from datetime import datetime, timezone
from typing import Optional

import pandas as pd
from oandapyV20 import API
from oandapyV20.endpoints import accounts, instruments, orders, trades, pricing

from app.core.config import settings
from app.core.exchange.base import (
    AbstractExchange,
    AccountInfo,
    OpenTrade,
    OrderResult,
)


# Granularités OANDA valides
GRANULARITIES = {
    "M1", "M5", "M15", "M30",
    "H1", "H2", "H4", "H6", "H8", "H12",
    "D", "W", "M",
}

# Nombre max de candles par requête OANDA
MAX_CANDLES_PER_REQUEST = 5000


def _parse_time(ts: str) -> datetime:
    """Parse RFC3339 timestamp OANDA → datetime UTC."""
    return datetime.fromisoformat(ts.replace("Z", "+00:00"))


class OandaExchange(AbstractExchange):
    def __init__(self) -> None:
        env = "practice" if settings.oanda_environment == "practice" else "live"
        self._client = API(
            access_token=settings.oanda_api_key,
            environment=env,
        )
        self._account_id = settings.oanda_account_id

    async def get_candles(
        self,
        instrument: str,
        granularity: str = "H1",
        count: int = 200,
        from_time: Optional[datetime] = None,
        to_time: Optional[datetime] = None,
    ) -> pd.DataFrame:
        if granularity not in GRANULARITIES:
            raise ValueError(f"Granularité invalide: {granularity}. Valides: {GRANULARITIES}")

        params: dict = {"granularity": granularity, "price": "M"}

        if from_time and to_time:
            params["from"] = from_time.strftime("%Y-%m-%dT%H:%M:%SZ")
            params["to"] = to_time.strftime("%Y-%m-%dT%H:%M:%SZ")
        else:
            params["count"] = min(count, MAX_CANDLES_PER_REQUEST)

        r = instruments.InstrumentsCandles(instrument, params=params)
        self._client.request(r)

        candles = r.response.get("candles", [])
        rows = []
        for c in candles:
            if c.get("complete", True):
                mid = c["mid"]
                rows.append({
                    "time": _parse_time(c["time"]),
                    "open": float(mid["o"]),
                    "high": float(mid["h"]),
                    "low": float(mid["l"]),
                    "close": float(mid["c"]),
                    "volume": int(c.get("volume", 0)),
                })

        df = pd.DataFrame(rows)
        if not df.empty:
            df.sort_values("time", inplace=True)
            df.reset_index(drop=True, inplace=True)
        return df

    async def place_order(
        self,
        instrument: str,
        units: float,
        stop_loss: float,
        take_profit: float,
    ) -> OrderResult:
        data = {
            "order": {
                "type": "MARKET",
                "instrument": instrument,
                "units": str(int(units)),
                "stopLossOnFill": {"price": f"{stop_loss:.5f}"},
                "takeProfitOnFill": {"price": f"{take_profit:.5f}"},
                "timeInForce": "FOK",
            }
        }
        r = orders.OrderCreate(self._account_id, data=data)
        self._client.request(r)

        resp = r.response
        fill = resp.get("orderFillTransaction") or resp.get("relatedTransactionIDs", {})
        trade_id = resp.get("orderFillTransaction", {}).get("tradeOpened", {}).get("tradeID", "unknown")
        entry_price = float(resp.get("orderFillTransaction", {}).get("price", 0))
        direction = "buy" if units > 0 else "sell"

        return OrderResult(
            trade_id=trade_id,
            instrument=instrument,
            direction=direction,
            units=abs(units),
            entry_price=entry_price,
            stop_loss=stop_loss,
            take_profit=take_profit,
            opened_at=datetime.now(timezone.utc),
        )

    async def close_trade(self, trade_id: str) -> float:
        r = trades.TradeClose(self._account_id, tradeID=trade_id)
        self._client.request(r)
        pnl = float(r.response.get("orderFillTransaction", {}).get("pl", 0))
        return pnl

    async def get_open_trades(self) -> list[OpenTrade]:
        r = trades.OpenTrades(self._account_id)
        self._client.request(r)
        result = []
        for t in r.response.get("trades", []):
            units = float(t["currentUnits"])
            direction = "buy" if units > 0 else "sell"
            sl = float(t.get("stopLoss", {}).get("price", 0)) if t.get("stopLoss") else 0.0
            tp = float(t.get("takeProfit", {}).get("price", 0)) if t.get("takeProfit") else 0.0
            result.append(OpenTrade(
                trade_id=t["id"],
                instrument=t["instrument"],
                direction=direction,
                units=abs(units),
                entry_price=float(t["price"]),
                stop_loss=sl,
                take_profit=tp,
                unrealized_pnl=float(t.get("unrealizedPL", 0)),
                opened_at=_parse_time(t["openTime"]),
            ))
        return result

    async def get_account_info(self) -> AccountInfo:
        r = accounts.AccountSummary(self._account_id)
        self._client.request(r)
        acc = r.response["account"]
        return AccountInfo(
            balance=float(acc["balance"]),
            nav=float(acc["NAV"]),
            unrealized_pnl=float(acc.get("unrealizedPL", 0)),
            currency=acc.get("currency", "USD"),
        )

    async def get_price(self, instrument: str) -> float:
        r = pricing.PricingInfo(
            self._account_id,
            params={"instruments": instrument},
        )
        self._client.request(r)
        prices = r.response.get("prices", [])
        if not prices:
            raise ValueError(f"Aucun prix pour {instrument}")
        bid = float(prices[0]["bids"][0]["price"])
        ask = float(prices[0]["asks"][0]["price"])
        return (bid + ask) / 2