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

import '../../features/menu/menu_provider.dart';
import '../../features/home/home_provider.dart';
import '../../shared/models/meal_type.dart';
import 'recognition_service.dart';

/// Bottom sheet that shows dish recognition candidates and lets the user
/// confirm a dish entry before adding it to the diary.
class DishResultSheet extends ConsumerStatefulWidget {
  const DishResultSheet({
    super.key,
    required this.dish,
    required this.onAdded,
    this.preselectedMealType,
  });

  final DishResult dish;
  final VoidCallback onAdded;
  final String? preselectedMealType;

  @override
  ConsumerState<DishResultSheet> createState() => _DishResultSheetState();
}

class _DishResultSheetState extends ConsumerState<DishResultSheet> {
  late int _selectedIndex;
  late int _portionGrams;
  late String _mealType;
  bool _saving = false;

  final TextEditingController _portionController = TextEditingController();

  @override
  void initState() {
    super.initState();
    _selectedIndex = 0;
    _portionGrams = widget.dish.candidates.isNotEmpty
        ? widget.dish.candidates.first.weightGrams
        : 300;
    _mealType = widget.preselectedMealType ??
        kAllMealTypes.first.id;
    _portionController.text = '$_portionGrams';
  }

  @override
  void dispose() {
    _portionController.dispose();
    super.dispose();
  }

  DishCandidate get _selected => widget.dish.candidates[_selectedIndex];

  /// Scales nutrition linearly to the current portion weight.
  double _scale(double baseValue) {
    final baseWeight = _selected.weightGrams;
    if (baseWeight <= 0) return baseValue;
    return baseValue * _portionGrams / baseWeight;
  }

  void _selectCandidate(int index) {
    setState(() {
      _selectedIndex = index;
      _portionGrams = widget.dish.candidates[index].weightGrams;
      _portionController.text = '$_portionGrams';
    });
  }

  void _adjustPortion(int delta) {
    final newValue = (_portionGrams + delta).clamp(10, 9999);
    setState(() {
      _portionGrams = newValue;
      _portionController.text = '$newValue';
    });
  }

  void _onPortionEdited(String value) {
    final parsed = int.tryParse(value);
    if (parsed != null && parsed >= 10) {
      setState(() => _portionGrams = parsed.clamp(10, 9999));
    }
  }

  Future<void> _addToDiary() async {
    if (_saving) return;
    setState(() => _saving = true);

    final selectedDate = ref.read(selectedDateProvider);
    final dateString = formatDateForDiary(selectedDate);

    final scaledCalories = _scale(_selected.calories);
    final scaledProtein  = _scale(_selected.proteinG);
    final scaledFat      = _scale(_selected.fatG);
    final scaledCarbs    = _scale(_selected.carbsG);

    try {
      await ref.read(diaryProvider(dateString).notifier).add({
        'date': dateString,
        'meal_type': _mealType,
        'name': _selected.dishName,
        'calories': scaledCalories,
        'protein_g': scaledProtein,
        'fat_g': scaledFat,
        'carbs_g': scaledCarbs,
        'portion_g': _portionGrams,
        'source': 'recognition',
      });
      if (mounted) widget.onAdded();
    } catch (addError) {
      debugPrint('Add to diary error: $addError');
      if (mounted) {
        setState(() => _saving = false);
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Не удалось добавить. Попробуйте ещё раз.')),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final hasCandidates = widget.dish.candidates.isNotEmpty;

    return Column(
      children: [
        // Drag handle
        Center(
          child: Container(
            width: 40,
            height: 4,
            margin: const EdgeInsets.symmetric(vertical: 12),
            decoration: BoxDecoration(
              color: theme.colorScheme.onSurfaceVariant.withValues(alpha: 0.4),
              borderRadius: BorderRadius.circular(2),
            ),
          ),
        ),
        // Title row
        Padding(
          padding: const EdgeInsets.fromLTRB(20, 0, 8, 0),
          child: Row(
            children: [
              Text('Распознано блюдо', style: theme.textTheme.titleMedium),
              const Spacer(),
              IconButton(
                icon: const Icon(Icons.close),
                onPressed: () => Navigator.pop(context),
              ),
            ],
          ),
        ),
        // Scrollable content
        Expanded(
          child: hasCandidates
              ? ListView(
                  padding: const EdgeInsets.all(20),
                  children: [
                    _CandidatesSection(
                      candidates: widget.dish.candidates,
                      selectedIndex: _selectedIndex,
                      onSelect: _selectCandidate,
                    ),
                    const SizedBox(height: 20),
                    _NutritionCard(
                      calories: _scale(_selected.calories),
                      proteinG: _scale(_selected.proteinG),
                      fatG: _scale(_selected.fatG),
                      carbsG: _scale(_selected.carbsG),
                    ),
                    const SizedBox(height: 8),
                    Text(
                      'КБЖУ приблизительные — определены по фото.',
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                      textAlign: TextAlign.center,
                    ),
                    const SizedBox(height: 20),
                    _PortionRow(
                      controller: _portionController,
                      onMinus: () => _adjustPortion(-10),
                      onPlus: () => _adjustPortion(10),
                      onChanged: _onPortionEdited,
                    ),
                    const SizedBox(height: 20),
                    _MealTypeDropdown(
                      selected: _mealType,
                      onChanged: (value) {
                        if (value != null) setState(() => _mealType = value);
                      },
                    ),
                    const SizedBox(height: 16),
                  ],
                )
              : Center(
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(
                        'Блюдо не распознано',
                        style: theme.textTheme.titleMedium,
                      ),
                      const SizedBox(height: 8),
                      FilledButton(
                        onPressed: () => Navigator.pop(context),
                        child: const Text('Попробовать снова'),
                      ),
                    ],
                  ),
                ),
        ),
        // Bottom button
        if (hasCandidates)
          SafeArea(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(20, 8, 20, 16),
              child: FilledButton(
                onPressed: _saving ? null : _addToDiary,
                child: _saving
                    ? const SizedBox(
                        height: 20,
                        width: 20,
                        child: CircularProgressIndicator(strokeWidth: 2),
                      )
                    : const Text('Добавить в журнал'),
              ),
            ),
          ),
      ],
    );
  }
}

// ---------------------------------------------------------------------------
// Candidates selector
// ---------------------------------------------------------------------------

class _CandidatesSection extends StatelessWidget {
  const _CandidatesSection({
    required this.candidates,
    required this.selectedIndex,
    required this.onSelect,
  });

  final List<DishCandidate> candidates;
  final int selectedIndex;
  final ValueChanged<int> onSelect;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Выберите блюдо', style: theme.textTheme.titleMedium),
        const SizedBox(height: 8),
        ...candidates.asMap().entries.map((entry) {
          final index = entry.key;
          final candidate = entry.value;
          final confPct = (candidate.confidence * 100).toInt();
          final isSelected = index == selectedIndex;

          return Padding(
            padding: const EdgeInsets.only(bottom: 8),
            child: InkWell(
              borderRadius: BorderRadius.circular(12),
              onTap: () => onSelect(index),
              child: AnimatedContainer(
                duration: const Duration(milliseconds: 150),
                padding: const EdgeInsets.symmetric(
                    horizontal: 16, vertical: 12),
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(12),
                  border: Border.all(
                    color: isSelected
                        ? theme.colorScheme.primary
                        : theme.colorScheme.outlineVariant,
                    width: isSelected ? 2 : 1,
                  ),
                  color: isSelected
                      ? theme.colorScheme.primaryContainer
                          .withValues(alpha: 0.3)
                      : null,
                ),
                child: Row(
                  children: [
                    Icon(
                      isSelected
                          ? Icons.radio_button_checked
                          : Icons.radio_button_unchecked,
                      color: isSelected
                          ? theme.colorScheme.primary
                          : theme.colorScheme.onSurfaceVariant,
                    ),
                    const SizedBox(width: 8),
                    Expanded(
                      child: Text(
                        candidate.dishName,
                        style: theme.textTheme.bodyLarge?.copyWith(
                          fontWeight: isSelected
                              ? FontWeight.w600
                              : FontWeight.normal,
                        ),
                      ),
                    ),
                    _ConfidenceBadge(confidence: confPct),
                  ],
                ),
              ),
            ),
          );
        }),
      ],
    );
  }
}

class _ConfidenceBadge extends StatelessWidget {
  const _ConfidenceBadge({required this.confidence});

  final int confidence;

  @override
  Widget build(BuildContext context) {
    final Color badgeColor;
    if (confidence >= 80) {
      badgeColor = Colors.green;
    } else if (confidence >= 50) {
      badgeColor = Colors.orange;
    } else {
      badgeColor = Colors.red;
    }

    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      decoration: BoxDecoration(
        color: badgeColor.withValues(alpha: 0.15),
        borderRadius: BorderRadius.circular(8),
      ),
      child: Text(
        '$confidence%',
        style: TextStyle(
          color: badgeColor,
          fontWeight: FontWeight.bold,
          fontSize: 12,
        ),
      ),
    );
  }
}

// ---------------------------------------------------------------------------
// Nutrition card
// ---------------------------------------------------------------------------

class _NutritionCard extends StatelessWidget {
  const _NutritionCard({
    required this.calories,
    required this.proteinG,
    required this.fatG,
    required this.carbsG,
  });

  final double calories;
  final double proteinG;
  final double fatG;
  final double carbsG;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(16),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Text(
                  '≈ ${calories.toInt()} ккал',
                  style: theme.textTheme.titleLarge?.copyWith(
                    fontWeight: FontWeight.bold,
                    color: theme.colorScheme.primary,
                  ),
                ),
                const Spacer(),
                Tooltip(
                  message: 'Приблизительные значения на основе фото',
                  child: Text(
                    '≈',
                    style: theme.textTheme.titleLarge?.copyWith(
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 12),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                _MacroChip(
                  label: 'Белки',
                  value: '${proteinG.toStringAsFixed(1)} г',
                  color: Colors.blue,
                ),
                _MacroChip(
                  label: 'Жиры',
                  value: '${fatG.toStringAsFixed(1)} г',
                  color: Colors.orange,
                ),
                _MacroChip(
                  label: 'Углеводы',
                  value: '${carbsG.toStringAsFixed(1)} г',
                  color: Colors.green,
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

class _MacroChip extends StatelessWidget {
  const _MacroChip({
    required this.label,
    required this.value,
    required this.color,
  });

  final String label;
  final String value;
  final Color color;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Text(
          value,
          style: TextStyle(
            fontWeight: FontWeight.bold,
            fontSize: 16,
            color: color,
          ),
        ),
        Text(label, style: Theme.of(context).textTheme.labelSmall),
      ],
    );
  }
}

// ---------------------------------------------------------------------------
// Portion row
// ---------------------------------------------------------------------------

class _PortionRow extends StatelessWidget {
  const _PortionRow({
    required this.controller,
    required this.onMinus,
    required this.onPlus,
    required this.onChanged,
  });

  final TextEditingController controller;
  final VoidCallback onMinus;
  final VoidCallback onPlus;
  final ValueChanged<String> onChanged;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Порция', style: theme.textTheme.titleSmall),
        const SizedBox(height: 8),
        Row(
          children: [
            IconButton.outlined(
              icon: const Icon(Icons.remove),
              onPressed: onMinus,
            ),
            const SizedBox(width: 8),
            Expanded(
              child: TextField(
                controller: controller,
                textAlign: TextAlign.center,
                keyboardType: TextInputType.number,
                inputFormatters: [FilteringTextInputFormatter.digitsOnly],
                onChanged: onChanged,
                decoration: const InputDecoration(
                  suffixText: 'г',
                  border: OutlineInputBorder(),
                ),
              ),
            ),
            const SizedBox(width: 8),
            IconButton.outlined(
              icon: const Icon(Icons.add),
              onPressed: onPlus,
            ),
          ],
        ),
      ],
    );
  }
}

// ---------------------------------------------------------------------------
// Meal type dropdown
// ---------------------------------------------------------------------------

class _MealTypeDropdown extends StatelessWidget {
  const _MealTypeDropdown({
    required this.selected,
    required this.onChanged,
  });

  final String selected;
  final ValueChanged<String?> onChanged;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Приём пищи', style: theme.textTheme.titleSmall),
        const SizedBox(height: 8),
        DropdownButtonFormField<String>(
          initialValue: selected,
          decoration: const InputDecoration(
            border: OutlineInputBorder(),
          ),
          items: kAllMealTypes
              .map((mealTypeOption) => DropdownMenuItem(
                    value: mealTypeOption.id,
                    child: Text(
                        '${mealTypeOption.emoji} ${mealTypeOption.label}'),
                  ))
              .toList(),
          onChanged: onChanged,
        ),
      ],
    );
  }
}