Itunes category identifier model.

ItunesCategoryIdentifier.swift

enum ItunesCategoryIdentifier: Int, CaseIterable {

    // 1
    case apps
    case podcasts
    case tvShows

    // 2
    var title: String {
        switch self {
        case .apps: return "Apps From the Appstore"
        case .podcasts: return "Podcasts"
        case .music: return "Music"
        }
    }

    // 3
    private static let limit = 4 // the number of results that we want from each category.

    // 4
    var mediaType: MediaType {
        switch self {
        case .apps: return .apps(contentType: .apps, chart: .topFree, limit: Self.limit, format: .json)
        case .podcasts: return .podcasts(contentType: .episodes, chart: .top, limit: Self.limit, format: .json)
        case .music: return .music(contentType: .albums, chart: .mostPlayed, limit: Self.limit, format: .json)
        }
    }
}