"""20일 모멘텀."""

import pandas as pd

from .base import ScoreNode, percentile_rank


class Momentum20(ScoreNode):
    name  = "momentum"
    label = "20일 모멘텀"
    default_params = {"window_days": 20}
    param_schema = {
        "type": "object",
        "properties": {
            "window_days": {"type": "integer", "minimum": 5, "maximum": 120, "default": 20}
        },
    }

    def compute(self, ctx, params: dict) -> pd.Series:
        window = int(params.get("window_days", 20))
        prices = ctx.prices
        if prices.empty:
            return pd.Series(dtype=float)

        ordered = prices.sort_values("date")
        last = ordered.groupby("ticker").tail(window + 1)

        def _ret(s):
            if len(s) < window + 1:
                return float("nan")
            return s.iloc[-1] / s.iloc[0] - 1

        raw = last.groupby("ticker")["close"].apply(_ret)
        return percentile_rank(raw).fillna(50.0)
