/* =============================================================================
 * A00_Common/design/logic/design_calc_node_follow.ts
 * 계산 Node 입구(`design_calc_node.ts`)의 따라감 몫(PLAN 472-4 ①) — 측점 열쇠 · 시설 따라감 · 추가 측점 ·
 * 꼭짓점 세움. 브라우저 묶음이 쓰는 같은 TS 를 부름 · 파이썬은 `common_util_calc_runner.run_calc` 로.
 *
 *   profile.seat  입력 seat { ground_s · ground_z(저장 선형 표본) · policy(파이썬 `AlignmentPolicy.as_dict`) ·
 *                 base_pvi(옮기기 전) · base(옮긴 꼭짓점) · born · held } → 꼭짓점 목록(`seatBornNodes`)
 *   facility.follow  입력 follow { items: [{ placement · chainage_m · start_m · end_m · x · y }] · line ·
 *                 max_drift_m · interval_m(site 맞춤 간격) } → [{ item · drift_m · far }](`followStructures`)
 *                 — follow.fill { previous?: { structure_id: 항목 } · only_missing } 있으면 = 저장 좌표 맞춤(같은 F1 ·
 *                 511-B B-5) → { xy: [{ x · y } | null(그대로)] · filled }(`fillStructureCoordinates` · items 에 structure_id)
 *   facility.plus_follow  입력 plus { rows: [{ chainage_m · x · y }] · line: [[x, y]](새 노선) } →
 *                 { rows: [{ chainage_m · x · y }](`followPlusRows` · 정수 m · 같은 m 하나) · moved: 옮긴 수 }
 * ========================================================================== */

import { seatBornNodes } from "../../../B05_Profile/logic/B05_Profile_Grade_Seat";
import {
  fillStructureCoordinates,
  followPlusRows,
  followStructures,
  type FollowingStructure,
} from "@util/common_util_route_follow";
import type {
  AlignmentNode,
  AlignmentPolicy,
} from "../../../B05_Profile/logic/B05_Profile_UI_Profile_Alignment";

type Line = Array<[number, number]>;
const xyOf = (line: Line) => line.map(([x, y]) => ({ x, y }));

export interface FollowInputs {
  follow?: {
    items: Array<FollowingStructure & { structure_id?: string | null }>;
    line: Line;
    max_drift_m?: number;
    interval_m?: number | null;
    fill?: { previous?: Record<string, FollowingStructure> | null; only_missing?: boolean };
  };
  plus?: { rows: Array<{ chainage_m: number; x?: number | null; y?: number | null }>; line: Line };
  seat?: {
    ground_s: number[];
    ground_z: number[];
    policy: AlignmentPolicy;
    base_pvi: AlignmentNode[];
    base: AlignmentNode[];
    born: number[];
    held?: number[];
  };
}

/** id → 셈(입구 `RUNNERS` 에 얹음). */
export function followRunners(inputs: FollowInputs): Record<string, () => unknown> {
  return {
    "profile.seat": () => {
      const seat = inputs.seat;
      if (!seat) return null;
      const base = {
        chainage: seat.ground_s,
        ground: seat.ground_z,
        policy: seat.policy,
        basePvi: seat.base_pvi,
      };
      return seatBornNodes(base, seat.base, seat.born, seat.held ?? []);
    },
    "facility.follow": () => {
      const follow = inputs.follow;
      if (!follow) return null;
      if (follow.fill)
        return fillStructureCoordinates(
          follow.items,
          xyOf(follow.line),
          follow.fill.previous ?? null,
          follow.fill.only_missing ?? false,
          follow.interval_m ?? null,
        );
      return followStructures(
        follow.items,
        xyOf(follow.line),
        follow.max_drift_m,
        follow.interval_m ?? null,
      );
    },
    "facility.plus_follow": () => {
      const plus = inputs.plus;
      if (!plus) return null;
      const line = xyOf(plus.line);
      const moved = followStructures(plus.rows, line).filter(
        ({ item }, index) => item.chainage_m !== plus.rows[index].chainage_m,
      ).length;
      const rows = followPlusRows(plus.rows, line).map(({ chainage_m, x, y }) => ({
        chainage_m,
        x: x ?? null,
        y: y ?? null,
      }));
      return { rows, moved };
    },
  };
}