// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

using System.Runtime.InteropServices;

namespace Swift.Runtime {
    /// <summary>
    /// Represents a Swift value type.
    /// </summary>
    public unsafe interface ISwiftValueType {
        byte* SwiftData { get; set; }
    }

    /// <summary>
    /// Represents a Swift enum.
    /// </summary>
    public interface ISwiftEnum : ISwiftValueType {
    }

    /// <summary>
    /// Represents a Swift struct.
    /// </summary>
    public interface ISwiftStruct : ISwiftValueType {
    }

    // <summary>
    // Represents Swift Unsafe[Mutable]RawPointer in C#.
    // </summary>
    public unsafe struct Unsafe[Mutable]RawPointer : ISwiftStruct
    {
        public byte* SwiftData { get; set; }
        public Unsafe[Mutable]RawPointer(void* p)
        {
            SwiftData = (byte*)p;
        }
    }

    // <summary>
    // Represents Swift Unsafe[Mutable]RawBufferPointer in C#.
    // </summary>
    public unsafe struct Unsafe[Mutable]RawBufferPointer : ISwiftStruct
    {
        public byte* SwiftData { get; set; }
        public Unsafe[Mutable]RawBufferPointer(void* start, int count)
        {
            SwiftData = (byte*)_Initialize(start, count);
        }

        ~Unsafe[Mutable]RawBufferPointer()
        {
            // Release memory
         }

        // <summary>
        // Represents init(start: UnsafeRawPointer?, count: Int)
        // https://developer.apple.com/documentation/swift/unsaferawbufferpointer/init(start:count:)
        // </summary>
        [DllImport("libSwiftCore.dylib", EntryPoint = "$sSR5start5countSRyxGSPyxGSg_Sitcfc")]
        internal static extern void* _Initialize (void* start, int count);
    }
}

[DllImport("libHelloLibrary.dylib", EntryPoint = "$s12HelloLibrary41AppleCryptoNative_ChaCha20Poly1305Encrypt6keyPtr0J6Length05nonceK00mL009plaintextK00nL016ciphertextBuffer0opL003tagP00qpL003aadK00rL0s5Int32VSv_APSvAPSvAPSvAPSvAPSvAPtF")]
internal static extern Int32 PIfunc_AppleCryptoNative_ChaCha20Poly1305Encrypt(void* keyPtr, Int32 keyLength, void* noncePtr, Int32 nonceLength, void* plaintextPtr, Int32 plaintextLength, void* ciphertextBuffer, Int32 ciphertextBufferLength, void* tagBuffer, Int32 tagBufferLength, void* aadPtr, Int32 aadLength);

public static unsafe Int32 AppleCryptoNative_ChaCha20Poly1305Encrypt(
    UnsafeRawPointer keyPtr, Int32 keyLength,
    UnsafeMutableRawPointer noncePtr, Int32 nonceLength,
    UnsafeMutableRawPointer plaintextPtr, Int32 plaintextLength,
    UnsafeMutableRawPointer ciphertextPtr, Int32 ciphertexLength,
    UnsafeMutableRawPointer tagPtr, Int32 tagLength,
    UnsafeMutableRawPointer aadPtr, Int32 aadLength)
{
    int result;

    fixed (void* pKeyPtr = keyPtr.SwiftData)
    fixed (void* pNoncePtr = noncePtr.SwiftData)
    fixed (void* pPlaintextPtr = plaintextPtr.SwiftData)
    fixed (void* pCiphertextBuffer = ciphertextPtr.SwiftData)
    fixed (void* pTagBuffer = tagPtr.SwiftData)
    fixed (void* pAadPtr = aadPtr.SwiftData)
    {
        result = PIfunc_AppleCryptoNative_ChaCha20Poly1305Encrypt(
            pKeyPtr, keyLength,
            pNoncePtr, nonceLength,
            pPlaintextPtr, plaintextLength,
            pCiphertextBuffer, ciphertextBufferLength,
            pTagBuffer, tagBufferLength,
            pAadPtr, aadLength);
    }

    return result;
}

var keyBuffer = new UnsafeMutableRawPointer(keyPtr);
var nonceBuffer = new UnsafeMutableRawPointer(noncePtr);
var plaintextBuffer = new UnsafeMutableRawPointer(plaintextPtr);
var ciphertextBuffer = new UnsafeMutableRawPointer(keyPtr);
var tagBuffer = new UnsafeMutableRawPointer(tagPtr);
var aadBuffer = new UnsafeMutableRawPointer(aadPtr);

int result = HelloLibrary.AppleCryptoNative_ChaCha20Poly1305Encrypt(
                    keyBuffer, key.Length,
                    nonceBuffer, nonce.Length,
                    plaintextBuffer, plaintext.Length,
                    ciphertextBuffer, ciphertext.Length,
                    tagBuffer, tag.Length,
                    aadBuffer, aad.Length);