Tally follows MMO Stream (darkice connected) automatically

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

main.go

@@ -30,6 +30,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -55,6 +56,7 @@ var (
 	sourceName      = flag.String("source", "motu_mixminus.monitor", "PipeWire source sent to the guest")
 	hostLabel       = flag.String("host-label", "Host", "name the guest sees on host chat messages")
 	testPlayoutFile = flag.String("test-playout-file", "", "TEST ONLY: write guest audio to this raw file instead of the sink")
+	tallyAuto       = flag.Bool("tally-auto", true, "set the guest's tally from the MMO Stream app: ON AIR while any darkice is connected to its server")
 	stateDir        = flag.String("state", filepath.Join(os.Getenv("HOME"), ".local/state/guestlink"), "state directory (invite token)")
 )
 
@@ -82,16 +84,17 @@ func (w *wsConn) send(v any) {
 }
 
 type Hub struct {
-	mu        sync.Mutex
-	token     string
-	guest     *wsConn
-	guestName string
-	call      *Call
-	hosts     map[*wsConn]bool
-	chat      []chatMsg
-	onAir     bool // tally shown on the guest page; set by the host, never automatic
-	udp       *net.UDPConn
-	mux       ice.UDPMux
+	mu         sync.Mutex
+	token      string
+	guest      *wsConn
+	guestName  string
+	call       *Call
+	hosts      map[*wsConn]bool
+	chat       []chatMsg
+	onAir      bool // tally shown on the guest page (sign only, no audio effect)
+	streamLive bool // MMO Stream (darkice) currently connected, per watchStream
+	udp        *net.UDPConn
+	mux        ice.UDPMux
 }
 
 var hub = &Hub{hosts: map[*wsConn]bool{}}
@@ -131,6 +134,8 @@ func (h *Hub) stateLocked() map[string]any {
 		"guestOnline": h.guest != nil,
 		"guestName":   h.guestName,
 		"onAir":       h.onAir,
+		"tallyAuto":   *tallyAuto,
+		"streamLive":  h.streamLive,
 		"call":        nil,
 	}
 	if h.call != nil {
@@ -466,7 +471,7 @@ func hostWS(w http.ResponseWriter, r *http.Request) {
 			hub.token = randToken()
 			hub.chat = nil
 			hub.guestName = ""
-			hub.onAir = false
+			hub.onAir = *tallyAuto && hub.streamLive // a new session starts matching the stream
 			hub.saveToken()
 			hub.mu.Unlock()
 			log.Printf("new invite link created")
@@ -476,7 +481,7 @@ func hostWS(w http.ResponseWriter, r *http.Request) {
 			hub.kickGuest("The host closed this session.")
 			hub.mu.Lock()
 			hub.token = ""
-			hub.onAir = false
+			hub.onAir = *tallyAuto && hub.streamLive // a new session starts matching the stream
 			hub.saveToken()
 			hub.mu.Unlock()
 			log.Printf("invite link revoked")
@@ -492,15 +497,7 @@ func hostWS(w http.ResponseWriter, r *http.Request) {
 				g.send(map[string]any{"t": "callended"})
 			}
 		case "onair":
-			hub.mu.Lock()
-			hub.onAir = m.On
-			g := hub.guest
-			hub.mu.Unlock()
-			log.Printf("tally: on air %v", m.On)
-			if g != nil {
-				g.send(map[string]any{"t": "onair", "on": m.On})
-			}
-			hub.pushState()
+			hub.setTally(m.On, "set by host")
 		case "clearchat":
 			hub.mu.Lock()
 			hub.chat = nil
@@ -515,12 +512,86 @@ func hostWS(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// ---------------------------------------------------------------- automatic tally
+
+// streamLive reports whether any darkice process (launched by mmo-stream) holds an
+// established TCP connection, i.e. a stream server accepted it. That is the same moment
+// mmo-stream shows LIVE. Read-only: it never touches mmo-stream or darkice.
+func streamLive() (bool, error) {
+	out, err := exec.Command("ss", "-Htnp", "state", "established").Output()
+	if err != nil {
+		return false, err
+	}
+	return strings.Contains(string(out), `(("darkice",`), nil
+}
+
+// setTally sets the tally and tells the guest and the consoles.
+func (h *Hub) setTally(on bool, why string) {
+	h.mu.Lock()
+	changed := h.onAir != on
+	h.onAir = on
+	g := h.guest
+	h.mu.Unlock()
+	if !changed {
+		return
+	}
+	log.Printf("tally: on air %v (%s)", on, why)
+	if g != nil {
+		g.send(map[string]any{"t": "onair", "on": on})
+	}
+	h.pushState()
+}
+
+// watchStream follows the stream state. It acts only on a CHANGE of stream state, so a
+// manual click on the console sticks until the stream next connects or stops. ON after two
+// polls (a refused connection is open for a moment), OFF after 15 s down, which rides out
+// mmo-stream's 5 s reconnect.
+func watchStream() {
+	const poll = 2 * time.Second
+	live, upPolls, downSince := false, 0, time.Time{}
+	for range time.Tick(poll) {
+		up, err := streamLive()
+		if err != nil {
+			continue
+		}
+		if up {
+			upPolls++
+			downSince = time.Time{}
+			if !live && upPolls >= 2 {
+				live = true
+				hub.setStreamLive(true)
+				hub.setTally(true, "MMO Stream connected")
+			}
+		} else {
+			upPolls = 0
+			if downSince.IsZero() {
+				downSince = time.Now()
+			}
+			if live && time.Since(downSince) >= 15*time.Second {
+				live = false
+				hub.setStreamLive(false)
+				hub.setTally(false, "MMO Stream stopped")
+			}
+		}
+	}
+}
+
+func (h *Hub) setStreamLive(v bool) {
+	h.mu.Lock()
+	h.streamLive = v
+	h.mu.Unlock()
+	h.pushState()
+}
+
 // ---------------------------------------------------------------- main
 
 func main() {
 	flag.Parse()
 	log.SetFlags(log.LstdFlags)
 	hub.loadToken()
+	if *tallyAuto {
+		go watchStream()
+	}
 
 	udp, err := net.ListenUDP("udp4", &net.UDPAddr{Port: *udpPort})
 	if err != nil {