IGListKit/Examples/Examples-iOS/IGListKitExamples/SectionControllers/HorizontalSectionController.swift

/**
 Copyright (c) Facebook, Inc. and its affiliates.
 
 The examples provided by Facebook are for non-commercial testing and evaluation
 purposes only. Facebook reserves all rights not expressly granted.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

import IGListKit
import UIKit

final class HorizontalSectionController: ListSectionController, ListAdapterDataSource {

    private var number: Int?

    lazy var adapter: ListAdapter = {
        let adapter = ListAdapter(updater: ListAdapterUpdater(),
                                  viewController: self.viewController)
        adapter.dataSource = self
        return adapter
    }()

    override func sizeForItem(at index: Int) -> CGSize {
        return CGSize(width: collectionContext!.containerSize.width, height: 100)
    }

    override func cellForItem(at index: Int) -> UICollectionViewCell {
        guard let cell: EmbeddedCollectionViewCell = collectionContext?.dequeueReusableCell(
            for: self,
            at: index
        ) else {
            fatalError()
        }
        adapter.collectionView = cell.collectionView
        return cell
    }

    override func didUpdate(to object: Any) {
        number = object as? Int
    }

    // MARK: ListAdapterDataSource

    func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
        guard let number = number else { return [] }
        return (0..<number).map { $0 as ListDiffable }
    }

    func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
        return EmbeddedSectionController()
    }

    func emptyView(for listAdapter: ListAdapter) -> UIView? {
        return nil
    }

}