/**
Group member number change

 @param groupID group id
 @param membersNumber Number of members
 */
- (void)group:(NSString*)groupID didMembersNumberUpdeted:(NSInteger)membersNumber
{
}

/**
 You are removed from the current group     

 @param groupID group id
 */
- (void)groupUserKicked:(NSString*)groupID
{
}

/**
 Group deleted notification         

 @param groupID group id
 */
- (void)groupDidDeleted:(NSString*)groupID
{
}

/**
Receive group message

 @param aMessage message
 @param fromID   message sender
 */
- (void)groupMessagesDidReceive:(NSString *)aMessage fromID:(NSString *)fromID
{
}

/**
 Create a group
 @param groupName Group name
 @param completion callback
 */
- (void)createGroup:(NSString *)groupName completion:(void(^)(NSString *groupID,NSError *error))completion;
/**
 Delete the group
 @param groupID group ID
 @param completion callback
 */
- (void)deleteGroup:(NSString *)groupID completion:(void(^)(NSError *error))completion;

/**
 Add group members
 @param memberIds the array of Member ID 
 @param groupID group ID
 @param completion callback
 */
- (void)addGroupMembers:(NSArray<NSString*> *)memberIds toGroup:(NSString *)groupID completion:(void(^)(NSError *error))completion;

/**
 Delete the group member
 @param memberIds the array of Member ID
 @param groupID group ID
 */
- (void)deleteGroupMembers:(NSArray<NSString*> *)memberIds fromGroup:(NSString *)groupID completion:(void(^)(NSError *error))completion;

/**
 Set DND
 @param groupId group member
 @param enable YES means DND, NO means undoing DND
 @param completion 回调
 */
- (void)setGroup:(NSString *)groupId pushEnable:(BOOL)enable completion:(void(^)(NSError *error))completion;

/**
 Send a message
 @param message message cotent
 @param groupID group ID
 @param atUsers @user
 @param completion callback
 */
- (void)sendMessage:(NSString *)message toGroup:(NSString *)groupID atUsers:(NSArray<NSString*> *)atUsers completion:(void(^)(NSError *error))completion;