"""SQLite 캔들 조회."""

from __future__ import annotations

from datetime import timedelta
from pathlib import Path

import pandas as pd

from bithumb.data.candle_store import CandleStore


def load_candles(
    db_path: Path | str,
    symbol: str,
    interval_min: int,
    lookback_days: int | None = None,
) -> pd.DataFrame:
    """DB에서 캔들 DataFrame을 로드한다.

    Args:
        db_path: SQLite 경로.
        symbol: 코인 심볼 (예: TRX).
        interval_min: 분 단위 인터벌 코드.
        lookback_days: 최근 N일만 사용. None이면 전체.

    Returns:
        ``datetime``, ``open``, ``high``, ``low``, ``close``, ``volume`` 컬럼.
        시간 오름차순 정렬.
    """
    store = CandleStore(db_path)
    try:
        since = None
        if lookback_days is not None and lookback_days > 0:
            _, _, db_max = store.get_range(symbol, interval_min)
            if db_max is not None:
                since = db_max - timedelta(days=lookback_days)
        df = store.read_dataframe(symbol, interval_min, since=since)
    finally:
        store.close()

    if df.empty:
        return df

    if lookback_days is not None and lookback_days > 0:
        cutoff = df["datetime"].max() - timedelta(days=lookback_days)
        df = df[df["datetime"] >= cutoff].reset_index(drop=True)

    return df


def load_last_candles(
    db_path: Path | str,
    symbol: str,
    interval_min: int,
    last_n: int,
) -> pd.DataFrame:
    """최신 N봉만 로드 (차트 API용, SQL LIMIT)."""
    store = CandleStore(db_path)
    try:
        return store.read_dataframe(symbol, interval_min, last_n=int(last_n))
    finally:
        store.close()