import 'dart:async';

import 'package:contacts_plus_plus/apis/user_api.dart';
import 'package:contacts_plus_plus/clients/api_client.dart';
import 'package:contacts_plus_plus/models/user.dart';
import 'package:contacts_plus_plus/widgets/default_error_widget.dart';
import 'package:contacts_plus_plus/widgets/user_list_tile.dart';
import 'package:flutter/material.dart';

class SearchError {
  final String message;
  final IconData icon;

  const SearchError({required this.message, required this.icon});
}

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

  @override
  State<StatefulWidget> createState() => _UserSearchState();
}

class _UserSearchState extends State<UserSearch> {
  final TextEditingController _searchInputController = TextEditingController();
  Timer? _searchDebouncer;
  late Future<List<User>>? _usersFuture = _emptySearch;
  bool _isLoading = false;

  Future<List<User>> get _emptySearch => Future(() => throw const SearchError(
      message: "Start typing to search for users", icon: Icons.search)
  );

  void _querySearch(BuildContext context, String needle) {
    if (needle.isEmpty) {
      _usersFuture = _emptySearch;
      return;
    }
    _usersFuture = UserApi.searchUsers(ClientHolder
        .of(context).apiClient, needle: needle).then((value) {
      final res = value.toList();
      if (res.isEmpty) throw SearchError(message: "No user found with username '$needle'", icon: Icons.search_off);
      res.sort(
              (a, b) => a.username.length.compareTo(b.username.length)
      );
      return res;
    }).whenComplete(() => setState(() => _isLoading = false));
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Find Users"),
      ),
      body: Column(
        children: [
          if(_isLoading) const LinearProgressIndicator(),
          Expanded(
            child: FutureBuilder(
                future: _usersFuture,
                builder: (context, snapshot) {
                  if (snapshot.hasData) {
                    final users = (snapshot.data as List<User>);
                    final mClient = ClientHolder.of(context).messagingClient;
                    return ListView.builder(
                      itemCount: users.length,
                      itemBuilder: (context, index) {
                        final user = users[index];
                        return UserListTile(user: user, isFriend: mClient.getAsFriend(user.id) != null,);
                      },
                    );
                  } else if (snapshot.hasError) {
                    final err = snapshot.error;
                    if (err is SearchError) {
                      return DefaultErrorWidget(
                        title: err.message,
                        iconOverride: err.icon,
                      );
                    } else {
                      FlutterError.reportError(
                          FlutterErrorDetails(exception: snapshot.error!, stack: snapshot.stackTrace));
                      return DefaultErrorWidget(title: "${snapshot.error}",);
                    }
                  } else {
                    return const SizedBox.shrink();
                  }
                }
            ),
          ),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
            child: TextField(
              decoration: InputDecoration(
                  isDense: true,
                  hintText: "Search for users...",
                  contentPadding: const EdgeInsets.all(16),
                  border: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(24)
                  )
              ),
              autocorrect: false,
              controller: _searchInputController,
              onChanged: (String value) {
                _searchDebouncer?.cancel();
                if (value.isEmpty) {
                  setState(() {
                    _isLoading = false;
                    _querySearch(context, value);
                  });
                  return;
                }
                setState(() {
                  _isLoading = true;
                });
                _searchDebouncer = Timer(const Duration(milliseconds: 300), () {
                  setState(() {
                    _querySearch(context, value);
                  });
                });
              },
            ),
          ),
        ],
      ),
    );
  }
}