BlogPost_20201112_6.swift

class MenuViewController: UIViewController {
    
    let table = MenuTableHandler()
    var categories: [MenuCategory] = []
    var selections = Set<MenuItem>()
    
    fileprivate var searchText: String? {
        didSet {
            if oldValue == searchText { return }
            categories = MenuOption.allCases.map {
                let category = $0.makeCategory(searchText: searchText)
                category.dataSource = self
                return category
            }
            table.update(with: categories, animate: false)
        }
    }    
}

extension MenuViewController: MenuCategoryDataSource {
    
    func menuItemIsSelected(_ item: MenuItem) -> Bool {
        return selections.contains(item)
    }
}

final class MenuItem: Hashable, Comparable {
    
    unowned let category: MenuCategory
    
    var isSelected: Bool {
        return category.dataSource?.menuItemIsSelected(self) ?? false
    }
}

protocol MenuCategoryDataSource: AnyObject {
    func menuItemIsSelected(_ item: MenuItem) -> Bool
}