/**
 * 도면에서 받침 ELEVATION TABLE 읽기 (승인 2026-10-23). Reads the TEXT entities of a DXF file and places each value
 * by position: the header row names the columns (EL.X, h1 … h4, A, B, C1 …), the first column holds the bearing No.
 * Pure: works on the text entities (x, y, text) of the drawing, not on the file itself.
 */
import type { DrawingBearing } from './bearing-ref';

export interface DxfText {
  x: number;
  y: number;
  text: string;
}

/** Reads TEXT and MTEXT entities (x, y, string) from DXF text. */
export function readDxfTexts(dxf: string): DxfText[] {
  const lines = dxf.split(/\r?\n/);
  const pairs: [string, string][] = [];
  for (let i = 0; i + 1 < lines.length; i += 2) pairs.push([lines[i].trim(), lines[i + 1].trim()]);
  const out: DxfText[] = [];
  for (let i = 0; i < pairs.length; i++) {
    if (pairs[i][0] !== '0' || (pairs[i][1] !== 'TEXT' && pairs[i][1] !== 'MTEXT')) continue;
    let text: string | null = null;
    let x = NaN;
    let y = NaN;
    let j = i + 1;
    for (; j < pairs.length && pairs[j][0] !== '0'; j++) {
      const [c, v] = pairs[j];
      if (c === '1') text = v;
      if (c === '10') x = Number(v);
      if (c === '20') y = Number(v);
    }
    if (text !== null && Number.isFinite(x) && Number.isFinite(y)) out.push({ x, y, text });
    i = j - 1;
  }
  return out;
}

const norm = (s: string) => s.replace(/[\s.'"]/g, '').toLowerCase();
const NUMBER = /^-?\d+(\.\d+)?$/;

export interface BearingTableRow {
  no: number;
  values: Record<string, number>;
}

export interface BearingTableResult {
  /** Values per column as read from the drawing (keyed by header name). */
  rows: BearingTableRow[];
  /** The rows in the form the 받침 입력 uses (EL.X in m, h1 and h2 in mm). */
  drawing: DrawingBearing[];
  errors: string[];
}

/**
 * Reads the bearing ELEVATION TABLE. The header is the text row with "EL.X" (as EL.'X', EL. "X"); the No column is the
 * integer column just left of the 교량받침 column; each value sits under its header (x within 150) on the same row (y within 120).
 */
export function parseBearingElevationTable(texts: DxfText[]): BearingTableResult {
  const errors: string[] = [];
  const elHeader = texts.find((t) => norm(t.text) === 'el' + 'x' || norm(t.text) === 'elx');
  if (!elHeader) return { rows: [], drawing: [], errors: ['EL.X 머리글을 찾지 못했습니다.'] };
  const headerY = elHeader.y;
  // Column headers: texts on the header row (within 60 of its y) with a short name (EL.X, h1 … h4, A, B, C1 …).
  const headerRow = texts.filter((t) => Math.abs(t.y - headerY) <= 60 && /^(elx|h\d|[a-z]\d?)$/.test(norm(t.text)));
  const cols = headerRow.map((t) => ({ key: norm(t.text), x: t.x }));
  const noHeader = texts.find((t) => norm(t.text) === 'no');
  // The No column: integers 1…10 below the header, within 150 of the No header (or the left-most integer column).
  const numbers = texts.filter((t) => NUMBER.test(t.text) && Number.isInteger(Number(t.text)) && Number(t.text) >= 1 && Number(t.text) <= 99 && t.y < headerY - 60);
  if (numbers.length === 0) return { rows: [], drawing: [], errors: ['받침 번호 열을 찾지 못했습니다.'] };
  const noX = noHeader ? noHeader.x : Math.min(...numbers.map((t) => t.x));
  const noCells = numbers.filter((t) => Math.abs(t.x - noX) <= 250).sort((a, b) => b.y - a.y);

  const rows: BearingTableRow[] = [];
  for (const cell of noCells) {
    const values: Record<string, number> = {};
    for (const col of cols) {
      const hit = texts.find((t) => Math.abs(t.x - col.x) <= 150 && Math.abs(t.y - cell.y) <= 120 && NUMBER.test(t.text));
      if (hit) values[col.key] = Number(hit.text);
    }
    rows.push({ no: Number(cell.text), values });
  }
  const drawing: DrawingBearing[] = [];
  for (const r of rows) {
    const elx = r.values.elx;
    const h1 = r.values.h1;
    const h2 = r.values.h2;
    if (elx === undefined || h1 === undefined || h2 === undefined) {
      errors.push(`No ${r.no}: EL.X·h1·h2 중 값이 없습니다.`);
      continue;
    }
    drawing.push({ no: r.no, elx, h1, h2 });
  }
  return { rows, drawing: drawing.sort((a, b) => a.no - b.no), errors };
}