import streamlit as st
import math

st.title("Scientific Calculator")

# All operations
operations = [
    "+", "-", "*", "/", "^ (power)", "% (modulus)", "// (floor division)",
    "√ (square root)", "log10", "ln (natural log)", "n! (factorial)",
    "sin", "cos", "tan", "exp (e^x)"
]

operation = st.selectbox("Select operation", operations)

# Input fields
num1 = st.number_input("Enter first number", format="%.4f")

# Only show num2 for operations that need two inputs
if operation in ["+", "-", "*", "/", "^ (power)", "% (modulus)", "// (floor division)"]:
    num2 = st.number_input("Enter second number", format="%.4f")
else:
    num2 = None

result = None
error = None

if st.button("Calculate"):
    try:
        if operation == "+":
            result = num1 + num2
        elif operation == "-":
            result = num1 - num2
        elif operation == "*":
            result = num1 * num2
        elif operation == "/":
            if num2 != 0:
                result = num1 / num2
            else:
                error = "Cannot divide by zero"
        elif operation == "^ (power)":
            result = num1 ** num2
        elif operation == "% (modulus)":
            if num2 != 0:
                result = num1 % num2
            else:
                error = "Cannot perform modulus by zero"
        elif operation == "// (floor division)":
            if num2 != 0:
                result = num1 // num2
            else:
                error = "Cannot perform floor division by zero"
        elif operation == "√ (square root)":
            if num1 >= 0:
                result = math.sqrt(num1)
            else:
                error = "Cannot take square root of a negative number"
        elif operation == "log10":
            if num1 > 0:
                result = math.log10(num1)
            else:
                error = "Log10 undefined for non-positive numbers"
        elif operation == "ln (natural log)":
            if num1 > 0:
                result = math.log(num1)
            else:
                error = "Natural log undefined for non-positive numbers"
        elif operation == "n! (factorial)":
            if num1 >= 0 and num1 == int(num1):
                result = math.factorial(int(num1))
            else:
                error = "Factorial only defined for non-negative integers"
        elif operation == "sin":
            result = math.sin(math.radians(num1))
        elif operation == "cos":
            result = math.cos(math.radians(num1))
        elif operation == "tan":
            result = math.tan(math.radians(num1))
        elif operation == "exp (e^x)":
            result = math.exp(num1)
    except Exception as e:
        error = str(e)

    if error:
        st.error(error)
    else:
        st.success(f"Result: {result:.6f}")