import streamlit as st

def main():
    st.title("Enhanced Calculator")

    # Select an operation
    operations = [
        "Addition", 
        "Subtraction", 
        "Multiplication", 
        "Division", 
        "Modulus", 
        "Exponentiation", 
        "Average"
    ]
    operator = st.selectbox("Select an operation", operations)

    # For exponentiation, ask for base and exponent.
    if operator == "Exponentiation":
        base = st.number_input("Enter the base value", value=0.0)
        exponent = st.number_input("Enter the exponent value", value=0.0)
    else:
        # For all other operations, ask for three numbers.
        num1 = st.number_input("Enter the first number", value=0.0)
        num2 = st.number_input("Enter the second number", value=0.0)
        num3 = st.number_input("Enter the third number", value=0.0)

    if st.button("Calculate"):
        result = None
        
        try:
            if operator == "Addition":
                result = num1 + num2 + num3

            elif operator == "Subtraction":
                result = num1 - num2 - num3

            elif operator == "Multiplication":
                result = num1 * num2 * num3

            elif operator == "Division":
                # Check for division by zero
                if num2 == 0 or num3 == 0:
                    st.error("Error: Division by zero is not allowed.")
                else:
                    result = num1 / num2 / num3

            elif operator == "Modulus":
                # Check for modulus by zero
                if num2 == 0 or num3 == 0:
                    st.error("Error: Modulus by zero is not allowed.")
                else:
                    result = (num1 % num2) % num3

            elif operator == "Exponentiation":
                # Now we take an input value for the exponent and compute base**exponent.
                result = base ** exponent

            elif operator == "Average":
                result = (num1 + num2 + num3) / 3

            if result is not None:
                st.success(f"Result: {result}")

        except Exception as e:
            st.error(f"An error occurred: {e}")

if __name__ == '__main__':
    main()