iOS custom view to display books on shelf

import ShelfView

class PlainShelfController: UIViewController, PlainShelfViewDelegate {
    var shelfView: PlainShelfView!

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let books = [
            BookModel(bookCoverSource: "https://files.kerching.raywenderlich.com/covers/d5693015-46b6-44f8-bf7b-7a222b28d9fe.png",
                      bookId: "0",
                      bookTitle: "Realm: Building Modern Swift Apps with Realm"),
            BookModel(bookCoverSource: "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTYEkCQ_wu8HoGJzzs_gUH_FVusgI2RhntBKQ-WkmqnDJZnriwY6Q",
                      bookId: "1",
                      bookTitle: "iOS 10 by Tutorials: Learning the new iOS APIs with Swift 3")
        ]        
        
        shelfView = PlainShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                                   bookModel: books, bookSource: PlainShelfView.BOOK_SOURCE_URL)

        shelfView.delegate = self
        self.view.addSubview(shelfView)
    }

    func onBookClicked(_ shelfView: PlainShelfView, index: Int, bookId: String, bookTitle: String) {
        print("I just clicked \"\(bookTitle)\" with bookId \(bookId), at index \(index)")
    }

}

import ShelfView

class SectionShelfController: UIViewController, SectionShelfViewDelegate {
    var shelfView: SectionShelfView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let books = [
            BookModel(bookCoverSource: "https://files.kerching.raywenderlich.com/covers/d5693015-46b6-44f8-bf7b-7a222b28d9fe.png",
                      bookId: "0",
                      bookTitle: "Realm: Building Modern Swift Apps with Realm"),
            BookModel(bookCoverSource: "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTYEkCQ_wu8HoGJzzs_gUH_FVusgI2RhntBKQ-WkmqnDJZnriwY6Q",
                      bookId: "1",
                      bookTitle: "iOS 10 by Tutorials: Learning the new iOS APIs with Swift 3")
        ]
        let bookModelSectionArray = [BookModelSection(sectionName: "RAYWENDERLICH",
                                                      sectionId: "0",
                                                      sectionBooks: books)]

        shelfView = SectionShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                                     bookModelSection: bookModelSectionArray,
                                     bookSource: SectionShelfView.BOOK_SOURCE_URL)

        shelfView.delegate = self
        self.view.addSubview(shelfView)
    }

    func onBookClicked(_ shelfView: SectionShelfView, section: Int, index: Int,
                       sectionId: String, sectionTitle: String, bookId: String,
                       bookTitle: String) {
        print("I just clicked \"\(bookTitle)\" with bookId \(bookId), at index \(index). Section details --> section \(section), sectionId \(sectionId), sectionTitle \(sectionTitle)")
    }

}

addBooks(bookModel: [BookModel])

addBooks(bookModelSection: [BookModelSection])

reloadBooks(bookModel: [BookModel])

reloadBooks(bookModelSection: [BookModelSection])

let books = [
    BookModel(bookCoverSource: "bookcover0.png", bookId: "0", bookTitle: "Book Title 0"),
    BookModel(bookCoverSource: "bookcover1.png", bookId: "1", bookTitle: "Book Title 1")
        ]
shelfView = PlainShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                           bookModel: books, bookSource: PlainShelfView.BOOK_SOURCE_DEVICE_DOCUMENTS)

let books = [
    BookModel(bookCoverSource: "bookcover0.png", bookId: "0", bookTitle: "Book Title 0"),
    BookModel(bookCoverSource: "bookcover1.png", bookId: "1", bookTitle: "Book Title 1")
        ]
shelfView = PlainShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                           bookModel: books, bookSource: PlainShelfView.BOOK_SOURCE_DEVICE_LIBRARY)

let books = [
    BookModel(bookCoverSource: "bookcover0.png", bookId: "0", bookTitle: "Book Title 0"),
    BookModel(bookCoverSource: "bookcover1.png", bookId: "1", bookTitle: "Book Title 1")
        ]
shelfView = PlainShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                           bookModel: books, bookSource: PlainShelfView.BOOK_SOURCE_DEVICE_CACHE)

let books = [
    BookModel(bookCoverSource: "bookcover0.png", bookId: "0", bookTitle: "Book Title 0"),
    BookModel(bookCoverSource: "bookcover1.png", bookId: "1", bookTitle: "Book Title 1")
        ]
shelfView = PlainShelfView(frame: CGRect(x: 0, y: 0, width: 350, height: 500),
                           bookModel: books, bookSource: PlainShelfView.BOOK_SOURCE_RAW)