PeerConnectiveChat/PCC.Shared/App/Tpm/TrustedPeerManager.cs

using System.Collections.Concurrent;
using Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets;
using PCC.App.Security;
using PCC.Common.AssemblyInject.Interfaces;
using PCC.Common.EventBus;

namespace PCC.App.Tpm;

// Handshake 1 → Public Key SHA256
// Handshake 2 ← ACK for Yes or No(close connection)
// *Complete Handshake

// SendText 1 → Payload
// SendText 2 ← ACK

// ACK: SHA256(incoming payload)

public abstract class TrustedPeerManager(IPeerInfoProvider peerInfoProvider, IEventBus eventBus, ILogger<TrustedPeerManager> logger) : IAssemblyInjectSyncInitStarStop
{
    private const int NONCE_LENGTH_BYTES = 16;
    private const int NONCE_EXPIRE_SECOND = 60;
    private const int NONCE_SKEW_SECOND = 30;

    private readonly SocketConnectionContextFactory _connectionContextFactory = new(new(), logger);

    private readonly ConcurrentDictionary<string, LocalPeerManager> _localPeers = new();

    private TimestampNonceManager? _nonceManager;

    public void Init()
    { }

    public void Start()
    {
        _nonceManager = new(NONCE_LENGTH_BYTES - TimestampNonceManager.TimestampLength, TimeSpan.FromMicroseconds(NONCE_EXPIRE_SECOND), TimeSpan.FromSeconds(NONCE_SKEW_SECOND));

        foreach (var item in peerInfoProvider.PeerInfo)
        {
            _localPeers[item.PeerId] = new LocalPeerManager(_connectionContextFactory, _nonceManager, item, eventBus, logger);
        }

        foreach (var item in _localPeers.Values) item.Start();
    }

    public void Stop()
    {
        foreach (var item in _localPeers.Values) item.Stop();

        _localPeers.Clear();

        _nonceManager?.Dispose();
    }

    public void AddOrReplaceLocalPeer(ILocalPeerInfo localPeerInfo)
    {
        RemoveLocalPeer(localPeerInfo.PeerId);
        _localPeers[localPeerInfo.PeerId] = new LocalPeerManager(_connectionContextFactory, _nonceManager, localPeerInfo, eventBus, logger);
    }

    public bool AddOrReplaceRemotePeer(string localPeerId, IRemotePeerInfo remotePeerInfo)
    {
        if (!_localPeers.TryGetValue(localPeerId, out var localPeerManager)) return false;
        localPeerManager.AddOrReplaceRemotePeer(remotePeerInfo);
        return true;
    }

    public bool RemoveLocalPeer(string localPeerId)
    {
        if (_localPeers.Remove(localPeerId, out var localPeerManager) == false) return false;
        localPeerManager.Stop();
        return true;
    }

    public bool RemoveRemotePeer(string localPeerId, string remotePeerId)
    {
        return _localPeers.TryGetValue(localPeerId, out var localPeerManager) && localPeerManager.RemoveRemotePeer(remotePeerId);
    }

    public bool ConnectToPeerAsync(string localPeerId, string remotePeerId)
    {
        return _localPeers.TryGetValue(localPeerId, out var localPeerManager) && localPeerManager.ConnectToRemotePeer(remotePeerId);
    }

    public bool SendToPeer(string localPeerId, string remotePeerId, byte[] payload)
    {
        return _localPeers.TryGetValue(localPeerId, out var localPeerManager) && localPeerManager.SendToRemotePeer(remotePeerId, payload);
    }
}