import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../shared/models/diary_entry.dart';
import 'menu_provider.dart';

String formatDate(String d) {
  try {
    final dt = DateTime.parse(d);
    const months = [
      'января', 'февраля', 'марта', 'апреля', 'мая', 'июня',
      'июля', 'августа', 'сентября', 'октября', 'ноября', 'декабря',
    ];
    return '${dt.day} ${months[dt.month - 1]}';
  } catch (_) {
    return d;
  }
}

class DiaryScreen extends ConsumerWidget {
  final String date;

  const DiaryScreen({super.key, required this.date});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(diaryProvider(date));
    final theme = Theme.of(context);

    return Scaffold(
      appBar: AppBar(
        title: Text('Дневник — ${formatDate(date)}'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _showAddSheet(context, ref),
        child: const Icon(Icons.add),
      ),
      body: state.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (_, __) => Center(
          child: FilledButton(
            onPressed: () => ref.read(diaryProvider(date).notifier).load(),
            child: const Text('Повторить'),
          ),
        ),
        data: (entries) => entries.isEmpty
            ? Center(
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Icon(Icons.book_outlined,
                        size: 72,
                        color: theme.colorScheme.onSurfaceVariant),
                    const SizedBox(height: 16),
                    const Text('Нет записей за этот день'),
                    const SizedBox(height: 8),
                    FilledButton.icon(
                      onPressed: () => _showAddSheet(context, ref),
                      icon: const Icon(Icons.add),
                      label: const Text('Добавить запись'),
                    ),
                  ],
                ),
              )
            : _DiaryList(entries: entries, date: date),
      ),
    );
  }

  void _showAddSheet(BuildContext context, WidgetRef ref) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (_) => _AddEntrySheet(date: date, ref: ref),
    );
  }
}

class _DiaryList extends ConsumerWidget {
  final List<DiaryEntry> entries;
  final String date;

  const _DiaryList({required this.entries, required this.date});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    // Group by meal type.
    const order = ['breakfast', 'lunch', 'dinner'];
    final grouped = <String, List<DiaryEntry>>{};
    for (final e in entries) {
      grouped.putIfAbsent(e.mealType, () => []).add(e);
    }

    // Total calories for the day.
    final totalCal = entries.fold<double>(
      0,
      (sum, e) => sum + ((e.calories ?? 0) * e.portions),
    );

    return ListView(
      padding: const EdgeInsets.only(bottom: 100),
      children: [
        if (totalCal > 0)
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
            child: Text(
              'Итого за день: ≈${totalCal.toInt()} ккал',
              style: Theme.of(context).textTheme.titleSmall,
            ),
          ),
        for (final mealType in [...order, ...grouped.keys.where((k) => !order.contains(k))])
          if (grouped.containsKey(mealType)) ...[
            _MealHeader(mealType: mealType),
            for (final entry in grouped[mealType]!)
              _EntryTile(entry: entry, date: date),
          ],
      ],
    );
  }
}

class _MealHeader extends StatelessWidget {
  final String mealType;

  const _MealHeader({required this.mealType});

  @override
  Widget build(BuildContext context) {
    final entry = DiaryEntry(
      id: '', date: '', mealType: mealType, name: '',
      portions: 1, source: '',
    );
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 4),
      child: Text(
        entry.mealLabel,
        style: Theme.of(context).textTheme.titleSmall?.copyWith(
              fontWeight: FontWeight.w600,
            ),
      ),
    );
  }
}

class _EntryTile extends ConsumerWidget {
  final DiaryEntry entry;
  final String date;

  const _EntryTile({required this.entry, required this.date});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final cal = entry.calories != null
        ? '≈${(entry.calories! * entry.portions).toInt()} ккал'
        : '';

    return Dismissible(
      key: ValueKey(entry.id),
      direction: DismissDirection.endToStart,
      background: Container(
        color: Colors.red,
        alignment: Alignment.centerRight,
        padding: const EdgeInsets.only(right: 20),
        child: const Icon(Icons.delete_outline, color: Colors.white),
      ),
      onDismissed: (_) =>
          ref.read(diaryProvider(date).notifier).remove(entry.id),
      child: ListTile(
        title: Text(entry.name),
        subtitle: entry.portions != 1
            ? Text('${entry.portions} порций')
            : null,
        trailing: cal.isNotEmpty
            ? Text(cal,
                style: Theme.of(context)
                    .textTheme
                    .bodySmall
                    ?.copyWith(fontWeight: FontWeight.w600))
            : null,
      ),
    );
  }
}

// ── Add entry bottom sheet ─────────────────────────────────────

class _AddEntrySheet extends StatefulWidget {
  final String date;
  final WidgetRef ref;

  const _AddEntrySheet({required this.date, required this.ref});

  @override
  State<_AddEntrySheet> createState() => _AddEntrySheetState();
}

class _AddEntrySheetState extends State<_AddEntrySheet> {
  final _nameController = TextEditingController();
  final _calController = TextEditingController();
  String _mealType = 'breakfast';
  bool _saving = false;

  static const _mealTypes = [
    ('breakfast', 'Завтрак'),
    ('lunch', 'Обед'),
    ('dinner', 'Ужин'),
  ];

  @override
  void dispose() {
    _nameController.dispose();
    _calController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final insets = MediaQuery.viewInsetsOf(context);
    return Padding(
      padding: EdgeInsets.fromLTRB(16, 16, 16, 16 + insets.bottom),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Text('Добавить запись',
              style: Theme.of(context).textTheme.titleMedium),
          const SizedBox(height: 16),
          DropdownMenu<String>(
            initialSelection: _mealType,
            expandedInsets: EdgeInsets.zero,
            label: const Text('Приём пищи'),
            dropdownMenuEntries: _mealTypes
                .map((t) => DropdownMenuEntry(value: t.$1, label: t.$2))
                .toList(),
            onSelected: (v) => setState(() => _mealType = v ?? _mealType),
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _nameController,
            decoration: const InputDecoration(
              labelText: 'Название блюда',
              border: OutlineInputBorder(),
            ),
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _calController,
            keyboardType: TextInputType.number,
            decoration: const InputDecoration(
              labelText: 'Калории (необязательно)',
              border: OutlineInputBorder(),
            ),
          ),
          const SizedBox(height: 16),
          FilledButton(
            onPressed: _saving ? null : _save,
            child: _saving
                ? const SizedBox(
                    height: 20,
                    width: 20,
                    child: CircularProgressIndicator(strokeWidth: 2),
                  )
                : const Text('Добавить'),
          ),
        ],
      ),
    );
  }

  Future<void> _save() async {
    final name = _nameController.text.trim();
    if (name.isEmpty) return;
    setState(() => _saving = true);
    try {
      final cal = double.tryParse(_calController.text);
      await widget.ref.read(diaryProvider(widget.date).notifier).add({
        'date': widget.date,
        'meal_type': _mealType,
        'name': name,
        'portions': 1,
        if (cal != null) 'calories': cal,
        'source': 'manual',
      });
      if (mounted) Navigator.pop(context);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }
}