Fix for git issue 5657 to add lines of code added/removed telemetry (#5823)

Co-authored-by: Ravikant Agarwal <ravikantag@google.com>

packages/core/src/tools/diffOptions.ts

@@ -5,8 +5,61 @@
  */
 
 import * as Diff from 'diff';
+import { DiffStat } from './tools.js';
 
 export const DEFAULT_DIFF_OPTIONS: Diff.PatchOptions = {
   context: 3,
   ignoreWhitespace: true,
 };
+
+export function getDiffStat(
+  fileName: string,
+  oldStr: string,
+  aiStr: string,
+  userStr: string,
+): DiffStat {
+  const countLines = (patch: Diff.ParsedDiff) => {
+    let added = 0;
+    let removed = 0;
+    patch.hunks.forEach((hunk: Diff.Hunk) => {
+      hunk.lines.forEach((line: string) => {
+        if (line.startsWith('+')) {
+          added++;
+        } else if (line.startsWith('-')) {
+          removed++;
+        }
+      });
+    });
+    return { added, removed };
+  };
+
+  const patch = Diff.structuredPatch(
+    fileName,
+    fileName,
+    oldStr,
+    aiStr,
+    'Current',
+    'Proposed',
+    DEFAULT_DIFF_OPTIONS,
+  );
+  const { added: aiAddedLines, removed: aiRemovedLines } = countLines(patch);
+
+  const userPatch = Diff.structuredPatch(
+    fileName,
+    fileName,
+    aiStr,
+    userStr,
+    'Proposed',
+    'User',
+    DEFAULT_DIFF_OPTIONS,
+  );
+  const { added: userAddedLines, removed: userRemovedLines } =
+    countLines(userPatch);
+
+  return {
+    ai_added_lines: aiAddedLines,
+    ai_removed_lines: aiRemovedLines,
+    user_added_lines: userAddedLines,
+    user_removed_lines: userRemovedLines,
+  };
+}