Swap Control and Target (#2311)

In circuit editing, when moving a control onto a target or vise-versa,
the control and target should swap positions.

![Swap control
target](https://github.com/user-attachments/assets/29a422d4-fc2c-4b5e-9021-2bdd946ad897)

This also fixes an issue with copy-moving controls. The behavior is now
that it will create a new control for the same operation and possibly
move the operation horizontally in the circuit.

![Copy-move
control](https://github.com/user-attachments/assets/462253ec-f7a1-453c-8b57-e2b744104755)

Author: ScottCarda-MS

npm/qsharp/ux/circuit-vis/circuitManipulation.ts

@@ -129,27 +129,49 @@ const _moveY = (
   movingControl: boolean,
 ): void => {
   // Check if the source operation already has a target or control on the target wire
-  let registers: Register[];
+  let targets: Register[];
   switch (sourceOperation.kind) {
     case "unitary":
-      registers = [
-        ...sourceOperation.targets,
-        ...(sourceOperation.controls || []),
-      ];
+    case "ket":
+      targets = sourceOperation.targets;
       break;
     case "measurement":
-      registers = [...sourceOperation.qubits, ...sourceOperation.results];
+      targets = sourceOperation.qubits;
+      break;
+  }
+
+  let controls: Register[];
+  switch (sourceOperation.kind) {
+    case "unitary":
+      controls = sourceOperation.controls || [];
       break;
+    case "measurement":
     case "ket":
-      registers = sourceOperation.targets;
+      controls = [];
       break;
   }
 
-  if (registers.find((target) => target.qubit === targetWire)) {
-    // If the target or control already exists, don't move the target/control
+  let likeRegisters: Register[];
+  let unlikeRegisters: Register[];
+  if (movingControl) {
+    likeRegisters = controls;
+    unlikeRegisters = targets;
+  } else {
+    likeRegisters = targets;
+    unlikeRegisters = controls;
+  }
+
+  // If a similar register already exists, don't move the gate
+  if (likeRegisters.find((reg) => reg.qubit === targetWire)) {
     return;
   }
 
+  // If a different kind of register already exists, swap the control and target
+  if (unlikeRegisters.find((reg) => reg.qubit === targetWire)) {
+    const index = unlikeRegisters.findIndex((reg) => reg.qubit === targetWire);
+    unlikeRegisters[index].qubit = sourceWire;
+  }
+
   switch (sourceOperation.kind) {
     case "unitary":
       if (movingControl) {

npm/qsharp/ux/circuit-vis/events.ts

@@ -483,7 +483,7 @@ class CircuitEvents {
                 targetLoc,
                 this.selectedWire,
                 targetWire,
-                false,
+                this.movingControl,
                 insertNewColumn,
               );
             } else {