From 7a4d66bcf860549b8f73fbc5c72a4eaed2fbe61a Mon Sep 17 00:00:00 2001
From: Nick Dumas <drakonik@gmail.com>
Date: Sat, 24 Jan 2026 19:24:13 -0500
Subject: [PATCH] working telnet echo server

---
 core/core.go   |  9 +++++++--
 core/server.go | 48 +++++++++++++++++++++++++++++++++---------------
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/core/core.go b/core/core.go
index 0f5908d..35599d7 100644
--- a/core/core.go
+++ b/core/core.go
@@ -66,7 +66,12 @@ func (a *App) Run(ctx context.Context) {
 	s := NewServer(ctx, a.L, a.Config.Port)
 	go s.Start()
 
-	for session := range s.Sessions {
-		go session.Start()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case session := <-s.Sessions:
+			go session.Start()
+		}
 	}
 }
diff --git a/core/server.go b/core/server.go
index 4fdc535..71f22e2 100644
--- a/core/server.go
+++ b/core/server.go
@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"log/slog"
 	"net"
+
+	"github.com/google/uuid"
 )
 
 type Server struct {
@@ -64,31 +66,47 @@ type Session struct {
 }
 
 func NewSession(ctx context.Context, c net.Conn, p Printer, l *slog.Logger) *Session {
+	sid := uuid.New()
 	return &Session{
 		ctx: ctx,
-		l:   l,
-		p:   p,
+		l:   l.With(slog.String("sid", sid.String())),
 		c:   c,
 	}
 }
 
+func (s *Session) bufferInput(commands chan string) {
+	scanner := bufio.NewScanner(s.c)
+	defer close(commands)
+
+	for scanner.Scan() {
+		err := scanner.Err()
+		switch err {
+		case nil:
+			commands <- scanner.Text()
+		default:
+			s.l.With(slog.Any("error", scanner.Err())).Error("error scanning input")
+			return
+		}
+	}
+
+	s.l.Debug("session terminated")
+}
+
 func (s *Session) Start() {
 	s.l.Debug("starting telnet session")
 	fmt.Fprint(s.c, "Welcome to Bing Bong.\n")
-	scanner := bufio.NewScanner(s.c)
-	var line string
-	for {
-		select {
-		case <-s.ctx.Done():
-			s.l.Error("cancelled")
+
+	commands := make(chan string)
+	go s.bufferInput(commands)
+
+	for command := range commands {
+		s.l.With(slog.String("command", command)).Debug("command recieved")
+		_, err := fmt.Fprintf(s.c, "> %q\n", command)
+		if err != nil {
+			s.l.With(
+				slog.Any("error", err),
+			).Error("connection closed on write")
 			return
-		default:
-			if scanner.Scan() {
-				line = scanner.Text()
-				fmt.Fprintf(s.c, "> %q\n", line)
-			}
-			// a.L.Info("scanning input")
-			s.l.With(slog.String("input", line)).Info("received command")
 		}
 	}
 }