refactor(sessions): move session summary generation to startup (#14691)

packages/core/src/services/sessionSummaryUtils.ts

@@ -8,62 +8,172 @@ import type { Config } from '../config/config.js';
 import { SessionSummaryService } from './sessionSummaryService.js';
 import { BaseLlmClient } from '../core/baseLlmClient.js';
 import { debugLogger } from '../utils/debugLogger.js';
+import {
+  SESSION_FILE_PREFIX,
+  type ConversationRecord,
+} from './chatRecordingService.js';
+import fs from 'node:fs/promises';
+import path from 'node:path';
+
+const MIN_MESSAGES_FOR_SUMMARY = 1;
 
 /**
- * Generates and saves a summary for the current session.
- * This is called during session cleanup and is non-blocking - errors are logged but don't prevent exit.
+ * Generates and saves a summary for a session file.
  */
-export async function generateAndSaveSummary(config: Config): Promise<void> {
+async function generateAndSaveSummary(
+  config: Config,
+  sessionPath: string,
+): Promise<void> {
+  // Read session file
+  const content = await fs.readFile(sessionPath, 'utf-8');
+  const conversation: ConversationRecord = JSON.parse(content);
+
+  // Skip if summary already exists
+  if (conversation.summary) {
+    debugLogger.debug(
+      `[SessionSummary] Summary already exists for ${sessionPath}, skipping`,
+    );
+    return;
+  }
+
+  // Skip if no messages
+  if (conversation.messages.length === 0) {
+    debugLogger.debug(
+      `[SessionSummary] No messages to summarize in ${sessionPath}`,
+    );
+    return;
+  }
+
+  // Create summary service
+  const contentGenerator = config.getContentGenerator();
+  if (!contentGenerator) {
+    debugLogger.debug(
+      '[SessionSummary] Content generator not available, skipping summary generation',
+    );
+    return;
+  }
+  const baseLlmClient = new BaseLlmClient(contentGenerator, config);
+  const summaryService = new SessionSummaryService(baseLlmClient);
+
+  // Generate summary
+  const summary = await summaryService.generateSummary({
+    messages: conversation.messages,
+  });
+
+  if (!summary) {
+    debugLogger.warn(
+      `[SessionSummary] Failed to generate summary for ${sessionPath}`,
+    );
+    return;
+  }
+
+  // Re-read the file before writing to handle race conditions
+  const freshContent = await fs.readFile(sessionPath, 'utf-8');
+  const freshConversation: ConversationRecord = JSON.parse(freshContent);
+
+  // Check if summary was added by another process
+  if (freshConversation.summary) {
+    debugLogger.debug(
+      `[SessionSummary] Summary was added by another process for ${sessionPath}`,
+    );
+    return;
+  }
+
+  // Add summary and write back
+  freshConversation.summary = summary;
+  freshConversation.lastUpdated = new Date().toISOString();
+  await fs.writeFile(sessionPath, JSON.stringify(freshConversation, null, 2));
+  debugLogger.debug(
+    `[SessionSummary] Saved summary for ${sessionPath}: "${summary}"`,
+  );
+}
+
+/**
+ * Finds the most recently created session that needs a summary.
+ * Returns the path if it needs a summary, null otherwise.
+ */
+export async function getPreviousSession(
+  config: Config,
+): Promise<string | null> {
   try {
-    // Get the chat recording service from config
-    const chatRecordingService = config
-      .getGeminiClient()
-      ?.getChatRecordingService();
-    if (!chatRecordingService) {
-      debugLogger.debug('[SessionSummary] No chat recording service available');
-      return;
+    const chatsDir = path.join(config.storage.getProjectTempDir(), 'chats');
+
+    // Check if chats directory exists
+    try {
+      await fs.access(chatsDir);
+    } catch {
+      debugLogger.debug('[SessionSummary] No chats directory found');
+      return null;
     }
 
-    // Get the current conversation
-    const conversation = chatRecordingService.getConversation();
-    if (!conversation) {
-      debugLogger.debug('[SessionSummary] No conversation to summarize');
-      return;
+    // List session files
+    const allFiles = await fs.readdir(chatsDir);
+    const sessionFiles = allFiles.filter(
+      (f) => f.startsWith(SESSION_FILE_PREFIX) && f.endsWith('.json'),
+    );
+
+    if (sessionFiles.length === 0) {
+      debugLogger.debug('[SessionSummary] No session files found');
+      return null;
     }
 
-    // Skip if summary already exists (e.g., resumed session)
-    if (conversation.summary) {
-      debugLogger.debug('[SessionSummary] Summary already exists, skipping');
-      return;
+    // Sort by filename descending (most recently created first)
+    // Filename format: session-YYYY-MM-DDTHH-MM-XXXXXXXX.json
+    sessionFiles.sort((a, b) => b.localeCompare(a));
+
+    // Check the most recently created session
+    const mostRecentFile = sessionFiles[0];
+    const filePath = path.join(chatsDir, mostRecentFile);
+
+    try {
+      const content = await fs.readFile(filePath, 'utf-8');
+      const conversation: ConversationRecord = JSON.parse(content);
+
+      if (conversation.summary) {
+        debugLogger.debug(
+          '[SessionSummary] Most recent session already has summary',
+        );
+        return null;
+      }
+
+      // Only generate summaries for sessions with more than 1 user message
+      const userMessageCount = conversation.messages.filter(
+        (m) => m.type === 'user',
+      ).length;
+      if (userMessageCount <= MIN_MESSAGES_FOR_SUMMARY) {
+        debugLogger.debug(
+          `[SessionSummary] Most recent session has ${userMessageCount} user message(s), skipping (need more than ${MIN_MESSAGES_FOR_SUMMARY})`,
+        );
+        return null;
+      }
+
+      return filePath;
+    } catch {
+      debugLogger.debug('[SessionSummary] Could not read most recent session');
+      return null;
     }
+  } catch (error) {
+    debugLogger.debug(
+      `[SessionSummary] Error finding previous session: ${error instanceof Error ? error.message : String(error)}`,
+    );
+    return null;
+  }
+}
 
-    // Skip if no messages
-    if (conversation.messages.length === 0) {
-      debugLogger.debug('[SessionSummary] No messages to summarize');
-      return;
-    }
-
-    // Create summary service
-    const contentGenerator = config.getContentGenerator();
-    const baseLlmClient = new BaseLlmClient(contentGenerator, config);
-    const summaryService = new SessionSummaryService(baseLlmClient);
-
-    // Generate summary
-    const summary = await summaryService.generateSummary({
-      messages: conversation.messages,
-    });
-
-    // Save summary if generated successfully
-    if (summary) {
-      chatRecordingService.saveSummary(summary);
-      debugLogger.debug(`[SessionSummary] Saved summary: "${summary}"`);
-    } else {
-      debugLogger.warn('[SessionSummary] Failed to generate summary');
+/**
+ * Generates summary for the previous session if it lacks one.
+ * This is designed to be called fire-and-forget on startup.
+ */
+export async function generateSummary(config: Config): Promise<void> {
+  try {
+    const sessionPath = await getPreviousSession(config);
+    if (sessionPath) {
+      await generateAndSaveSummary(config, sessionPath);
     }
   } catch (error) {
     // Log but don't throw - we want graceful degradation
     debugLogger.warn(
-      `[SessionSummary] Error in generateAndSaveSummary: ${error instanceof Error ? error.message : String(error)}`,
+      `[SessionSummary] Error generating summary: ${error instanceof Error ? error.message : String(error)}`,
     );
   }
 }