import { DEFAULT_MATERIAL, hookLength, Material, NOMINAL_DIAMETER, spliceLength } from './common';

/**
 * C1–C8 상·하면 주철근 (plan C3 continued). Source: RAG/코핑철근.md §5, 2026-10-22 최종 정리.
 * Lengths in mm, heights in m (EL).
 */
export const MAIN = {
  /** 피복 (최외측 철근 중심까지). */
  cover: 100,
  /** 기본 간격 s_m and minimum end gap g_min. */
  spacing: 125,
  endGapMin: 80,
  /** 상면 단 간격 s_lay (EL, m) and its horizontal step (mm). */
  layEl: 0.057,
  layHorizontal: 57.2,
  /** 90° 갈고리 l_h (mm, as in the document). */
  hook: 472,
  /** 하면 경사 구간 수평 길이 (mm, each side) and Level width. */
  slopeEach: 5067.8,
  level: 2100,
} as const;

export interface WidthLayout {
  /** Edge bar centre from the coping side face: c + (d_st + d_m)/2. */
  yE: number;
  /** Clear length between the two edge bars: B − 2·y_e. */
  S: number;
  /** Bars inside the edge bars: n (so n + 3 in all, including the two edges and the two 110.5 ends). */
  n: number;
  /** Equal end gap g = (S − n·s_m)/2. */
  g: number;
  /** Bars in all: n + 3. */
  count: number;
  /** Bars per cycle (alternating): 12 / 12 for 24. */
  cyclePerKind: number;
  /** Dimension string, e.g. "127 · 110.5 · 21@125 · 110.5 · 127". */
  text: string;
}

/** 폭 방향 배치 (코핑철근.md §5.1). d_st = H25 stirrup, d_m = H29 main. */
export function widthLayout(B: number, dSt = NOMINAL_DIAMETER.H25, dM = NOMINAL_DIAMETER.H29): WidthLayout {
  const yE = MAIN.cover + (dSt + dM) / 2;
  const S = B - 2 * yE;
  const n = Math.floor((S - 2 * MAIN.endGapMin) / MAIN.spacing);
  const g = (S - n * MAIN.spacing) / 2;
  const count = n + 3;
  const r = (v: number) => Math.round(v * 10) / 10;
  return {
    yE: r(yE),
    S: r(S),
    n,
    g: r(g),
    count,
    cyclePerKind: count / 2,
    text: `${r(yE)} · ${r(g)} · ${n}@${MAIN.spacing} · ${r(g)} · ${r(yE)}`,
  };
}

/** Top-layer EL of the k-th row (k = 1, 2, 3): z_k = z_1 − (k − 1)·s_lay (m). */
export function topRowEl(z1: number, k: number): number {
  return Math.round((z1 - (k - 1) * MAIN.layEl) * 1000) / 1000;
}

/** Length of one top bar on row k: path L − 2·(c + (k−1)·step), plus two 90° hooks. */
export function topBarLength(L: number, k: number): number {
  const path = L - 2 * (MAIN.cover + (k - 1) * MAIN.layHorizontal);
  return path + 2 * MAIN.hook;
}

/**
 * Bottom bar C7·C8 (spliced at the column centre, 하면 겹침이음). Each piece:
 * path/2 + l_s/2 + l_h, with path = 2·slope + Level and l_s = 1.3·l_d for H29 (nominal 28.6, with the material inputs).
 */
export function bottomPiece(m: Material = DEFAULT_MATERIAL): { path: number; ls: number; piece: number } {
  const path = 2 * MAIN.slopeEach + MAIN.level;
  const ls = spliceLength(NOMINAL_DIAMETER.H29, m.fyH, m.fck);
  const lh = hookLength('main90', NOMINAL_DIAMETER.H29);
  return { path, ls, piece: path / 2 + ls / 2 + lh };
}