import streamlit as st
import math

st.set_page_config(page_title="Advanced Calculator", page_icon="🧮")

st.title("🧮 Advanced Calculator")
st.caption("Streamlit App for Hugging Face Spaces")

# Initialize expression
if "expression" not in st.session_state:
    st.session_state.expression = ""

# Display
st.text_input(
    "Calculator",
    st.session_state.expression,
    disabled=True,
)

# Button handler
def press(key):
    st.session_state.expression += str(key)

def clear():
    st.session_state.expression = ""

def calculate():
    try:
        result = eval(st.session_state.expression)
        st.session_state.expression = str(result)
    except:
        st.session_state.expression = "Error"

# Layout
buttons = [
    ["7", "8", "9", "/"],
    ["4", "5", "6", "*"],
    ["1", "2", "3", "-"],
    ["0", ".", "+", "="],
]

for row in buttons:
    cols = st.columns(4)
    for i, btn in enumerate(row):
        if cols[i].button(btn):
            if btn == "=":
                calculate()
            else:
                press(btn)

# Extra controls
col1, col2 = st.columns(2)
if col1.button("C"):
    clear()

if col2.button("√"):
    try:
        value = float(st.session_state.expression)
        st.session_state.expression = str(math.sqrt(value))
    except:
        st.session_state.expression = "Error"

st.markdown("---")

# Scientific buttons
st.subheader("Scientific Functions")

sci_cols = st.columns(3)

if sci_cols[0].button("sin"):
    try:
        value = float(st.session_state.expression)
        st.session_state.expression = str(math.sin(math.radians(value)))
    except:
        st.session_state.expression = "Error"

if sci_cols[1].button("cos"):
    try:
        value = float(st.session_state.expression)
        st.session_state.expression = str(math.cos(math.radians(value)))
    except:
        st.session_state.expression = "Error"

if sci_cols[2].button("tan"):
    try:
        value = float(st.session_state.expression)
        st.session_state.expression = str(math.tan(math.radians(value)))
    except:
        st.session_state.expression = "Error"