"""예정노선 따라가기 곡선 최적(758-1 · 요구 598-1) — 따라간 선에 「토공 최소」와 같은 둘째 단계.

`B05_Profile_Route_Polyline_Write.followed_table`(체인 처음 · `/route/follow` · 받은 노선으로) ·
추천 「예상노선 추적」(`..._RouteInitial.generate_initial_route` `follow_line`)이 같이 부름.

차례(`merged_follow`) = ① 예정노선 폴리라인(꺾임점 · 묶기 · R 맞춤 · 기본 규칙) → 큰 R
(`..._Radius.widen`) → 꺾임만 곡선으로(`curve_every_kink`) → 같은 쪽 이웃 곡선 합치기
(`..._Merge.merge_same_side`) → ② 곡선 MC 일반측점 맞춤. 큰 R · 합치기 · 측점 맞춤 모두 직접 잼
(`Guard` · 지형 · 계류 격자 · 토공 최소 갈래와 같은 판 — 이격도 판 `keeping_offset` 은 합치기 0 ·
측점 맞춤이 더 벗어나 안 씀) · 합치기 멈춤 = 못 지킨 곳 수 · 노선 횡단 토공 +10 %.
지형이 없으면(`FollowLand` None) 부르는 쪽이 옛 길(순수 기하 `snapped_initial`)을 씀.
"""

from __future__ import annotations

import math
from collections import OrderedDict
from dataclasses import dataclass
from typing import Any

import numpy as np
from shapely.geometry import LineString

from B05_Profile.B05_Profile_Engine_RouteInitial_CrossEarth import (
    cross_earthwork,
    cross_earthwork_delta,
)
from B05_Profile.B05_Profile_Engine_RouteInitial_Merge import Guard, RouteEarth, merge_same_side
from B05_Profile.B05_Profile_Engine_RouteInitial_Metrics import STATION_M, route_metrics
from B05_Profile.B05_Profile_Engine_RouteInitial_Pool import hard_limits
from B05_Profile.B05_Profile_Engine_RouteInitial_Radius import curve_every_kink, widen
from B05_Profile.B05_Profile_Engine_RouteInitial_Search import (
    CORRIDOR_M,
    ROAD_WIDTH_M,
    SearchGrid,
    Terrain,
)
from B05_Profile.B05_Profile_Engine_RouteInitial_Station import snap_curves_to_stations
from common_util.common_util_route_polyline import PlannedPolyline, build_planned_polyline

Xy = tuple[float, float]
# 같은 입력 다시 셈 막기(끌 때 · 체인 · 추천이 같은 선을 거듭 부름) — 최근 몇 벌만
MEMO_SIZE = 8
_MEMO: OrderedDict[tuple, PlannedPolyline] = OrderedDict()


@dataclass(frozen=True)
class FollowLand:
    """따라가기 곡선 최적의 지형 · 제약 — 추천 엔진과 같은 풀이 값(`resolve_inputs` 뒤)."""

    terrain: Terrain
    streams: list[list[Xy]]
    max_grade: float
    stream_offset_m: float
    grade_smooth_m: float
    target_grade: float
    standard: dict[str, Any] | None = None
    corridor_m: float = CORRIDOR_M


def cross_total(line: PlannedPolyline, terrain: Terrain, standard: dict[str, Any] | None) -> float:
    """합치기 멈춤 잣대 — 계획고 지반고 횡단 토공(1차 종단 규칙 · 종단 끔과 같음) · 못 재면 inf."""
    try:
        found = cross_earthwork(
            line.vertices,
            None,
            None,
            terrain,
            standard,
            design_curves=[curve.as_dict() for curve in line.curves],
        )
    except ValueError:
        return math.inf
    return found["cut"] + found["fill"]


def cross_delta(
    before: PlannedPolyline,
    after: PlannedPolyline,
    window: tuple[float, float],
    terrain: Terrain,
    standard: dict[str, Any] | None,
) -> float:
    """바뀐 자리 측점만 횡단 토공 차 — 뒤 측점은 같은 선 따라 밀림(옛 끝 s1 → 새 s1 + 연장 차)."""
    shift = LineString(after.vertices).length - LineString(before.vertices).length
    first = math.ceil(window[0] / STATION_M) * STATION_M
    try:
        return cross_earthwork_delta(
            before.vertices,
            after.vertices,
            np.arange(first, window[1] + shift + 1e-9, STATION_M),
            terrain,
            standard,
            before_chainages=np.arange(first, window[1] + 1e-9, STATION_M),
            design_curves_before=[curve.as_dict() for curve in before.curves],
            design_curves_after=[curve.as_dict() for curve in after.curves],
        )["earth"]
    except ValueError:
        return math.inf


def merged_follow(
    points: list[Xy], min_radius_m: float, land: FollowLand, grid: SearchGrid | None = None
) -> PlannedPolyline:
    """예정노선 점 묶음 → 곡선 최적 · 측점 맞춘 폴리라인(못 맞추면 맞추기 전 선). `grid` = 이미 짠
    탐색 격자(같은 예정노선 · 추천 묶음) · 없으면 짬."""
    key = (
        tuple((float(x), float(y)) for x, y in points),
        round(min_radius_m, 6),
        land.terrain.signature or id(land.terrain),
        land.max_grade,
        land.stream_offset_m,
        land.grade_smooth_m,
        land.target_grade,
        land.corridor_m,
        repr(land.standard),
        len(land.streams),
    )
    if key in _MEMO:
        _MEMO.move_to_end(key)
        return _MEMO[key]

    def measure(line: PlannedPolyline) -> dict[str, Any]:
        # 추천 「예상노선 추적」 잣대(follow · 못 지킨 곳 = R · 계류 · 측점 · 원지반 기울기 참고)
        return hard_limits(
            route_metrics(
                line.vertices,
                points,
                land.terrain,
                land.streams,
                line.curves,
                max_grade=land.max_grade,
                min_radius_m=min_radius_m,
                stream_offset_m=land.stream_offset_m,
                road_width_m=ROAD_WIDTH_M,
                bound_pct=None,
                grade_smooth_m=land.grade_smooth_m,
                follow=True,
                target_grade=land.target_grade,
            )
        )

    if grid is None:
        grid = SearchGrid(
            points,
            land.terrain,
            land.streams,
            stream_offset_m=land.stream_offset_m,
            grade_smooth_m=land.grade_smooth_m,
            target_grade=land.target_grade,
            corridor_m=land.corridor_m,
        )
    guard = Guard(grid, land.max_grade)
    outline = build_planned_polyline(points, min_radius_m=min_radius_m)
    route = (outline, measure(outline))
    larger = widen(outline, points, min_radius_m, guard=guard)
    if larger is not outline:
        trial = (larger, measure(larger))
        if trial[1]["over_limit"]["total"] <= route[1]["over_limit"]["total"]:
            route = trial
    kinked = curve_every_kink(route[0], min_radius_m)
    if kinked is not route[0]:
        route = (kinked, measure(kinked))
    route = merge_same_side(
        route,
        guard,
        min_radius_m,
        measure,
        RouteEarth(
            lambda line: cross_total(line, land.terrain, land.standard),
            lambda before, after, window: cross_delta(
                before, after, window, land.terrain, land.standard
            ),
        ),
    )
    snapped = snap_curves_to_stations(route[0], min_radius_m, guard=guard)
    found = route[0] if snapped is None else snapped
    _MEMO[key] = found
    while len(_MEMO) > MEMO_SIZE:
        _MEMO.popitem(last=False)
    return found