CreateSection(title, codeName string) (section *DSection.Section)
    UpdateSection(updateSection *DSection.Section) (section *DSection.Section)
    RemoveSection(sectionId int64) (err *CoreError.CompositableError)
    SetCurrentSection(sectionId int64) (section *DSection.Section)
    GetCurrentSection() (section *DSection.Section)
    NextSection() (section *DSection.Section)
    PreviousSection() (section *DSection.Section)
    GetSections() (sections SectionListInterface.List)
    GetSectionById(sectionId int64) (section *DSection.Section)
    AddCategoryToSection(sectionId, categoryId int64) (err *CoreError.CompositableError)
    RemoveCategoryOfSection(sectionId, categoryId int64) (err *CoreError.CompositableError)

    CreateCategory(title, codeName string) (category *DCategory.Category)
    UpdateCategory(updateCategory *DCategory.Category) (category *DCategory.Category)
    RemoveCategory(categoryId int64) (err *CoreError.CompositableError)
    GetCategoryById(categoryId int64) (category *DCategory.Category)
    GetCategoryList(sectionId int64, page int) (categoryList CategoryListInterface.List)

    GetSectionChatList(sectionId int64, page int) (chatList ChatListInterface.List)
    GetCurrentSectionChatList(page int) (chatList ChatListInterface.List)
    GetCategoryChatList(categoryId int64, page int) (chatList ChatListInterface.List)
    GetCurrentCategoryChatList(page int) (chatList ChatListInterface.List)

    GetSectionContactList(sectionId int64, page int) (contactList ContactListInterface.List)   // TODO 07.04.2020: Red_byte move to Contact manager?
    GetCurrentSectionContactList(page int) (contactList ContactListInterface.List)             // TODO 07.04.2020: Red_byte move to Contact manager?
    GetCategoryContactList(categoryId int64, page int) (contactList ContactListInterface.List) // TODO 07.04.2020: Red_byte move to Contact manager?
    GetCurrentCategoryContactList(page int) (contactList ContactListInterface.List)
    PreviousSectionsCountUnreadMessage() (count int64)
    NextSectionsCountUnreadMessage() (count int64)