import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../../../core/di/injection.dart';
import '../../../../core/theme/design_tokens.dart';
import '../../../../shared/widgets/toast/index.dart';
import '../../../../shared/widgets/page_header.dart' as widgets;
import '../../../friends/data/friends_api.dart';
import '../../../users/data/models/user_response.dart';
import '../../../users/data/users_api.dart';

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

  @override
  State<ContactsScreen> createState() => _ContactsScreenState();
}

class _ContactsScreenState extends State<ContactsScreen> {
  final _searchController = TextEditingController();
  final _searchFocusNode = FocusNode();

  List<FriendResponse> _friends = [];
  List<UserResponse> _searchResults = [];
  bool _isLoading = true;
  bool _isSearching = false;
  bool _hasSearched = false;
  final Set<String> _sentRequestIds = {};
  Set<String> _friendIds = {};

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

  Future<void> _loadFriends() async {
    try {
      final friendsApi = sl<FriendsApi>();
      final friends = await friendsApi.getFriends();
      if (mounted) {
        setState(() {
          _friends = friends;
          _friendIds = friends.map((f) => f.friend.id).toSet();
          _isLoading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  bool _isValidEmail(String email) {
    final emailRegex = RegExp(r'^[\w-\.]+@([\w-]+\.)+[\w-]{2,}$');
    return emailRegex.hasMatch(email);
  }

  Future<void> _onSearch() async {
    final query = _searchController.text.trim();

    if (query.isEmpty) {
      Toast.show(context, '请输入邮箱地址', type: ToastType.warning);
      return;
    }

    if (!_isValidEmail(query)) {
      Toast.show(context, '请输入有效的邮箱地址', type: ToastType.warning);
      return;
    }

    setState(() {
      _isSearching = true;
      _searchResults = [];
      _hasSearched = true;
    });

    try {
      final usersApi = sl<UsersApi>();
      final results = await usersApi.searchUsers(query);

      if (mounted) {
        setState(() {
          _searchResults = results;
          _isSearching = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _isSearching = false;
        });
        Toast.show(context, '搜索失败，请稍后重试', type: ToastType.error);
      }
    }
  }

  Future<void> _sendFriendRequest(String targetUserId, String? content) async {
    try {
      final friendsApi = sl<FriendsApi>();
      await friendsApi.sendRequest(targetUserId);

      if (mounted) {
        setState(() {
          _sentRequestIds.add(targetUserId);
        });
        Toast.show(context, '好友请求已发送', type: ToastType.success);
      }
    } catch (e) {
      if (mounted) {
        Toast.show(context, '发送失败，请稍后重试', type: ToastType.error);
      }
    }
  }

  void _showAddFriendDialog(UserResponse user) {
    final controller = TextEditingController();

    showDialog(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: const Text('添加好友'),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text('向 ${user.username} 发送好友请求'),
            const SizedBox(height: 16),
            TextField(
              controller: controller,
              decoration: const InputDecoration(
                labelText: '验证消息（可选）',
                hintText: '你好，我是...',
                border: OutlineInputBorder(),
              ),
              maxLines: 3,
              maxLength: 200,
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () {
              controller.dispose();
              Navigator.pop(dialogContext);
            },
            child: const Text('取消'),
          ),
          FilledButton(
            onPressed: () {
              Navigator.pop(dialogContext);
              _sendFriendRequest(
                user.id,
                controller.text.isEmpty ? null : controller.text,
              );
            },
            child: const Text('发送'),
          ),
        ],
      ),
    ).then((_) => controller.dispose());
  }

  @override
  void dispose() {
    _searchController.dispose();
    _searchFocusNode.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppColors.surfaceSecondary,
      body: SafeArea(
        child: Column(
          children: [
            widgets.PageHeader(leading: widgets.BackButton()),
            Expanded(
              child: SingleChildScrollView(
                padding: const EdgeInsets.fromLTRB(20, 8, 20, 20),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    _buildSearchRow(),
                    _buildSearchResults(),
                    const SizedBox(height: 16),
                    _buildSectionTitle('全部联系人'),
                    const SizedBox(height: 8),
                    if (_isLoading)
                      const Center(
                        child: Padding(
                          padding: EdgeInsets.all(20),
                          child: CircularProgressIndicator(),
                        ),
                      )
                    else if (_friends.isEmpty)
                      _buildEmptyState()
                    else
                      _buildContactCard(_friends),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildSearchRow() {
    return Row(
      children: [
        Expanded(
          child: Container(
            height: 40,
            decoration: BoxDecoration(
              color: AppColors.surfaceTertiary,
              borderRadius: BorderRadius.circular(12),
              border: Border.all(color: const Color(0xFFE4EBF7)),
            ),
            child: TextField(
              controller: _searchController,
              focusNode: _searchFocusNode,
              decoration: const InputDecoration(
                hintText: '输入邮箱搜索用户',
                hintStyle: TextStyle(
                  fontSize: 13,
                  fontWeight: FontWeight.w500,
                  color: AppColors.slate400,
                ),
                prefixIcon: Icon(
                  Icons.search,
                  size: 16,
                  color: AppColors.slate400,
                ),
                border: InputBorder.none,
                contentPadding: EdgeInsets.symmetric(
                  horizontal: 12,
                  vertical: 10,
                ),
              ),
              style: const TextStyle(fontSize: 13),
              keyboardType: TextInputType.emailAddress,
              textInputAction: TextInputAction.search,
              onSubmitted: (_) => _onSearch(),
              onChanged: (value) {
                if (value.isEmpty) {
                  setState(() {
                    _hasSearched = false;
                    _searchResults = [];
                  });
                }
              },
            ),
          ),
        ),
        const SizedBox(width: 10),
        GestureDetector(
          onTap: _onSearch,
          child: Container(
            width: 40,
            height: 40,
            decoration: BoxDecoration(
              color: const Color(0xFFF1F7FF),
              borderRadius: BorderRadius.circular(12),
              border: Border.all(color: const Color(0xFFD7E6FF)),
            ),
            child: _isSearching
                ? const Padding(
                    padding: EdgeInsets.all(10),
                    child: CircularProgressIndicator(strokeWidth: 2),
                  )
                : const Icon(Icons.search, size: 16, color: AppColors.blue500),
          ),
        ),
      ],
    );
  }

  Widget _buildSearchResults() {
    if (!_hasSearched) {
      return const SizedBox.shrink();
    }

    return Container(
      margin: const EdgeInsets.only(top: 8),
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: Colors.black.withValues(alpha: 0.08),
            blurRadius: 8,
            offset: const Offset(0, 2),
          ),
        ],
      ),
      child: Column(
        children: [
          if (_isSearching)
            Container(
              padding: const EdgeInsets.all(20),
              child: const Center(child: CircularProgressIndicator()),
            )
          else if (_searchResults.isEmpty)
            Container(
              padding: const EdgeInsets.all(20),
              child: const Center(
                child: Text(
                  '未找到该用户',
                  style: TextStyle(fontSize: 14, color: AppColors.slate500),
                ),
              ),
            )
          else
            Column(
              children: [
                for (int i = 0; i < _searchResults.length; i++) ...[
                  _buildSearchResultItem(_searchResults[i]),
                  if (i < _searchResults.length - 1)
                    Container(
                      height: 1,
                      margin: const EdgeInsets.symmetric(horizontal: 14),
                      color: const Color(0xFFEEF2F7),
                    ),
                ],
              ],
            ),
        ],
      ),
    );
  }

  Widget _buildSearchResultItem(UserResponse user) {
    final isFriend = _friendIds.contains(user.id);
    final isSent = _sentRequestIds.contains(user.id);
    final avatarColor = _getAvatarColor(user.id);

    return Container(
      height: 70,
      padding: const EdgeInsets.symmetric(horizontal: 14),
      child: Row(
        children: [
          Container(
            width: 42,
            height: 42,
            decoration: BoxDecoration(
              color: _getAvatarBackground(avatarColor),
              borderRadius: BorderRadius.circular(21),
              border: Border.all(color: _getAvatarBorder(avatarColor)),
            ),
            child: user.avatarUrl != null
                ? ClipRRect(
                    borderRadius: BorderRadius.circular(21),
                    child: Image.network(
                      user.avatarUrl!,
                      width: 42,
                      height: 42,
                      fit: BoxFit.cover,
                      errorBuilder: (_, __, ___) => Icon(
                        Icons.person,
                        size: 18,
                        color: _getAvatarColor(user.id),
                      ),
                    ),
                  )
                : Icon(Icons.person, size: 18, color: _getAvatarColor(user.id)),
          ),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  user.username,
                  style: const TextStyle(
                    fontSize: 15,
                    fontWeight: FontWeight.w600,
                    color: AppColors.slate900,
                  ),
                ),
                if (user.bio != null) ...[
                  const SizedBox(height: 2),
                  Text(
                    user.bio!,
                    style: const TextStyle(
                      fontSize: 12,
                      color: AppColors.slate500,
                    ),
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                  ),
                ],
              ],
            ),
          ),
          _buildAddButton(user.id, isFriend, isSent),
        ],
      ),
    );
  }

  Widget _buildAddButton(String userId, bool isFriend, bool isSent) {
    if (isFriend) {
      return Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
        decoration: BoxDecoration(
          color: AppColors.slate300,
          borderRadius: BorderRadius.circular(8),
        ),
        child: const Text(
          '已是好友',
          style: TextStyle(fontSize: 12, color: AppColors.slate500),
        ),
      );
    }

    if (isSent) {
      return Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
        decoration: BoxDecoration(
          color: AppColors.slate300,
          borderRadius: BorderRadius.circular(8),
        ),
        child: const Text(
          '已发送',
          style: TextStyle(fontSize: 12, color: AppColors.slate500),
        ),
      );
    }

    return GestureDetector(
      onTap: () {
        final user = _searchResults.firstWhere((u) => u.id == userId);
        _showAddFriendDialog(user);
      },
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
        decoration: BoxDecoration(
          color: const Color(0xFFF1F7FF),
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: const Color(0xFFD7E6FF)),
        ),
        child: const Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.person_add, size: 14, color: AppColors.blue500),
            SizedBox(width: 4),
            Text(
              '添加',
              style: TextStyle(
                fontSize: 12,
                fontWeight: FontWeight.w500,
                color: AppColors.blue500,
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildEmptyState() {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(32),
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: const Color(0xFFE3EAF6)),
      ),
      child: Column(
        children: [
          const Icon(Icons.person_outline, size: 48, color: AppColors.slate400),
          const SizedBox(height: 12),
          const Text(
            '暂无联系人',
            style: TextStyle(
              fontSize: 15,
              fontWeight: FontWeight.w500,
              color: AppColors.slate500,
            ),
          ),
          const SizedBox(height: 4),
          const Text(
            '搜索邮箱添加好友开始聊天吧',
            style: TextStyle(fontSize: 13, color: AppColors.slate400),
          ),
        ],
      ),
    );
  }

  Widget _buildSectionTitle(String title) {
    return Text(
      title,
      style: const TextStyle(
        fontSize: 13,
        fontWeight: FontWeight.w600,
        color: AppColors.slate500,
      ),
    );
  }

  Widget _buildContactCard(List<FriendResponse> friends) {
    return Container(
      decoration: BoxDecoration(
        color: AppColors.white,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: const Color(0xFFE3EAF6)),
      ),
      child: Column(
        children: [
          for (int i = 0; i < friends.length; i++) ...[
            _buildContactItem(friends[i]),
            if (i < friends.length - 1)
              Container(
                height: 1,
                margin: const EdgeInsets.symmetric(horizontal: 14),
                color: const Color(0xFFEEF2F7),
              ),
          ],
        ],
      ),
    );
  }

  Widget _buildContactItem(FriendResponse friend) {
    final friendInfo = friend.friend;
    final color = _getAvatarColor(friendInfo.id);

    return GestureDetector(
      onTap: () => context.push('/contacts/add?id=${friendInfo.id}'),
      child: Container(
        height: 70,
        padding: const EdgeInsets.symmetric(horizontal: 14),
        child: Row(
          children: [
            Container(
              width: 42,
              height: 42,
              decoration: BoxDecoration(
                color: _getAvatarBackground(color),
                borderRadius: BorderRadius.circular(21),
                border: Border.all(color: _getAvatarBorder(color)),
              ),
              child: friendInfo.avatarUrl != null
                  ? ClipRRect(
                      borderRadius: BorderRadius.circular(21),
                      child: Image.network(
                        friendInfo.avatarUrl!,
                        width: 42,
                        height: 42,
                        fit: BoxFit.cover,
                        errorBuilder: (_, __, ___) =>
                            Icon(Icons.person, size: 18, color: color),
                      ),
                    )
                  : Icon(Icons.person, size: 18, color: color),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    friendInfo.username,
                    style: const TextStyle(
                      fontSize: 15,
                      fontWeight: FontWeight.w600,
                      color: AppColors.slate900,
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Color _getAvatarColor(String id) {
    final colors = [
      AppColors.blue500,
      AppColors.violet600,
      AppColors.blue600,
      const Color(0xFF0EA5E9),
      AppColors.violet500,
    ];
    final index = id.hashCode.abs() % colors.length;
    return colors[index];
  }

  Color _getAvatarBackground(Color color) {
    if (color == AppColors.blue500) return const Color(0xFFEEF4FF);
    if (color == AppColors.violet600) return AppColors.surfaceInfoLight;
    if (color == AppColors.blue600) return const Color(0xFFEDF5FF);
    if (color == const Color(0xFF0EA5E9)) return const Color(0xFFF2F8FF);
    if (color == AppColors.violet500) return const Color(0xFFF5F7FF);
    return const Color(0xFFEEF4FF);
  }

  Color _getAvatarBorder(Color color) {
    if (color == AppColors.blue500) return const Color(0xFFDDE8FB);
    if (color == AppColors.violet600) return const Color(0xFFE2EAFB);
    if (color == AppColors.blue600) return const Color(0xFFDCE9FB);
    if (color == const Color(0xFF0EA5E9)) return const Color(0xFFDFEAFA);
    if (color == AppColors.violet500) return const Color(0xFFE4E8FA);
    return const Color(0xFFDDE8FB);
  }
}