refactor: move findCaretTokenIndex file to parser/common/utils

src/parser/common/basicParser.ts

@@ -9,7 +9,7 @@ import {
 } from 'antlr4ts';
 import { ParseTreeWalker, ParseTreeListener } from 'antlr4ts/tree';
 import { CandidatesCollection, CodeCompletionCore } from 'antlr4-c3';
-import { findCaretTokenIndex } from '../../utils/findCaretTokenIndex';
+import { findCaretTokenIndex } from './utils/findCaretTokenIndex';
 import {
     CaretPosition,
     Suggestions,

src/parser/common/utils/findCaretTokenIndex.ts

@@ -0,0 +1,34 @@
+import { Token } from 'antlr4ts';
+import { CaretPosition } from '../basic-parser-types';
+
+/**
+ * find token index via caret position (cursor position)
+ * @param caretPosition
+ * @param allTokens all the tokens
+ * @returns caretTokenIndex
+ */
+export function findCaretTokenIndex(caretPosition: CaretPosition, allTokens: Token[]) {
+    const { lineNumber: caretLine, column: caretCol } = caretPosition;
+    let left = 0;
+    let right = allTokens.length - 1;
+
+    while (left <= right) {
+        const mid = left + ((right - left) >> 1);
+        const token = allTokens[mid];
+        if (
+            token.line > caretLine ||
+            (token.line === caretLine && token.charPositionInLine + 1 >= caretCol)
+        ) {
+            right = mid - 1;
+        } else if (
+            token.line < caretLine ||
+            (token.line === caretLine &&
+                token.charPositionInLine + token.text.length + 1 < caretCol)
+        ) {
+            left = mid + 1;
+        } else {
+            return allTokens[mid].tokenIndex;
+        }
+    }
+    return null;
+}