Add delete commands for box brush, entity, and model instance

src/commands/delete-model-instance-command.ts

@@ -0,0 +1,82 @@
+import { createOpaqueId } from "../core/ids";
+import { cloneEditorSelection, type EditorSelection } from "../core/selection";
+import type { ToolMode } from "../core/tool-mode";
+import { cloneModelInstance, type ModelInstance } from "../assets/model-instances";
+
+import type { EditorCommand } from "./command";
+
+function selectionIncludesModelInstance(selection: EditorSelection, modelInstanceId: string): boolean {
+  return selection.kind === "modelInstances" && selection.ids.includes(modelInstanceId);
+}
+
+export function createDeleteModelInstanceCommand(modelInstanceId: string): EditorCommand {
+  let previousModelInstance: ModelInstance | null = null;
+  let previousSelection: EditorSelection | null = null;
+  let previousToolMode: ToolMode | null = null;
+
+  return {
+    id: createOpaqueId("command"),
+    label: "Delete model instance",
+    execute(context) {
+      const currentDocument = context.getDocument();
+      const currentModelInstance = currentDocument.modelInstances[modelInstanceId];
+
+      if (currentModelInstance === undefined) {
+        throw new Error(`Model instance ${modelInstanceId} does not exist.`);
+      }
+
+      if (previousModelInstance === null) {
+        previousModelInstance = cloneModelInstance(currentModelInstance);
+      }
+
+      if (previousSelection === null) {
+        previousSelection = cloneEditorSelection(context.getSelection());
+      }
+
+      if (previousToolMode === null) {
+        previousToolMode = context.getToolMode();
+      }
+
+      const nextModelInstances = {
+        ...currentDocument.modelInstances
+      };
+      delete nextModelInstances[modelInstanceId];
+
+      context.setDocument({
+        ...currentDocument,
+        modelInstances: nextModelInstances
+      });
+
+      if (selectionIncludesModelInstance(context.getSelection(), modelInstanceId)) {
+        context.setSelection({
+          kind: "none"
+        });
+      }
+
+      context.setToolMode("select");
+    },
+    undo(context) {
+      if (previousModelInstance === null) {
+        return;
+      }
+
+      const currentDocument = context.getDocument();
+
+      context.setDocument({
+        ...currentDocument,
+        modelInstances: {
+          ...currentDocument.modelInstances,
+          [previousModelInstance.id]: cloneModelInstance(previousModelInstance)
+        }
+      });
+
+      if (previousSelection !== null) {
+        context.setSelection(previousSelection);
+      }
+
+      if (previousToolMode !== null) {
+        context.setToolMode(previousToolMode);
+      }
+    }
+  };
+}