app.py

import streamlit as st
import pandas as pd

# Sidebar for Navigation
with st.sidebar:
    st.title("Navigation")
    st.markdown("### Select an Option:")
    selected = st.radio("", ["Temperature Converter", "Conversion History"])

# Title and Description
st.title("🌡️ Temperature Converter")
st.write("Easily convert temperatures between Celsius, Fahrenheit, and Kelvin with an intuitive interface.")

if selected == "Temperature Converter":
    st.markdown("### Input Temperature Details")
    col1, col2 = st.columns(2)

    with col1:
        temperature_value = st.number_input("🔢 Enter temperature value:", value=0.0, format="%.2f")
        input_unit = st.selectbox("📥 Select input unit:", ["Celsius", "Fahrenheit", "Kelvin"])

    with col2:
        output_unit = st.selectbox("📤 Select output unit:", ["Celsius", "Fahrenheit", "Kelvin"])

    # Conversion Function
    def convert_temperature(value, from_unit, to_unit):
        if from_unit == to_unit:
            return value
        elif from_unit == "Celsius":
            if to_unit == "Fahrenheit":
                return (value * 9/5) + 32
            elif to_unit == "Kelvin":
                return value + 273.15
        elif from_unit == "Fahrenheit":
            if to_unit == "Celsius":
                return (value - 32) * 5/9
            elif to_unit == "Kelvin":
                return (value - 32) * 5/9 + 273.15
        elif from_unit == "Kelvin":
            if to_unit == "Celsius":
                return value - 273.15
            elif to_unit == "Fahrenheit":
                return (value - 273.15) * 9/5 + 32

    # Perform Conversion
    converted_value = convert_temperature(temperature_value, input_unit, output_unit)

    # Display Result
    st.metric(label=f"Converted Temperature ({output_unit})", value=f"{converted_value:.2f}", delta=None)

elif selected == "Conversion History":
    if "history" not in st.session_state:
        st.session_state["history"] = []

    # Add New Conversion to History
    if "temperature_value" in locals():
        st.session_state["history"].append({
            "Input Value": temperature_value,
            "Input Unit": input_unit,
            "Output Unit": output_unit,
            "Converted Value": converted_value
        })

    # Display Conversion History
    st.markdown("### Conversion History")
    if len(st.session_state["history"]) > 0:
        history_df = pd.DataFrame(st.session_state["history"])
        st.dataframe(history_df)
    else:
        st.info("No conversion history available yet.")