import Foundation

struct RawBooking: Codable { let id: String; let minutes: Int }
enum DecodeFailure: Error { case invalid }
func decodeBooking(_ data: Data) throws -> RawBooking {
    guard data.count <= 1024 else { throw DecodeFailure.invalid }
    let value = try JSONDecoder().decode(RawBooking.self, from: data)
    guard !value.id.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty,
          (1...240).contains(value.minutes) else { throw DecodeFailure.invalid }
    return value
}

@main
struct Lesson {
    static func main() {
        for raw in [#"{"id":"P-31","minutes":45}"#, #"{"id":"P-31","minutes":0}"#, #"{"id":"","minutes":30}"#] {
            do { let value = try decodeBooking(Data(raw.utf8)); print(value.id, value.minutes) }
            catch { print("refused") }
        }
    }
}