refactor telnet server and sessions into standalone types

cmd/server/main.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"io"
+	"log/slog"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"code.ndumas.com/ndumas/muddy/core"
+)
+
+func main() {
+	var (
+		level   string
+		logFile string
+	)
+
+	flag.StringVar(&level, "level", "INFO", "Log level: INFO/info, DEBUG/debug, or ERROR/error.")
+	flag.StringVar(&logFile, "log", "out.log", "Path to log file.")
+
+	flag.Parse()
+
+	f, err := os.Create(logFile)
+	if err != nil {
+		slog.With(
+			slog.Any("error", err),
+		).Error("could not open log file")
+		os.Exit(1)
+	}
+
+	appConfig := core.AppConfig{
+		Port: ":3001",
+
+		LogDest:  io.MultiWriter(f, os.Stderr),
+		LogLevel: level,
+
+		TickInterval: time.Millisecond * 30,
+	}
+
+	app := core.New(appConfig)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		<-c
+		cancel()
+	}()
+
+	app.Run(ctx)
+}

core/core.go

@@ -1,24 +1,35 @@
 package core
 
 import (
-	"bufio"
 	"context"
 	"io"
 	"log/slog"
-	"os"
 	"time"
 
 	"github.com/EngoEngine/ecs"
 )
 
+type Printer struct {
+}
+
+type AppConfig struct {
+	LogDest  io.Writer
+	LogLevel string
+
+	Port string
+
+	TickInterval time.Duration
+}
+
 type App struct {
-	W *ecs.World
-	L *slog.Logger
+	Config AppConfig
+	W      *ecs.World
+	L      *slog.Logger
 }
 
-func New(level string, logFile io.Writer) *App {
+func New(ac AppConfig) *App {
 	var logLevel slog.Level
-	switch level {
+	switch ac.LogLevel {
 	case "INFO", "info":
 		logLevel = slog.LevelInfo
 	case "DEBUG", "debug":
@@ -28,7 +39,7 @@ func New(level string, logFile io.Writer) *App {
 	}
 
 	l := slog.New(slog.NewTextHandler(
-		logFile, &slog.HandlerOptions{
+		ac.LogDest, &slog.HandlerOptions{
 			Level: logLevel,
 		},
 	),
@@ -37,34 +48,25 @@ func New(level string, logFile io.Writer) *App {
 	world := &ecs.World{}
 
 	return &App{
-		L: l,
-		W: world,
+		L:      l,
+		W:      world,
+		Config: ac,
 	}
 
 }
 
 func (a *App) Run(ctx context.Context) {
 	go func() {
-		t := time.NewTicker(time.Millisecond * 30)
+		t := time.NewTicker(a.Config.TickInterval)
 		for range t.C {
 			a.W.Update(1)
 		}
 	}()
 
-	scanner := bufio.NewScanner(os.Stdin)
-	var line string
-	for {
-		select {
-		case <-ctx.Done():
-			a.L.Error("cancelled")
-			return
-		default:
-			if scanner.Scan() {
-				line = scanner.Text()
-			}
-			a.L.Info("scanning input")
-			a.L.With(slog.String("input", line)).Info("received command")
-		}
-	}
+	s := NewServer(ctx, a.L, a.Config.Port)
+	go s.Start()
 
+	for session := range s.Sessions {
+		go session.Start()
+	}
 }

core/server.go

@@ -0,0 +1,94 @@
+package core
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"log/slog"
+	"net"
+)
+
+type Server struct {
+	l        *slog.Logger
+	port     string
+	ctx      context.Context
+	Sessions chan *Session
+	ln       net.Listener
+}
+
+func NewServer(ctx context.Context, l *slog.Logger, port string) *Server {
+	var s Server
+
+	// TODO: Check for context cancellation and cleanup
+
+	c := make(chan *Session)
+	s.Sessions = c
+	ln, err := net.Listen("tcp", port)
+	if err != nil {
+		s.l.With(
+			slog.Any("error", err),
+		).Error("could not start tcp listener")
+		return &s
+	}
+
+	s.ctx = ctx
+	s.ln = ln
+	s.l = l
+	s.port = port
+
+	return &s
+}
+
+func (s *Server) Start() {
+	s.l.Debug("starting telnet server")
+	// TODO: Check for context cancellation and cleanup
+	for {
+		conn, err := s.ln.Accept()
+		if err != nil {
+			s.l.With(
+				slog.Any("error", err),
+			).Error("could not accept tcp connection")
+		}
+		s.Sessions <- NewSession(s.ctx, conn, Printer{}, s.l)
+
+	}
+}
+
+type Session struct {
+	c   net.Conn
+	ctx context.Context
+	p   Printer
+	l   *slog.Logger
+
+	userID uint64
+}
+
+func NewSession(ctx context.Context, c net.Conn, p Printer, l *slog.Logger) *Session {
+	return &Session{
+		ctx: ctx,
+		l:   l,
+		p:   p,
+		c:   c,
+	}
+}
+
+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")
+			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")
+		}
+	}
+}