import { describe, expect, it } from 'vitest';
import { toDxf } from '../src/lib/export-dxf';

const shape = {
  outer: [{ x: 0, y: 0 }, { x: 100, y: 0 }, { x: 100, y: 50 }, { x: 0, y: 50 }],
  holes: [[{ x: 10, y: 10 }, { x: 20, y: 10 }, { x: 20, y: 20 }]],
};

/** Split DXF text into [groupCode, value] pairs. */
function pairs(dxf: string): [string, string][] {
  const lines = dxf.split('\r\n');
  if (lines[lines.length - 1] === '') lines.pop();
  const out: [string, string][] = [];
  for (let i = 0; i < lines.length; i += 2) out.push([lines[i].trim(), lines[i + 1]]);
  return out;
}

describe('toDxf', () => {
  it('is a well-formed R12 file in mm with CRLF line endings', () => {
    const dxf = toDxf(shape);
    expect(dxf).not.toMatch(/[^\r]\n/);
    const p = pairs(dxf);
    expect(p[0]).toEqual(['0', 'SECTION']);
    expect(p).toContainEqual(['1', 'AC1009']);
    const unitsIdx = p.findIndex(([c, v]) => c === '9' && v === '$INSUNITS');
    expect(p[unitsIdx + 1]).toEqual(['70', '4']);
    expect(p[p.length - 1]).toEqual(['0', 'EOF']);
  });

  it('writes one closed POLYLINE per ring with all vertices', () => {
    const p = pairs(toDxf(shape));
    const entities = p.filter(([c]) => c === '0').map(([, v]) => v);
    expect(entities.filter((e) => e === 'POLYLINE')).toHaveLength(2);
    expect(entities.filter((e) => e === 'VERTEX')).toHaveLength(7);
    expect(entities.filter((e) => e === 'SEQEND')).toHaveLength(2);
    const polyIdx = p.findIndex(([c, v]) => c === '0' && v === 'POLYLINE');
    const flags = p.slice(polyIdx, polyIdx + 8).find(([c]) => c === '70');
    expect(flags).toEqual(['70', '1']);
  });

  it('flips Y so the piece is not mirrored', () => {
    const p = pairs(toDxf(shape));
    const firstVertex = p.findIndex(([c, v]) => c === '0' && v === 'VERTEX');
    const x = p.slice(firstVertex).find(([c]) => c === '10')![1];
    const y = p.slice(firstVertex).find(([c]) => c === '20')![1];
    expect([x, y]).toEqual(['0', '50']); // (0,0) top-left → (0,50) in Y-up space
  });
});