import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:food_ai/l10n/app_localizations.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../core/auth/auth_provider.dart';
import '../../core/locale/language_provider.dart';
import '../../core/theme/app_colors.dart';
import '../../shared/models/meal_type.dart';
import '../../shared/models/user.dart';
import 'profile_provider.dart';
import 'profile_service.dart';

class ProfileScreen extends ConsumerWidget {
  const ProfileScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context)!;
    final state = ref.watch(profileProvider);

    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.profileTitle),
        actions: [
          if (state.hasValue)
            TextButton(
              onPressed: () => _openEdit(context, state.value!),
              child: Text(l10n.edit),
            ),
        ],
      ),
      body: state.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (_, __) => Center(
          child: FilledButton(
            onPressed: () => ref.read(profileProvider.notifier).load(),
            child: Text(l10n.retry),
          ),
        ),
        data: (user) => _ProfileBody(user: user),
      ),
    );
  }

  void _openEdit(BuildContext context, User user) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      builder: (_) => EditProfileSheet(user: user),
    );
  }
}

// ── Profile body ──────────────────────────────────────────────

class _ProfileBody extends ConsumerWidget {
  final User user;
  const _ProfileBody({required this.user});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context)!;

    String? genderLabel(String? gender) => switch (gender) {
      'male' => l10n.genderMale,
      'female' => l10n.genderFemale,
      _ => null,
    };

    String? goalLabel(String? goal) => switch (goal) {
      'lose' => l10n.goalLoss,
      'maintain' => l10n.goalMaintain,
      'gain' => l10n.goalGain,
      _ => null,
    };

    String? activityLabel(String? activity) => switch (activity) {
      'low' => l10n.activityLow,
      'moderate' => l10n.activityMedium,
      'high' => l10n.activityHigh,
      _ => null,
    };

    return ListView(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 32),
      children: [
        _ProfileHeader(user: user),
        const SizedBox(height: 24),

        // Body params
        _SectionLabel(l10n.bodyParams),
        const SizedBox(height: 6),
        _InfoCard(children: [
          _InfoRow(l10n.height, user.heightCm != null ? '${user.heightCm} см' : null),
          const Divider(height: 1, indent: 16),
          _InfoRow(l10n.weight,
              user.weightKg != null ? '${_fmt(user.weightKg!)} кг' : null),
          const Divider(height: 1, indent: 16),
          _InfoRow(l10n.age, user.age != null ? '${user.age}' : null),
          const Divider(height: 1, indent: 16),
          _InfoRow(l10n.gender, genderLabel(user.gender)),
        ]),
        if (user.heightCm == null && user.weightKg == null) ...[
          const SizedBox(height: 8),
          _HintBanner(l10n.calorieHint),
        ],
        const SizedBox(height: 16),

        // Goal & activity
        _SectionLabel(l10n.goalActivity),
        const SizedBox(height: 6),
        _InfoCard(children: [
          _InfoRow(l10n.goalLabel.replaceAll(':', '').trim(), goalLabel(user.goal)),
          const Divider(height: 1, indent: 16),
          _InfoRow('Активность', activityLabel(user.activity)),
        ]),
        const SizedBox(height: 16),

        // Calories + meal types
        _SectionLabel(l10n.nutrition),
        const SizedBox(height: 6),
        _InfoCard(children: [
          _InfoRow(
            l10n.calorieGoal,
            user.dailyCalories != null
                ? '${user.dailyCalories} ${l10n.caloriesUnit}/день'
                : null,
          ),
          const Divider(height: 1, indent: 16),
          _InfoRow(
            l10n.mealTypes,
            user.mealTypes
                .map((mealTypeId) => mealTypeLabel(mealTypeId, l10n))
                .join(', '),
          ),
        ]),
        if (user.dailyCalories != null) ...[
          const SizedBox(height: 4),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 4),
            child: Text(
              l10n.formulaNote,
              style: Theme.of(context).textTheme.labelSmall?.copyWith(
                    color: AppColors.textSecondary,
                  ),
            ),
          ),
        ],
        const SizedBox(height: 16),

        // Settings
        _SectionLabel(l10n.settings),
        const SizedBox(height: 6),
        _InfoCard(children: [
          _InfoRow(
            l10n.language,
            ref.watch(supportedLanguagesProvider).valueOrNull?[
                    user.preferences['language'] as String? ?? 'ru'] ??
                'Русский',
          ),
        ]),
        const SizedBox(height: 32),

        _LogoutButton(),
      ],
    );
  }

  static String _fmt(double weight) =>
      weight == weight.truncateToDouble()
          ? weight.toInt().toString()
          : weight.toStringAsFixed(1);
}

// ── Header ────────────────────────────────────────────────────

class _ProfileHeader extends StatelessWidget {
  final User user;
  const _ProfileHeader({required this.user});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final initials = user.name.isNotEmpty ? user.name[0].toUpperCase() : '?';

    return Column(
      children: [
        const SizedBox(height: 8),
        CircleAvatar(
          radius: 40,
          backgroundColor: AppColors.primary.withValues(alpha: 0.15),
          child: Text(
            initials,
            style: theme.textTheme.headlineMedium?.copyWith(
              color: AppColors.primary,
              fontWeight: FontWeight.w600,
            ),
          ),
        ),
        const SizedBox(height: 12),
        Text(user.name, style: theme.textTheme.titleMedium),
        const SizedBox(height: 2),
        Text(
          user.email,
          style: theme.textTheme.bodySmall
              ?.copyWith(color: AppColors.textSecondary),
        ),
      ],
    );
  }
}

// ── Shared widgets ────────────────────────────────────────────

class _SectionLabel extends StatelessWidget {
  final String text;
  const _SectionLabel(this.text);

  @override
  Widget build(BuildContext context) => Padding(
        padding: const EdgeInsets.only(left: 4),
        child: Text(
          text,
          style: Theme.of(context).textTheme.labelSmall?.copyWith(
                color: AppColors.textSecondary,
                letterSpacing: 0.5,
              ),
        ),
      );
}

class _InfoCard extends StatelessWidget {
  final List<Widget> children;
  const _InfoCard({required this.children});

  @override
  Widget build(BuildContext context) =>
      Card(child: Column(children: children));
}

class _InfoRow extends StatelessWidget {
  final String label;
  final String? value;
  const _InfoRow(this.label, this.value);

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final theme = Theme.of(context);
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 13),
      child: Row(
        children: [
          Text(label, style: theme.textTheme.bodyMedium),
          const Spacer(),
          Text(
            value ?? l10n.notSet,
            style: theme.textTheme.bodyMedium?.copyWith(
              color: value != null
                  ? AppColors.textPrimary
                  : AppColors.textSecondary,
            ),
          ),
        ],
      ),
    );
  }
}

class _HintBanner extends StatelessWidget {
  final String text;
  const _HintBanner(this.text);

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      decoration: BoxDecoration(
        color: AppColors.warning.withValues(alpha: 0.12),
        borderRadius: BorderRadius.circular(8),
      ),
      child: Row(
        children: [
          const Icon(Icons.info_outline, size: 16, color: AppColors.warning),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              text,
              style: Theme.of(context)
                  .textTheme
                  .bodySmall
                  ?.copyWith(color: AppColors.warning),
            ),
          ),
        ],
      ),
    );
  }
}

class _LogoutButton extends ConsumerWidget {
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context)!;
    return OutlinedButton(
      style: OutlinedButton.styleFrom(
        foregroundColor: AppColors.error,
        side: const BorderSide(color: AppColors.error),
      ),
      onPressed: () => _confirmLogout(context, ref),
      child: Text(l10n.logout),
    );
  }

  Future<void> _confirmLogout(BuildContext context, WidgetRef ref) async {
    final l10n = AppLocalizations.of(context)!;
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: Text('${l10n.logout}?'),
        content: const Text('Вы будете перенаправлены на экран входа.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(dialogContext).pop(false),
            child: Text(l10n.cancel),
          ),
          TextButton(
            style: TextButton.styleFrom(foregroundColor: AppColors.error),
            onPressed: () => Navigator.of(dialogContext).pop(true),
            child: Text(l10n.logout),
          ),
        ],
      ),
    );
    if (confirmed == true) {
      await ref.read(authProvider.notifier).signOut();
    }
  }
}

// ── Edit sheet ────────────────────────────────────────────────

class EditProfileSheet extends ConsumerStatefulWidget {
  final User user;
  const EditProfileSheet({super.key, required this.user});

  @override
  ConsumerState<EditProfileSheet> createState() => _EditProfileSheetState();
}

class _EditProfileSheetState extends ConsumerState<EditProfileSheet> {
  final _formKey = GlobalKey<FormState>();
  late final TextEditingController _nameController;
  late final TextEditingController _heightController;
  late final TextEditingController _weightController;
  DateTime? _selectedDob;
  String? _gender;
  String? _goal;
  String? _activity;
  String? _language;
  List<String> _mealTypes = [];
  bool _saving = false;

  @override
  void initState() {
    super.initState();
    final user = widget.user;
    _nameController = TextEditingController(text: user.name);
    _heightController = TextEditingController(text: user.heightCm?.toString() ?? '');
    _weightController = TextEditingController(
        text: user.weightKg != null ? _fmt(user.weightKg!) : '');
    _selectedDob =
        user.dateOfBirth != null ? DateTime.tryParse(user.dateOfBirth!) : null;
    _gender = user.gender;
    _goal = user.goal;
    _activity = user.activity;
    _language = user.preferences['language'] as String? ?? 'ru';
    _mealTypes = List<String>.from(user.mealTypes);
  }

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

  String _fmt(double weight) =>
      weight == weight.truncateToDouble()
          ? weight.toInt().toString()
          : weight.toStringAsFixed(1);

  Future<void> _pickDob() async {
    final now = DateTime.now();
    final initial = _selectedDob ?? DateTime(now.year - 25, now.month, now.day);
    final picked = await showDatePicker(
      context: context,
      initialDate: initial,
      firstDate: DateTime(now.year - 120),
      lastDate: DateTime(now.year - 10, now.month, now.day),
    );
    if (picked != null) setState(() => _selectedDob = picked);
  }

  Future<void> _save() async {
    final l10n = AppLocalizations.of(context)!;
    if (!_formKey.currentState!.validate()) return;
    setState(() => _saving = true);

    final request = UpdateProfileRequest(
      name: _nameController.text.trim(),
      heightCm: int.tryParse(_heightController.text),
      weightKg: double.tryParse(_weightController.text),
      dateOfBirth: _selectedDob != null
          ? '${_selectedDob!.year.toString().padLeft(4, '0')}-'
              '${_selectedDob!.month.toString().padLeft(2, '0')}-'
              '${_selectedDob!.day.toString().padLeft(2, '0')}'
          : null,
      gender: _gender,
      goal: _goal,
      activity: _activity,
      language: _language,
      mealTypes: _mealTypes,
    );

    final ok = await ref.read(profileProvider.notifier).update(request);

    if (!mounted) return;
    setState(() => _saving = false);

    if (ok) {
      Navigator.of(context).pop();
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(l10n.profileUpdated)),
      );
    } else {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(l10n.profileSaveFailed)),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context)!;
    final theme = Theme.of(context);
    final bottomInset = MediaQuery.viewInsetsOf(context).bottom;

    return Padding(
      padding: EdgeInsets.only(bottom: bottomInset),
      child: DraggableScrollableSheet(
        expand: false,
        initialChildSize: 0.85,
        maxChildSize: 0.95,
        builder: (_, controller) => Column(
          children: [
            const SizedBox(height: 12),
            // Drag handle
            Container(
              width: 36,
              height: 4,
              decoration: BoxDecoration(
                color: AppColors.separator,
                borderRadius: BorderRadius.circular(2),
              ),
            ),
            const SizedBox(height: 12),
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 16),
              child: Row(
                children: [
                  Text(l10n.editProfile, style: theme.textTheme.titleMedium),
                  const Spacer(),
                  TextButton(
                    onPressed: () => Navigator.of(context).pop(),
                    child: Text(l10n.cancel),
                  ),
                ],
              ),
            ),
            const Divider(height: 1),
            Expanded(
              child: Form(
                key: _formKey,
                child: ListView(
                  controller: controller,
                  padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
                  children: [
                    // Name
                    TextFormField(
                      controller: _nameController,
                      decoration: InputDecoration(labelText: l10n.nameLabel),
                      textCapitalization: TextCapitalization.words,
                      validator: (value) =>
                          (value == null || value.trim().isEmpty)
                              ? l10n.nameRequired
                              : null,
                    ),
                    const SizedBox(height: 12),

                    // Height + Weight
                    Row(
                      children: [
                        Expanded(
                          child: TextFormField(
                            controller: _heightController,
                            decoration: InputDecoration(labelText: l10n.heightCm),
                            keyboardType: TextInputType.number,
                            inputFormatters: [
                              FilteringTextInputFormatter.digitsOnly
                            ],
                            validator: (value) {
                              if (value == null || value.isEmpty) return null;
                              final number = int.tryParse(value);
                              if (number == null || number < 100 || number > 250) {
                                return '100–250';
                              }
                              return null;
                            },
                          ),
                        ),
                        const SizedBox(width: 12),
                        Expanded(
                          child: TextFormField(
                            controller: _weightController,
                            decoration: InputDecoration(labelText: l10n.weightKg),
                            keyboardType: const TextInputType.numberWithOptions(
                                decimal: true),
                            inputFormatters: [
                              FilteringTextInputFormatter.allow(
                                  RegExp(r'[0-9.]'))
                            ],
                            validator: (value) {
                              if (value == null || value.isEmpty) return null;
                              final number = double.tryParse(value);
                              if (number == null || number < 30 || number > 300) {
                                return '30–300';
                              }
                              return null;
                            },
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 12),

                    // Date of birth
                    InkWell(
                      onTap: _pickDob,
                      child: InputDecorator(
                        decoration: InputDecoration(labelText: l10n.birthDate),
                        child: Text(
                          _selectedDob != null
                              ? '${_selectedDob!.day.toString().padLeft(2, '0')}.'
                                  '${_selectedDob!.month.toString().padLeft(2, '0')}.'
                                  '${_selectedDob!.year}'
                              : l10n.notSet,
                          style: Theme.of(context).textTheme.bodyMedium,
                        ),
                      ),
                    ),
                    const SizedBox(height: 20),

                    // Gender
                    Text(l10n.gender, style: theme.textTheme.labelMedium),
                    const SizedBox(height: 8),
                    SegmentedButton<String>(
                      segments: [
                        ButtonSegment(value: 'male', label: Text(l10n.genderMale)),
                        ButtonSegment(value: 'female', label: Text(l10n.genderFemale)),
                      ],
                      selected: _gender != null ? {_gender!} : const {},
                      emptySelectionAllowed: true,
                      onSelectionChanged: (selection) =>
                          setState(() => _gender = selection.isEmpty ? null : selection.first),
                    ),
                    const SizedBox(height: 20),

                    // Goal
                    Text(l10n.goalLabel.replaceAll(':', '').trim(),
                        style: theme.textTheme.labelMedium),
                    const SizedBox(height: 8),
                    SegmentedButton<String>(
                      segments: [
                        ButtonSegment(value: 'lose', label: Text(l10n.goalLoss)),
                        ButtonSegment(value: 'maintain', label: Text(l10n.goalMaintain)),
                        ButtonSegment(value: 'gain', label: Text(l10n.goalGain)),
                      ],
                      selected: _goal != null ? {_goal!} : const {},
                      emptySelectionAllowed: true,
                      onSelectionChanged: (selection) =>
                          setState(() => _goal = selection.isEmpty ? null : selection.first),
                    ),
                    const SizedBox(height: 20),

                    // Activity
                    Text('Активность', style: theme.textTheme.labelMedium),
                    const SizedBox(height: 8),
                    SegmentedButton<String>(
                      segments: [
                        ButtonSegment(value: 'low', label: Text(l10n.activityLow)),
                        ButtonSegment(value: 'moderate', label: Text(l10n.activityMedium)),
                        ButtonSegment(value: 'high', label: Text(l10n.activityHigh)),
                      ],
                      selected: _activity != null ? {_activity!} : const {},
                      emptySelectionAllowed: true,
                      onSelectionChanged: (selection) => setState(
                          () => _activity = selection.isEmpty ? null : selection.first),
                    ),
                    const SizedBox(height: 20),

                    // Meal types
                    Text(l10n.mealTypes, style: theme.textTheme.labelMedium),
                    const SizedBox(height: 8),
                    Wrap(
                      spacing: 8,
                      runSpacing: 6,
                      children: kAllMealTypes.map((mealTypeOption) {
                        final isSelected =
                            _mealTypes.contains(mealTypeOption.id);
                        return FilterChip(
                          label: Text(
                              '${mealTypeOption.emoji} ${mealTypeLabel(mealTypeOption.id, l10n)}'),
                          selected: isSelected,
                          onSelected: (selected) {
                            setState(() {
                              if (selected) {
                                _mealTypes.add(mealTypeOption.id);
                              } else if (_mealTypes.length > 1) {
                                _mealTypes.remove(mealTypeOption.id);
                              }
                            });
                          },
                        );
                      }).toList(),
                    ),
                    const SizedBox(height: 20),

                    // Language
                    ref.watch(supportedLanguagesProvider).when(
                      data: (languages) => DropdownButtonFormField<String>(
                        decoration: InputDecoration(labelText: l10n.language),
                        initialValue: _language,
                        items: languages.entries
                            .map((entry) => DropdownMenuItem(
                                  value: entry.key,
                                  child: Text(entry.value),
                                ))
                            .toList(),
                        onChanged: (value) => setState(() => _language = value),
                      ),
                      loading: () => const Center(
                          child: CircularProgressIndicator()),
                      error: (_, __) =>
                          Text(l10n.historyLoadError),
                    ),
                    const SizedBox(height: 32),

                    // Save
                    FilledButton(
                      onPressed: _saving ? null : _save,
                      child: _saving
                          ? const SizedBox(
                              height: 20,
                              width: 20,
                              child: CircularProgressIndicator(
                                  strokeWidth: 2, color: Colors.white),
                            )
                          : Text(l10n.save),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}