import gradio as gr

def calculate_mpg(miles, fuel):
    """
    Core logic function to calculate MPG.
    This replaces the logic inside the Tkinter class.
    """
    try:
        # Input validation
        if fuel <= 0:
            return "Error: Fuel must be > 0"
        if miles < 0:
            return "Error: Miles cannot be negative"
        
        # Calculation
        mpg = miles / fuel
        return f"{round(mpg, 2)} MPG"
        
    except Exception as e:
        return f"Error: {str(e)}"

# Define the Gradio Interface
# 1. Inputs: Two number boxes
# 2. Output: A text box for the result
# 3. Title/Description: For the top of the web page
interface = gr.Interface(
    fn=calculate_mpg,
    inputs=[
        gr.Number(label="Miles Driven", value=0),
        gr.Number(label="Fuel Consumption (Gallons)", value=0)
    ],
    outputs=gr.Textbox(label="Calculated Fuel Economy"),
    title="FUEL ECONOMY CALCULATOR",
    description="Enter miles and fuel to calculate your MPG. This is a web-based version of our Tkinter assignment.",
    theme="soft" # Optional: gives it a modern look
)

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