import asyncio
import logging
from functools import partial

from eth_account import Account
from hyperliquid.exchange import Exchange
from hyperliquid.info import Info

logger = logging.getLogger(__name__)

HL_MAINNET = "https://api.hyperliquid.xyz"

# Coin name mapping: our asset -> Hyperliquid coin
COIN_MAP = {
    "BTC": "BTC",
    "ETH": "ETH",
}


class HyperliquidTrader:
    def __init__(self, private_key: str):
        self.account = Account.from_key(private_key)
        self.exchange = Exchange(self.account, HL_MAINNET)
        self.info = Info(HL_MAINNET)
        self._loop = asyncio.get_event_loop()

    # ── helpers ──────────────────────────────────────────────────────────────

    async def _run_sync(self, fn, *args, **kwargs):
        """Run a blocking SDK call in the default thread pool."""
        return await self._loop.run_in_executor(None, partial(fn, *args, **kwargs))

    def _wallet(self) -> str:
        return self.account.address

    # ── public interface ─────────────────────────────────────────────────────

    async def get_balance(self) -> float:
        """Return USDC balance (withdrawable)."""
        try:
            state = await self._run_sync(
                self.info.user_state, self._wallet()
            )
            return float(state.get("withdrawable", 0))
        except Exception as exc:
            logger.error("get_balance error: %s", exc)
            return 0.0

    async def open_position(self, asset: str, side: str, size_usd: float) -> dict:
        """Place a market order.

        Args:
            asset: "BTC" or "ETH"
            side: "long" (buy) or "short" (sell)
            size_usd: notional size in USD

        Returns:
            {"order_id": str, "fill_price": float}
        """
        coin = COIN_MAP.get(asset.upper(), asset.upper())
        is_buy = side.lower() == "long"

        try:
            # Get current price to compute size in coins
            meta = await self._run_sync(self.info.meta)
            universe = {u["name"]: u for u in meta.get("universe", [])}
            coin_meta = universe.get(coin, {})
            sz_decimals = int(coin_meta.get("szDecimals", 3))

            # Use mid-price approximation from user state
            all_mids = await self._run_sync(self.info.all_mids)
            mid_price = float(all_mids.get(coin, 0))
            if mid_price <= 0:
                raise ValueError(f"Could not get mid price for {coin}")

            size_coins = round(size_usd / mid_price, sz_decimals)

            # Slippage: 1% for longs (limit above mid), 1% for shorts (limit below mid)
            slippage = 0.01
            if is_buy:
                limit_px = round(mid_price * (1 + slippage), 1)
            else:
                limit_px = round(mid_price * (1 - slippage), 1)

            order_result = await self._run_sync(
                self.exchange.order,
                coin,
                is_buy,
                size_coins,
                limit_px,
                {"limit": {"tif": "Ioc"}},  # IOC ~ market
            )

            status = order_result.get("response", {}).get("data", {})
            filled = status.get("statuses", [{}])[0]
            fill_price = float(filled.get("filled", {}).get("avgPx", mid_price) or mid_price)
            order_id = str(filled.get("resting", {}).get("oid", ""))

            logger.info(
                "Opened %s %s position: size=%.4f coins @ %.2f",
                side, coin, size_coins, fill_price,
            )
            return {"order_id": order_id, "fill_price": fill_price}

        except Exception as exc:
            logger.error("open_position error: %s", exc)
            raise

    async def close_position(self, asset: str) -> dict:
        """Close all open positions for the given asset.

        Returns:
            {"fill_price": float}
        """
        coin = COIN_MAP.get(asset.upper(), asset.upper())
        try:
            positions = await self.get_open_positions()
            target = next(
                (p for p in positions if p.get("coin") == coin), None
            )
            if target is None:
                logger.warning("No open position found for %s", coin)
                return {"fill_price": 0.0}

            szi = float(target.get("szi", 0))
            is_buy = szi < 0  # closing a short means buying

            all_mids = await self._run_sync(self.info.all_mids)
            mid_price = float(all_mids.get(coin, 0))

            slippage = 0.01
            if is_buy:
                limit_px = round(mid_price * (1 + slippage), 1)
            else:
                limit_px = round(mid_price * (1 - slippage), 1)

            close_result = await self._run_sync(
                self.exchange.order,
                coin,
                is_buy,
                abs(szi),
                limit_px,
                {"limit": {"tif": "Ioc"}},
                reduce_only=True,
            )

            status = close_result.get("response", {}).get("data", {})
            filled = status.get("statuses", [{}])[0]
            fill_price = float(filled.get("filled", {}).get("avgPx", mid_price) or mid_price)

            logger.info("Closed %s position @ %.2f", coin, fill_price)
            return {"fill_price": fill_price}

        except Exception as exc:
            logger.error("close_position error: %s", exc)
            raise

    async def get_open_positions(self) -> list:
        """Return list of open positions from Hyperliquid."""
        try:
            state = await self._run_sync(self.info.user_state, self._wallet())
            positions = []
            for asset_pos in state.get("assetPositions", []):
                pos = asset_pos.get("position", {})
                szi = float(pos.get("szi", 0))
                if szi != 0:
                    positions.append({
                        "coin": pos.get("coin"),
                        "szi": szi,
                        "entry_px": float(pos.get("entryPx", 0) or 0),
                        "unrealized_pnl": float(pos.get("unrealizedPnl", 0) or 0),
                    })
            return positions
        except Exception as exc:
            logger.error("get_open_positions error: %s", exc)
            return []