Stable Codable extension for ChordType in Tonic

ChordType+Codable.swift

import Tonic
import Foundation

extension ChordType: Codable {
    public init(from decoder: Decoder) throws {
        let values = try decoder.container(keyedBy: CodingKeys.self)
        let chordKey = try values.decode(String.self, forKey: .chordKey)
        self.init(chordKey: chordKey)
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(self.chordKey, forKey: .chordKey)
    }
    
    public init(chordKey: String) {
        for chordType in ChordType.allCases {
            if chordKey == chordType.chordKey {
                self = chordType
                return
            }
        }
        
        // some default case
        self = ChordType.augmentedTriad
    }
    
    enum CodingKeys: String, CodingKey {
        case chordKey
    }
    
    
    /// by having a constant name, we can ensure that breaking changes don't happen due to integer value mismatch in ChordType (such as from adding additional cases, thus changing rawValues of ChordType)
    var chordKey: String {
        switch self {
        case .majorTriad: return "majorTriad"
        case .minorTriad: return "minorTriad"
        case .diminishedTriad: return "diminishedTriad"
        case .augmentedTriad: return "augmentedTriad"
        case .suspendedSecondTriad: return "suspended2Triad"
        case .suspendedFourthTriad: return "suspendedTriad" // leaving this since it was changed later
        case .sixth: return "sixth"
        case .minorSixth: return "minorSixth"
        case .halfDiminishedSeventh: return "halfDiminishedSeventh"
        case .diminishedSeventh: return "diminishedSeventh"
        case .dominantSeventh: return "dominantSeventh"
        case .majorSeventh: return "majorSeventh"
        case .minorSeventh: return "minorSeventh"
        case .minorMajorSeventh: return "minorMajorSeventh"
        case .halfDiminishedNinth: return "halfDiminishedNinth"
        case .dominantNinth: return "dominantNinth"
        case .flatNinth: return "flatNinth"
        case .sharpNinth: return "sharpNinth"
        case .majorNinth: return "majorNinth"
        case .minorNinth: return "minorNinth"
        case .minorFlatNinth: return "minorFlatNinth"
        case .majorAddNine: return "majorAddNine"
        case .minorAddNine: return "minorAddNine"
        case .sixOverNine: return "sixOverNine"
        case .majorEleventh: return "majorEleventh"
        case .dominantEleventh: return "dominantEleventh"
        case .minorEleventh: return "minorEleventh"
        case .halfDiminishedEleventh: return "halfDiminishedEleventh"
        case .majorSeventhFlatFifth: return "majorSeventhFlatFifth"
        case .minorSeventhSharpFifth: return "minorSeventhSharpFifth"
        case .majorNinthSharpEleventh: return "majorNinthSharpEleventh"
        case .dominantFlatFifth: return "dominantFlatFifth"
        case .dominantSharpFifth: return "dominantSharpFifth"
        case .dominantFlatNinthSharpEleventh: return "dominantFlatNinthSharpEleventh"
        case .dominantSharpNinthSharpEleventh: return "dominantSharpNinthSharpEleventh"
        case .minorSeventhFlatNinthAddEleventh: return "minorSeventhFlatNinthAddEleventh"
        case .majorThirteenth: return "majorThirteenth"
        case .minorThirteenth: return "minorThirteenth"
        case .minorFlatThirteenthFlatNinth: return "minorFlatThirteenthFlatNinth"
        case .majorThirteenthSharpEleventh: return "majorThirteenthSharpEleventh"
        case .dominantThirteenth: return "dominantThirteenth"
        case .minorEleventhFlatThirteenth: return "majorEleventhFlatThirteenth"
        case .halfDiminishedFlatThirteenth: return "halfDiminishedFlatThirteenth"
        }
    }
}