iTunes search lab

ItunesSearch

//: Playground - noun: a place where people can play

import Foundation
import PlaygroundSupport

var url = URL(string: "https://itunes.apple.com/search?")!

struct MusicTrack: Decodable {
    enum CodingKeys: String, CodingKey {
        case artistID = "artistId"
        case collectionID = "collectionId"
        case trackID = "trackId"
        case artistName
        case trackName
    }
    
    let artistID: Int
    let collectionID: Int
    let trackID: Int
    let artistName: String
    let trackName: String
}

struct StoreItemClientResponse: Decodable {
    let resultCount: Int
    let results: [MusicTrack]
}

enum QueryParameter {
    case term(String)
    case limit(Int)
    case entity(Entity)
    case country(Country)
    
    enum Country {
        case australia
        case us
        
        var countryCode: String {
            switch self {
            case .australia:
                return "AU"
            case .us:
                return "US"
            }
        }
    }
    
    enum Entity: String {
        case musicTrack
        case software
    }
    
    var queryItem: URLQueryItem {
        switch self {
        case let .term(value):
            return URLQueryItem(name: "term", value: value)
        case let .limit(value):
            return URLQueryItem(name: "limit", value: String(value))
        case let .entity(value):
            return URLQueryItem(name: "entity", value: value.rawValue)
        case let .country(value):
            return URLQueryItem(name: "country", value: value.countryCode)
        }
    }
}

func url(fromQueryParameters queryParameters: QueryParameter...) -> URL! {
    var components = URLComponents(url: url, resolvingAgainstBaseURL: true)
    components?.queryItems = queryParameters.map { $0.queryItem }
    return components?.url
}

func searchResult(forSearchTerm searchTerm: String, withCompletionHandler completionHandler: @escaping (Data) -> Void) {
    let escapedTerm = searchTerm.replacingOccurrences(of: " ", with: "+")
    let task = URLSession.shared.dataTask(with: url(fromQueryParameters: .term(escapedTerm), .limit(10), .entity(.musicTrack), .country(.australia))) { (data, response, error) in
        guard error == nil,
            let data = data else {
                return
        }
        
        completionHandler(data)
    }
    task.resume()
}

searchResult(forSearchTerm: "swift") { (data) in
//    print(String.init(data: data, encoding: String.Encoding.utf8))
    
    let decoder = JSONDecoder()
    let response = try! decoder.decode(StoreItemClientResponse.self, from: data)
    
    print(response.results)
}

PlaygroundPage.current.needsIndefiniteExecution = true