import 'dart:math';

import 'package:flutter/material.dart';
import 'package:logging/logging.dart';
import 'package:result_monad/result_monad.dart';

import '../globals.dart';
import '../models/connection.dart';
import '../models/exec_error.dart';
import '../models/group_data.dart';
import 'auth_service.dart';

class ConnectionsManager extends ChangeNotifier {
  static final _logger = Logger('$ConnectionsManager');
  final _connectionsById = <String, Connection>{};
  final _connectionsByName = <String, Connection>{};
  final _connectionsByProfileUrl = <Uri, Connection>{};
  final _groupsForConnection = <String, List<GroupData>>{};
  final _myGroups = <GroupData>{};
  final _myContacts = <Connection>[];
  var _myContactsInitialized = false;

  int get length => _connectionsById.length;

  void clearCaches() {
    _connectionsById.clear();
    _connectionsByName.clear();
    _connectionsByProfileUrl.clear();
    _groupsForConnection.clear();
    _myGroups.clear();
    _myContacts.clear();
  }

  bool addConnection(Connection connection) {
    if (_connectionsById.containsKey(connection.id)) {
      return false;
    }
    return updateConnection(connection);
  }

  List<Connection> getKnownUsersByName(String name) {
    return _connectionsByName.values.where((it) {
      final normalizedHandle = it.handle.toLowerCase();
      final normalizedName = it.name.toLowerCase();
      final normalizedQuery = name.toLowerCase();
      return normalizedHandle.contains(normalizedQuery) ||
          normalizedName.contains(normalizedQuery);
    }).toList();
  }

  bool updateConnection(Connection connection) {
    _connectionsById[connection.id] = connection;
    _connectionsByName[connection.name] = connection;
    _connectionsByProfileUrl[connection.profileUrl] = connection;
    int index = _myContacts.indexWhere((c) => c.id == connection.id);
    if (index >= 0) {
      _myContacts.removeAt(index);
    }
    switch (connection.status) {
      case ConnectionStatus.youFollowThem:
      case ConnectionStatus.theyFollowYou:
      case ConnectionStatus.mutual:
        if (index > 0) {
          _myContacts.insert(index, connection);
        } else {
          _myContacts.add(connection);
        }
        break;
      default:
        break;
    }

    return true;
  }

  bool addAllConnections(Iterable<Connection> newConnections) {
    bool result = true;

    for (final connection in newConnections) {
      result &= addConnection(connection);
    }

    return result;
  }

  Future<void> acceptFollowRequest(Connection connection) async {
    _logger.finest(
        'Attempting to accept follow request ${connection.name}: ${connection.status}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.acceptFollow(connection))
        .match(
      onSuccess: (update) {
        _logger
            .finest('Successfully followed ${update.name}: ${update.status}');
        updateConnection(update);
        notifyListeners();
      },
      onError: (error) {
        _logger.severe('Error following ${connection.name}');
      },
    );
  }

  Future<void> rejectFollowRequest(Connection connection) async {
    _logger.finest(
        'Attempting to accept follow request ${connection.name}: ${connection.status}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.rejectFollow(connection))
        .match(
      onSuccess: (update) {
        _logger
            .finest('Successfully followed ${update.name}: ${update.status}');
        updateConnection(update);
        notifyListeners();
      },
      onError: (error) {
        _logger.severe('Error following ${connection.name}');
      },
    );
  }

  Future<void> ignoreFollowRequest(Connection connection) async {
    _logger.finest(
        'Attempting to accept follow request ${connection.name}: ${connection.status}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.ignoreFollow(connection))
        .match(
      onSuccess: (update) {
        _logger
            .finest('Successfully followed ${update.name}: ${update.status}');
        updateConnection(update);
        notifyListeners();
      },
      onError: (error) {
        _logger.severe('Error following ${connection.name}');
      },
    );
  }

  Future<void> follow(Connection connection) async {
    _logger.finest(
        'Attempting to follow ${connection.name}: ${connection.status}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.followConnection(connection))
        .match(
      onSuccess: (update) {
        _logger
            .finest('Successfully followed ${update.name}: ${update.status}');
        updateConnection(update);
        notifyListeners();
      },
      onError: (error) {
        _logger.severe('Error following ${connection.name}');
      },
    );
  }

  Future<void> unfollow(Connection connection) async {
    _logger.finest(
        'Attempting to unfollow ${connection.name}: ${connection.status}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.unFollowConnection(connection))
        .match(
      onSuccess: (update) {
        _logger
            .finest('Successfully unfollowed ${update.name}: ${update.status}');
        updateConnection(update);
        notifyListeners();
      },
      onError: (error) {
        _logger.severe('Error following ${connection.name}');
      },
    );
  }

  List<Connection> getMyContacts() {
    if (!_myContactsInitialized) {
      updateAllContacts();
      _myContactsInitialized = true;
    }

    return _myContacts.toList(growable: false);
  }

  Future<void> updateAllContacts() async {
    _logger.fine('Updating all contacts');
    final clientResult = getIt<AuthService>().currentClient;
    if (clientResult.isFailure) {
      _logger.severe(
          'Unable to update contacts due to client error: ${clientResult.error}');
      return;
    }
    final client = clientResult.value;
    final results = <String, Connection>{};
    var moreResults = true;
    var maxId = -1;
    const limit = 1000;
    while (moreResults) {
      await client.getMyFollowers(sinceId: maxId, limit: limit).match(
          onSuccess: (followers) {
        for (final f in followers) {
          results[f.id] = f.copy(status: ConnectionStatus.theyFollowYou);
          int id = int.parse(f.id);
          maxId = max(maxId, id);
        }
        moreResults = followers.length >= limit;
      }, onError: (error) {
        _logger.severe('Error getting followers data: $error');
      });
    }

    moreResults = true;
    maxId = -1;
    while (moreResults) {
      await client.getMyFollowing(sinceId: maxId, limit: limit).match(
          onSuccess: (following) {
        for (final f in following) {
          if (results.containsKey(f.id)) {
            results[f.id] = f.copy(status: ConnectionStatus.mutual);
          } else {
            results[f.id] = f.copy(status: ConnectionStatus.youFollowThem);
          }
          int id = int.parse(f.id);
          maxId = max(maxId, id);
        }
        moreResults = following.length >= limit;
      }, onError: (error) {
        _logger.severe('Error getting followers data: $error');
      });
    }

    _myContacts.clear();
    _myContacts.addAll(results.values);
    addAllConnections(results.values);
    _myContacts.sort((c1, c2) => c1.name.compareTo(c2.name));
    _logger.finest('# Contacts:${_myContacts.length}');
    notifyListeners();
  }

  List<GroupData> getMyGroups() {
    if (_myGroups.isNotEmpty) {
      return _myGroups.toList(growable: false);
    }
    _updateMyGroups(true);
    return [];
  }

  Result<List<GroupData>, ExecError> getGroupsForUser(String id) {
    if (!_groupsForConnection.containsKey(id)) {
      _refreshGroupListData(id, true);
      return Result.ok([]);
    }

    return Result.ok(_groupsForConnection[id]!);
  }

  FutureResult<bool, ExecError> addUserToGroup(
      GroupData group, Connection connection) async {
    _logger.finest('Adding ${connection.name} to group: ${group.name}');
    final result = await getIt<AuthService>().currentClient.andThenAsync(
        (client) => client.addConnectionToGroup(group, connection));
    result.match(
      onSuccess: (_) => _refreshGroupListData(connection.id, true),
      onError: (error) {
        _logger
            .severe('Error adding ${connection.name} to group: ${group.name}');
      },
    );

    return result.execErrorCast();
  }

  FutureResult<bool, ExecError> removeUserFromGroup(
      GroupData group, Connection connection) async {
    _logger.finest('Removing ${connection.name} from group: ${group.name}');
    final result = await getIt<AuthService>().currentClient.andThenAsync(
        (client) => client.removeConnectionFromGroup(group, connection));
    result.match(
      onSuccess: (_) => _refreshGroupListData(connection.id, true),
      onError: (error) {
        _logger.severe(
            'Error removing ${connection.name} from group: ${group.name}');
      },
    );

    return result.execErrorCast();
  }

  Result<Connection, String> getById(String id) {
    final result = _connectionsById[id];
    if (result == null) {
      return Result.error('$id not found');
    }
    if (result.status == ConnectionStatus.unknown) {
      _refreshConnection(result, true);
    }
    return Result.ok(result);
  }

  Result<Connection, String> getByName(String name) {
    final result = _connectionsByName[name];
    if (result == null) {
      Result.error('$name not found');
    }
    if (result!.status == ConnectionStatus.unknown) {
      _refreshConnection(result, true);
    }
    return Result.ok(result);
  }

  Result<Connection, String> getByProfileUrl(Uri url) {
    final result = _connectionsByProfileUrl[url];
    if (result == null) {
      Result.error('$url not found');
    }
    if (result!.status == ConnectionStatus.unknown) {
      _refreshConnection(result, true);
    }
    return Result.ok(result);
  }

  Future<void> fullRefresh(Connection connection) async {
    await _updateMyGroups(false);
    await _refreshGroupListData(connection.id, false);
    await _refreshConnection(connection, false);
    notifyListeners();
  }

  Future<void> _refreshGroupListData(String id, bool withNotification) async {
    _logger.finest('Refreshing member list data for Connection $id');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.getMemberGroupsForConnection(id))
        .match(
      onSuccess: (lists) {
        _groupsForConnection[id] = lists;
        if (withNotification) {
          notifyListeners();
        }
      },
      onError: (error) {
        _logger.severe('Error getting list data for $id: $error');
      },
    );
  }

  Future<void> _refreshConnection(
      Connection connection, bool withNotification) async {
    _logger.finest('Refreshing connection data for ${connection.name}');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.getConnectionWithStatus(connection))
        .match(
      onSuccess: (update) {
        updateConnection(update);
        if (withNotification) {
          notifyListeners();
        }
      },
      onError: (error) {
        _logger.severe('Error getting updates for ${connection.name}: $error');
      },
    );
  }

  Future<void> _updateMyGroups(bool withNotification) async {
    _logger.finest('Refreshing my groups list');
    await getIt<AuthService>()
        .currentClient
        .andThenAsync((client) => client.getGroups())
        .match(
      onSuccess: (groups) {
        _logger.finest('Got updated groups:${groups.map((e) => e.name)}');
        _myGroups.clear();
        _myGroups.addAll(groups);
        if (withNotification) {
          notifyListeners();
        }
      },
      onError: (error) {
        _logger.severe('Error getting my groups: $error');
      },
    );
  }
}