import 'dart:async';

import 'package:drift/drift.dart';
import 'package:libsignal_protocol_dart/libsignal_protocol_dart.dart';
import 'package:twonly/locator.dart';
import 'package:twonly/src/database/tables/groups.table.dart';
import 'package:twonly/src/database/twonly.db.dart';
import 'package:twonly/src/model/protobuf/client/generated/messages.pb.dart';
import 'package:twonly/src/services/api/messages.api.dart';
import 'package:twonly/src/services/api/utils.api.dart';
import 'package:twonly/src/services/group.service.dart';
import 'package:twonly/src/utils/log.dart';

Future<void> handleGroupCreate(
  int fromUserId,
  String groupId,
  EncryptedContent_GroupCreate newGroup,
  String receiptId,
) async {
  final user = await twonlyDB.contactsDao
      .getContactByUserId(fromUserId)
      .getSingleOrNull();
  if (user == null) {
    // Only contacts can invite other contacts, so this can (via the UI) not happen.
    Log.error(
      '[$receiptId] User is not a contact. Aborting.',
    );
    return;
  }

  // 1. Store the new group -> e.g. store the stateKey and groupPublicKey
  // 2. Call function that should fetch all jobs
  //    1. This function is also called in the main function, in case the state stored on the server could not be loaded
  //    2. This function will also send the GroupJoin to all members -> so they get there public key
  // 3. Finished

  final myGroupKey = generateIdentityKeyPair();

  var group = await twonlyDB.groupsDao.getGroup(groupId);
  if (group == null) {
    // Group state is joinedGroup -> As the current state has not yet been downloaded.
    group = await twonlyDB.groupsDao.createNewGroup(
      GroupsCompanion(
        groupId: Value(groupId),
        stateVersionId: const Value(0),
        stateEncryptionKey: Value(Uint8List.fromList(newGroup.stateKey)),
        myGroupPrivateKey: Value(myGroupKey.serialize()),
        groupName: Value(newGroup.hasGroupName() ? newGroup.groupName : ''),
        joinedGroup: const Value(false),
      ),
    );
  } else {
    // In this case make a group state update and check if the fromUserId is still a admin. otherwise return with an log error message
    final updatedState = await fetchGroupState(group);
    if (updatedState == null) {
      Log.error(
        '[$receiptId] Received group invite/create for $groupId, but failed to fetch group state from server.',
      );
      return;
    }
    final (_, state) = updatedState;
    if (!state.adminIds.any((id) => id.toInt() == fromUserId)) {
      Log.error(
        '[$receiptId] Received group invite/create for $groupId from $fromUserId, but they are not an admin of this group.',
      );
      return;
    }
    // User was already in the group, so update leftGroup back to false
    await twonlyDB.groupsDao.updateGroup(
      groupId,
      GroupsCompanion(
        stateVersionId: const Value(0),
        stateEncryptionKey: Value(Uint8List.fromList(newGroup.stateKey)),
        myGroupPrivateKey: Value(myGroupKey.serialize()),
        joinedGroup: const Value(false),
        leftGroup: const Value(false),
        deletedContent: const Value(false),
      ),
    );
  }

  if (group == null) {
    Log.error(
      '[$receiptId] Could not create new group. Probably because the group already existed.',
    );
    return;
  }

  await twonlyDB.groupsDao.insertGroupAction(
    GroupHistoriesCompanion(
      groupId: Value(groupId),
      contactId: Value(fromUserId),
      affectedContactId: const Value(null),
      type: const Value(GroupActionType.addMember),
    ),
  );

  // Load group members from the server as this is the single source of truth.
  // This can be done in the background, so the WebSocket message can be ACKed.
  unawaited(fetchGroupStatesForUnjoinedGroups());

  await sendCipherTextToGroup(
    groupId,
    EncryptedContent(
      groupJoin: EncryptedContent_GroupJoin(
        groupPublicKey: myGroupKey.getPublicKey().serialize(),
      ),
    ),
  );
}

Future<void> handleGroupUpdate(
  int fromUserId,
  String groupId,
  EncryptedContent_GroupUpdate update,
  String receiptId,
) async {
  Log.info('[$receiptId] Got group update for $groupId from $fromUserId');

  final actionType = groupActionTypeFromString(update.groupActionType);
  if (actionType == null) {
    Log.error(
      '[$receiptId] Group action ${update.groupActionType} is unknown ignoring.',
    );
    return;
  }

  final group = (await twonlyDB.groupsDao.getGroup(groupId))!;

  if (!group.isDirectChat) {
    unawaited(fetchGroupState(group));
  }

  switch (actionType) {
    case GroupActionType.updatedGroupName:
      await twonlyDB.groupsDao.insertGroupAction(
        GroupHistoriesCompanion(
          groupId: Value(groupId),
          type: Value(actionType),
          oldGroupName: Value(group.groupName),
          newGroupName: Value(update.newGroupName),
          contactId: Value(fromUserId),
        ),
      );
    case GroupActionType.changeDisplayMaxTime:
      await twonlyDB.groupsDao.insertGroupAction(
        GroupHistoriesCompanion(
          groupId: Value(groupId),
          type: Value(actionType),
          newDeleteMessagesAfterMilliseconds: Value(
            update.newDeleteMessagesAfterMilliseconds.toInt(),
          ),
          contactId: Value(fromUserId),
        ),
      );
      if (group.isDirectChat) {
        await twonlyDB.groupsDao.updateGroup(
          group.groupId,
          GroupsCompanion(
            deleteMessagesAfterMilliseconds: Value(
              update.newDeleteMessagesAfterMilliseconds.toInt(),
            ),
          ),
        );
      }
    case GroupActionType.removedMember:
    case GroupActionType.addMember:
    case GroupActionType.leftGroup:
    case GroupActionType.promoteToAdmin:
    case GroupActionType.demoteToMember:
      int? affectedContactId = update.affectedContactId.toInt();

      if (affectedContactId == userService.currentUser.userId) {
        affectedContactId = null;
        if (actionType == GroupActionType.removedMember) {
          // Oh no, I just got removed from the group...
          // This state is handle this case in the fetchGroupState....
        }
      }

      await twonlyDB.groupsDao.insertGroupAction(
        GroupHistoriesCompanion(
          groupId: Value(groupId),
          type: Value(actionType),
          affectedContactId: Value(affectedContactId),
          contactId: Value(fromUserId),
        ),
      );
    case GroupActionType.createdGroup:
    case GroupActionType.updatedContactUsername:
    case GroupActionType.updatedContactDisplayName:
      break;
  }
}

Future<bool> handleGroupJoin(
  int fromUserId,
  String groupId,
  EncryptedContent_GroupJoin join,
  String receiptId,
) async {
  if (await twonlyDB.contactsDao.getContactById(fromUserId) == null) {
    if (!await addNewHiddenContact(fromUserId)) {
      Log.error('[$receiptId] Got group join, but could not load contact.');
      // This can happen in case the group join was received before the group create.
      // In this case return false, which will cause the receipt to fail and the user
      // will resend this message.
      return false;
    }
  }
  await twonlyDB.groupsDao.updateMember(
    groupId,
    fromUserId,
    GroupMembersCompanion(
      groupPublicKey: Value(Uint8List.fromList(join.groupPublicKey)),
    ),
  );
  return true;
}

Future<void> handleResendGroupPublicKey(
  int fromUserId,
  String groupId,
  EncryptedContent_GroupJoin join,
  String receiptId,
) async {
  final group = await twonlyDB.groupsDao.getGroup(groupId);
  if (group == null || group.myGroupPrivateKey == null) return;
  final keyPair = IdentityKeyPair.fromSerialized(group.myGroupPrivateKey!);
  await sendCipherText(
    fromUserId,
    EncryptedContent(
      groupId: groupId,
      groupJoin: EncryptedContent_GroupJoin(
        groupPublicKey: keyPair.getPublicKey().serialize(),
      ),
    ),
    blocking: false,
  );
}

Future<void> handleTypingIndicator(
  int fromUserId,
  String groupId,
  EncryptedContent_TypingIndicator indicator,
  String receiptId,
) async {
  var lastTypeIndicator = const Value<DateTime?>.absent();

  if (indicator.isTyping) {
    lastTypeIndicator = Value(fromTimestamp(indicator.createdAt));
  }

  await twonlyDB.groupsDao.updateMember(
    groupId,
    fromUserId,
    GroupMembersCompanion(
      lastChatOpened: Value(fromTimestamp(indicator.createdAt)),
      lastTypeIndicator: lastTypeIndicator,
    ),
  );
}