feat(telnet): React to the current terminal size

Ref #35

internal/server/telnet.go

@@ -13,6 +13,7 @@ import (
 	"github.com/gabe565/ascii-movie/internal/server/idleconn"
 	"github.com/gabe565/ascii-movie/internal/server/telnet"
 	"github.com/gabe565/ascii-movie/internal/util"
+	"github.com/muesli/termenv"
 	flag "github.com/spf13/pflag"
 )
 
@@ -112,13 +113,20 @@ func (s *TelnetServer) Handler(ctx context.Context, conn net.Conn, m *movie.Movi
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	termCh := make(chan string)
+	termCh := make(chan telnet.TermInfo)
 	go func() {
 		// Proxy input to program
 		_ = telnet.Proxy(conn, inW, termCh)
 		cancel()
 	}()
-	profile := util.Profile(<-termCh)
+
+	var profile termenv.Profile
+	select {
+	case info := <-termCh:
+		profile = util.Profile(info.Term)
+	case <-time.After(250 * time.Millisecond):
+		profile = termenv.ANSI256
+	}
 
 	player := movie.NewPlayer(m, logger, profile)
 	program := tea.NewProgram(
@@ -129,8 +137,20 @@ func (s *TelnetServer) Handler(ctx context.Context, conn net.Conn, m *movie.Movi
 	)
 
 	go func() {
-		<-ctx.Done()
-		program.Send(movie.Quit())
+		for {
+			select {
+			case info := <-termCh:
+				if info.Width != 0 && info.Height != 0 {
+					program.Send(tea.WindowSizeMsg{
+						Width:  int(info.Width),
+						Height: int(info.Height),
+					})
+				}
+			case <-ctx.Done():
+				program.Send(movie.Quit())
+				return
+			}
+		}
 	}()
 
 	go func() {

internal/server/telnet/proxy.go

@@ -2,6 +2,8 @@ package telnet
 
 import (
 	"bufio"
+	"bytes"
+	"encoding/binary"
 	"errors"
 	"io"
 	"net"
@@ -11,8 +13,18 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-func Proxy(conn net.Conn, proxy io.Writer, termCh chan string) error {
+type TermInfo struct {
+	Term string
+	WindowSize
+}
+
+type WindowSize struct {
+	Width, Height uint16
+}
+
+func Proxy(conn net.Conn, proxy io.Writer, termCh chan TermInfo) error {
 	reader := bufio.NewReaderSize(conn, 64)
+	var info TermInfo
 	var wroteTelnetCommands bool
 	var wroteTermType bool
 
@@ -23,15 +35,6 @@ func Proxy(conn net.Conn, proxy io.Writer, termCh chan string) error {
 		return err
 	}
 
-	go func() {
-		time.Sleep(250 * time.Millisecond)
-		if !wroteTermType {
-			wroteTermType = true
-			log.Trace("Did not get terminal type in time")
-			close(termCh)
-		}
-	}()
-
 	for {
 		b, err := reader.ReadByte()
 		if err != nil {
@@ -48,6 +51,7 @@ func Proxy(conn net.Conn, proxy io.Writer, termCh chan string) error {
 					Iac, Will, Echo,
 					Iac, Will, SuppressGoAhead,
 					Iac, Do, TerminalType,
+					Iac, Do, NegotiateAboutWindowSize,
 				); err != nil {
 					log.WithError(err).Error("Failed to write Telnet commands")
 				}
@@ -77,10 +81,18 @@ func Proxy(conn net.Conn, proxy io.Writer, termCh chan string) error {
 					case TerminalType:
 						if len(command) > 5 && !wroteTermType {
 							wroteTermType = true
-							term := string(command[2 : len(command)-2])
+							info.Term = string(command[2 : len(command)-2])
 							log.Trace("Got terminal type")
-							termCh <- term
-							close(termCh)
+							termCh <- info
+						}
+					case NegotiateAboutWindowSize:
+						if len(command) > 5 {
+							log.Trace("Got window size")
+							r := bytes.NewReader(command[1 : len(command)-2])
+							if err := binary.Read(r, binary.BigEndian, &info.WindowSize); err != nil {
+								return err
+							}
+							termCh <- info
 						}
 					}
 				}