Monaco: check suggestions against current word (#25992)

* trigger on current word

* proper index

* test suggestsions

* test suggestsions

* fix test

packages/grafana-ui/src/components/Monaco/suggestions.test.ts

+import { findInsertIndex } from './suggestions';
+
+describe('Check suggestion index', () => {
+  it('find last $ sign', () => {
+    const line = ' hello $123';
+    const { index, prefix } = findInsertIndex(line);
+    expect(index).toEqual(line.indexOf('$'));
+    expect(prefix).toEqual('$123');
+  });
+
+  it('insert into empty line', () => {
+    const line = '';
+    const { index, prefix } = findInsertIndex(line);
+    expect(index).toEqual(0);
+    expect(prefix).toEqual('');
+  });
+
+  it('insert new word', () => {
+    const line = 'this is a new ';
+    const { index, prefix } = findInsertIndex(line);
+    expect(index).toEqual(line.length);
+    expect(prefix).toEqual('');
+  });
+
+  it('complte a simple word', () => {
+    const line = 'SELECT * FROM tab';
+    const { index, prefix } = findInsertIndex(line);
+    expect(index).toEqual(line.lastIndexOf(' ') + 1);
+    expect(prefix).toEqual('tab');
+  });
+
+  it('complete a quoted word', () => {
+    const line = 'SELECT "hello", "wo';
+    const { index, prefix } = findInsertIndex(line);
+    expect(index).toEqual(line.lastIndexOf('"') + 1);
+    expect(prefix).toEqual('wo');
+  });
+});

packages/grafana-ui/src/components/Monaco/suggestions.ts

@@ -2,6 +2,33 @@ import * as monaco from 'monaco-editor/esm/vs/editor/editor.api';
 
 import { CodeEditorSuggestionItem, CodeEditorSuggestionItemKind, CodeEditorSuggestionProvider } from './types';
 
+/**
+ * @internal -- only exported for tests
+ */
+export function findInsertIndex(line: string): { index: number; prefix: string } {
+  for (let i = line.length - 1; i > 0; i--) {
+    const ch = line.charAt(i);
+    if (ch === '$') {
+      return {
+        index: i,
+        prefix: line.substring(i),
+      };
+    }
+
+    // Keep these seperators
+    if (ch === ' ' || ch === '\t' || ch === '"' || ch === "'") {
+      return {
+        index: i + 1,
+        prefix: line.substring(i + 1),
+      };
+    }
+  }
+  return {
+    index: 0,
+    prefix: line,
+  };
+}
+
 function getCompletionItems(
   prefix: string,
   suggestions: CodeEditorSuggestionItem[],
@@ -53,51 +80,39 @@ export function registerSuggestions(
     triggerCharacters: ['$'],
 
     provideCompletionItems: (model, position, context) => {
+      const range = {
+        startLineNumber: position.lineNumber,
+        endLineNumber: position.lineNumber,
+        startColumn: position.column,
+        endColumn: position.column,
+      };
+
+      // Simple check if this was triggered by pressing `$`
       if (context.triggerCharacter === '$') {
-        const range = {
-          startLineNumber: position.lineNumber,
-          endLineNumber: position.lineNumber,
-          startColumn: position.column - 1,
-          endColumn: position.column,
-        };
+        range.startColumn = position.column - 1;
         return {
           suggestions: getCompletionItems('$', getSuggestions(), range),
         };
       }
 
-      // find out if we are completing a property in the 'dependencies' object.
-      const lineText = model.getValueInRange({
+      // Find the replacement region
+      const currentLine = model.getValueInRange({
         startLineNumber: position.lineNumber,
         startColumn: 1,
         endLineNumber: position.lineNumber,
         endColumn: position.column,
       });
 
-      const idx = lineText.lastIndexOf('$');
-      if (idx >= 0) {
-        const range = {
-          startLineNumber: position.lineNumber,
-          endLineNumber: position.lineNumber,
-          startColumn: idx, // the last $ we found
-          endColumn: position.column,
-        };
-        return {
-          suggestions: getCompletionItems(lineText.substr(idx), getSuggestions(), range),
-        };
-      }
+      const { index, prefix } = findInsertIndex(currentLine);
+      range.startColumn = index + 1;
 
-      // Empty line that asked for suggestion
-      if (lineText.trim().length < 1) {
-        return {
-          suggestions: getCompletionItems('', getSuggestions(), {
-            startLineNumber: position.lineNumber,
-            endLineNumber: position.lineNumber,
-            startColumn: position.column,
-            endColumn: position.column,
-          }),
-        };
+      const suggestions = getCompletionItems(prefix, getSuggestions(), range);
+      if (suggestions.length) {
+        // NOTE, this will replace any language provided suggestions
+        return { suggestions };
       }
-      // console.log('complete?', lineText, context);
+
+      // Default language suggestions
       return undefined;
     },
   });