feat(cli): export chat history in /bug and prefill GitHub issue (#16115)

packages/cli/src/ui/utils/historyExportUtils.ts

@@ -0,0 +1,79 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as fsPromises from 'node:fs/promises';
+import path from 'node:path';
+import type { Content } from '@google/genai';
+
+/**
+ * Serializes chat history to a Markdown string.
+ */
+export function serializeHistoryToMarkdown(history: Content[]): string {
+  return history
+    .map((item) => {
+      const text =
+        item.parts
+          ?.map((part) => {
+            if (part.text) {
+              return part.text;
+            }
+            if (part.functionCall) {
+              return (
+                `**Tool Command**:\n` +
+                '```json\n' +
+                JSON.stringify(part.functionCall, null, 2) +
+                '\n```'
+              );
+            }
+            if (part.functionResponse) {
+              return (
+                `**Tool Response**:\n` +
+                '```json\n' +
+                JSON.stringify(part.functionResponse, null, 2) +
+                '\n```'
+              );
+            }
+            return '';
+          })
+          .join('') || '';
+      const roleIcon = item.role === 'user' ? '🧑‍💻' : '✨';
+      return `## ${(item.role || 'model').toUpperCase()} ${roleIcon}\n\n${text}`;
+    })
+    .join('\n\n---\n\n');
+}
+
+/**
+ * Options for exporting chat history.
+ */
+export interface ExportHistoryOptions {
+  history: Content[];
+  filePath: string;
+}
+
+/**
+ * Exports chat history to a file (JSON or Markdown).
+ */
+export async function exportHistoryToFile(
+  options: ExportHistoryOptions,
+): Promise<void> {
+  const { history, filePath } = options;
+  const extension = path.extname(filePath).toLowerCase();
+
+  let content: string;
+  if (extension === '.json') {
+    content = JSON.stringify(history, null, 2);
+  } else if (extension === '.md') {
+    content = serializeHistoryToMarkdown(history);
+  } else {
+    throw new Error(
+      `Unsupported file extension: ${extension}. Use .json or .md.`,
+    );
+  }
+
+  const dir = path.dirname(filePath);
+  await fsPromises.mkdir(dir, { recursive: true });
+  await fsPromises.writeFile(filePath, content, 'utf-8');
+}