// ============================================================
// BMI-FOR-AGE parity tests.
// ============================================================

import { describe, expect, it } from 'vitest';
import * as fs from 'node:fs';
import * as path from 'node:path';
import { computeBmi } from './bmi';
import type { Sex } from './fenton';

interface BmiCase {
  name: string;
  inputs: { weightKg: number; heightCm: number; ageMonths: number; sex: Sex };
  output: {
    bmi: number; z: number; percentile: number;
    L: number; M: number; S: number;
    classification: { label: string; pctOf95: number; bmi95: number };
  };
}
interface Vectors { bmi: BmiCase[] }

const vectors: Vectors = JSON.parse(
  fs.readFileSync(path.join(__dirname, '..', '..', 'e2e', 'fixtures', 'calc-vectors.json'), 'utf8'),
);

describe('CDC 2000 BMI-for-age — parity with vanilla calculators.js', () => {
  it.each(vectors.bmi)('$name', ({ inputs, output }) => {
    const actual = computeBmi(inputs.weightKg, inputs.heightCm, inputs.ageMonths, inputs.sex);
    expect(actual.bmi).toBeCloseTo(output.bmi, 10);
    expect(actual.z).toBeCloseTo(output.z, 10);
    expect(actual.percentile).toBeCloseTo(output.percentile, 6);
    expect(actual.L).toBeCloseTo(output.L, 10);
    expect(actual.M).toBeCloseTo(output.M, 10);
    expect(actual.S).toBeCloseTo(output.S, 10);
    expect(actual.classification.label).toBe(output.classification.label);
    expect(actual.classification.pctOf95).toBeCloseTo(output.classification.pctOf95, 6);
    expect(actual.classification.bmi95).toBeCloseTo(output.classification.bmi95, 10);
  });
});