/**
 * 교대 확대기초 · 말뚝 평면 삽도 (2026-11-04, 시안 ② 확대기초·말뚝 카드). 순수 문자열 함수.
 * 생성본 값으로 그린다: 저판(skew 평행사변형, 굵은 선), 벽체 윤곽(실선), 교대축(점선), 말뚝 3열(원), 열 위치, 폭 치수.
 * 가로(s)와 세로(t) 축척이 같다. 위가 전면, 아래가 배면이다.
 */

export interface AbutFootingDrawing {
  /** 교대축 길이 L (m). */
  lengthM: number;
  /** s per m of t along the wing (skew): s = s_axis + k·t. */
  skewK: number;
  /** t (m): 저판 앞굽 끝, 뒷굽 끝, 벽체 전면, 벽체 배면. */
  footingFrontM: number;
  footingBackM: number;
  wallFrontM: number;
  wallBackM: number;
  /** 말뚝 열: t (m), s (m, 교대축 기준, skew 전), 열 이름 (1열 · 전면 …). */
  rows: { t: number; s: number[]; name: string }[];
  pileDiameterM: number;
  /** 열 위치 치수 (mm, 배면부터): 배면 연단, 간격, 간격, 전면 연단. */
  rowDimsMm: [number, number, number, number];
  footingWidthMm: number;
}

const INK = '#18212b';
const MUTED = '#55606e';
const label = (x: number, y: number, s: string, anchor = 'start', fill = INK) =>
  `<text x="${x.toFixed(1)}" y="${y.toFixed(1)}" text-anchor="${anchor}" font-size="11" fill="${fill}" font-family="JetBrains Mono, monospace">${s}</text>`;

export function abutFootingPlanSvg(d: AbutFootingDrawing): string {
  const k = 36; // px per m, both directions
  const sMin = Math.min(d.skewK * d.footingFrontM, d.skewK * d.footingBackM) - 0.4;
  const sMax = d.lengthM + Math.max(d.skewK * d.footingFrontM, d.skewK * d.footingBackM) + 0.4;
  const tTop = d.footingFrontM + 0.4;
  const X = (s: number, t: number) => 20 + (s + d.skewK * t - sMin) * k;
  const Y = (t: number) => 14 + (tTop - t) * k;
  const W = 20 + (sMax - sMin) * k + 170;
  const H = Y(d.footingBackM - 0.4) + 34;
  const quad = (t0: number, t1: number, style: string) =>
    `<polygon points="${[[0, t0], [d.lengthM, t0], [d.lengthM, t1], [0, t1]].map(([s, t]) => `${X(s, t).toFixed(1)},${Y(t).toFixed(1)}`).join(' ')}" ${style}/>`;
  const parts: string[] = [];
  parts.push(quad(d.footingBackM, d.footingFrontM, `fill="#e6ebf0" stroke="${INK}" stroke-width="2"`));
  parts.push(quad(d.wallBackM, d.wallFrontM, `fill="none" stroke="${MUTED}"`));
  parts.push(`<line x1="${X(0, 0).toFixed(1)}" y1="${Y(0).toFixed(1)}" x2="${X(d.lengthM, 0).toFixed(1)}" y2="${Y(0).toFixed(1)}" stroke="#c0392b" stroke-dasharray="6 3"/>`);
  parts.push(label(X(d.lengthM, 0) + 6, Y(0) + 4, '교대축', 'start', '#c0392b'));
  const r = Math.max(2, (d.pileDiameterM / 2) * k);
  for (const row of d.rows) {
    for (const s of row.s) parts.push(`<circle cx="${X(s, row.t).toFixed(1)}" cy="${Y(row.t).toFixed(1)}" r="${r.toFixed(1)}" fill="#ffffff" stroke="${INK}"/>`);
    const tLabel = `${row.t >= 0 ? '+' : '−'}${Math.round(Math.abs(row.t) * 1000)}`;
    parts.push(label(X(d.lengthM, row.t) + r + 8, Y(row.t) + 4, `${row.name} · t ${tLabel} · ${row.s.length}본`));
  }
  const [e1, g1, g2, e2] = d.rowDimsMm;
  parts.push(label(20, H - 10, `${d.footingWidthMm} = 뒷굽쪽 ${e1} · ${g1} · ${g2} · ${e2} 전면 · 위 = 전면`, 'start', MUTED));
  return [
    `<svg viewBox="0 0 ${W.toFixed(0)} ${H.toFixed(0)}" width="100%" role="img" aria-label="확대기초 평면: skew 평행사변형, 폭 ${d.footingWidthMm}, 말뚝 ${d.rows.map((r2) => r2.s.length).join(' + ')}본">`,
    ...parts,
    '</svg>',
  ].join('');
}