feat(jam-session): add connection state management and update UI feedback for session status

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/core/jam/JamSessionService.kt

@@ -74,6 +74,9 @@ class JamSessionService(
     private val _localParticipantId = MutableStateFlow<String?>(null)
     val localParticipantId: StateFlow<String?> = _localParticipantId.asStateFlow()
 
+    private val _isConnected = MutableStateFlow(false)
+    val isConnected: StateFlow<Boolean> = _isConnected.asStateFlow()
+
     private val _incomingMessages = MutableSharedFlow<JamMessage>(extraBufferCapacity = 64)
     val incomingMessages = _incomingMessages.asSharedFlow()
 
@@ -174,7 +177,7 @@ class JamSessionService(
         return true
     }
 
-    suspend fun joinSession(offerSdp: String): String {
+    suspend fun joinSession(offerSdp: String, hostName: String? = null): String {
         log.i { "Joining jam session" }
         val participantName = resolveParticipantName(defaultPrefix = "Guest")
 
@@ -186,6 +189,13 @@ class JamSessionService(
         hostConnection = pc
         _role.value = JamRole.Guest
         _localParticipantId.value = "guest"
+        _participants.value = listOf(
+            JamParticipant(
+                id = "host",
+                displayName = hostName?.ifBlank { null } ?: "Host",
+                isHost = true,
+            )
+        )
         _isActive.value = true
 
         // The data channel arrives in-band from the host's offer via on_data_channel;
@@ -226,6 +236,7 @@ class JamSessionService(
         _role.value = null
         _participants.value = emptyList()
         _isActive.value = false
+        _isConnected.value = false
         _localParticipantId.value = null
     }
 
@@ -303,6 +314,7 @@ class JamSessionService(
 
         override fun onDataChannelOpen(label: String) {
             log.i { "[$guestId] Data channel '$label' open" }
+            _isConnected.value = true
         }
 
         override fun onDataChannelMessage(label: String, data: String) {
@@ -329,6 +341,7 @@ class JamSessionService(
 
         override fun onDataChannelOpen(label: String) {
             log.i { "Data channel '$label' open" }
+            _isConnected.value = true
         }
 
         override fun onDataChannelMessage(label: String, data: String) {

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/modules/jam/JamScreen.kt

@@ -295,13 +295,24 @@ private fun GuestSessionView(
         ParticipantsSection(state.participants)
 
         val answerLink = state.answerLink
-        if (answerLink == null) {
+        when {
+            state.isConnected -> {
+                Text(
+                    text = "Connected to the session",
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.primary,
+                )
+            }
+
+            answerLink == null -> {
                 Text(
                     text = "Connecting to the session...",
                     style = MaterialTheme.typography.bodyMedium,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
-        } else {
+            }
+
+            else -> {
                 Text(
                     text = "Almost there! Send your answer back to the host:",
                     style = MaterialTheme.typography.titleSmall,
@@ -313,6 +324,7 @@ private fun GuestSessionView(
                     onShare = { onShare(answerLink) },
                 )
             }
+        }
 
         LeaveButton(onLeave)
     }

composeApp/src/commonMain/kotlin/dev/krtirtho/spotube/modules/jam/JamViewModel.kt

@@ -37,6 +37,7 @@ import kotlinx.coroutines.launch
 
 data class JamUiState(
     val isActive: Boolean = false,
+    val isConnected: Boolean = false,
     val role: JamRole? = null,
     val participants: List<JamParticipant> = emptyList(),
     /** Host: deep link containing this session's SDP offer, ready to share. */
@@ -69,6 +70,7 @@ class JamViewModel(
                 _uiState.update {
                     it.copy(
                         isActive = active,
+                        isConnected = jamSession.isConnected.value,
                         role = jamSession.role.value,
                         participants = jamSession.participants.value,
                         inviteLink = if (!active) null else it.inviteLink,
@@ -84,6 +86,11 @@ class JamViewModel(
                 _uiState.update { it.copy(participants = participants) }
             }
         }
+        viewModelScope.launch {
+            jamSession.isConnected.collect { connected ->
+                _uiState.update { it.copy(isConnected = connected) }
+            }
+        }
         viewModelScope.launch {
             deepLinks.pendingLink.collect { link ->
                 handleDeepLink(link)
@@ -119,16 +126,17 @@ class JamViewModel(
 
     fun joinWithIncomingInvite() {
         val sdp = _uiState.value.incomingOfferSdp ?: return
-        join(sdp)
+        join(sdp, _uiState.value.incomingHostName)
     }
 
     fun joinWithPasted(input: String) {
-        val sdp = JamInviteCodec.extractSdp(input)
+        val parsed = JamInviteCodec.parse(input)
+        val sdp = parsed?.sdp ?: JamInviteCodec.extractSdp(input)
         if (sdp == null) {
             _uiState.update { it.copy(error = "That doesn't look like a valid jam invite.") }
             return
         }
-        join(sdp)
+        join(sdp, (parsed as? JamInviteLink.HostInvite)?.peerName)
     }
 
     /**
@@ -171,10 +179,10 @@ class JamViewModel(
         _uiState.update { it.copy(incomingOfferSdp = null, incomingHostName = null) }
     }
 
-    private fun join(offerSdp: String) {
+    private fun join(offerSdp: String, hostName: String? = null) {
         viewModelScope.launch {
             runCatching {
-                val answer = jamSession.joinSession(offerSdp)
+                val answer = jamSession.joinSession(offerSdp, hostName)
                 JamInviteCodec.buildGuestAnswer(localName(), answer)
             }.onSuccess { link ->
                 _uiState.update {