Fix alt-drag binding

Signed-off-by: Mark Tolmacs <mark@lazycat.hu>

packages/element/src/binding.ts

@@ -55,6 +55,7 @@ import { getBoundTextElement, handleBindTextResize } from "./textElement";
 import {
   isArrowElement,
   isBindableElement,
+  isBindingElement,
   isBoundToContainer,
   isElbowArrow,
   isFixedPointBinding,
@@ -1422,7 +1423,7 @@ const getLinearElementEdgeCoors = (
   );
 };
 
-export const fixBindingsAfterDuplication = (
+export const fixDuplicatedBindingsAfterDuplication = (
   newElements: ExcalidrawElement[],
   oldIdToDuplicatedId: Map<ExcalidrawElement["id"], ExcalidrawElement["id"]>,
   duplicatedElementsMap: NonDeletedSceneElementsMap,
@@ -1493,6 +1494,196 @@ export const fixBindingsAfterDuplication = (
   }
 };
 
+const fixReversedBindingsForBindables = (
+  original: ExcalidrawBindableElement,
+  duplicate: ExcalidrawBindableElement,
+  originalElements: Map<string, ExcalidrawElement>,
+  elementsWithClones: ExcalidrawElement[],
+  oldIdToDuplicatedId: Map<ExcalidrawElement["id"], ExcalidrawElement["id"]>,
+) => {
+  original.boundElements?.forEach((binding, idx) => {
+    if (binding.type !== "arrow") {
+      return;
+    }
+
+    const oldArrow = elementsWithClones.find((el) => el.id === binding.id);
+
+    if (!isBindingElement(oldArrow)) {
+      return;
+    }
+
+    if (originalElements.has(binding.id)) {
+      // Linked arrow is in the selection, so find the duplicate pair
+      const newArrowId = oldIdToDuplicatedId.get(binding.id) ?? binding.id;
+      const newArrow = elementsWithClones.find(
+        (el) => el.id === newArrowId,
+      )! as ExcalidrawArrowElement;
+
+      mutateElement(newArrow, {
+        startBinding:
+          oldArrow.startBinding?.elementId === binding.id
+            ? {
+                ...oldArrow.startBinding,
+                elementId: duplicate.id,
+              }
+            : newArrow.startBinding,
+        endBinding:
+          oldArrow.endBinding?.elementId === binding.id
+            ? {
+                ...oldArrow.endBinding,
+                elementId: duplicate.id,
+              }
+            : newArrow.endBinding,
+      });
+      mutateElement(duplicate, {
+        boundElements: [
+          ...(duplicate.boundElements ?? []).filter(
+            (el) => el.id !== binding.id && el.id !== newArrowId,
+          ),
+          {
+            type: "arrow",
+            id: newArrowId,
+          },
+        ],
+      });
+    } else {
+      // Linked arrow is outside the selection,
+      // so we move the binding to the duplicate
+      mutateElement(oldArrow, {
+        startBinding:
+          oldArrow.startBinding?.elementId === original.id
+            ? {
+                ...oldArrow.startBinding,
+                elementId: duplicate.id,
+              }
+            : oldArrow.startBinding,
+        endBinding:
+          oldArrow.endBinding?.elementId === original.id
+            ? {
+                ...oldArrow.endBinding,
+                elementId: duplicate.id,
+              }
+            : oldArrow.endBinding,
+      });
+      mutateElement(duplicate, {
+        boundElements: [
+          ...(duplicate.boundElements ?? []),
+          {
+            type: "arrow",
+            id: oldArrow.id,
+          },
+        ],
+      });
+      mutateElement(original, {
+        boundElements:
+          original.boundElements?.filter((_, i) => i !== idx) ?? null,
+      });
+    }
+  });
+};
+
+const fixReversedBindingsForArrows = (
+  original: ExcalidrawArrowElement,
+  duplicate: ExcalidrawArrowElement,
+  originalElements: Map<string, ExcalidrawElement>,
+  bindingProp: "startBinding" | "endBinding",
+  oldIdToDuplicatedId: Map<ExcalidrawElement["id"], ExcalidrawElement["id"]>,
+  elementsWithClones: ExcalidrawElement[],
+) => {
+  const oldBindableId = original[bindingProp]?.elementId;
+
+  if (oldBindableId) {
+    if (originalElements.has(oldBindableId)) {
+      // Linked element is in the selection
+      const newBindableId =
+        oldIdToDuplicatedId.get(oldBindableId) ?? oldBindableId;
+      const newBindable = elementsWithClones.find(
+        (el) => el.id === newBindableId,
+      ) as ExcalidrawBindableElement;
+      mutateElement(duplicate, {
+        [bindingProp]: {
+          ...original[bindingProp],
+          elementId: newBindableId,
+        },
+      });
+      mutateElement(newBindable, {
+        boundElements: [
+          ...(newBindable.boundElements ?? []).filter(
+            (el) => el.id !== original.id && el.id !== duplicate.id,
+          ),
+          {
+            id: duplicate.id,
+            type: "arrow",
+          },
+        ],
+      });
+    } else {
+      // Linked element is outside the selection
+      const originalBindable = elementsWithClones.find(
+        (el) => el.id === oldBindableId,
+      );
+      if (originalBindable) {
+        mutateElement(duplicate, {
+          [bindingProp]: original[bindingProp],
+        });
+        mutateElement(original, {
+          [bindingProp]: null,
+        });
+        mutateElement(originalBindable, {
+          boundElements: [
+            ...(originalBindable.boundElements?.filter(
+              (el) => el.id !== original.id,
+            ) ?? []),
+            {
+              id: duplicate.id,
+              type: "arrow",
+            },
+          ],
+        });
+      }
+    }
+  }
+};
+
+export const fixReversedBindings = (
+  originalElements: Map<string, ExcalidrawElement>,
+  elementsWithClones: ExcalidrawElement[],
+  oldIdToDuplicatedId: Map<ExcalidrawElement["id"], ExcalidrawElement["id"]>,
+) => {
+  for (const original of originalElements.values()) {
+    const duplicate = elementsWithClones.find(
+      (el) => el.id === oldIdToDuplicatedId.get(original.id),
+    )!;
+
+    if (isBindableElement(original) && isBindableElement(duplicate)) {
+      fixReversedBindingsForBindables(
+        original,
+        duplicate,
+        originalElements,
+        elementsWithClones,
+        oldIdToDuplicatedId,
+      );
+    } else if (isArrowElement(original) && isArrowElement(duplicate)) {
+      fixReversedBindingsForArrows(
+        original,
+        duplicate,
+        originalElements,
+        "startBinding",
+        oldIdToDuplicatedId,
+        elementsWithClones,
+      );
+      fixReversedBindingsForArrows(
+        original,
+        duplicate,
+        originalElements,
+        "endBinding",
+        oldIdToDuplicatedId,
+        elementsWithClones,
+      );
+    }
+  }
+};
+
 export const fixBindingsAfterDeletion = (
   sceneElements: readonly ExcalidrawElement[],
   deletedElements: readonly ExcalidrawElement[],

packages/element/src/duplicate.ts

@@ -36,7 +36,10 @@ import {
 
 import { getBoundTextElement, getContainerElement } from "./textElement";
 
-import { fixBindingsAfterDuplication } from "./binding";
+import {
+  fixDuplicatedBindingsAfterDuplication,
+  fixReversedBindings,
+} from "./binding";
 
 import type {
   ElementsMap,
@@ -381,12 +384,20 @@ export const duplicateElements = (
 
   // ---------------------------------------------------------------------------
 
-  fixBindingsAfterDuplication(
+  fixDuplicatedBindingsAfterDuplication(
     newElements,
     oldIdToDuplicatedId,
     duplicatedElementsMap as NonDeletedSceneElementsMap,
   );
 
+  if (reverseOrder) {
+    fixReversedBindings(
+      _idsOfElementsToDuplicate,
+      elementsWithClones,
+      oldIdToDuplicatedId,
+    );
+  }
+
   bindElementsToFramesAfterDuplication(
     elementsWithClones,
     oldElements,