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

import '../../../core/api/api_error_mapper.dart';
import '../../../core/l10n/l10n.dart';
import '../../auth/data/auth_providers.dart';
import '../data/profile_repository.dart';
import '../domain/user_profile.dart';

enum _ProfileTab { profile }

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

  @override
  ConsumerState<ProfileScreen> createState() => _ProfileScreenState();
}

class _ProfileScreenState extends ConsumerState<ProfileScreen> {
  final _formKey = GlobalKey<FormState>();
  bool _isLoading = true;
  bool _isSaving = false;
  String? _error;
  UserProfile? _profile;
  _ProfileTab _activeTab = _ProfileTab.profile;

  late final TextEditingController _emailCtrl;
  late final TextEditingController _firstNameCtrl;
  late final TextEditingController _lastNameCtrl;

  @override
  void initState() {
    super.initState();
    _emailCtrl = TextEditingController();
    _firstNameCtrl = TextEditingController();
    _lastNameCtrl = TextEditingController();
    _loadProfile();
  }

  @override
  void dispose() {
    _emailCtrl.dispose();
    _firstNameCtrl.dispose();
    _lastNameCtrl.dispose();
    super.dispose();
  }

  Future<void> _loadProfile() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });
    try {
      final profile = await ref.read(profileRepositoryProvider).getMe();
      if (!mounted) return;
      setState(() {
        _profile = profile;
        _emailCtrl.text = profile.email;
        _firstNameCtrl.text = profile.firstName ?? '';
        _lastNameCtrl.text = profile.lastName ?? '';
      });
    } catch (e) {
      if (!mounted) return;
      setState(() => _error = mapErrorToUserMessage(e, context));
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  Future<void> _save() async {
    if (!_formKey.currentState!.validate()) return;
    setState(() => _isSaving = true);
    try {
      final updated = await ref.read(profileRepositoryProvider).updateMe(
            email: _emailCtrl.text.trim(),
            firstName: _firstNameCtrl.text.trim().isEmpty ? null : _firstNameCtrl.text.trim(),
            lastName: _lastNameCtrl.text.trim().isEmpty ? null : _lastNameCtrl.text.trim(),
          );
      if (!mounted) return;
      setState(() => _profile = updated);
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(context.l10n.profileSaved)),
      );
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(mapErrorToUserMessage(e, context))),
      );
    } finally {
      if (mounted) setState(() => _isSaving = false);
    }
  }

  Future<void> _logout() async {
    await ref.read(authStateProvider.notifier).logout();
    if (!mounted) return;
    context.go('/login');
  }


  List<_ProfileTab> _visibleTabs(bool isAdmin) {
    return [
      _ProfileTab.profile,
    ];
  }

  String _tabLabel(_ProfileTab tab) {
    switch (tab) {
      case _ProfileTab.profile:
        return context.l10n.profileMyProfileTab;
    }
  }

  Widget _buildTabBar(BuildContext context, List<_ProfileTab> tabs) {
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(
        children: tabs
            .map(
              (tab) => Padding(
                padding: const EdgeInsets.only(right: 8),
                child: ChoiceChip(
                  label: Text(_tabLabel(tab)),
                  selected: _activeTab == tab,
                  onSelected: (_) => setState(() => _activeTab = tab),
                ),
              ),
            )
            .toList(),
      ),
    );
  }

  Widget _buildProfileForm(BuildContext context, ThemeData theme) {
    return Form(
      key: _formKey,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            context.l10n.profileUsernameLabel,
            style: theme.textTheme.labelMedium?.copyWith(
              color: theme.colorScheme.onSurfaceVariant,
            ),
          ),
          const SizedBox(height: 4),
          Text(_profile?.username ?? '', style: theme.textTheme.bodyLarge),
          const Divider(height: 32),
          TextFormField(
            controller: _emailCtrl,
            decoration: InputDecoration(
              labelText: context.l10n.profileEmailLabel,
              border: const OutlineInputBorder(),
            ),
            keyboardType: TextInputType.emailAddress,
            validator: (v) {
              if (v == null || v.isEmpty) return context.l10n.profileEmailHint;
              if (!RegExp(r'^[^@]+@[^@]+\.[^@]+').hasMatch(v)) {
                return context.l10n.profileEmailInvalid;
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: _firstNameCtrl,
            decoration: InputDecoration(
              labelText: context.l10n.profileFirstNameLabel,
              border: const OutlineInputBorder(),
            ),
          ),
          const SizedBox(height: 16),
          TextFormField(
            controller: _lastNameCtrl,
            decoration: InputDecoration(
              labelText: context.l10n.profileLastNameLabel,
              border: const OutlineInputBorder(),
            ),
          ),
          const SizedBox(height: 24),
          SizedBox(
            width: double.infinity,
            child: FilledButton(
              onPressed: _isSaving ? null : _save,
              child: _isSaving
                  ? const SizedBox(
                      height: 20,
                      width: 20,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : Text(context.l10n.profileSaveAction),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildActiveTabContent(BuildContext context, ThemeData theme) {
    switch (_activeTab) {
      case _ProfileTab.profile:
        return _buildProfileForm(context, theme);
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final tabs = _visibleTabs(_profile?.isAdmin == true);
    if (!tabs.contains(_activeTab)) {
      _activeTab = _ProfileTab.profile;
    }

    if (_isLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_error != null) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(_error!, style: TextStyle(color: theme.colorScheme.error)),
            const SizedBox(height: 16),
            FilledButton(onPressed: _loadProfile, child: Text(context.l10n.retryAction)),
          ],
        ),
      );
    }

    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        Row(
          children: [
            CircleAvatar(
              radius: 28,
              child: Text(
                (_profile?.username.isNotEmpty == true
                        ? _profile!.username[0]
                        : '?')
                    .toUpperCase(),
              ),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    _profile?.username ?? '',
                    style: theme.textTheme.titleLarge,
                  ),
                  if ((_profile?.email ?? '').isNotEmpty)
                    Text(
                      _profile!.email,
                      style: theme.textTheme.bodyMedium?.copyWith(
                        color: theme.colorScheme.onSurfaceVariant,
                      ),
                    ),
                ],
              ),
            ),
            if (_profile?.isAdmin == true)
              Chip(
                label: const Text('Admin'),
                avatar: const Icon(Icons.shield_outlined, size: 16),
                backgroundColor: theme.colorScheme.primaryContainer,
                labelStyle: TextStyle(color: theme.colorScheme.onPrimaryContainer),
              ),
          ],
        ),
        const SizedBox(height: 16),
        _buildTabBar(context, tabs),
        const SizedBox(height: 16),
        _buildActiveTabContent(context, theme),
        const SizedBox(height: 24),
        SizedBox(
          width: double.infinity,
          child: OutlinedButton.icon(
            onPressed: _logout,
            icon: const Icon(Icons.logout),
            label: Text(context.l10n.logoutAction),
          ),
        ),
      ],
    );
  }
}