BooksCollectionInterfaceProvider.swift

BooksCollectionInterfaceProvider.swift

//
//  BooksCollectionProvider.swift
//  Glose
//
//  Created by Thomas Ricouard on 10/11/2017.
//  Copyright © 2017 Thomas Ricouard. All rights reserved.
//

import Foundation
import UIKit

protocol BooksCollectionInterfaceProviderDelegate: class {
    func booksCollectionInterfaceProviderDidChangeDisplayMode(provider: BooksCollectionInterfaceProvider,
                                                              displayMode: BooksCollectionInterfaceProvider.DisplayMode)
    func booksCollectionInterfaceProviderScrollViewDidScroll(scrollView: UIScrollView)
    func booksCollectionInterfaceProviderCollectionView(collectionView: UICollectionView,
                                                        layout collectionViewLayout: UICollectionViewLayout,
                                                        referenceSizeForHeaderInSection section: Int) -> CGSize
    func booksCollectionInterfaceProviderCollectionView(collectionView: UICollectionView,
                                                        viewForSupplementaryElementOfKind kind: String,
                                                        at indexPath: IndexPath) -> UICollectionReusableView
}

class BooksCollectionInterfaceProvider: NSObject {

    weak var parentController: UIViewController?
    weak var collectionView: UICollectionView?

    var datasource: [ObjectId] = [] {
        didSet {
            collectionView?.reloadData()
        }
    }

    weak var delegate: BooksCollectionInterfaceProviderDelegate?

    enum DisplayMode {
        case grid, list

        func margin() -> CGFloat {
            switch self {
            case .grid:
                return 10
            default:
                return 0
            }
        }
    }

    var displayMode = DisplayMode.grid {
        didSet {
            delegate?.booksCollectionInterfaceProviderDidChangeDisplayMode(provider: self, displayMode: displayMode)
            collectionView?.reloadData()
        }
    }

    init(parentController: UIViewController, collectionView: UICollectionView) {
        self.parentController = parentController
        self.collectionView = collectionView

        super.init()

        self.collectionView?.dataSource = self
        self.collectionView?.delegate = self
        registerBooksCells()

        self.parentController?.registerForPreviewing(with: self, sourceView: self.collectionView!)

        collectionView.reloadData()
    }

    func registerBooksCells() {
        var nib = UINib(nibName: "BookCollectionViewCell", bundle: Bundle.main)
        collectionView?.register(nib, forCellWithReuseIdentifier: BookCollectionViewCell.id)
        nib = UINib(nibName: "ListBookCollectionViewCell", bundle: Bundle.main)
        collectionView?.register(nib, forCellWithReuseIdentifier: ListBookCollectionViewCell.id)
    }
}

extension BooksCollectionInterfaceProvider: UICollectionViewDelegate,
                                   UICollectionViewDataSource,
                                   UICollectionViewDelegateFlowLayout {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return datasource.count
    }

    func collectionView(_ collectionView: UICollectionView,
                        cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        if displayMode == .grid {
            guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: BookCollectionViewCell.id,
                                                                for: indexPath) as? BookCollectionViewCell else {
                                                                    return UICollectionViewCell()
            }
            cell.bookId = datasource[indexPath.row]
            return cell
        }
        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ListBookCollectionViewCell.id,
                                                            for: indexPath) as? ListBookCollectionViewCell else {
                                                                return UICollectionViewCell()
        }
        cell.delegate = self
        cell.bookId = datasource[indexPath.row]
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        if let vc = Storyboards.Controllers.book.instantiate() as? BookViewController {
            vc.bookId = datasource[indexPath.row]
            parentController?.navigationController?.pushViewController(vc, animated: true)
        }
    }

    func collectionView(_ collectionView: UICollectionView, layout
        collectionViewLayout: UICollectionViewLayout,
                        sizeForItemAt indexPath: IndexPath) -> CGSize {
        if displayMode == .grid {
            let size = // Your logic for your grid cell size. In my case I want each cell to be 1/3 of the width of the screen - my margin.
            return size
        }
        return CGSize(width: collectionView.frame.size.width, height: ListBookCollectionViewCell.height)
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return displayMode.margin()
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return displayMode.margin()
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 0,
                            left: displayMode.margin(),
                            bottom: 0,
                            right: displayMode.margin())
    }

    func collectionView(_ collectionView: UICollectionView,
                        layout collectionViewLayout: UICollectionViewLayout,
                        referenceSizeForHeaderInSection section: Int) -> CGSize {
        return delegate?.booksCollectionInterfaceProviderCollectionView(collectionView: collectionView,
                                                               layout: collectionViewLayout,
                                                               referenceSizeForHeaderInSection: section) ?? CGSize.zero
    }

    func collectionView(_ collectionView: UICollectionView,
                        viewForSupplementaryElementOfKind kind: String,
                        at indexPath: IndexPath) -> UICollectionReusableView {
        return delegate?.booksCollectionInterfaceProviderCollectionView(collectionView: collectionView,
                                                               viewForSupplementaryElementOfKind: kind,
                                                               at: indexPath) ?? UICollectionReusableView()
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        delegate?.booksCollectionInterfaceProviderScrollViewDidScroll(scrollView: scrollView)
    }
}

extension BooksCollectionInterfaceProvider: UIViewControllerPreviewingDelegate {
    func previewingContext(_ previewingContext: UIViewControllerPreviewing,
                           viewControllerForLocation location: CGPoint) -> UIViewController? {
        // Your preview context code.
    }

    func previewingContext(_ previewingContext: UIViewControllerPreviewing,
                           commit viewControllerToCommit: UIViewController) {
      // Your preview context commit code.
    }
}

extension BooksCollectionInterfaceProvider: ListBookCollectionViewCellDelegate {

    func onListBookCellAddToListButton(cell: ListBookCollectionViewCell) {
  
    }

    func onListBookCellActionButton(cell: ListBookCollectionViewCell) {

    }
}