import streamlit as st
import requests
import time

# Function to get the list of available cryptocurrencies
@st.cache_data
def get_available_cryptos():
    url = "https://api.coingecko.com/api/v3/coins/markets?vs_currency=usd"
    try:
        response = requests.get(url)
        response.raise_for_status()
        data = response.json()
        # Create a dictionary to map lowercase IDs to their uppercase symbols
        cryptos = {coin["id"]: coin["symbol"].upper() for coin in data}
        return cryptos
    except requests.exceptions.RequestException as e:
        st.error(f"Error fetching cryptocurrency list: {e}")
        return {}

# Function to get the current price of the selected cryptocurrency in USD
def get_crypto_price(crypto_id):
    url = f"https://api.coingecko.com/api/v3/simple/price?ids={crypto_id}&vs_currencies=usd"
    try:
        response = requests.get(url)
        response.raise_for_status()
        price_data = response.json()
        if crypto_id in price_data:
            return price_data[crypto_id]['usd']
        else:
            st.error(f"Invalid cryptocurrency ID: {crypto_id}")
            return None
    except requests.exceptions.RequestException as e:
        st.error(f"Error fetching data: {e}")
        return None

# Streamlit app layout
st.title("Crypto to USD Converter")
st.write("Get the current price of cryptocurrencies in USD.")

# Fetch the list of available cryptocurrencies
available_cryptos = get_available_cryptos()

if available_cryptos:
    selected_crypto = st.selectbox("Select Cryptocurrency:", list(available_cryptos.values()))
    
    # Get the crypto ID based on the selected symbol
    crypto_id = [key for key, value in available_cryptos.items() if value == selected_crypto][0]
    
    amount = st.number_input(f"Enter amount of {selected_crypto}:", min_value=0.0, step=0.01)

    if st.button("Convert to USD"):
        with st.spinner("Fetching price..."):
            # Add a delay to avoid hitting the rate limit
            time.sleep(2)
            crypto_price = get_crypto_price(crypto_id)
            if crypto_price is not None:
                total_usd = crypto_price * amount
                st.success(f"1 {selected_crypto} = {crypto_price:.2f} USD")
                st.success(f"{amount} {selected_crypto} = {total_usd:.2f} USD")
            else:
                st.warning("Could not fetch the price. Try again later.")
else:
    st.warning("No cryptocurrencies available for conversion at this time.")

# Footer information
st.markdown("### Note:")
st.markdown("Prices are fetched in real-time API. Thank-you, regards Rahul Juneja.")