feat: Display action menu, containing insert action, for stack connections (#209)

* style: Use === instead of ==

* refactor: openActionMenu

  - Always call .openActionMenu() from the menu shortcut handler,
    regardless of the type of the current node; let openActionMenu
    decide if the action menu can be opened or not.

  - Pass workspace instead of curNode to .openActionMenu().

  - Remove extraneous call to BlockSvg.prototype.showContextMenu()
    at the top of .openActionMenu that seems to have been left in
    accidentally while debugging PR #158, and that made the rest
    of the body of the method redundant.

* feat: Make insert action compatible with stack connections

  Doesn't necessarily work properly with connections yet, but
  at least can appear in the action menu for them.

* feat: Show action menu for NEXT/PREVIOUS connections

Author: cpcallen

src/navigation.ts

@@ -724,22 +724,22 @@ export class Navigation {
       // Connect the moving block to the stationary connection using
       // the most plausible connection on the moving block.
       if (
-        movingType == Blockly.ASTNode.types.BLOCK ||
-        movingType == Blockly.ASTNode.types.STACK
+        movingType === Blockly.ASTNode.types.BLOCK ||
+        movingType === Blockly.ASTNode.types.STACK
       ) {
         const stationaryAsConnection =
           stationaryLoc as Blockly.RenderedConnection;
         const movingAsBlock = movingLoc as Blockly.BlockSvg;
         return this.insertBlock(movingAsBlock, stationaryAsConnection);
       }
-    } else if (stationaryType == Blockly.ASTNode.types.WORKSPACE) {
+    } else if (stationaryType === Blockly.ASTNode.types.WORKSPACE) {
       const block = movingNode
         ? (movingNode.getSourceBlock() as Blockly.BlockSvg)
         : null;
       return this.moveBlockToWorkspace(block, stationaryNode);
     } else if (
-      stationaryType == Blockly.ASTNode.types.BLOCK &&
-      movingType == Blockly.ASTNode.types.BLOCK
+      stationaryType === Blockly.ASTNode.types.BLOCK &&
+      movingType === Blockly.ASTNode.types.BLOCK
     ) {
       // Insert the moving block above the stationary block, if the
       // appropriate connections exist.
@@ -783,19 +783,19 @@ export class Navigation {
     const cursorType = cursorNode.getType();
 
     // Check the marker for invalid types.
-    if (markerType == Blockly.ASTNode.types.FIELD) {
+    if (markerType === Blockly.ASTNode.types.FIELD) {
       this.warn('Should not have been able to mark a field.');
       return false;
-    } else if (markerType == Blockly.ASTNode.types.STACK) {
+    } else if (markerType === Blockly.ASTNode.types.STACK) {
       this.warn('Should not have been able to mark a stack.');
       return false;
     }
 
     // Check the cursor for invalid types.
-    if (cursorType == Blockly.ASTNode.types.FIELD) {
+    if (cursorType === Blockly.ASTNode.types.FIELD) {
       this.warn('Cannot attach a field to anything else.');
       return false;
-    } else if (cursorType == Blockly.ASTNode.types.WORKSPACE) {
+    } else if (cursorType === Blockly.ASTNode.types.WORKSPACE) {
       this.warn('Cannot attach a workspace to anything else.');
       return false;
     }
@@ -1255,9 +1255,9 @@ export class Navigation {
     if (!cursor) return;
     const curNode = cursor.getCurNode();
     const nodeType = curNode.getType();
-    if (nodeType == Blockly.ASTNode.types.FIELD) {
+    if (nodeType === Blockly.ASTNode.types.FIELD) {
       (curNode.getLocation() as Blockly.Field).showEditor();
-    } else if (nodeType == Blockly.ASTNode.types.BLOCK) {
+    } else if (nodeType === Blockly.ASTNode.types.BLOCK) {
       const block = curNode.getLocation() as Blockly.Block;
       if (!tryShowFullBlockFieldEditor(block)) {
         const metaKey = navigator.platform.startsWith('Mac') ? 'Cmd' : 'Ctrl';
@@ -1271,10 +1271,10 @@ export class Navigation {
       }
     } else if (
       curNode.isConnection() ||
-      nodeType == Blockly.ASTNode.types.WORKSPACE
+      nodeType === Blockly.ASTNode.types.WORKSPACE
     ) {
       this.openToolboxOrFlyout(workspace);
-    } else if (nodeType == Blockly.ASTNode.types.STACK) {
+    } else if (nodeType === Blockly.ASTNode.types.STACK) {
       this.warn('Cannot mark a stack.');
     }
   }
@@ -1294,55 +1294,90 @@ export class Navigation {
   }
 
   /**
-   * Show the action menu for a given node.
+   * Show the action menu for the current node.
    *
    * The action menu will contain entries for relevant actions for the
    * node's location.  If the location is a block, this will include
    * the contents of the block's context menu (if any).
+   *
+   * Returns true if it is possible to open the action menu in the
+   * current location, even if the menu was not opened due there being
+   * no applicable menu items.
    */
-  openActionMenu(node: Blockly.ASTNode) {
-    const fakeEvent = fakeEventForNode(node);
-    (node.getLocation() as Blockly.BlockSvg).showContextMenu(fakeEvent);
-
+  openActionMenu(workspace: Blockly.WorkspaceSvg): boolean {
     let menuOptions: Array<
       | Blockly.ContextMenuRegistry.ContextMenuOption
       | Blockly.ContextMenuRegistry.LegacyContextMenuOption
-    > | null = null;
+    > = [];
     let rtl: boolean;
-    let workspace: Blockly.WorkspaceSvg;
 
+    const cursor = workspace.getCursor();
+    if (!cursor) throw new Error('workspace has no cursor');
+    const node = cursor.getCurNode();
     const nodeType = node.getType();
     switch (nodeType) {
       case Blockly.ASTNode.types.BLOCK:
         const block = node.getLocation() as Blockly.BlockSvg;
-        workspace = block.workspace as Blockly.WorkspaceSvg;
         rtl = block.RTL;
-
         // Reimplement BlockSvg.prototype.generateContextMenu as that
         // method is protected.
-        if (!workspace.options.readOnly && !block.contextMenu) {
+        if (!workspace.options.readOnly && block.contextMenu) {
           menuOptions =
             Blockly.ContextMenuRegistry.registry.getContextMenuOptions(
               Blockly.ContextMenuRegistry.ScopeType.BLOCK,
               {block},
             );
 
           // Allow the block to add or modify menuOptions.
-          if (block.customContextMenu) {
-            block.customContextMenu(menuOptions);
-          }
+          block.customContextMenu?.(menuOptions);
         }
         // End reimplement.
         break;
+
+      // case Blockly.ASTNode.types.INPUT:
+      case Blockly.ASTNode.types.NEXT:
+      case Blockly.ASTNode.types.PREVIOUS:
+        const connection = node.getLocation() as Blockly.Connection;
+        rtl = connection.getSourceBlock().RTL;
+
+        // Slightly hacky: get insert action from registry.  Hacky
+        // because registry typings don't include {connection: ...} as
+        // a possible kind of scope.
+        const insertAction =
+          Blockly.ContextMenuRegistry.registry.getItem('insert');
+        if (!insertAction) throw new Error("can't find insert action");
+        const possibleOptions = [insertAction /* etc.*/];
+
+        // Check preconditions and get menu texts.
+        const scope = {
+          connection,
+        } as unknown as Blockly.ContextMenuRegistry.Scope;
+        for (const option of possibleOptions) {
+          const precondition = option.preconditionFn(scope);
+          if (precondition === 'hidden') continue;
+          const displayText =
+            typeof option.displayText === 'function'
+              ? option.displayText(scope)
+              : option.displayText;
+          menuOptions.push({
+            text: displayText,
+            enabled: precondition === 'enabled',
+            callback: option.callback,
+            scope,
+            weight: option.weight,
+          });
+        }
+        break;
+
       default:
-        throw new TypeError(
-          `unable to show action menu for ASTNode of type ${nodeType}`,
-        );
+        console.info(`No action menu for ASTNode of type ${nodeType}`);
+        return false;
     }
 
-    if (!menuOptions || !menuOptions.length) return;
-
+    if (!menuOptions?.length) return true;
+    const fakeEvent = fakeEventForNode(node);
     Blockly.ContextMenu.show(fakeEvent, menuOptions, rtl, workspace);
+    return true;
   }
 
   /**
@@ -1411,12 +1446,29 @@ export class Navigation {
  * Create a fake PointerEvent for opening the action menu for the
  * given ASTNode.
  *
- * Currently only works for block nodes.
- *
  * @param node The node to open the action menu for.
  * @returns A synthetic pointerdown PointerEvent.
  */
 function fakeEventForNode(node: Blockly.ASTNode): PointerEvent {
+  switch (node.getType()) {
+    case Blockly.ASTNode.types.BLOCK:
+      return fakeEventForBlockNode(node);
+    case Blockly.ASTNode.types.NEXT:
+    case Blockly.ASTNode.types.PREVIOUS:
+      return fakeEventForStackNode(node);
+    default:
+      throw new TypeError('unhandled node type');
+  }
+}
+
+/**
+ * Create a fake PointerEvent for opening the action menu for the
+ * given ASTNode of type BLOCK.
+ *
+ * @param node The node to open the action menu for.
+ * @returns A synthetic pointerdown PointerEvent.
+ */
+function fakeEventForBlockNode(node: Blockly.ASTNode): PointerEvent {
   if (node.getType() !== Blockly.ASTNode.types.BLOCK) {
     throw new TypeError('can only create PointerEvents for BLOCK nodes');
   }
@@ -1449,6 +1501,36 @@ function fakeEventForNode(node: Blockly.ASTNode): PointerEvent {
   });
 }
 
+/**
+ * Create a fake PointerEvent for opening the action menu for the
+ * given ASTNode of type NEXT or PREVIOUS.
+ *
+ * For now this just puts the action menu in the same place as the
+ * context menu for the source block.
+ *
+ * @param node The node to open the action menu for.
+ * @returns A synthetic pointerdown PointerEvent.
+ */
+function fakeEventForStackNode(node: Blockly.ASTNode): PointerEvent {
+  if (
+    node.getType() !== Blockly.ASTNode.types.NEXT &&
+    node.getType() !== Blockly.ASTNode.types.PREVIOUS
+  ) {
+    throw new TypeError(
+      'can only create PointerEvents for NEXT / PREVIOUS nodes',
+    );
+  }
+
+  const connection = node.getLocation() as Blockly.Connection;
+
+  return fakeEventForBlockNode(
+    new Blockly.ASTNode(
+      Blockly.ASTNode.types.BLOCK,
+      connection.getSourceBlock(),
+    ),
+  );
+}
+
 /**
  * If this block has a full block field then show its editor.
  *