using Renci.SshNet;

namespace McpSsh.Server.Ssh;

public interface ISshClientFactory
{
    SshClient CreateSshClient(SshConnectionRequest request);

    SftpClient CreateSftpClient(SshConnectionRequest request);

    ScpClient CreateScpClient(SshConnectionRequest request);
}

public sealed record SshConnectionRequest(
    string Host,
    string Username,
    int Port,
    string? KeyPath,
    string? KeyPassphrase,
    TimeSpan? Timeout = null);

public sealed class SshNetClientFactory : ISshClientFactory
{
    private readonly ISshKeyResolver _keyResolver;

    public SshNetClientFactory(ISshKeyResolver keyResolver)
    {
        _keyResolver = keyResolver;
    }

    public SshClient CreateSshClient(SshConnectionRequest request)
    {
        var client = new SshClient(CreateConnectionInfo(request));
        ApplyTimeout(client, request.Timeout);
        return client;
    }

    public SftpClient CreateSftpClient(SshConnectionRequest request)
    {
        var client = new SftpClient(CreateConnectionInfo(request));
        ApplyTimeout(client, request.Timeout);
        return client;
    }

    public ScpClient CreateScpClient(SshConnectionRequest request)
    {
        var client = new ScpClient(CreateConnectionInfo(request));
        ApplyTimeout(client, request.Timeout);
        return client;
    }

    private ConnectionInfo CreateConnectionInfo(SshConnectionRequest request)
    {
        var keyPath = _keyResolver.ResolveKeyPath(request.KeyPath);
        var keyFile = string.IsNullOrEmpty(request.KeyPassphrase)
            ? new PrivateKeyFile(keyPath)
            : new PrivateKeyFile(keyPath, request.KeyPassphrase);

        var auth = new PrivateKeyAuthenticationMethod(request.Username, keyFile);
        return new ConnectionInfo(request.Host, request.Port, request.Username, auth);
    }

    private static void ApplyTimeout(BaseClient client, TimeSpan? timeout)
    {
        if (timeout is { } value)
        {
            client.ConnectionInfo.Timeout = value;
        }
    }
}