from __future__ import annotations


def field_float(item: list[str], idx: int) -> float | None:
    """Parse one K-line field; empty or invalid strings return None."""
    if idx >= len(item):
        return None
    raw = str(item[idx]).strip()
    if not raw:
        return None
    try:
        return float(raw)
    except (TypeError, ValueError):
        return None


def rows_to_ohlcv(
    rows: list[list[str]],
    *,
    require_volume: bool = True,
) -> tuple[list[float], list[float], list[float], list[float], list[float]]:
    """
    Gate candle rows: [ts_ms, o, h, l, c, v, ...].
    Skips rows with missing/invalid OHLC; skips rows with missing volume when require_volume=True.
    """
    o, h, l, c, v = [], [], [], [], []
    for item in rows:
        if len(item) < 5:
            continue
        o_val = field_float(item, 1)
        h_val = field_float(item, 2)
        l_val = field_float(item, 3)
        c_val = field_float(item, 4)
        if o_val is None or h_val is None or l_val is None or c_val is None:
            continue
        vol_val = field_float(item, 5) if len(item) > 5 else None
        if require_volume and vol_val is None:
            continue
        o.append(o_val)
        h.append(h_val)
        l.append(l_val)
        c.append(c_val)
        v.append(vol_val if vol_val is not None else 0.0)
    return o, h, l, c, v


def rows_to_hlc(rows: list[list[str]]) -> tuple[list[float], list[float], list[float]]:
    """High / low / close series aligned to valid OHLC rows."""
    h, l_, c = [], [], []
    for item in rows:
        if len(item) < 5:
            continue
        h_val = field_float(item, 2)
        l_val = field_float(item, 3)
        c_val = field_float(item, 4)
        if h_val is None or l_val is None or c_val is None:
            continue
        h.append(h_val)
        l_.append(l_val)
        c.append(c_val)
    return h, l_, c


def rows_to_ohl(rows: list[list[str]]) -> tuple[list[float], list[float], list[float], list[float]]:
    """Open / high / low / close for chart rendering."""
    o, h, l, c = [], [], [], []
    for item in rows:
        if len(item) < 5:
            continue
        o_val = field_float(item, 1)
        h_val = field_float(item, 2)
        l_val = field_float(item, 3)
        c_val = field_float(item, 4)
        if o_val is None or h_val is None or l_val is None or c_val is None:
            continue
        o.append(o_val)
        h.append(h_val)
        l.append(l_val)
        c.append(c_val)
    return o, h, l, c


def rows_to_close(rows: list[list[str]]) -> list[float]:
    out: list[float] = []
    for item in rows:
        if len(item) < 5:
            continue
        c_val = field_float(item, 4)
        if c_val is not None:
            out.append(c_val)
    return out