"""Daily exit-scan job for the Kevin bridge.

Walks open Kevin trades (Trade.strategy_id == KEVIN_STRATEGY_UUID, status
FILLED, no offsetting SELL) and publishes EXIT TradeSignals for any whose
holding period has elapsed.
"""

from __future__ import annotations

import logging
from datetime import datetime, timedelta, timezone
from typing import Any, Callable

from sqlalchemy import and_, select

from shared.constants.kevin import KEVIN_STRATEGY_UUID
from shared.models.meet_kevin_trading import KevinSignalBridgeState
from shared.models.trading import Trade, TradeStatus
from shared.schemas.trading import SignalDirection, TradeSignal

logger = logging.getLogger(__name__)


class ExitScanner:
    def __init__(
        self,
        session_factory: Callable[..., Any],
        publisher: Any,
        config: Any,
        broker: Any,
    ) -> None:
        self.session_factory = session_factory
        self.publisher = publisher
        self.config = config
        self.broker = broker

    async def scan_and_emit_exits(self) -> int:
        """Returns the number of EXIT signals emitted."""
        now = datetime.now(timezone.utc)
        emitted = 0

        # Offsetting-SELL guard: only emit exits for tickers STILL held at the
        # broker, so we never re-emit for an already-closed position. With zero
        # open positions this set is empty → the scan is a safe no-op.
        positions = await self.broker.get_positions()
        held_tickers = {p.ticker for p in positions if p.qty != 0}
        if not held_tickers:
            return 0

        async with self.session_factory() as session:
            # Find open Kevin trades (FILLED, no closing trade yet on same ticker)
            open_trades = (
                (
                    await session.execute(
                        select(Trade).where(
                            and_(
                                Trade.strategy_id == KEVIN_STRATEGY_UUID,
                                Trade.status == TradeStatus.FILLED,
                            )
                        )
                    )
                )
                .scalars()
                .all()
            )

        for trade in open_trades:
            # Skip tickers no longer held at the broker (already closed).
            if trade.ticker not in held_tickers:
                continue
            # Find the source audit row to learn the original holding_days target
            async with self.session_factory() as session:
                audit = (
                    (
                        await session.execute(
                            select(KevinSignalBridgeState).where(
                                KevinSignalBridgeState.trade_id == trade.id
                            )
                        )
                    )
                    .scalars()
                    .one_or_none()
                )
            if audit is None:
                continue

            hold_days = self._holding_days(audit)
            target_exit_at = audit.decided_at + timedelta(days=hold_days)
            if now < target_exit_at:
                continue

            signal = TradeSignal(
                ticker=trade.ticker,
                direction=SignalDirection.EXIT,
                strength=1.0,
                strategy_id=KEVIN_STRATEGY_UUID,
                strategy_sources=[f"kevin:exit_scan:hold_expired:{hold_days}d"],
            )
            try:
                await self.publisher.publish(signal)
                emitted += 1
            except Exception:
                logger.exception("exit-scan publish failed for trade %s", trade.id)

        return emitted

    def _holding_days(self, audit: KevinSignalBridgeState) -> int:
        """Best-effort holding days from notes; fallback to config default."""
        notes = audit.notes or ""
        # Try to find ' hold=Nd' in the audit notes
        for token in notes.split():
            if token.startswith("hold=") and token.endswith("d"):
                try:
                    return int(token.removeprefix("hold=").removesuffix("d"))
                except ValueError:
                    pass
        default_map = getattr(self.config, "kevin_hold_days", {})
        return int(default_map.get("unspecified", 10))