完善建模交互、组件图标与系统协议

app/simulation/systems/network.py

@@ -91,8 +91,10 @@ class SimulationNetwork:
     ) -> Connection:
         endpoint_a = Endpoint(endpoint_a_component, endpoint_a_port)
         endpoint_b = Endpoint(endpoint_b_component, endpoint_b_port)
-        if endpoint_a == endpoint_b:
-            raise ValueError(f"Cannot connect endpoint {endpoint_a} to itself.")
+        if endpoint_a.component == endpoint_b.component:
+            raise ValueError(
+                f"Cannot connect component {endpoint_a.component} to itself."
+            )
 
         first_port = self._port_for(endpoint_a)
         second_port = self._port_for(endpoint_b)
@@ -131,6 +133,16 @@ class SimulationNetwork:
                     + ", ".join(occupied)
                     + ". Use a junction component for branching."
                 )
+        else:
+            signal_input = (
+                endpoint_a
+                if first_definition.nominal_role == "input"
+                else endpoint_b
+            )
+            if signal_input in occupied_endpoints:
+                raise ValueError(
+                    f"Signal input {signal_input} already has a driver."
+                )
 
         if first_definition.kind == "physical" and endpoint_b.key < endpoint_a.key:
             endpoint_a, endpoint_b = endpoint_b, endpoint_a