MyViewController.swift

extension MyViewController: DropDownViewDelegate {

    private func setupData() {
        guard let model = self.dropDownView.cellItems.first else { return }
        self.handleDates(model: model)
    }
  
    private func hideOnOtherView() {
        if self.dropDownView.isVisible {
            self.dropDownView.toggleMenu()
        }
    }
    
    private func setupDropDown() {
        let cellItems = [DropDownCellModel(item: .daily, isSelected: true),
                         DropDownCellModel(item: .weekly),
                         DropDownCellModel(item: .monthly)]
        self.dropDownView.setUpItems(cellItems)
        self.dropDownView.delegate = self
    }
    
    func didSelect(_ dropDown: DropDownView, model: DropDownCellModel) {
        self.handleDates(model: model)
    }
    
    private func handleDates(model: DropDownCellModel) {
        
        switch model.item {
        case .daily:
            self.dates = Date.getDates(days: -90).map {
                ScheduleDateCellModel(date: $0)
            }
        case .weekly:
            self.dates = Date().getPreviousWeeks(range: 12).map {
                ScheduleDateCellModel(dates: $0, dateGroup: model.item)
            }
        case .monthly:
            self.dates = Date.getMonths(range: -3).map {
                ScheduleDateCellModel(date: $0, dateGroup: model.item)
            }
        default:
            return
        }
        
        self.collectionView.reloadData()
        self.selectDate(IndexPath(row: self.dates.count - 1, section: 0))
    }