import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';
import 'package:provider/provider.dart';

import '../../../../core/di/injection_container.dart';
import '../viewmodels/daily_tasks_viewmodel.dart';
import '../widgets/task_tile.dart';
import '../widgets/filter_chips.dart';

class DailyAgendaPage extends StatelessWidget {
  const DailyAgendaPage({super.key});

  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (_) => getIt<DailyTasksViewModel>()..loadTasks(),
      child: const _DailyAgendaView(),
    );
  }
}

class _DailyAgendaView extends StatelessWidget {
  const _DailyAgendaView();

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final vm = context.watch<DailyTasksViewModel>();
    final locale = Localizations.localeOf(context).languageCode;

    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.appTitle),
        actions: [
          IconButton(
            icon: const Icon(Icons.calendar_month),
            onPressed: () => context.push('/calendar'),
            tooltip: l10n.calendar,
          ),
          IconButton(
            icon: const Icon(Icons.settings),
            onPressed: () => context.push('/settings'),
            tooltip: l10n.settings,
          ),
        ],
      ),
      body: Column(
        children: [
          _DateNavigation(
            date: vm.selectedDate,
            locale: locale,
            onPrevious: vm.previousDay,
            onNext: vm.nextDay,
          ),
          FilterChips(
            currentFilter: vm.filter,
            onFilterChanged: vm.setFilter,
          ),
          Expanded(
            child: _buildBody(context, vm, l10n),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          final dateStr = DateFormat('yyyy-MM-dd').format(vm.selectedDate);
          context.push('/task/new?date=$dateStr');
        },
        child: const Icon(Icons.add),
      ),
    );
  }

  Widget _buildBody(BuildContext context, DailyTasksViewModel vm, AppLocalizations l10n) {
    switch (vm.status) {
      case TasksStatus.initial:
      case TasksStatus.loading:
        return const Center(child: CircularProgressIndicator());
      case TasksStatus.error:
        return Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Text(
                vm.failure?.message ?? l10n.errorOccurred,
                style: Theme.of(context).textTheme.bodyLarge,
              ),
              const SizedBox(height: 16),
              ElevatedButton(
                onPressed: vm.loadTasks,
                child: Text(l10n.retry),
              ),
            ],
          ),
        );
      case TasksStatus.success:
        if (vm.tasks.isEmpty) {
          return Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Icon(
                  Icons.task_alt,
                  size: 64,
                  color: Theme.of(context).colorScheme.outline,
                ),
                const SizedBox(height: 16),
                Text(
                  l10n.noTasks,
                  style: Theme.of(context).textTheme.bodyLarge,
                ),
              ],
            ),
          );
        }
        return RefreshIndicator(
          onRefresh: vm.loadTasks,
          child: ListView.builder(
            padding: const EdgeInsets.only(bottom: 80),
            itemCount: vm.tasks.length,
            itemBuilder: (context, index) {
              final task = vm.tasks[index];
              return TaskTile(
                task: task,
                onToggle: () => vm.toggleTask(task.id),
                onTap: () => context.push('/task/${task.id}/edit'),
                onDelete: () => vm.deleteTask(task.id),
                onReschedule: () => vm.rescheduleToTomorrow(task.id),
              );
            },
          ),
        );
    }
  }
}

class _DateNavigation extends StatelessWidget {
  final DateTime date;
  final String locale;
  final VoidCallback onPrevious;
  final VoidCallback onNext;

  const _DateNavigation({
    required this.date,
    required this.locale,
    required this.onPrevious,
    required this.onNext,
  });

  @override
  Widget build(BuildContext context) {
    final dateFormat = DateFormat.yMMMMEEEEd(locale);

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 12),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          IconButton(
            icon: const Icon(Icons.chevron_left),
            onPressed: onPrevious,
          ),
          Expanded(
            child: Text(
              dateFormat.format(date),
              textAlign: TextAlign.center,
              style: Theme.of(context).textTheme.titleMedium,
            ),
          ),
          IconButton(
            icon: const Icon(Icons.chevron_right),
            onPressed: onNext,
          ),
        ],
      ),
    );
  }
}