/* =============================================================================
 * B06_Section_UI_Cross_Body_Guard.ts
 * 세월교 · 박스 유입 · 유출 흙막이(73-4) — 관보호공 흙막이와 **같은 벽 · 같은 자리 규칙**.
 *
 * 세트는 배관 흙막이와 같은 `section.culvert`(관 숨김 · `body`)로 얹혀 그림 · 연동 · 경사 · 3D ·
 * 면적 길을 그대로 탐. 다른 점은 자동 자리 하나 — 벽 전면이 관(세월교) · 본체(박스) 끝에 옴
 * (배관 벽 전면이 관 끝인 것과 같음). 좌우 x 는 그 자리 기준 · 상하 d 는 배관과 같은 절대값.
 * 본체가 이 측점에 없으면(연동 옆 측점) 배관 규칙 그대로 — 소유 측점 값을 절대값으로 넘겨 받음.
 * ========================================================================== */

import type { CrossSection, SectionSample } from "./B06_Section_Api_Fetch";
import { computeBoxLayout, DEFAULT_BOX_SIDE_ADJUST } from "./B06_Section_UI_Cross_Box_Geom";
import type { BoxLayout } from "./B06_Section_UI_Cross_Box_Geom";
import { FILL_SLOPE_RATIO_MIN } from "./B06_Section_UI_Cross_Culvert_Const";
import { outletPipeEnd } from "./B06_Section_UI_Cross_Culvert_Tiers";
import type {
  CulvertDesignTrim,
  CulvertLayout,
  OffsetPoint,
  WallAdjust,
  WallLayout,
} from "./B06_Section_UI_Cross_Culvert_Types";
import { computeFordLayout, DEFAULT_FORD_WALL_ADJUST } from "./B06_Section_UI_Cross_Ford_Geom";
import type { FordLayout } from "./B06_Section_UI_Cross_Ford_Geom";
import { buildRevetWallGeometry } from "./B06_Section_UI_Cross_Wall";

type Role = "inlet" | "outlet";

/** 본체 끝(관 invert · 박스 저판 밑) + 본체 설계선 트림 — 본체가 이 측점에 없으면 null. */
export interface BodyGuardBase {
  ends: Record<Role, OffsetPoint | null>;
  trim: CulvertDesignTrim;
}

export function bodyGuardBase(
  section: CrossSection,
  samples: SectionSample[],
): BodyGuardBase | null {
  const body = section.culvert?.body;
  const adjust = section.design;
  if (body === "box" && section.box) {
    const layout = computeBoxLayout(section, samples, {
      left: { ...DEFAULT_BOX_SIDE_ADJUST, ...(adjust?.box_adjust?.left ?? {}) },
      right: { ...DEFAULT_BOX_SIDE_ADJUST, ...(adjust?.box_adjust?.right ?? {}) },
    });
    if (!layout) return null;
    const inletOnLeft = (section.uphill_side ?? "left") === "left";
    const endOf = (role: Role): OffsetPoint | null => {
      const side = layout.sides.find(
        (s) => (s.role === "left") === ((role === "inlet") === inletOnLeft),
      );
      return side ? { offset: side.offset, elevation: side.bottomElevation } : null;
    };
    return { ends: { inlet: endOf("inlet"), outlet: endOf("outlet") }, trim: layout.designTrim };
  }
  if (body === "ford" && section.ford) {
    const layout = computeFordLayout(section, samples, {
      inlet: { ...DEFAULT_FORD_WALL_ADJUST, ...(adjust?.ford_adjust?.inlet ?? {}) },
      outlet: { ...DEFAULT_FORD_WALL_ADJUST, ...(adjust?.ford_adjust?.outlet ?? {}) },
    });
    if (!layout) return null;
    const endOf = (role: Role): OffsetPoint | null =>
      layout.sides.find((s) => s.role === role)?.pipeEnd ?? null;
    return { ends: { inlet: endOf("inlet"), outlet: endOf("outlet") }, trim: layout.designTrim };
  }
  return null;
}

/**
 * 벽 전면을 본체 끝에 맞춘 배관 벽 4축(x · d) — `placePipeWall` 역산.
 * 바닥 기준(invert) = 본체 끝 표고 · 상단 = 노견 − d/1.2 · 자리 = 0점 + (x + d).
 */
export function bodyGuardAxes(
  end: OffsetPoint,
  wall: {
    autoOffset: number;
    outward: number;
    height: number;
    edgeElevation: number;
    lean: number;
    thickness: number;
  },
): { x: number; d: number } {
  const d = FILL_SLOPE_RATIO_MIN * (wall.edgeElevation - wall.height - end.elevation);
  // 전면 위치는 자리(offset)에 평행이동만 함 — 0 에 세워 재고 옮김(노면 멈춤도 같게).
  const probe = buildRevetWallGeometry({
    anchor: { offset: 0, elevation: end.elevation },
    outward: wall.outward,
    height: wall.height,
    material: "dry",
    role: "outlet",
    thickness: wall.thickness,
    lean: wall.lean,
    roadElevation: wall.edgeElevation,
  });
  const anchorOffset = end.offset - outletPipeEnd(probe).offset;
  return { x: (anchorOffset - wall.autoOffset) * wall.outward - d, d };
}

/** 벽이 선 쪽은 흙막이 트림 · 안 선 쪽은 본체 트림(73-4). 벽이 하나도 없으면 null. */
export function mergeGuardTrim(
  guard: CulvertDesignTrim,
  body: CulvertDesignTrim,
  walls: readonly WallLayout[],
): CulvertDesignTrim | null {
  if (!walls.length) return null;
  const max = walls.some((w) => w.outward > 0) ? guard : body;
  const min = walls.some((w) => w.outward < 0) ? guard : body;
  return {
    minOffset: min.minOffset,
    maxOffset: max.maxOffset,
    minElevation: min.minElevation,
    maxElevation: max.maxElevation,
    minSlope: min.minSlope,
    maxSlope: max.maxSlope,
  };
}

/** 소유 측점 적용값(x = 본체 기준) → 옆 측점이 받을 절대값 — 옆 측점엔 본체가 없음. */
export function bodyAbsolute(layout: CulvertLayout): CulvertLayout["revetShift"] {
  const shift = layout.revetShift;
  const bodyX = layout.bodyX;
  if (!bodyX) return shift;
  const plus = (adjust: WallAdjust, dx: number): WallAdjust => ({ ...adjust, x: adjust.x + dx });
  return {
    ...shift,
    inlet: plus(shift.inlet, bodyX.inlet),
    outlet: plus(shift.outlet, bodyX.outlet),
  };
}

/** 흙막이가 선 쪽의 본체 성토선을 걷음 — 그 쪽 성토선은 흙막이 벽이 냄(두 줄 방지). */
export function withoutGuardedFill<T extends BoxLayout | FordLayout>(
  layout: T | null,
  culvert: CulvertLayout | null,
): T | null {
  if (!layout || !culvert?.culvert.body) return layout;
  const guarded = (outward: number): boolean => culvert.walls.some((w) => w.outward === outward);
  if ("box" in layout && "topSlab" in layout) {
    const sides = layout.sides.map((side) =>
      guarded(side.role === "left" ? 1 : -1) ? { ...side, fillLine: [] } : side,
    );
    return { ...layout, sides };
  }
  const ford = layout as FordLayout;
  const sides = ford.sides.map((side) =>
    guarded(side.outward) ? { ...side, fillSegments: [] } : side,
  );
  return { ...ford, sides } as T;
}