ios/BitwardenWatchApp/Entities/StringEncryptionTransformer.swift

import Foundation
import UIKit

@objc(StringEncryptionTransformer)
class StringEncryptionTransformer: ValueTransformer {
    var cryptoService: CryptoService = .init()

    override class func allowsReverseTransformation() -> Bool {
        true
    }

    override func transformedValue(_ value: Any?) -> Any? {
        var toEncrypt: String

        switch value {
        case let aString as String:
            toEncrypt = aString
        default:
            return nil
        }

        if let encryptedData = cryptoService.encrypt(toEncrypt) {
            return encryptedData
        }

        return nil
    }

    override func reverseTransformedValue(_ value: Any?) -> Any? {
        if let encryptedData = value as? Data {
            if let decryptedData = cryptoService.decrypt(encryptedData) {
                return String(decoding: decryptedData, as: UTF8.self)
            }
        }

        return nil
    }
}

extension StringEncryptionTransformer {
    static let name = NSValueTransformerName(rawValue: String(describing: StringEncryptionTransformer.self))

    /// Registers the value transformer with `ValueTransformer`.
    static func register() {
        let transformer = StringEncryptionTransformer()
        ValueTransformer.setValueTransformer(transformer, forName: name)
    }
}