Initial flame_lua_runtime package

lib/runtime/lifecycle/runtime_session.dart

@@ -0,0 +1,71 @@
+enum RuntimeSessionState { created, loading, active, disposing, disposed }
+
+class RuntimeSession {
+  RuntimeSession({required this.gameId}) : id = _nextId++;
+
+  static int _nextId = 1;
+
+  final int id;
+  final String gameId;
+  RuntimeSessionState _state = RuntimeSessionState.created;
+
+  RuntimeSessionState get state => _state;
+
+  bool get isLoading => _state == RuntimeSessionState.loading;
+
+  bool get isActive => _state == RuntimeSessionState.active;
+
+  bool get isDisposing => _state == RuntimeSessionState.disposing;
+
+  bool get isDisposed => _state == RuntimeSessionState.disposed;
+
+  bool get acceptsWork =>
+      _state != RuntimeSessionState.disposing &&
+      _state != RuntimeSessionState.disposed;
+
+  void beginLoading() {
+    _transition(
+      RuntimeSessionState.loading,
+      allowedFrom: const {RuntimeSessionState.created},
+    );
+  }
+
+  void activate() {
+    _transition(
+      RuntimeSessionState.active,
+      allowedFrom: const {
+        RuntimeSessionState.created,
+        RuntimeSessionState.loading,
+      },
+    );
+  }
+
+  void beginDisposing() {
+    if (_state == RuntimeSessionState.disposed ||
+        _state == RuntimeSessionState.disposing) {
+      return;
+    }
+    _state = RuntimeSessionState.disposing;
+  }
+
+  void dispose() {
+    _state = RuntimeSessionState.disposed;
+  }
+
+  bool accepts(int sessionId) => isActive && id == sessionId;
+
+  bool acceptsWorkFor(int sessionId) => acceptsWork && id == sessionId;
+
+  void _transition(
+    RuntimeSessionState next, {
+    required Set<RuntimeSessionState> allowedFrom,
+  }) {
+    if (_state == next) {
+      return;
+    }
+    if (!allowedFrom.contains(_state)) {
+      throw StateError('Invalid runtime session transition: $_state -> $next');
+    }
+    _state = next;
+  }
+}