/*
 *   Famedly Matrix SDK
 *   Copyright (C) 2019, 2020 Famedly GmbH
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU Affero General Public License as
 *   published by the Free Software Foundation, either version 3 of the
 *   License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *   GNU Affero General Public License for more details.
 *
 *   You should have received a copy of the GNU Affero General Public License
 *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

import '../famedlysdk.dart';
import '../matrix_api.dart';
import 'event.dart';
import 'room.dart';

/// Represents a Matrix User which may be a participant in a Matrix Room.
class User extends Event {
  factory User(
    String id, {
    String membership,
    String displayName,
    String avatarUrl,
    Room room,
  }) {
    var content = <String, String>{};
    if (membership != null) content['membership'] = membership;
    if (displayName != null) content['displayname'] = displayName;
    if (avatarUrl != null) content['avatar_url'] = avatarUrl;
    return User.fromState(
      stateKey: id,
      content: content,
      typeKey: EventTypes.RoomMember,
      roomId: room?.id,
      room: room,
      originServerTs: DateTime.now(),
    );
  }

  User.fromState(
      {dynamic prevContent,
      String stateKey,
      dynamic content,
      String typeKey,
      String eventId,
      String roomId,
      String senderId,
      DateTime originServerTs,
      dynamic unsigned,
      Room room})
      : super(
            stateKey: stateKey,
            prevContent: prevContent,
            content: content,
            type: typeKey,
            eventId: eventId,
            roomId: roomId,
            senderId: senderId,
            originServerTs: originServerTs,
            unsigned: unsigned,
            room: room);

  /// The full qualified Matrix ID in the format @username:server.abc.
  String get id => stateKey;

  /// The displayname of the user if the user has set one.
  String get displayName =>
      content != null && content.containsKey('displayname')
          ? content['displayname']
          : (prevContent != null ? prevContent['displayname'] : null);

  /// Returns the power level of this user.
  int get powerLevel => room?.getPowerLevelByUserId(id);

  /// The membership status of the user. One of:
  /// join
  /// invite
  /// leave
  /// ban
  Membership get membership => Membership.values.firstWhere((e) {
        if (content['membership'] != null) {
          return e.toString() == 'Membership.' + content['membership'];
        }
        return false;
      }, orElse: () => Membership.join);

  /// The avatar if the user has one.
  Uri get avatarUrl => content != null && content.containsKey('avatar_url')
      ? (content['avatar_url'] is String
          ? Uri.parse(content['avatar_url'])
          : null)
      : (prevContent != null && prevContent['avatar_url'] is String
          ? Uri.parse(prevContent['avatar_url'])
          : null);

  /// Returns the displayname or the local part of the Matrix ID if the user
  /// has no displayname. If [formatLocalpart] is true, then the localpart will
  /// be formatted in the way, that all "_" characters are becomming white spaces and
  /// the first character of each word becomes uppercase.
  /// If [mxidLocalPartFallback] is true, then the local part of the mxid will be shown
  /// if there is no other displayname available. If not then this will return "Unknown user".
  String calcDisplayname(
      {bool formatLocalpart = true, bool mxidLocalPartFallback = true}) {
    if (displayName?.isNotEmpty ?? false) {
      return displayName;
    }
    if (stateKey != null && mxidLocalPartFallback) {
      if (!formatLocalpart) {
        return stateKey.localpart;
      }
      var words = stateKey.localpart.replaceAll('_', ' ').split(' ');
      for (var i = 0; i < words.length; i++) {
        if (words[i].isNotEmpty) {
          words[i] = words[i][0].toUpperCase() + words[i].substring(1);
        }
      }
      return words.join(' ');
    }
    return 'Unknown user';
  }

  /// Call the Matrix API to kick this user from this room.
  Future<void> kick() => room.kick(id);

  /// Call the Matrix API to ban this user from this room.
  Future<void> ban() => room.ban(id);

  /// Call the Matrix API to unban this banned user from this room.
  Future<void> unban() => room.unban(id);

  /// Call the Matrix API to change the power level of this user.
  Future<void> setPower(int power) => room.setPower(id, power);

  /// Returns an existing direct chat ID with this user or creates a new one.
  /// Returns null on error.
  Future<String> startDirectChat() async {
    // Try to find an existing direct chat
    var roomID = await room.client?.getDirectChatFromUserId(id);
    if (roomID != null) return roomID;

    // Start a new direct chat
    final newRoomID = await room.client.createRoom(
      invite: [id],
      isDirect: true,
      preset: CreateRoomPreset.trusted_private_chat,
    );

    if (newRoomID == null) return newRoomID;

    await Room(id: newRoomID, client: room.client).addToDirectChat(id);

    return newRoomID;
  }

  /// The newest presence of this user if there is any and null if not.
  Presence get presence => room.client.presences[id];

  /// Whether the client is able to ban/unban this user.
  bool get canBan =>
      membership != Membership.ban &&
      room.canBan &&
      powerLevel < room.ownPowerLevel;

  /// Whether the client is able to kick this user.
  bool get canKick =>
      [Membership.join, Membership.invite].contains(membership) &&
      room.canKick &&
      powerLevel < room.ownPowerLevel;

  /// Whether the client is allowed to change the power level of this user.
  /// Please be aware that you can only set the power level to at least your own!
  bool get canChangePowerLevel =>
      room.canChangePowerLevel && powerLevel < room.ownPowerLevel;
}