/* =============================================================================
 * B06_Section_Cross_Enforce.ts
 * 계산 묶음 cross 단계의 [확정] 보정(PLAN 349-0n) — 서버 `_enforce_stored_designs` 차례 그대로
 * (미교차 넓힘 → 포장 구간 → 세월교 노면 하강 → 사토장 맨 뒤). 넓힘은 `B06_Section_Cross_Stage`.
 *
 *   facilityRanges · facilityAt  새 노선 관 · 구조물 자리 → 측점마다 포장 · 기울임 · 노면 하강.
 *     ⚠ ① 짝 — `B06_Section_Router_Design.py` `pavement_ranges` · `ford_surface_drops` · `paved_at` ·
 *     `ford_drop_at` + `B06_Section_Engine_Tilt.py` `tilt_ranges` · `tilt_args`.
 *   spoilSites · enforceSpoilFills  사토장 기준 측점 하나 · 용량에서 폭 하나(이분법).
 *     ⚠ ① 짝 — `B06_Section_Engine_SpoilFill.py` `spoil_sites` · `enforce_spoil_fills`.
 *   거울 시험 `resources/tester/test_349_0n_cross_enforce_mirror.py`.
 * 세트 · 포장 · 맹암거 제원은 이미 있는 짝(`buildCulvertSets` · `pavementSpecsFrom` · `underdrainSpecsFrom`).
 * 순수 — 화면 · fetch · 세션 없음.
 * ========================================================================== */

import { buildCulvertSets, type CulvertPipePoint } from "@util/common_util_culvert_sets";
import { catalogRow } from "@util/common_util_structure_catalog";
import {
  pavementSpecsFrom,
  type PavementStructureInput,
} from "@util/common_util_structure_pavement";
import { underdrainSpecsFrom, type UnderdrainInput } from "@util/common_util_structure_underdrain";

/** 포장 · 기울임 · 노면 하강 판정 폭(m) — 파이썬 `EDGE_TOLERANCE_M` · `_FORD_DROP_TOLERANCE_M`. */
const EDGE_M = 0.02;

export type FacilityStructure = PavementStructureInput &
  UnderdrainInput & { structure_id?: string | null };

export interface FacilityRanges {
  paved: Array<[number, number]>;
  tilt: Array<[number, number, number | null]>;
  drops: Array<[number, number]>;
}

const num = (value: unknown): number | null => {
  const parsed = typeof value === "string" && value.trim() ? Number(value) : value;
  return typeof parsed === "number" && Number.isFinite(parsed) ? parsed : null;
};

/** 관 · 구조물 → 포장 구간 · 기울임 구간 · 세월교 하강(서버와 같은 차례 — 첫 것이 이김). */
export function facilityRanges(
  pipes: readonly CulvertPipePoint[],
  structures: readonly FacilityStructure[],
): FacilityRanges {
  // ponytail: 레지스트리 기본값 없이 세트를 지음 — 물넘이 폭 · 경사를 비운 관만 기본 상수(10 m · 3°)
  const sets = buildCulvertSets(pipes, {});
  const pavementIds = new Set(
    structures.filter((s) => catalogRow(s.type_id)?.shape === "pavement").map((s) => s.type_id),
  );
  const paved: FacilityRanges["paved"] = pavementSpecsFrom(structures, pavementIds).map((s) => [
    s.start_m,
    s.end_m,
  ]);
  const tilt: FacilityRanges["tilt"] = [];
  const drops: FacilityRanges["drops"] = [];
  for (const [at, spec] of sets) {
    if (spec.type === "ford_pavement") {
      const half = (num(spec.span_m) ?? 0) / 2;
      paved.push([at - half, at + half]);
      tilt.push([at - half, at + half, num(spec.slope_pct)]);
    }
    const depth = num(spec.overflow_depth_m) ?? 0;
    if (spec.type === "ford" && depth > 0) drops.push([at, depth]);
  }
  for (const drain of underdrainSpecsFrom(structures))
    tilt.push([drain.chainage_m, drain.chainage_m, drain.slope_pct]);
  return { paved, tilt, drops };
}

/** 그 측점의 포장 · 기울임 · 노면 하강 — 횡단 엔진 입력 칸 이름 그대로. */
export function facilityAt(ranges: FacilityRanges, chainageM: number) {
  const inside = (start: number, end: number) =>
    start - EDGE_M <= chainageM && chainageM <= end + EDGE_M;
  const hit = ranges.tilt.find(([start, end]) => inside(start, end));
  return {
    paved: ranges.paved.some(([start, end]) => inside(start, end)),
    tilted: hit !== undefined,
    tiltPct: hit?.[2] ?? null,
    surfaceDropM: ranges.drops.find(([at]) => Math.abs(chainageM - at) <= EDGE_M)?.[1] ?? 0,
  };
}

/* ── 사토장 ───────────────────────────────────────────────────────────── */

const SOLVE_STEPS = 24;
const MAX_PROBE_WIDTH_M = 1000;
const SIDE_AUTO = "자동(성토 쪽)";
/** 단면 유형 → [좌, 우] 성토면인가(파이썬 `structure_face_role` 표). */
const FILL_SIDES: Record<string, [boolean, boolean]> = {
  left_cut: [false, true],
  right_cut: [true, false],
  both_cut: [false, false],
  both_fill: [true, true],
};

export interface SpoilSite {
  structureId: string | null;
  chainageM: number;
  capacityM3: number;
  sideOption: unknown;
  slopeRatioN: unknown;
  extraDistanceM: unknown;
}

/** 배치된 사토장만 — 기준 측점 · 용량 > 0(서버 정본 읽기 = 구조물 객체 길 · 시작 측점으로 갈음 안 함). */
export function spoilSites(structures: readonly FacilityStructure[]): SpoilSite[] {
  return structures.flatMap((item) => {
    if (catalogRow(item.type_id)?.shape !== "spoil") return [];
    const options = (item.options ?? {}) as Record<string, unknown>;
    const chainage = num(item.chainage_m);
    const capacity = num(options.capacity_m3);
    if (chainage === null || capacity === null || capacity <= 0) return [];
    return [
      {
        structureId: item.structure_id ?? null,
        chainageM: chainage,
        capacityM3: capacity,
        sideOption: options.side,
        slopeRatioN: options.fill_slope_ratio,
        extraDistanceM: options.extra_distance_m,
      },
    ];
  });
}

/** 쌓는 쪽 — 「좌 · 우」 그대로 · 「자동」 · 빈칸 = 그 측점 성토면(좌 먼저) · 못 가르면 null. */
export function spoilSideOf(
  design: Record<string, unknown>,
  option: unknown,
): "left" | "right" | null {
  const word = String(option ?? "").trim();
  if (word === "좌") return "left";
  if (word === "우") return "right";
  if (word && word !== SIDE_AUTO) return null;
  const sides = FILL_SIDES[String(design.section_mode ?? "")];
  if (!sides) return null;
  return sides[0] ? "left" : sides[1] ? "right" : null;
}

type Design = Record<string, unknown>;

/** 측점 하나 — 설계 + 사토장 폭으로 다시 셈(못 세면 null). */
export interface SpoilStation {
  chainageM: number;
  design: Design | null;
  recompute: (side: "left" | "right", widthM: number, slopeRatioN: unknown) => Design | null;
}

const round4 = (value: number) => Math.round(value * 1e4) / 1e4;

/** 사토장 측점 설계를 다시 셈 — `stations[i].design` 을 갈아 끼움 · 바뀐 측점 수. */
export function enforceSpoilFills(stations: SpoilStation[], sites: readonly SpoilSite[]): number {
  const chainages = [...new Set(stations.map((s) => s.chainageM))].sort((a, b) => a - b);
  const spanOf = (here: number) => {
    const index = chainages.indexOf(here);
    const left = index ? chainages[index - 1] : here;
    const right = index + 1 < chainages.length ? chainages[index + 1] : here;
    return (right - left) / 2;
  };
  let changed = 0;
  for (const site of sites) {
    if (!stations.length) continue;
    // 기준 측점에 가장 가까운 측점 하나(가운데면 앞 측점)
    const station = stations.reduce((best, s) => {
      const gap = Math.abs(s.chainageM - site.chainageM);
      const bestGap = Math.abs(best.chainageM - site.chainageM);
      return gap < bestGap || (gap === bestGap && s.chainageM < best.chainageM) ? s : best;
    });
    const span = spanOf(station.chainageM);
    const side = spoilSideOf(station.design ?? {}, site.sideOption);
    const volume = (widthM: number): [number, Design | null] => {
      if (side === null || widthM <= 0 || !station.design) return [0, null];
      const design = station.recompute(side, widthM, site.slopeRatioN);
      return [design ? (num(design.spoil_fill_area_m2) ?? 0) * span : 0, design];
    };
    const limit = num(volume(MAX_PROBE_WIDTH_M)[1]?.spoil_fill_max_width_m) ?? 0;
    if (limit <= 0) continue;
    let [total, design] = volume(limit);
    if (total > site.capacityM3) {
      let low = 0;
      let high = limit;
      for (let step = 0; step < SOLVE_STEPS; step += 1) {
        const mid = (low + high) / 2;
        if (volume(mid)[0] < site.capacityM3) low = mid;
        else high = mid;
      }
      [total, design] = volume(round4(high));
    }
    if (!design) continue;
    station.design = {
      ...design,
      spoil_fill_capacity_m3: round4(site.capacityM3),
      spoil_fill_placed_m3: round4(total),
      spoil_fill_unplaced_m3: round4(Math.max(site.capacityM3 - total, 0)),
      spoil_fill_structure_id: site.structureId,
      spoil_fill_extra_distance_m: site.extraDistanceM,
    };
    changed += 1;
  }
  return changed;
}