UKTrad.swift

import Foundation

enum Tech {
    case UK(level: Int, modifier: Character)
    
    init?(level: Int, modifier: Character) {
        if (4..<7 ~= level) && (find(["a", "b", "c"] as [Character], modifier) != nil) {
            self = .UK(level: level, modifier: modifier)
        } else {
            return nil
        }
    }
    
    var description: String {
        switch self {
        case let UK(level, modifier):
            return "\(level)\(modifier)"
        default:
            return "Bad UK tech grade"
        }
    }
}

enum Adjectival: Printable {
    case Diff, VeryDifficult, Severe, HardSevere, VerySevere, HardVerySevere, Extreme(level: Int), Error
    var description: String {
        switch self {
        case Diff:
            return "D"
        case VeryDifficult:
            return "VDiff"
        case Severe:
            return "S"
        case HardSevere:
            return "HS"
        case VerySevere:
            return "VS"
        case HardVerySevere:
            return "HVS"
        case let Extreme(level):
            return "E\(level)"
        default:
            return "Bad grade"
        }
    }
}

enum Grade: Printable {
    case UKTrad(adjectival: Adjectival, technical: Tech?)
    
    var description: String {
        switch self {
        case let UKTrad(adjectival, technical):
            if technical == nil {
                return adjectival.description
            }
            
            return "\(adjectival.description) \(technical!.description)"
        }
    }
}