import datetime as dt
import pandas as pd
import pytest

from app.screener.engine import ScreenContext, Screener, combine
from app.screener.nodes.hygiene import HygieneGate
from app.screener.nodes.foreign_buy import ForeignBuy
from app.screener.nodes.momentum import Momentum20
from app.screener._test_fixtures import make_master, make_prices, make_flow, make_kospi


def _ctx(master, prices, flow):
    return ScreenContext(master=master, prices=prices, flow=flow,
                         kospi=make_kospi(days=260),
                         asof=dt.date(2026, 5, 12))


def test_combine_weighted_average():
    scores = {
        "foreign_buy": pd.Series({"A": 80, "B": 20}),
        "momentum":    pd.Series({"A": 60, "B": 40}),
    }
    weights = {"foreign_buy": 2.0, "momentum": 1.0}
    out = combine(scores, weights)
    # A: (80*2 + 60*1)/3 = 73.33
    assert abs(out["A"] - 73.333) < 0.1
    assert abs(out["B"] - 26.666) < 0.1


def test_combine_all_zero_weight_raises():
    scores = {"foreign_buy": pd.Series({"A": 80})}
    with pytest.raises(ValueError, match="no active"):
        combine(scores, {"foreign_buy": 0})


def test_screener_run_end_to_end():
    asof = dt.date(2026, 5, 12)
    master = make_master(["GOOD", "SMALL"],
                         market_caps={"GOOD": 200_000_000_000, "SMALL": 1_000_000_000})
    prices = make_prices(["GOOD", "SMALL"], days=260, asof=asof, trend_pct=0.1)
    flow = make_flow(["GOOD", "SMALL"], days=260, asof=asof,
                     foreign_per_day={"GOOD": 100_000_000, "SMALL": 0})
    ctx = _ctx(master, prices, flow)

    screener = Screener(
        gate=HygieneGate(),
        score_nodes=[ForeignBuy(), Momentum20()],
        weights={"foreign_buy": 1.0, "momentum": 1.0},
        node_params={"foreign_buy": {"window_days": 5}, "momentum": {"window_days": 20}},
        gate_params={**HygieneGate.default_params, "min_listed_days": 0},
        top_n=10,
    )
    result = screener.run(ctx)
    assert result.survivors_count == 1                  # SMALL은 게이트 탈락
    assert result.ranked.index[0] == "GOOD"