app.py

import gradio as gr
import tensorflow as tf
from tensorflow import keras
import numpy as np
from PIL import Image

# --- Configuration ---
MODEL_PATH = "cats-vs-dogs-finetuned.keras"
IMAGE_SIZE = (150, 150) # Adjust this to match the input size your model expects!
CLASS_LABELS = ['Cat', 'Dog']

# --- Load the Model ---
# We load the Keras model. Hugging Face Spaces will automatically find this file
# if you upload it to your repository.
try:
    model = keras.models.load_model(MODEL_PATH)
    print(f"Model loaded successfully from {MODEL_PATH}")
except Exception as e:
    # If the model fails to load (e.g., during initial setup before it's uploaded),
    # we use a placeholder function. This helps the app start.
    print(f"Error loading model: {e}. Using a placeholder function.")
    model = None

# --- Prediction Function ---
def predict_image(input_img_pil):
    """
    Predicts the class (Cat or Dog) given a PIL Image object.
    
    Args:
        input_img_pil: A PIL Image object received from Gradio's Image input.
        
    Returns:
        A dictionary of class labels and their probabilities (for Gradio's Label output).
    """
    if model is None:
        # Placeholder behavior if model loading failed
        return {"Error": 1.0}

    # 1. Preprocessing: Resize and convert to NumPy array
    img_resized = input_img_pil.resize(IMAGE_SIZE)
    print("image resized")
    img_array = keras.preprocessing.image.img_to_array(img_resized)
    print(" image converted to array")
        
    # 2. Rescaling and Batch dimension:
    # Keras models usually expect input shapes like (Batch_Size, Height, Width, Channels)
    # and often expect pixel values to be normalized (e.g., 0-1 range).
    # Please adjust the normalization based on how your model was trained!
    img_array = img_array / 255.0  # Common normalization step
    img_array = np.expand_dims(img_array, axis=0) # Add batch dimension

    # 3. Prediction
    predictions = model.predict(img_array)[0] # Get the single prediction result

    # 4. Format the output for Gradio's Label component
    # The output is expected to be a dictionary: {'label': probability, ...}
    
    # Assuming predictions is a 2-element array: [prob_cat, prob_dog]
    output_dict = {
        CLASS_LABELS[0]: float(predictions[0]),
        CLASS_LABELS[1]: float(predictions[1])
    }
    
    return output_dict


# --- Gradio Interface Setup ---

# Define the input component (Image) and output component (Label)
image_input = gr.Image(type="pil", label="Upload a Cat or Dog Image")
label_output = gr.Label(num_top_classes=2, label="Prediction")

# Example images for users to try (place these in your Space if you use them)
examples = [
    # To use these, you would need to upload files named 'example_cat.jpg' and 'example_dog.jpg'
    # 'example_cat.jpg', 
    # 'example_dog.jpg'
]

# Create the Gradio interface
demo = gr.Interface(
    fn=predict_image,
    inputs=image_input,
    outputs=label_output,
    title="Keras Cat vs Dog Classifier",
    description="Upload an image of a cat or dog to see the model's prediction. The model is loaded from cat-vs-dog.keras.",
    theme=gr.themes.Soft(),
    # Optional: Add examples if you upload them
    # examples=examples
)

# Launch the app
if __name__ == "__main__":
    demo.launch()