/* =============================================================================
 * A00_Common/design/logic/design_pipeline_probe_station.ts
 * 아무 누가거리 측점 하나(368-4) — [측점 추가] 뒤 묶음 stations 단계(`buildStations`)가 낼 그 측점과 같은
 * 자리 · 틀 · 방위 · 반경 · 확폭(기존 측점 + 그 자리 누가거리로 셈) · 열쇠 = 추가 측점(`structure:plus-{m}`).
 * 거울 시험 = `resources/tester/test_368_4_probe_station.py`(buildStations + 추가 측점과 대조).
 * ========================================================================== */

import { stationFrameAt } from "../../../B05_Profile/logic/B05_Profile_UI_RouteEdit_Frame";
import {
  curveWidenings,
  designCurveWidenings,
  designSpans,
  planRadii,
  stationKey,
} from "../../../B05_Profile/logic/B05_Profile_Sections_Stations";
import { PLUS_OWNER_PREFIX } from "../../../common_util/common_util_structure_station";
import type { DesignCurve, PipelineStation, Vertex } from "./design_pipeline_types";

const round = (value: number, digits: number): number => Number(value.toFixed(digits));

/** 그 자리 측점(지반 전) — 노선 밖이면 null. `stations` = 지금 묶음 측점(반경 · 확폭 테이퍼 이웃). */
export function probeStation(
  line: ReadonlyArray<Vertex>,
  curves: ReadonlyArray<DesignCurve>,
  stations: ReadonlyArray<PipelineStation>,
  chainageM: number,
): PipelineStation | null {
  const frame = stationFrameAt(line, chainageM);
  if (!frame) return null;
  const chainages = [...stations.map((s) => s.chainageM), chainageM].sort((a, b) => a - b);
  const index = chainages.indexOf(chainageM);
  const spans = designSpans(line, curves);
  let radius: number | null;
  let side: "left" | "right" | null;
  let widening: number;
  if (spans.length) {
    const out = designCurveWidenings(chainages, spans);
    [radius, side, widening] = [out.radii[index], out.sides[index], out.widenings[index]];
  } else {
    const total = Math.max(...stations.map((s) => s.chainageM), chainageM);
    const measured = planRadii(line, chainages, total);
    const tapered = curveWidenings(chainages, measured.radii, measured.sides);
    [radius, side, widening] = [
      measured.radii[index],
      tapered.sides[index],
      tapered.widenings[index],
    ];
  }
  const tangent: Vertex = [frame.left[1], -frame.left[0]];
  const owner = `${PLUS_OWNER_PREFIX}${Math.round(chainageM)}`;
  return {
    key: stationKey("structure", owner, "anchor"),
    chainageM: round(chainageM, 6),
    x: round(frame.origin[0], 6),
    y: round(frame.origin[1], 6),
    azimuthDeg: round(((Math.atan2(tangent[0], tangent[1]) * 180) / Math.PI + 360) % 360, 6),
    left: [round(frame.left[0], 9), round(frame.left[1], 9)],
    kind: "structure",
    id: owner,
    ground: null,
    planRadiusM: radius,
    curveOuterSide: side,
    curveWideningM: widening,
  };
}