import streamlit as st
import math
st.set_page_config(page_title="Advanced Calculator", page_icon="🧮")

st.title("🧮 Advanced Calculator")
st.write("A simple advanced calculator built with Streamlit and deployed on Hugging Face.")

# Initialize history in session state
if "history" not in st.session_state:
    st.session_state.history = []

# User inputs
num1 = st.number_input("Enter first number", value=0.0, step=1.0)
num2 = st.number_input("Enter second number", value=0.0, step=1.0)

operation = st.selectbox(
    "Choose operation",
    ["Addition (+)", "Subtraction (-)", "Multiplication (*)", "Division (/)", "Power (a^b)", "Modulus (%)"]
)

# Calculate button
if st.button("Calculate"):
    if operation == "Addition (+)":
        result = num1 + num2
        record = f"{num1} + {num2} = {result}"

    elif operation == "Subtraction (-)":
        result = num1 - num2
        record = f"{num1} - {num2} = {result}"

    elif operation == "Multiplication (*)":
        result = num1 * num2
        record = f"{num1} * {num2} = {result}"

    elif operation == "Division (/)":
        if num2 == 0:
            st.error("❌ Division by zero is not allowed.")
            result = None
            record = None
        else:
            result = num1 / num2
            record = f"{num1} / {num2} = {result}"

    elif operation == "Power (a^b)":
        result = num1 ** num2
        record = f"{num1} ^ {num2} = {result}"

    elif operation == "Modulus (%)":
        if num2 == 0:
            st.error("❌ Modulus by zero is not allowed.")
            result = None
            record = None
        else:
            result = num1 % num2
            record = f"{num1} % {num2} = {result}"

    if result is not None:
        st.success(f"✅ Result: {result}")
        st.session_state.history.append(record)

# Show history
st.subheader("📜 Calculation History")
if len(st.session_state.history) == 0:
    st.info("No calculations yet.")
else:
    for item in st.session_state.history[::-1]:
        st.write("•", item)

# Clear history button
if st.button("Clear History"):
    st.session_state.history = []
    st.success("History cleared successfully!")

st.markdown("---")
st.caption("Built with ❤️ using Python & Streamlit")