        body: RefreshIndicator(
          onRefresh: () async => _taskListBloc.add(const TasksLoaded()),
          child: ListView(
            padding: const EdgeInsets.only(bottom: 100),
            children: [
              // Focus Mode card
              _FocusModeCard(onTap: () => context.go('/focus')),

              // Gentle nudge (shown conditionally)
              GentleNudgeCard(
                previousStreak: 7,
                onStartSmall: () => context.go('/focus'),
                onDismiss: () {},
              ),

              // ── Streak rings (horizontal scroll) ───────────────
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                child: Text('Your Streaks', style: theme.textTheme.titleMedium),
              ),
              SizedBox(
                height: 120,
                child: ListView(
                  scrollDirection: Axis.horizontal,
                  padding: const EdgeInsets.symmetric(horizontal: 12),
                  children: const [
                    Padding(
                      padding: EdgeInsets.symmetric(horizontal: 6),
                      child: StreakRing(
                        currentCount: 12,
                        graceDaysRemaining: 2,
                        totalGraceDays: 2,
                        label: 'Daily tasks',
                      ),
                    ),
                    Padding(
                      padding: EdgeInsets.symmetric(horizontal: 6),
                      child: StreakRing(
                        currentCount: 5,
                        graceDaysRemaining: 1,
                        totalGraceDays: 2,
                        label: 'Exercise',
                      ),
                    ),
                    Padding(
                      padding: EdgeInsets.symmetric(horizontal: 6),
                      child: StreakRing(
                        currentCount: 0,
                        isFrozen: true,
                        label: 'Frozen',
                      ),
                    ),
                  ],
                ),
              ),

              // ── Today's tasks ──────────────────────────────────
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
                child: Text('Today\'s Tasks', style: theme.textTheme.titleMedium),
              ),

              BlocBuilder<TaskListBloc, TaskListState>(
                builder: (context, state) {
                  if (state is TaskListLoading) {
                    return const Center(
                      child: Padding(
                        padding: EdgeInsets.all(32),
                        child: CircularProgressIndicator(),
                      ),
                    );
                  }

                  if (state is TaskListError) {
                    return _EmptyState(
                      icon: Icons.cloud_off_rounded,
                      title: 'Could not load tasks',
                      subtitle: state.message,
                    );
                  }

                  if (state is TaskListLoaded) {
                    final tasks = state.tasks;
                    if (tasks.isEmpty) {
                      return const _EmptyState(
                        icon: Icons.check_circle_outline_rounded,
                        title: 'All clear!',
                        subtitle: 'No tasks for today. Enjoy the calm.',
                      );
                    }

                    return Column(
                      children: tasks
                          .take(5)
                          .map((t) => TaskCard(
                                task: t,
                                onTap: () => context.go('/task/${t.id}'),
                                onComplete: () =>
                                    _taskListBloc.add(TaskCompleted(t.id)),
                                onSkip: () =>
                                    _taskListBloc.add(TaskSkipped(t.id)),
                              ))
                          .toList(),
                    );
                  }

                  return const SizedBox.shrink();
                },
              ),
            ],
          ),
        ),

        // ── FAB: create task ─────────────────────────────────────
        floatingActionButton: FloatingActionButton.extended(
          onPressed: () => context.go('/task-create'),
          icon: const Icon(Icons.add_rounded),
          label: const Text('New Task'),
        ),

        // ── Bottom nav ───────────────────────────────────────────
        bottomNavigationBar: BottomNavigationBar(
          currentIndex: _currentNavIndex,
          onTap: _onNavTap,
          items: const [
            BottomNavigationBarItem(icon: Icon(Icons.task_alt_rounded), label: 'Tasks'),
            BottomNavigationBarItem(icon: Icon(Icons.local_fire_department_rounded), label: 'Streaks'),
            BottomNavigationBarItem(icon: Icon(Icons.timer_outlined), label: 'Time'),
            BottomNavigationBarItem(icon: Icon(Icons.settings_rounded), label: 'Settings'),
          ],
        ),
      ),
    );
  }
}

// ── Focus Mode Card ────────────────────────────────────────────────

class _FocusModeCard extends StatelessWidget {
  final VoidCallback onTap;
  const _FocusModeCard({required this.onTap});

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

    return Card(
      margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      color: AppColors.primary,
      child: InkWell(
        borderRadius: BorderRadius.circular(16),
        onTap: onTap,
        child: Padding(
          padding: const EdgeInsets.all(20),
          child: Row(
            children: [
              const Icon(Icons.self_improvement_rounded, size: 40, color: Colors.white),
              const SizedBox(width: 16),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      'Focus Mode',
                      style: theme.textTheme.titleLarge?.copyWith(
                        color: Colors.white,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    const SizedBox(height: 4),
                    Text(
                      'Just do the next thing. One at a time.',
                      style: theme.textTheme.bodyMedium?.copyWith(
                        color: Colors.white.withAlpha(200),
                      ),
                    ),
                  ],
                ),
              ),
              const Icon(Icons.arrow_forward_rounded, color: Colors.white),
            ],
          ),
        ),
      ),
    );
  }
}

// ── Empty state ────────────────────────────────────────────────────

class _EmptyState extends StatelessWidget {
  final IconData icon;
  final String title;
  final String subtitle;

  const _EmptyState({
    required this.icon,
    required this.title,
    required this.subtitle,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Padding(
      padding: const EdgeInsets.all(32),
      child: Column(
        children: [
          Icon(icon, size: 56, color: AppColors.skipped),
          const SizedBox(height: 12),
          Text(title, style: theme.textTheme.titleMedium),
          const SizedBox(height: 4),
          Text(subtitle, style: theme.textTheme.bodyMedium, textAlign: TextAlign.center),
        ],
      ),
    );
  }
}