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/page_header.dart' as widgets;
import '../../../../shared/widgets/toast/toast.dart';
import '../../../../shared/widgets/toast/toast_type.dart';
import '../../../users/data/models/user_response.dart';
import '../../../users/data/users_api.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>();

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

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

  Future<void> _loadUser() async {
    try {
      final user = await _usersApi.getMe();
      if (mounted) {
        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,
      );
      await _usersApi.updateMe(request);

      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 Scaffold(
      backgroundColor: AppColors.surfaceSecondary,
      body: SafeArea(
        child: Column(
          children: [
            _buildHeader(),
            Expanded(
              child: _isLoading
                  ? const Center(child: AppLoadingIndicator(size: 22))
                  : SingleChildScrollView(
                      padding: const EdgeInsets.all(20),
                      child: Column(
                        children: [
                          _buildAvatarSection(),
                          const SizedBox(height: 24),
                          _buildFormSection(),
                          const SizedBox(height: 32),
                          SizedBox(
                            width: double.infinity,
                            height: 52,
                            child: AppButton(
                              text: '保存修改',
                              onPressed: _hasChanges && !_isSaving
                                  ? _saveProfile
                                  : null,
                              isLoading: _isSaving,
                            ),
                          ),
                        ],
                      ),
                    ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildHeader() {
    return SizedBox(
      height: 64,
      child: Padding(
        padding: const EdgeInsets.symmetric(horizontal: 20),
        child: Row(
          children: [
            widgets.BackButton(onPressed: () => context.pop()),
            const SizedBox(width: 12),
            const Text(
              '编辑资料',
              style: TextStyle(
                fontSize: 17,
                fontWeight: FontWeight.w600,
                color: AppColors.slate900,
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildAvatarSection() {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: AppColors.borderSecondary),
      ),
      child: Column(
        children: [
          Container(
            width: 72,
            height: 72,
            decoration: BoxDecoration(
              gradient: const LinearGradient(
                begin: Alignment.topLeft,
                end: Alignment.bottomRight,
                colors: [Color(0xFFEAF1FF), Color(0xFFF8FBFF)],
              ),
              borderRadius: BorderRadius.circular(36),
              border: Border.all(color: const Color(0xFFD9E5FA)),
            ),
            child: const Icon(Icons.person, size: 36, color: AppColors.blue500),
          ),
          const SizedBox(height: 12),
          Text(
            '点击更换头像',
            style: TextStyle(
              fontSize: 13,
              fontWeight: FontWeight.w500,
              color: AppColors.slate500,
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildFormSection() {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: AppColors.borderSecondary),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text(
            '用户名',
            style: TextStyle(
              fontSize: 14,
              fontWeight: FontWeight.w500,
              color: AppColors.slate700,
            ),
          ),
          const SizedBox(height: 8),
          TextField(
            controller: _usernameController,
            onChanged: (_) => _onFieldChanged(),
            decoration: InputDecoration(
              hintText: '请输入用户名',
              filled: true,
              fillColor: AppColors.surfaceSecondary,
              contentPadding: const EdgeInsets.symmetric(
                horizontal: 16,
                vertical: 14,
              ),
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: BorderSide.none,
              ),
              enabledBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: BorderSide.none,
              ),
              focusedBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: const BorderSide(
                  color: AppColors.blue500,
                  width: 1,
                ),
              ),
            ),
          ),
          const SizedBox(height: 20),
          const Text(
            '个人简介',
            style: TextStyle(
              fontSize: 14,
              fontWeight: FontWeight.w500,
              color: AppColors.slate700,
            ),
          ),
          const SizedBox(height: 8),
          TextField(
            controller: _bioController,
            onChanged: (_) => _onFieldChanged(),
            maxLines: 4,
            maxLength: 200,
            decoration: InputDecoration(
              hintText: '介绍一下自己吧',
              filled: true,
              fillColor: AppColors.surfaceSecondary,
              contentPadding: const EdgeInsets.all(16),
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: BorderSide.none,
              ),
              enabledBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: BorderSide.none,
              ),
              focusedBorder: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: const BorderSide(
                  color: AppColors.blue500,
                  width: 1,
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}