"""
Gainer snapshot collector — fetches top 100 day_gainers and stores per 5-min slot.
"""
import logging
from datetime import datetime, timezone

logger = logging.getLogger(__name__)


def _floor_to_5min(dt: datetime) -> datetime:
    """Round down to the nearest 5-minute boundary."""
    return dt.replace(minute=dt.minute - (dt.minute % 5), second=0, microsecond=0)


async def collect_gainer_snapshot() -> int:
    """Fetch 100 day_gainers and bulk-insert into gainer_snapshots. Returns inserted count."""
    from app.services.screener_service import screener_service
    from app.core.database import AsyncSessionLocal
    from app.models.gainer_snapshot import GainerSnapshot
    from sqlalchemy.dialects.postgresql import insert as pg_insert

    snapshot_at = _floor_to_5min(datetime.now(timezone.utc))

    result = await screener_service.screen_preset("day_gainers", page=1, page_size=100)
    stocks = result.get("stocks", [])
    if not stocks:
        logger.warning("[Gainers] No stocks returned from day_gainers preset")
        return 0

    rows = [
        {
            "snapshot_at": snapshot_at,
            "rank": rank,
            "symbol": s["symbol"],
            "name": s.get("name"),
            "exchange": s.get("exchange"),
            "price": s.get("price"),
            "change_percent": s.get("change_percent"),
            "volume": s.get("volume"),
            "avg_volume_3m": s.get("avg_volume_3m"),
            "market_cap": s.get("market_cap"),
            "pe_ratio": s.get("pe_ratio"),
            "forward_pe": s.get("forward_pe"),
            "eps_ttm": s.get("eps_ttm"),
            "dividend_yield": s.get("dividend_yield"),
            "fifty_two_week_high": s.get("fifty_two_week_high"),
            "fifty_two_week_low": s.get("fifty_two_week_low"),
        }
        for rank, s in enumerate(stocks, start=1)
    ]

    async with AsyncSessionLocal() as db:
        stmt = pg_insert(GainerSnapshot).values(rows)
        stmt = stmt.on_conflict_do_nothing(constraint="uq_gainer_snapshot_symbol")
        await db.execute(stmt)
        await db.commit()

    logger.info("[Gainers] snapshot %s — %d rows", snapshot_at.isoformat(), len(rows))
    return len(rows)