FirestoreSessionStore

export class FirestoreSessionStore<S extends MyState = MyState> implements SessionStore<S> {
  private sessionsCollection: CollectionReference;
  private collectionPath: string = '/genkit_sessions';

  constructor(firestoreDb: Firestore) {
    this.sessionsCollection = firestoreDb.collection(this.collectionPath);
  }

  async get(sessionId: string): Promise<SessionData<S> | undefined> {
    try {
      const docRef = this.sessionsCollection.doc(sessionId);
      const docSnap = await docRef.get();

      if (!docSnap.exists) {
        return undefined;
      }

      // Data from Firestore directly matches FirestoreSessionDoc structure
      const firestoreDoc = docSnap.data() as FirestoreSessionDoc<S>;

      // Reconstruct SessionData. state.formattedRecipe is already an object.
      const sessionData: SessionData<S> = {
        id: firestoreDoc.id,
      };

      if (firestoreDoc.state !== undefined) {
        // No special conversion needed for state.formattedRecipe
        sessionData.state = firestoreDoc.state;
      }

      if (firestoreDoc.threads !== undefined) {
        sessionData.threads = firestoreDoc.threads;
      }

      return sessionData;
    } catch (error: any) {
      if (error.code === "5" || error.code === "404") {
        console.error(`Error fetching session '${sessionId}' from Firestore:`, error.code);
        return undefined;
      } else {
        throw new Error(String(error));
      }
    }
  }

  async save(sessionId: string, sessionData: SessionData<S>): Promise<void> {
    try {
      const docRef = this.sessionsCollection.doc(sessionId);

      // Data to save. state.formattedRecipe is already an object.
      const dataToSave: FirestoreSessionDoc<S> = {
        id: sessionId, // or sessionData.id
        updatedAt: FieldValue.serverTimestamp(),
      };

      if (sessionData.state !== undefined) {
        // No special conversion needed for state.formattedRecipe
        dataToSave.state = sessionData.state;
      }
      if (sessionData.threads !== undefined) {
        dataToSave.threads = sessionData.threads;
      }

      await docRef.set(dataToSave);

    } catch (error: any) {
      console.error(`Error saving session '${sessionId}' to Firestore:`, error.code);
      if (error.code === "5" || error.code === "404") {
        return undefined;
      } else {
        throw new Error(String(error));
      }
    }
  }
}