Improve health check and UI messaging for fallback mode

app/main_fastai.py

@@ -203,14 +203,21 @@ async def api_info():
 @app.get("/health")
 async def health_check():
     """Health check endpoint"""
+    model_loaded = (learn is not None) or (pytorch_colorizer is not None)
     response = {
         "status": "healthy",
-        "model_loaded": (learn is not None) or (pytorch_colorizer is not None),
+        "model_loaded": model_loaded,
         "model_type": model_type,
-        "model_id": os.getenv("MODEL_ID", "Hammad712/GAN-Colorization-Model")
+        "model_id": os.getenv("MODEL_ID", "Hammad712/GAN-Colorization-Model"),
+        "using_fallback": not model_loaded
     }
     if model_load_error:
         response["model_error"] = model_load_error
+        response["message"] = "Model failed to load. Using fallback colorization method."
+    elif not model_loaded:
+        response["message"] = "No model loaded. Using fallback colorization method."
+    else:
+        response["message"] = f"Model loaded successfully ({model_type})"
     return response
 
 def simple_colorize_fallback(image: Image.Image) -> Image.Image:
@@ -306,7 +313,7 @@ def colorize_pil(image: Image.Image) -> Image.Image:
     
     else:
         # Final fallback: simple colorization
-        logger.warning("No model loaded, using simple colorization fallback")
+        logger.info("No model loaded, using enhanced colorization fallback (LAB color space method)")
         return simple_colorize_fallback(image)
 
 @app.post("/colorize")
@@ -362,8 +369,8 @@ def gradio_colorize(image):
         logger.error("Gradio colorization error: %s", str(e))
         return None
 
-title = "🎨 FastAI GAN Image Colorizer"
-description = "Upload a black & white photo to generate a colorized version using the FastAI GAN model."
+title = "🎨 Image Colorizer"
+description = "Upload a black & white photo to generate a colorized version. Uses AI model when available, otherwise uses enhanced colorization fallback."
 
 iface = gr.Interface(
     fn=gradio_colorize,