// import Swift
// import Foundation
// import Security
import CryptoKit
import LocalAuthentication

// reference:
// https://zenn.dev/iceman/scraps/380f69137c7ea2
// https://www.andyibanez.com/posts/cryptokit-secure-enclave/
@_cdecl("is_support_secure_enclave")
func isSupportSecureEnclave() -> Bool {
    return SecureEnclave.isAvailable
}

@_cdecl("print_greeting")
func printGreeting(modifier: UnsafePointer<CChar>) {
    print("Hello \(String(cString: modifier))World!")
}

enum StringError: Error {
    case base64error
}

func generateKeyPair() throws {
    var error: Unmanaged<CFError>? = nil;
    guard let accessCtrl = SecAccessControlCreateWithFlags(
       nil,
       kSecAttrAccessibleWhenUnlockedThisDeviceOnly,
       [.privateKeyUsage, .biometryCurrentSet],
       &error
    ) else {
      throw error!.takeRetainedValue() as Swift.Error
    }
    var privateKeyReference = try CryptoKit.SecureEnclave.P256.KeyAgreement.PrivateKey.init(
       accessControl: accessCtrl
    );
    var dataRepresentation = privateKeyReference.dataRepresentation;
    print("Private key reference: \(privateKeyReference)");
    print("Private key reference - publicKey: \(privateKeyReference.publicKey)");
    print("Private key reference - dataRepresentation: \(privateKeyReference.dataRepresentation)");
    print("Private key reference - dataRepresentation: \(privateKeyReference.dataRepresentation.base64EncodedString())");
}

func computeEcdh() throws {
    guard let dataRepresentation = Data(base64Encoded: "BIIB2DGCAdQwgfUMAnJrMYHuMAsMA2JpZAQElx-----"
    ) else {
       throw StringError.base64error
    }

    let context = LAContext();
    let p =  try SecureEnclave.P256.KeyAgreement.PrivateKey(
            dataRepresentation: dataRepresentation, authenticationContext: context)

    let ephemeralSecretKey = P256.KeyAgreement.PrivateKey()
    let sharedSecret = try ephemeralSecretKey.sharedSecretFromKeyAgreement(with: p.publicKey)
    let sharedSecret2 = try p.sharedSecretFromKeyAgreement(with: ephemeralSecretKey.publicKey)
    print("Shared secret: \(sharedSecret)")
    print("Shared secret: \(sharedSecret2)")
}