import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../../../core/theme/design_tokens.dart';
import '../../../../core/di/injection.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/app_loading_indicator.dart';
import '../../../../shared/widgets/toast/toast.dart';
import '../../../../shared/widgets/toast/toast_type.dart';
import '../../data/services/settings_user_cache.dart';
import '../../../users/data/models/user_response.dart';
import '../../../users/data/users_api.dart';
import '../widgets/account_section_card.dart';
import '../widgets/settings_page_scaffold.dart';

class EditProfileScreen extends StatefulWidget {
  const EditProfileScreen({super.key});

  @override
  State<EditProfileScreen> createState() => _EditProfileScreenState();
}

class _EditProfileScreenState extends State<EditProfileScreen> {
  final _usernameController = TextEditingController();
  final _bioController = TextEditingController();
  final _usersApi = sl<UsersApi>();
  final _userCache = sl<SettingsUserCache>();

  UserResponse? _user;
  bool _isLoading = true;
  bool _isSaving = false;
  bool _hasChanges = false;

  @override
  void initState() {
    super.initState();
    _loadUser();
  }

  Future<void> _loadUser() async {
    final cached = _userCache.cachedUser;
    if (cached != null) {
      setState(() {
        _user = cached;
        _usernameController.text = cached.username;
        _bioController.text = cached.bio ?? '';
        _isLoading = false;
      });
      return;
    }

    try {
      final user = await _usersApi.getMe();
      if (mounted) {
        _userCache.set(user);
        setState(() {
          _user = user;
          _usernameController.text = user.username;
          _bioController.text = user.bio ?? '';
          _isLoading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
        Toast.show(context, '加载用户信息失败', type: ToastType.error);
      }
    }
  }

  void _onFieldChanged() {
    if (_user == null) return;
    final usernameChanged = _usernameController.text != _user!.username;
    final bioChanged = _bioController.text != (_user!.bio ?? '');

    if ((usernameChanged || bioChanged) != _hasChanges) {
      setState(() {
        _hasChanges = usernameChanged || bioChanged;
      });
    }
  }

  Future<void> _saveProfile() async {
    if (!_hasChanges || _user == null) return;

    final newUsername = _usernameController.text.trim();
    final newBio = _bioController.text.trim();

    if (newUsername.isEmpty) {
      Toast.show(context, '用户名不能为空', type: ToastType.warning);
      return;
    }
    if (newUsername.length < 3 || newUsername.length > 30) {
      Toast.show(context, '用户名需要3-30个字符', type: ToastType.warning);
      return;
    }

    setState(() {
      _isSaving = true;
    });

    try {
      final request = UserUpdateRequest(
        username: newUsername,
        bio: newBio.isEmpty ? null : newBio,
      );
      final updatedUser = await _usersApi.updateMe(request);
      _userCache.set(updatedUser);

      if (mounted) {
        Toast.show(context, '保存成功', type: ToastType.success);
        context.pop(true);
      }
    } catch (e) {
      if (mounted) {
        Toast.show(context, '保存失败，请重试', type: ToastType.error);
      }
    } finally {
      if (mounted) {
        setState(() {
          _isSaving = false;
        });
      }
    }
  }

  @override
  void dispose() {
    _usernameController.dispose();
    _bioController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return SettingsPageScaffold(
      title: '编辑资料',
      onBack: () => context.pop(),
      resizeOnKeyboard: false,
      maintainBottomViewPadding: true,
      body: _isLoading
          ? const Center(
              child: AppLoadingIndicator(variant: AppLoadingVariant.surface),
            )
          : Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                _buildBasicInfoSection(),
                const SizedBox(height: AppSpacing.lg),
                _buildBioSection(),
              ],
            ),
      footer: SizedBox(
        width: double.infinity,
        height: 52,
        child: AppButton(
          text: '保存修改',
          onPressed: _hasChanges && !_isSaving ? _saveProfile : null,
          isLoading: _isSaving,
        ),
      ),
    );
  }

  Widget _buildBasicInfoSection() {
    return AccountSectionCard(
      title: '基础信息',
      backgroundColor: AppColors.white,
      borderColor: AppColors.borderSecondary,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '用户名',
            style: TextStyle(
              fontSize: 13,
              fontWeight: FontWeight.w700,
              color: AppColors.slate700,
            ),
          ),
          const SizedBox(height: AppSpacing.sm),
          TextField(
            controller: _usernameController,
            onChanged: (_) => _onFieldChanged(),
            style: const TextStyle(fontSize: 15, color: AppColors.slate900),
            decoration: _buildInputDecoration('请输入用户名'),
          ),
        ],
      ),
    );
  }

  Widget _buildBioSection() {
    return AccountSectionCard(
      title: '个人简介',
      backgroundColor: AppColors.white,
      borderColor: AppColors.borderSecondary,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '简介内容',
            style: TextStyle(
              fontSize: 13,
              fontWeight: FontWeight.w700,
              color: AppColors.slate700,
            ),
          ),
          const SizedBox(height: AppSpacing.sm),
          TextField(
            controller: _bioController,
            onChanged: (_) => _onFieldChanged(),
            maxLines: 4,
            maxLength: 200,
            style: const TextStyle(fontSize: 15, color: AppColors.slate900),
            decoration: _buildInputDecoration(
              '介绍一下自己吧',
            ).copyWith(contentPadding: const EdgeInsets.all(AppSpacing.lg)),
          ),
        ],
      ),
    );
  }

  InputDecoration _buildInputDecoration(String hintText) {
    return InputDecoration(
      hintText: hintText,
      hintStyle: const TextStyle(fontSize: 14, color: AppColors.slate400),
      filled: true,
      fillColor: AppColors.surfaceSecondary,
      contentPadding: const EdgeInsets.symmetric(
        horizontal: AppSpacing.lg,
        vertical: AppSpacing.lg,
      ),
      border: OutlineInputBorder(
        borderRadius: BorderRadius.circular(AppRadius.lg),
        borderSide: BorderSide.none,
      ),
      enabledBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(AppRadius.lg),
        borderSide: const BorderSide(color: AppColors.borderTertiary),
      ),
      focusedBorder: OutlineInputBorder(
        borderRadius: BorderRadius.circular(AppRadius.lg),
        borderSide: const BorderSide(color: AppColors.blue500),
      ),
    );
  }
}