import type { BlockModel } from './geometry';
import { integratedCheck, pairEccentricities } from './bearing-layout';

/**
 * 일체 블록 (승인 2026-10-26): one block per front–back pair, centred on the pair's midpoint.
 * Length 2500 across the 교축 (n) covers the pair (C1 600 + C2 1298 + C1 600), width 1200 along the 교각축 (s).
 * The top is stepped: the front half follows the front block top, the back half the back block top (단이 있는 블록).
 * Only built when every pair is within the eccentricity limit; otherwise the model keeps 분리 (see integratedCheck).
 */
export const INTEGRATED_BLOCK = { length: 2500, depth: 1200 } as const;

export interface IntegratedBlock {
  frontNo: number;
  backNo: number;
  /** Centre along the coping length (s, m) — the mean of the pair. */
  s: number;
  /** Centre across the 교축 (n, m) — the midpoint of the pair; the step line is here. */
  n: number;
  /** Bottom EL (m): the lower of the two bottoms. */
  bottom: number;
  /** Top EL of the front half (전열 side, m). */
  topFront: number;
  /** Top EL of the back half (후열 side, m). */
  topBack: number;
  /** Mean row skew (deg) of the pair. */
  rowSkewDeg: number;
}

/** Integrated blocks of a pier: empty unless 일체 is chosen and every pair is within the limit. */
export function buildIntegratedBlocks(blocks: BlockModel[], chosen: boolean): IntegratedBlock[] {
  if (!chosen || !integratedCheck(blocks).allowed) return [];
  const pick = (no: number, row: BlockModel['row']) => blocks.find((b) => b.no === no && b.row === row)!;
  return pairEccentricities(blocks).map((p) => {
    const f = pick(p.frontNo, '전열');
    const b = pick(p.backNo, '후열');
    return {
      frontNo: p.frontNo,
      backNo: p.backNo,
      s: (f.s + b.s) / 2,
      n: (f.n + b.n) / 2,
      bottom: Math.min(f.bottom, b.bottom),
      topFront: f.top,
      topBack: b.top,
      rowSkewDeg: (f.rowSkewDeg + b.rowSkewDeg) / 2,
    };
  });
}