ScryfallAbstractionsExample

scryfall-example.swift

import Foundation

enum Result<Value> {
  case success(Value)
  case failure(Error)

  func promote() throws -> Value {
    switch self {
    case .success(let value):
      return value
    case .failure(let error):
      throw error
    }
  }
}

let scryfall = URL(string: "https://api.scryfall.com")!

/// Retreives JSON data from URL and parses it with JSON decoder. Thanks Mitchell
func parseResource<ResultType: Decodable>(call: String, completion: @escaping (Result<ResultType>) -> ()) {

  let url = scryfall.appendingPathComponent(call)
  let task = URLSession.shared.dataTask(with: url) { (data, response, error) in

    guard let content = data else {
      print("Error: There was no data returned from JSON file.")
      return
    }

    //print("\(String(data: content,encoding: .utf8))")

    let decoder = JSONDecoder()
    do {
      // Decode JSON file starting from Response struct.
      let decoded = try decoder.decode(ResultType.self, from: content)
      completion(.success(decoded))
    } catch {
      // Known Issues:
      //  * Too broad of a request (needs handler)
      //
      // Present an alert if the JSON data cannot be decoded.
      do {
        let decoded = try decoder.decode(ScryfallError.self, from: content)
        completion(.failure(decoded))
      } catch {
        completion(.failure(error))
      }
      return
    }
  }
  task.resume()
}

struct Card: Codable {}
struct SomethingElse: Codable {}

parseResource(call: "cards/named") { (result: Result<Card>) in

}

func synchronouslyGetResource<T: Decodable>(call: String) throws -> T {
  var result: Result<T>?
  let semaphore = DispatchSemaphore(value: 0)

  parseResource(call: call) { (res: Result<T>) in
    result = res
    semaphore.signal()
  }

  semaphore.wait()
  return try result!.promote()
}



let fuck: Fuck = try synchronouslyGetResource(call: "something-else")