app.py

import gradio as gr
import torch
import torch.nn as nn
from torchvision import models, transforms
from PIL import Image

# 1. SETUP MODEL ARCHITECTURE
# (Matches the ResNet50 logs you provided)
model = models.resnet50(weights=None) 

# 2. MATCH THE FINAL LAYER
num_ftrs = model.fc.in_features 
model.fc = nn.Linear(num_ftrs, 2)

# 3. LOAD WEIGHTS
# Ensure this matches the EXACT filename you uploaded to the Files tab
model_path = "fire_detection_resnet50.pth" 

try:
    state_dict = torch.load(model_path, map_location=torch.device('cpu'))
    model.load_state_dict(state_dict)
    print("Model weights loaded successfully.")
except Exception as e:
    print(f"Error loading model weights: {e}")

model.eval()

# 4. DEFINE PREPROCESSING
transform = transforms.Compose([
    transforms.Resize((224, 224)),
    transforms.ToTensor(),
    transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
])

# 5. PREDICTION FUNCTION
labels = ['Non-Fire', 'Fire']

def predict(image):
    if image is None:
        return None
    
    try:
        # Preprocess
        image = image.convert('RGB')
        image_tensor = transform(image).unsqueeze(0) 
        
        # Inference
        with torch.no_grad():
            outputs = model(image_tensor)
            probabilities = torch.nn.functional.softmax(outputs[0], dim=0)
        
        # Return dictionary for Gradio Label
        return {labels[i]: float(probabilities[i]) for i in range(len(labels))}
    except Exception as e:
        return {f"Error: {str(e)}": 0.0}

# 6. LAUNCH GRADIO UI
# Removed 'examples' to prevent the crash
interface = gr.Interface(
    fn=predict,
    inputs=gr.Image(type="pil", label="Upload Image"),
    outputs=gr.Label(num_top_classes=2, label="Prediction"),
    title="Fire Detection System",
    description="Upload an image to detect if fire is present."
)

if __name__ == "__main__":
    interface.launch()