Looking for server implementation

I would love for the server side of this to be implemented. I tried to see if I could put something together, as I noticed that the SSHTransport class has an "isServer" flag to conditionally act like a client or a server. I got a server kinda working, but when I try to connect with an OpenSSH client, it stalls on debug1: expecting SSH2_MSG_KEX_ECDH_REPLY. I'm really new to the SSH protocol, but I tried figuring out how to construct a reply using one of the kex reply classes, but I got stuck at figuring out what to fill out the fields with.

It looks like the server version of this is really close to working, and I'd help if I understood the SSH protocol more. I'm looking forward to eventually being able to have my server code respond to plaintext over the ssh connection. Thanks!