import yfinance as yf
import pandas as pd
from typing import List
from .deriv_fetcher import DerivDataFetcher

class DataFetcher:
    """Unified data fetcher for forex, indices, and synthetic volatility products."""

    YAHOO_PAIRS = {
        # Major Forex
        "EUR/USD": "EURUSD=X", "GBP/USD": "GBPUSD=X", "USD/JPY": "USDJPY=X",
        "USD/CHF": "USDCHF=X", "AUD/USD": "AUDUSD=X", "USD/CAD": "USDCAD=X",
        "NZD/USD": "NZDUSD=X", "EUR/GBP": "EURGBP=X", "GBP/JPY": "GBPJPY=X",
        "EUR/JPY": "EURJPY=X",
        # Indices
        "S&P 500": "^GSPC", "NASDAQ": "^IXIC", "Dow Jones": "^DJI",
        "DAX": "^GDAXI", "FTSE 100": "^FTSE", "Nikkei 225": "^N225",
        # Volatility Indices (CBOE)
        "Volatility S&P 500 (VIX)": "^VIX",
        "Volatility NASDAQ 100 (VXN)": "^VXN",
        "Volatility Dow Jones (VXD)": "^VXD",
        "Volatility Russell 2000 (RVX)": "^RVX",
        "Volatility Crude Oil (OVX)": "^OVX",
        "Volatility Gold (GVZ)": "^GVZ",
        "Volatility EuroCurrency (EVZ)": "^EVZ",
    }

    _deriv_fetcher = None

    @classmethod
    def _get_deriv_fetcher(cls):
        if cls._deriv_fetcher is None:
            cls._deriv_fetcher = DerivDataFetcher()
        return cls._deriv_fetcher

    @classmethod
    def fetch_data(cls, symbol_key: str, period: str = "6mo", interval: str = "1h") -> pd.DataFrame:
        deriv_pairs = DerivDataFetcher.get_available_pairs()
        if symbol_key in deriv_pairs:
            return cls._get_deriv_fetcher().fetch_data(symbol_key, period, interval)

        ticker = cls.YAHOO_PAIRS.get(symbol_key, symbol_key)
        try:
            df = yf.download(ticker, period=period, interval=interval, progress=False)
            if df.empty:
                return pd.DataFrame()
            if isinstance(df.columns, pd.MultiIndex):
                df.columns = [col[0].lower() for col in df.columns]
            else:
                df.columns = [col.lower() for col in df.columns]
            return df
        except Exception as e:
            print(f"❌ Error fetching {symbol_key}: {e}")
            return pd.DataFrame()

    @classmethod
    def get_available_pairs(cls) -> List[str]:
        yahoo_pairs = list(cls.YAHOO_PAIRS.keys())
        deriv_pairs = DerivDataFetcher.get_available_pairs()
        return yahoo_pairs + deriv_pairs