State machine improvements

Author: pblazej

Sources/LiveKit/Agent/Agent.swift

@@ -43,25 +43,40 @@ public struct Agent: Loggable {
 
     // MARK: - Transitions
 
+    mutating func disconnected() {
+        log("Agent disconnected from \(state)", .debug)
+        // From any state
+        state = .disconnected
+    }
+
+    mutating func failed(_ error: Error) {
+        log("Agent failed with error \(error) from \(state)")
+        // From any state
+        state = .failed(error)
+    }
+
     mutating func connecting() {
+        log("Agent connecting from \(state)")
         switch state {
-        case .disconnected:
+        case .disconnected, .connecting, .connected: // pre-connect is listening (connected)
             state = .connecting
         default:
             log("Invalid transition from \(state) to connecting", .warning)
         }
     }
 
     mutating func listening() {
+        log("Agent listening from \(state)")
         switch state {
-        case .disconnected, .connecting:
+        case .disconnected:
             state = .connected(agentState: .listening, audioTrack: nil, avatarVideoTrack: nil)
         default:
             log("Invalid transition from \(state) to listening", .warning)
         }
     }
 
     mutating func connected(participant: Participant) {
+        log("Agent connected to \(participant) from \(state)")
         switch state {
         case .connecting, .connected:
             state = .connected(agentState: participant.agentState,
@@ -72,15 +87,6 @@ public struct Agent: Loggable {
         }
     }
 
-    mutating func failed(_ error: Error) {
-        switch state {
-        case .disconnected, .connecting, .connected:
-            state = .failed(error)
-        default:
-            log("Invalid transition from \(state) to failed", .warning)
-        }
-    }
-
     // MARK: - Public
 
     public var isConnected: Bool {

Sources/LiveKit/Agent/Session.swift

@@ -143,25 +143,21 @@ open class Session: ObservableObject {
         Task { [weak self] in
             for try await _ in room.changes {
                 guard let self else { return }
-
-                connectionState = room.connectionState
-                agent = updatedAgent(in: room)
+                updateAgent(in: room)
             }
         }
     }
 
-    private func updatedAgent(in room: Room) -> Agent {
-        var agent = Agent()
-
-        if connectionState != .disconnected {
-            agent.connecting()
-        }
+    private func updateAgent(in room: Room) {
+        connectionState = room.connectionState
 
-        if let firstAgent = room.agentParticipants.values.first {
+        if connectionState == .disconnected {
+            agent.disconnected()
+        } else if let firstAgent = room.agentParticipants.values.first {
             agent.connected(participant: firstAgent)
+        } else {
+            agent.connecting()
         }
-
-        return agent
     }
 
     private func observe(receivers: [any MessageReceiver]) {

Sources/LiveKit/Support/ObservableObject+.swift

@@ -17,7 +17,7 @@
 @preconcurrency import Combine
 
 extension ObservableObject {
-    /// An async sequence that emits the `objectWillChange` events.
+    /// An async stream that emits the `objectWillChange` events.
     var changes: AsyncStream<Void> {
         AsyncStream { continuation in
             let cancellable = objectWillChange.sink { _ in