from pycoingecko import CoinGeckoAPI
import json
import os
import dotenv

dotenv.load_dotenv()

fiat = os.getenv("fiat")
usd_to_fiat = float(os.getenv("usd_to_fiat"))
stablecoins = ["usdc", "usdt", "dai"]

# Get api key
if os.path.exists("api_keys/coingecko.txt"):
    with open("api_keys/coingecko.txt", "r") as f:
        apiKey = f.read()
else:
    apiKey = None


def get_historical_fiat_price(coin_id, date):
    """
    Fetches the historical price of a cryptocurrency in fiat on a specific date.

    Args:
    coin_id (str): The CoinGecko ID of the cryptocurrency (e.g., 'bitcoin', 'ethereum').
    date (str): The date in YYYY-MM-DD format.

    Returns:
    float: The historical price of the cryptocurrency in specified fiat currency.
    """

    if coin_id in stablecoins:
        return 1 * usd_to_fiat

    historical_prices = {}
    if os.path.exists(f"chain_data/{coin_id}_price.json"):
        with open(f"chain_data/{coin_id}_price.json", "r") as f:
            historical_prices = json.load(f)
        if date in historical_prices:
            return historical_prices[date]
        

    cg = CoinGeckoAPI()
    historical_data = cg.get_coin_history_by_id(id=coin_id, date=date, localization='false', demo_api_key=apiKey)
    price_data = historical_data['market_data']['current_price']
    fiat_price = price_data[fiat]
    historical_prices[date] = fiat_price

    with open(f"chain_data/{coin_id}_price.json", "w") as f:
        json.dump(historical_prices, f)

    return fiat_price