import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import '../../../../app/di/injection.dart';
import '../../../../core/l10n/l10n.dart';
import '../../data/models/user_profile.dart';
import '../../../../core/theme/design_tokens.dart';
import '../../../../shared/widgets/app_loading_indicator.dart';
import '../../../../shared/widgets/toast/index.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/back_title_page_header.dart';
import '../../../../shared/widgets/shared_divider.dart';
import '../../../contacts/data/apis/friends_api.dart';
import '../../../contacts/data/apis/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<FriendRequestResponse> _pendingRequests = [];
  List<UserProfile> _searchResults = [];
  bool _isLoading = true;
  bool _isSearching = false;
  bool _hasSearched = false;
  String? _sendingRequestUserId;
  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();
      final outgoingRequests = await friendsApi.getOutgoingRequests();
      final pendingRequests = outgoingRequests
          .where((r) => r.status == 'pending')
          .toList();
      if (mounted) {
        setState(() {
          _friends = friends;
          _friendIds = friends.map((f) => f.friend.id).toSet();
          _sentRequestIds.addAll(outgoingRequests.map((r) => r.recipient.id));
          _pendingRequests = pendingRequests;
          _isLoading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

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

    if (query.isEmpty) {
      Toast.show(
        context,
        context.l10n.contactsSearchEmptyQuery,
        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,
          context.l10n.contactsSearchFailed,
          type: ToastType.error,
        );
      }
    }
  }

  Future<void> _sendFriendRequest(String targetUserId, String? content) async {
    if (_sendingRequestUserId != null) {
      return;
    }
    try {
      setState(() {
        _sendingRequestUserId = targetUserId;
      });
      final friendsApi = sl<FriendsApi>();
      await friendsApi.sendRequest(targetUserId, content: content);

      if (mounted) {
        setState(() {
          _sentRequestIds.add(targetUserId);
          _sendingRequestUserId = null;
        });
        Toast.show(
          context,
          context.l10n.contactsFriendRequestSent,
          type: ToastType.success,
        );
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _sendingRequestUserId = null;
        });
        Toast.show(
          context,
          context.l10n.contactsSendFailed,
          type: ToastType.error,
        );
      }
    }
  }

  void _showAddFriendDialog(UserProfile user) {
    final controller = TextEditingController();
    showModalBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      backgroundColor: Theme.of(
        context,
      ).colorScheme.surface.withValues(alpha: 0),
      builder: (sheetContext) {
        final colorScheme = Theme.of(sheetContext).colorScheme;
        return Padding(
          padding: EdgeInsets.only(
            bottom: MediaQuery.of(sheetContext).viewInsets.bottom,
          ),
          child: Container(
            width: double.infinity,
            constraints: BoxConstraints(
              maxHeight: MediaQuery.of(sheetContext).size.height * 0.7,
            ),
            padding: const EdgeInsets.fromLTRB(
              AppSpacing.xxl,
              AppSpacing.lg,
              AppSpacing.xxl,
              AppSpacing.lg,
            ),
            decoration: BoxDecoration(
              color: colorScheme.surface,
              borderRadius: BorderRadius.vertical(
                top: Radius.circular(AppRadius.xxl),
              ),
            ),
            child: SingleChildScrollView(
              child: Column(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Center(
                    child: Container(
                      width: 40,
                      height: AppSpacing.xs,
                      decoration: BoxDecoration(
                        color: colorScheme.outlineVariant,
                        borderRadius: BorderRadius.circular(AppRadius.full),
                      ),
                    ),
                  ),
                  const SizedBox(height: AppSpacing.lg),
                  Text(
                    context.l10n.contactsAddSheetTitle(user.username),
                    style: TextStyle(
                      fontSize: 20,
                      fontWeight: FontWeight.w600,
                      color: colorScheme.onSurface,
                    ),
                  ),
                  const SizedBox(height: AppSpacing.sm),
                  Text(
                    context.l10n.contactsAddSheetDesc,
                    style: TextStyle(
                      fontSize: 13,
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  const SizedBox(height: AppSpacing.lg),
                  Container(
                    decoration: BoxDecoration(
                      color: colorScheme.surfaceContainerLowest,
                      borderRadius: BorderRadius.circular(AppRadius.lg),
                      border: Border.all(color: colorScheme.outlineVariant),
                    ),
                    child: TextField(
                      controller: controller,
                      maxLines: 3,
                      minLines: 2,
                      maxLength: 200,
                      decoration: InputDecoration(
                        hintText: context.l10n.contactsAddSheetMessageHint,
                        hintStyle: TextStyle(
                          fontSize: 13,
                          color: colorScheme.outline,
                        ),
                        border: InputBorder.none,
                        contentPadding: EdgeInsets.all(AppSpacing.lg),
                        counterStyle: TextStyle(
                          fontSize: 11,
                          color: colorScheme.outline,
                        ),
                      ),
                    ),
                  ),
                  const SizedBox(height: AppSpacing.lg),
                  Row(
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: [
                      Expanded(
                        child: AppButton(
                          text: context.l10n.commonCancel,
                          isOutlined: true,
                          onPressed: () => Navigator.pop(sheetContext),
                        ),
                      ),
                      const SizedBox(width: AppSpacing.md),
                      Expanded(
                        child: _buildSendButton(
                          user.id,
                          controller,
                          sheetContext,
                        ),
                      ),
                    ],
                  ),
                  SizedBox(
                    height:
                        MediaQuery.of(sheetContext).padding.bottom +
                        AppSpacing.sm,
                  ),
                ],
              ),
            ),
          ),
        );
      },
    );
  }

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

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    return Scaffold(
      backgroundColor: colorScheme.surfaceContainerLow,
      resizeToAvoidBottomInset: false,
      body: SafeArea(
        maintainBottomViewPadding: true,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            BackTitlePageHeader(
              title: context.l10n.contactsTitle,
              onBack: () => context.pop(),
            ),
            Expanded(
              child: SingleChildScrollView(
                padding: const EdgeInsets.fromLTRB(20, 8, 20, 20),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    _buildSearchRow(),
                    _buildSearchResults(),
                    const SizedBox(height: 16),
                    if (_pendingRequests.isNotEmpty) ...[
                      _buildSectionTitle(context.l10n.contactsSectionNew),
                      const SizedBox(height: 8),
                      _buildPendingRequestCard(_pendingRequests),
                      const SizedBox(height: 16),
                    ],
                    _buildSectionTitle(context.l10n.contactsSectionAll),
                    const SizedBox(height: 8),
                    if (_isLoading)
                      const Center(
                        child: Padding(
                          padding: EdgeInsets.all(20),
                          child: AppLoadingIndicator(size: 22),
                        ),
                      )
                    else if (_friends.isEmpty)
                      _buildEmptyState()
                    else
                      _buildContactCard(_friends),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildSearchRow() {
    final colorScheme = Theme.of(context).colorScheme;
    return Row(
      children: [
        Expanded(
          child: Container(
            height: 40,
            decoration: BoxDecoration(
              color: colorScheme.surfaceContainerHigh,
              borderRadius: BorderRadius.circular(12),
              border: Border.all(color: colorScheme.outlineVariant),
            ),
            child: TextField(
              controller: _searchController,
              focusNode: _searchFocusNode,
              decoration: InputDecoration(
                hintText: context.l10n.contactsSearchHint,
                hintStyle: TextStyle(
                  fontSize: 13,
                  fontWeight: FontWeight.w500,
                  color: colorScheme.outline,
                ),
                prefixIcon: Icon(
                  Icons.search,
                  size: 16,
                  color: colorScheme.outline,
                ),
                border: InputBorder.none,
                contentPadding: EdgeInsets.symmetric(
                  horizontal: 12,
                  vertical: 10,
                ),
              ),
              style: const TextStyle(fontSize: 13),
              keyboardType: TextInputType.text,
              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: colorScheme.primaryContainer.withValues(alpha: 0.4),
              borderRadius: BorderRadius.circular(12),
              border: Border.all(color: colorScheme.primaryContainer),
            ),
            child: _isSearching
                ? Padding(
                    padding: EdgeInsets.all(10),
                    child: AppLoadingIndicator(
                      size: 16,
                      strokeWidth: 2,
                      color: colorScheme.primary,
                      trackColor: colorScheme.primaryContainer,
                      withContainer: false,
                    ),
                  )
                : Icon(Icons.search, size: 16, color: colorScheme.primary),
          ),
        ),
      ],
    );
  }

  Widget _buildSearchResults() {
    final colorScheme = Theme.of(context).colorScheme;
    if (!_hasSearched) {
      return const SizedBox.shrink();
    }

    return Container(
      margin: const EdgeInsets.only(top: 8),
      decoration: BoxDecoration(
        color: colorScheme.surface,
        borderRadius: BorderRadius.circular(12),
        boxShadow: [
          BoxShadow(
            color: colorScheme.shadow.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: AppLoadingIndicator(size: 22)),
            )
          else if (_searchResults.isEmpty)
            Container(
              padding: const EdgeInsets.all(20),
              child: Center(
                child: Text(
                  context.l10n.contactsSearchNoUser,
                  style: TextStyle(
                    fontSize: 14,
                    color: colorScheme.onSurfaceVariant,
                  ),
                ),
              ),
            )
          else
            Column(
              children: [
                for (int i = 0; i < _searchResults.length; i++) ...[
                  _buildSearchResultItem(_searchResults[i]),
                  if (i < _searchResults.length - 1) SharedDivider(),
                ],
              ],
            ),
        ],
      ),
    );
  }

  Widget _buildSearchResultItem(UserProfile user) {
    final colorScheme = Theme.of(context).colorScheme;
    final isFriend = _friendIds.contains(user.id);
    final isSent = _sentRequestIds.contains(user.id);

    return Container(
      height: 70,
      padding: const EdgeInsets.symmetric(horizontal: 14),
      child: Row(
        children: [
          _buildAvatar(user.avatarUrl, user.id, colorScheme),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  user.username,
                  style: TextStyle(
                    fontSize: 15,
                    fontWeight: FontWeight.w600,
                    color: colorScheme.onSurface,
                  ),
                ),
                if (user.bio != null) ...[
                  const SizedBox(height: 2),
                  Text(
                    user.bio!,
                    style: TextStyle(
                      fontSize: 12,
                      color: colorScheme.onSurfaceVariant,
                    ),
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                  ),
                ],
              ],
            ),
          ),
          _buildAddButton(user.id, isFriend, isSent),
        ],
      ),
    );
  }

  Widget _buildAddButton(String userId, bool isFriend, bool isSent) {
    final colorScheme = Theme.of(context).colorScheme;
    if (isFriend) {
      return Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
        decoration: BoxDecoration(
          color: colorScheme.surfaceContainerHighest,
          borderRadius: BorderRadius.circular(8),
        ),
        child: Text(
          context.l10n.contactsStatusAlreadyFriend,
          style: TextStyle(fontSize: 12, color: colorScheme.onSurfaceVariant),
        ),
      );
    }

    if (isSent) {
      return Container(
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
        decoration: BoxDecoration(
          color: colorScheme.surfaceContainerHighest,
          borderRadius: BorderRadius.circular(8),
        ),
        child: Text(
          context.l10n.contactsStatusSent,
          style: TextStyle(fontSize: 12, color: colorScheme.onSurfaceVariant),
        ),
      );
    }

    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: colorScheme.primaryContainer.withValues(alpha: 0.4),
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: colorScheme.primaryContainer),
        ),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.person_add, size: 14, color: colorScheme.primary),
            const SizedBox(width: 4),
            Text(
              context.l10n.contactsAdd,
              style: TextStyle(
                fontSize: 12,
                fontWeight: FontWeight.w500,
                color: colorScheme.primary,
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildEmptyState() {
    final colorScheme = Theme.of(context).colorScheme;
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(32),
      decoration: BoxDecoration(
        color: colorScheme.surface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: colorScheme.outlineVariant),
      ),
      child: Column(
        children: [
          Icon(Icons.person_outline, size: 48, color: colorScheme.outline),
          const SizedBox(height: 12),
          Text(
            context.l10n.contactsEmptyTitle,
            style: TextStyle(
              fontSize: 15,
              fontWeight: FontWeight.w500,
              color: colorScheme.onSurfaceVariant,
            ),
          ),
          const SizedBox(height: 4),
          Text(
            context.l10n.contactsEmptyDesc,
            style: TextStyle(fontSize: 13, color: colorScheme.outline),
          ),
        ],
      ),
    );
  }

  Widget _buildSectionTitle(String title) {
    final colorScheme = Theme.of(context).colorScheme;
    return Text(
      title,
      style: TextStyle(
        fontSize: 13,
        fontWeight: FontWeight.w600,
        color: colorScheme.onSurfaceVariant,
      ),
    );
  }

  Widget _buildPendingRequestCard(List<FriendRequestResponse> requests) {
    final colorScheme = Theme.of(context).colorScheme;
    return Container(
      decoration: BoxDecoration(
        color: colorScheme.surface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: colorScheme.outlineVariant),
      ),
      child: Column(
        children: [
          for (int i = 0; i < requests.length; i++) ...[
            _buildPendingRequestItem(requests[i]),
            if (i < requests.length - 1) SharedDivider(),
          ],
        ],
      ),
    );
  }

  Widget _buildPendingRequestItem(FriendRequestResponse request) {
    final colorScheme = Theme.of(context).colorScheme;
    final recipient = request.recipient;

    return Container(
      height: 70,
      padding: const EdgeInsets.symmetric(horizontal: 14),
      child: Row(
        children: [
          _buildAvatar(recipient.avatarUrl, recipient.id, colorScheme),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  recipient.username,
                  style: TextStyle(
                    fontSize: 15,
                    fontWeight: FontWeight.w600,
                    color: colorScheme.onSurface,
                  ),
                ),
                const SizedBox(height: 2),
                Text(
                  context.l10n.contactsPendingConfirm,
                  style: TextStyle(
                    fontSize: 12,
                    color: colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildContactCard(List<FriendResponse> friends) {
    final colorScheme = Theme.of(context).colorScheme;
    return Container(
      decoration: BoxDecoration(
        color: colorScheme.surface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: colorScheme.outlineVariant),
      ),
      child: Column(
        children: [
          for (int i = 0; i < friends.length; i++) ...[
            _buildContactItem(friends[i]),
            if (i < friends.length - 1) SharedDivider(),
          ],
        ],
      ),
    );
  }

  Widget _buildContactItem(FriendResponse friend) {
    final colorScheme = Theme.of(context).colorScheme;
    final friendInfo = friend.friend;

    return GestureDetector(
      onTap: () =>
          context.push('/contacts/${friendInfo.id}', extra: friendInfo),
      child: Container(
        height: 70,
        padding: const EdgeInsets.symmetric(horizontal: 14),
        child: Row(
          children: [
            _buildAvatar(friendInfo.avatarUrl, friendInfo.id, colorScheme),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    friendInfo.username,
                    style: TextStyle(
                      fontSize: 15,
                      fontWeight: FontWeight.w600,
                      color: colorScheme.onSurface,
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Color _getAvatarBackground(
    Color color,
    ColorScheme colorScheme,
    AppColorPalette palette,
  ) {
    final avatarIndex = palette.avatarColors.indexOf(color);
    final opacities = [0.30, 0.20, 0.35, 0.15, 0.30];
    final opacity = avatarIndex >= 0 && avatarIndex < opacities.length
        ? opacities[avatarIndex]
        : 0.30;
    final isTertiary = avatarIndex == 4;
    return isTertiary
        ? colorScheme.tertiaryContainer.withValues(alpha: opacity)
        : colorScheme.primaryContainer.withValues(alpha: opacity);
  }

  Color _getAvatarBorder(
    Color color,
    ColorScheme colorScheme,
    AppColorPalette palette,
  ) {
    final avatarIndex = palette.avatarColors.indexOf(color);
    final opacities = [0.25, 0.20, 0.30, 0.15, 0.25];
    final opacity = avatarIndex >= 0 && avatarIndex < opacities.length
        ? opacities[avatarIndex]
        : 0.25;
    final isTertiary = avatarIndex == 4;
    return isTertiary
        ? colorScheme.tertiary.withValues(alpha: opacity)
        : colorScheme.primary.withValues(alpha: opacity);
  }

  Widget _buildAvatar(
    String? avatarUrl,
    String userId,
    ColorScheme colorScheme,
  ) {
    final palette = Theme.of(context).extension<AppColorPalette>()!;
    final avatarColor = palette
        .avatarColors[userId.hashCode.abs() % palette.avatarColors.length];

    return Container(
      width: 42,
      height: 42,
      decoration: BoxDecoration(
        color: _getAvatarBackground(avatarColor, colorScheme, palette),
        borderRadius: BorderRadius.circular(21),
        border: Border.all(
          color: _getAvatarBorder(avatarColor, colorScheme, palette),
        ),
      ),
      child: avatarUrl != null
          ? ClipRRect(
              borderRadius: BorderRadius.circular(21),
              child: Image.network(
                avatarUrl,
                width: 42,
                height: 42,
                fit: BoxFit.cover,
                errorBuilder: (context, error, stackTrace) =>
                    Icon(Icons.person, size: 18, color: avatarColor),
              ),
            )
          : Icon(Icons.person, size: 18, color: avatarColor),
    );
  }

  Widget _buildSendButton(
    String userId,
    TextEditingController controller,
    BuildContext sheetContext,
  ) {
    final colorScheme = Theme.of(context).colorScheme;
    return SizedBox(
      height: 44,
      child: ElevatedButton(
        onPressed: _sendingRequestUserId == userId
            ? null
            : () async {
                final content = controller.text.trim();
                Navigator.pop(sheetContext);
                await _sendFriendRequest(
                  userId,
                  content.isEmpty ? null : content,
                );
              },
        style: ElevatedButton.styleFrom(
          backgroundColor: colorScheme.primary,
          foregroundColor: colorScheme.onPrimary,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(AppRadius.sm),
          ),
        ),
        child: _sendingRequestUserId == userId
            ? AppLoadingIndicator(
                size: 16,
                strokeWidth: 2,
                color: colorScheme.onPrimary,
                trackColor: colorScheme.primary.withValues(alpha: 0.3),
                withContainer: false,
              )
            : Text(
                context.l10n.contactsSend,
                style: const TextStyle(
                  fontSize: 14,
                  fontWeight: FontWeight.w500,
                ),
              ),
      ),
    );
  }
}