"""520-6 배수유역 확장 한 번 셈 · 노선 무관 방향장 저장본.

- 한 번 셈(큰 방향장 전체 판정 → 도로로 오는 셀 + 띠 ∪ 1차 영역으로 자름) = 회차 확장과 도로로
  오는 셀 · 도로 셀 귀속이 셀마다 같음(합성 등고선 · 능선까지 비탈).
- 방향장 열쇠 · 짓기가 노선 최저점 하한과 무관 — 하한이 달라도 저장본 하나를 읽기만.
"""

import numpy as np
from shapely.geometry import LineString

from B04_PreProcess import B04_PreProcess_Engine_Watershed_Expand as expand
from B04_PreProcess.B04_PreProcess_Engine_Watershed_Flow import trace_flow
from B04_PreProcess.B04_PreProcess_Engine_Watershed_Grid import GridSpec


def _ridge_contours():
    """도로 북쪽 비탈 — y = −60 능선까지 오르고 그 밖 · 도로 남쪽은 내려감(곧은 등고선)."""
    features = []
    for y in range(-250, 0, 5):
        level = 290.0 - abs(y + 60.0)
        features.append(
            {
                "geometry": {"type": "LineString", "coordinates": [[0.0, y], [300.0, y]]},
                "properties": {"elevation": level},
            }
        )
    return features


def _case():
    spec = GridSpec(x_min=110.0, y_max=-130.0, cell_m=1.0, n_rows=40, n_cols=80)
    domain = np.zeros((40, 80), bool)
    domain[5:35, 5:75] = True
    route = LineString([(120.0, -150.0), (180.0, -150.0)])
    return spec, domain, route


def _run(monkeypatch, once, floor=None, store=None):
    monkeypatch.setattr(expand, "DESCENT_SPARE_M", 60.0)
    if not once:
        monkeypatch.setattr(expand, "_expand_once", lambda *args: None)
    spec, domain, route = _case()
    return expand.expand_by_red_boundary(
        spec, domain, _ridge_contours(), route, [], floor, band_m=10.0, descent_store=store
    )


def _world(analysis):
    """도로로 오는 셀 → {(x, y): 도로 셀 누가거리}."""
    spec = analysis.spec
    routing = trace_flow(analysis.terrain, analysis.road)
    red = analysis.flow.reaches_road & analysis.flow.analyzed
    chainage = analysis.road.chainage
    out = {}
    for index in np.flatnonzero(red):
        slot = routing.road_slot[index]
        x = spec.x_min + (index % spec.n_cols) * spec.cell_m
        y = spec.y_max - (index // spec.n_cols) * spec.cell_m
        out[(round(x, 3), round(y, 3))] = None if slot < 0 else round(float(chainage[slot]), 3)
    return out


def test_once_matches_round_expansion(monkeypatch):
    rounds = _run(monkeypatch, once=False)
    monkeypatch.undo()
    once = _run(monkeypatch, once=True)
    assert rounds.rounds >= 2 and rounds.closed  # 회차 확장이 실제로 여러 번 넓힘
    assert once.closed and once.rounds == 1 and once.added_cells > 0
    old, new = _world(rounds.analysis), _world(once.analysis)
    assert len(old) > 3_000
    assert old == new


def test_descent_key_and_build_ignore_floor(tmp_path, monkeypatch):
    built = []
    real = expand.build_contour_descent

    def counting(*args, **kwargs):
        built.append(args[2:] + tuple(kwargs.values()))
        return real(*args, **kwargs)

    monkeypatch.setattr(expand, "build_contour_descent", counting)
    store = (tmp_path, "도엽-1")
    low = _run(monkeypatch, once=True, floor=None, store=store)
    high = _run(monkeypatch, once=True, floor=230.0, store=store)
    assert len(built) == 1 and built[0] == ()  # 하한 없이 한 번만 지음 · 두 번째는 읽기만
    assert len(list(tmp_path.glob("descent_*.npz"))) == 1
    assert _world(low.analysis) == _world(high.analysis)