"""
exchange.py — Kraken connector via CCXT
Verantwoordelijk voor: marktdata ophalen, OHLCV, ticker info
"""
import ccxt
import os
import pandas as pd
from typing import Optional
import logging

logger = logging.getLogger(__name__)


def get_exchange() -> ccxt.kraken:
    """Initialiseer Kraken exchange connectie."""
    return ccxt.kraken({
        "apiKey": os.getenv("KRAKEN_API_KEY", ""),
        "secret": os.getenv("KRAKEN_SECRET", ""),
        "enableRateLimit": True,
        "options": {
            "defaultType": "spot",
        }
    })


# Universe van tradeable pairs — uitbreidbaar
TRADING_UNIVERSE = [
    "BTC/EUR", "ETH/EUR", "SOL/EUR", "ADA/EUR",
    "XRP/EUR", "DOT/EUR", "MATIC/EUR", "LINK/EUR",
    "AVAX/EUR", "ATOM/EUR", "UNI/EUR", "LTC/EUR",
    "ALGO/EUR", "NEAR/EUR", "FTM/EUR", "MANA/EUR",
    "SAND/EUR", "DOGE/EUR", "SHIB/EUR", "OP/EUR",
]


def fetch_ohlcv(symbol: str, timeframe: str = "5m", limit: int = 100) -> pd.DataFrame:
    """
    Haal OHLCV candledata op voor een pair.
    Timeframe: 1m, 5m, 15m, 1h, 4h, 1d
    """
    exchange = get_exchange()
    try:
        raw = exchange.fetch_ohlcv(symbol, timeframe=timeframe, limit=limit)
        df = pd.DataFrame(raw, columns=["timestamp", "open", "high", "low", "close", "volume"])
        df["timestamp"] = pd.to_datetime(df["timestamp"], unit="ms")
        df.set_index("timestamp", inplace=True)
        return df
    except Exception as e:
        logger.error(f"OHLCV fetch mislukt voor {symbol}: {e}")
        return pd.DataFrame()


def fetch_tickers(symbols: Optional[list[str]] = None) -> dict:
    """
    Haal huidige ticker data op voor meerdere pairs tegelijk.
    Geeft dict terug met per symbol: prijs, volume, change%.
    """
    exchange = get_exchange()
    targets = symbols or TRADING_UNIVERSE
    result = {}

    try:
        tickers = exchange.fetch_tickers(targets)
        for symbol, ticker in tickers.items():
            result[symbol] = {
                "symbol":        symbol,
                "price":         ticker.get("last") or 0,
                "volume_24h":    ticker.get("quoteVolume") or 0,
                "change_24h":    ticker.get("percentage") or 0,
                "high_24h":      ticker.get("high") or 0,
                "low_24h":       ticker.get("low") or 0,
                "bid":           ticker.get("bid") or 0,
                "ask":           ticker.get("ask") or 0,
            }
    except Exception as e:
        logger.error(f"Ticker fetch mislukt: {e}")

    return result