Scorekeeper sharing: join from any sheet, show waiting requests, diagnostics

A guest was timing out with nothing ever shown on the host. Without a
device to look at, this makes the next test say where it stops, and fixes
what was found on the way.

- The host's Sharing panel shows links received and join requests read, which
  tells "nobody reached this phone" from "reached it and not understood".
- The guest says when its link is up and it is waiting for an answer.
- A request waiting shows on the host's top bar ("Sharing . 1 waiting"), and
  the Sharing panel steps aside while one is up so two dialogs never stack.
- Join is a top-bar action on a sheet already under way; it was only offered
  on an empty one.
- LanTransport: a host being cleaned up no longer unregisters the
  advertisement or clears the address of a newer host started in its place.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01CBG7URddsUZjQ6KE1Kqf6G

app/src/main/java/org/prolibertate/games/net/LanTransport.kt

@@ -135,11 +135,19 @@ class LanTransport(private val context: Context) : Transport {
 
         awaitClose {
             acceptJob.cancel()
-            stopAdvertising()
+            // Only what this call set up. Hosting stopped and started again
+            // runs this for the old host after the new one has begun, and
+            // letting it clear the shared fields would unregister the new
+            // host's advertisement and blank the address it shows.
+            runCatching { nsdManager.unregisterService(listener) }
+            if (registrationListener === listener) registrationListener = null
             runCatching { server.close() }
+            if (serverSocket === server) {
+                serverSocket = null
                 _endpoint.value = null
             }
         }
+    }
 
     // -----------------------------------------------------------------------
     // Discovery

app/src/main/java/org/prolibertate/games/net/ScorekeeperSession.kt

@@ -70,6 +70,13 @@ class ScorekeeperSession(
         val discovered: List<DiscoveredHost> = emptyList(),
         /** Host: where this device is listening, for reading out. */
         val endpoint: HostEndpoint? = null,
+        /**
+         * Host: links accepted, and hellos read off them. For telling "nobody
+         * reached this phone" from "they reached it and were not understood",
+         * which look the same from the other end.
+         */
+        val connections: Int = 0,
+        val hellos: Int = 0,
         val message: String? = null,
     )
 
@@ -142,6 +149,7 @@ class ScorekeeperSession(
     }
 
     private fun listenToGuest(connection: Connection) {
+        _state.update { it.copy(connections = it.connections + 1) }
         jobs += scope.launch {
             connection.incoming.collect { message ->
                 synchronized(lock) { onHostMessage(connection, message) }
@@ -192,6 +200,7 @@ class ScorekeeperSession(
     }
 
     private fun onHello(connection: Connection, hello: Hello) {
+        _state.update { it.copy(hellos = it.hellos + 1) }
         val refusal = when {
             hello.purpose != PURPOSE_SCOREKEEPER -> "That is a score sheet, not a game."
             hello.protocol != PROTOCOL_VERSION -> "Different app version — update both devices."
@@ -377,6 +386,7 @@ class ScorekeeperSession(
             link = connection
             heardBack = false
             replica.reset()
+            _state.update { it.copy(message = "Connected. Waiting for ${it.hostName} to answer…") }
         }
         val hello = Hello(peerId = deviceId, displayName = joinedName, purpose = PURPOSE_SCOREKEEPER)
         linkJob = scope.launch {

app/src/main/java/org/prolibertate/games/ui/ScorekeeperScreen.kt

@@ -173,6 +173,9 @@ fun ScorekeeperScreen(
         actions = {
             when (role) {
                 Role.NONE -> if (sheet.started && !joining) {
+                    // A sheet already on the go is no reason to hide the way to
+                    // somebody else's.
+                    TextButton(onClick = { joining = true }) { Text("Join") }
                     TextButton(onClick = {
                         session.startHosting(playerName, local)
                         showShare = true
@@ -182,7 +185,13 @@ fun ScorekeeperScreen(
 
                 Role.HOST -> {
                     TextButton(onClick = { showShare = true }) {
-                        Text(if (shared.guests.isEmpty()) "Sharing" else "Sharing (${shared.guests.size})")
+                        Text(
+                            when {
+                                shared.requests.isNotEmpty() -> "Sharing · ${shared.requests.size} waiting"
+                                shared.guests.isNotEmpty() -> "Sharing (${shared.guests.size})"
+                                else -> "Sharing"
+                            }
+                        )
                     }
                     if (sheet.started) {
                         TextButton(onClick = { confirmNewGame = true }) { Text("New game") }
@@ -259,7 +268,8 @@ fun ScorekeeperScreen(
                 onDeny = { session.deny(request.id) },
             )
         }
-        if (showShare) {
+        // Not under a request: two dialogs stacked is how an answer gets missed.
+        if (showShare && shared.requests.isEmpty()) {
             ShareDialog(
                 shared = shared,
                 onRemove = { session.remove(it) },

app/src/main/java/org/prolibertate/games/ui/ScorekeeperShareUi.kt

@@ -210,6 +210,10 @@ internal fun ShareDialog(
                         style = MaterialTheme.typography.bodySmall,
                     )
                 }
+                Text(
+                    text = "Links received: ${shared.connections} · join requests: ${shared.hellos}",
+                    style = MaterialTheme.typography.labelSmall,
+                )
                 Divider()
                 Text("On the sheet", fontWeight = FontWeight.Bold)
                 if (shared.guests.isEmpty()) {