Update app.py

app.py

@@ -36,7 +36,7 @@ import typing_extensions as typing
 import nest_asyncio
 nest_asyncio.apply()
 
-# Import Vertex AI SDK and Google service account credentials support
+# Import Vertex AI SDK and Google credentials support
 import vertexai
 from vertexai.preview.vision_models import ImageGenerationModel
 from google.oauth2 import service_account
@@ -51,7 +51,7 @@ logging.basicConfig(
 )
 logger = logging.getLogger(__name__)
 
-# --- Configuration ---
+# --- App Configuration ---
 st.set_page_config(page_title="ChronoWeave", layout="wide", initial_sidebar_state="expanded")
 st.title("🌀 ChronoWeave: Advanced Branching Narrative Generator")
 st.markdown("""
@@ -63,8 +63,7 @@ Generate multiple, branching story timelines from a single theme using AI, compl
 TEXT_MODEL_ID = "models/gemini-1.5-flash"
 AUDIO_MODEL_ID = "models/gemini-1.5-flash"
 AUDIO_SAMPLING_RATE = 24000
-# Pretrained Imagen model identifier
-IMAGE_MODEL_ID = "imagen-3.0-generate-002"
+IMAGE_MODEL_ID = "imagen-3.0-generate-002"   # Vertex AI Imagen model identifier
 DEFAULT_ASPECT_RATIO = "1:1"
 VIDEO_FPS = 24
 VIDEO_CODEC = "libx264"
@@ -72,7 +71,7 @@ AUDIO_CODEC = "aac"
 TEMP_DIR_BASE = ".chrono_temp"
 
 # --- Secrets and Environment Variables ---
-GOOGLE_API_KEY = None
+# Load GOOGLE_API_KEY
 try:
     GOOGLE_API_KEY = st.secrets["GOOGLE_API_KEY"]
     logger.info("Google API Key loaded from Streamlit secrets.")
@@ -84,25 +83,30 @@ except KeyError:
         st.error("🚨 **Google API Key Not Found!** Please configure it.", icon="🚨")
         st.stop()
 
+# Load PROJECT_ID and LOCATION
 PROJECT_ID = st.secrets.get("PROJECT_ID") or os.environ.get("PROJECT_ID")
 LOCATION = st.secrets.get("LOCATION") or os.environ.get("LOCATION", "us-central1")
 if not PROJECT_ID:
     st.error("🚨 **PROJECT_ID not set!** Please add PROJECT_ID to your secrets.", icon="🚨")
     st.stop()
 
-# Load service account JSON from secret and create credentials
+# Load and verify SERVICE_ACCOUNT_JSON
+service_account_json = os.environ.get("SERVICE_ACCOUNT_JSON", "").strip()
+if not service_account_json:
+    st.error("🚨 **SERVICE_ACCOUNT_JSON is missing or empty!** Please add your service account JSON to your secrets.", icon="🚨")
+    st.stop()
 try:
-    service_account_info = json.loads(os.environ["SERVICE_ACCOUNT_JSON"])
+    service_account_info = json.loads(service_account_json)
     credentials = service_account.Credentials.from_service_account_info(service_account_info)
     logger.info("Service account credentials loaded successfully.")
 except Exception as e:
     st.error(f"🚨 Failed to load service account JSON: {e}", icon="🚨")
     st.stop()
 
-# Initialize Vertex AI with credentials
+# Initialize Vertex AI with service account credentials
 vertexai.init(project=PROJECT_ID, location=LOCATION, credentials=credentials)
 
-# --- Initialize Google Clients for text/audio ---
+# --- Initialize Google Clients for Text and Audio ---
 try:
     genai.configure(api_key=GOOGLE_API_KEY)
     logger.info("Configured google-generativeai with API key.")
@@ -153,6 +157,7 @@ class ChronoWeaveResponse(BaseModel):
         return self
 
 # --- Helper Functions ---
+
 @contextlib.contextmanager
 def wave_file_writer(filename: str, channels: int = 1, rate: int = AUDIO_SAMPLING_RATE, sample_width: int = 2):
     """Context manager to safely write WAV files."""
@@ -259,7 +264,7 @@ def generate_image_imagen(prompt: str, aspect_ratio: str = "1:1", task_id: str =
     Generates an image using Vertex AI's Imagen model via the Vertex AI preview API.
     
     Loads the pretrained Imagen model and attempts to generate an image.
-    If a quota exceeded error occurs, it informs you to request a quota increase.
+    If a quota exceeded error occurs, it advises you to request a quota increase.
     """
     logger.info(f"🖼️ [{task_id}] Requesting image: '{prompt[:70]}...' (Aspect: {aspect_ratio})")
     try: