pediatric-ai-scribe-v3/shared/clinical/calculators.test.ts

import { describe, expect, it } from 'vitest';
import {
  calculateGcs,
  calculateMostellerBsa,
  calculateWeightBasedDose,
  estimateWeightFromAgeMonths,
  formatAgeMonths,
  parseAgeMonths,
} from './calculators';

describe('parseAgeMonths', () => {
  it('parses flexible age strings from the legacy calculator parser', () => {
    expect(parseAgeMonths('3y')).toBe(36);
    expect(parseAgeMonths('2y5m')).toBe(29);
    expect(parseAgeMonths('2 years 5 months')).toBe(29);
    expect(parseAgeMonths('6 months')).toBe(6);
    expect(parseAgeMonths('2 wk')).toBeCloseTo(14 / 30.4375);
    expect(parseAgeMonths('15 days')).toBeCloseTo(15 / 30.4375);
  });

  it('keeps plain numbers as months for legacy parity', () => {
    expect(parseAgeMonths('36')).toBe(36);
    expect(parseAgeMonths(6)).toBe(6);
  });

  it('rejects blank and unparseable ages', () => {
    expect(parseAgeMonths('')).toBeNull();
    expect(parseAgeMonths('older child')).toBeNull();
    expect(parseAgeMonths(null)).toBeNull();
  });
});

describe('formatAgeMonths', () => {
  it('formats days, months, and years', () => {
    expect(formatAgeMonths(15 / 30.4375)).toBe('15 days (0.49 mo)');
    expect(formatAgeMonths(18)).toBe('18 months');
    expect(formatAgeMonths(29)).toBe('2 yr 5 mo (29 mo total)');
  });
});

describe('estimateWeightFromAgeMonths', () => {
  it('matches APLS infant band', () => {
    const result = estimateWeightFromAgeMonths(6);
    expect(result).toEqual({
      weight: 7,
      formulaLabel: 'APLS 0-12 mo',
      all: { apls: 7, bestGuess: 7.5 },
    });
  });

  it('matches APLS 1-5 year band', () => {
    const result = estimateWeightFromAgeMonths(36);
    expect(result?.weight).toBe(14);
    expect(result?.formulaLabel).toBe('APLS 1-5 yr');
    expect(result?.all).toEqual({ apls: 14, bestGuess: 16 });
  });

  it('matches APLS 6-12 year band', () => {
    const result = estimateWeightFromAgeMonths(96);
    expect(result?.weight).toBe(31);
    expect(result?.formulaLabel).toBe('APLS 6-12 yr');
    expect(result?.all).toEqual({ apls: 31, bestGuess: 32 });
  });

  it('uses Best Guess from 13 years onward', () => {
    const result = estimateWeightFromAgeMonths(168);
    expect(result?.weight).toBe(56);
    expect(result?.formulaLabel).toBe('Best Guess 5-14 yr');
  });

  it('rejects invalid ages', () => {
    expect(estimateWeightFromAgeMonths(null)).toBeNull();
    expect(estimateWeightFromAgeMonths(Number.NaN)).toBeNull();
    expect(estimateWeightFromAgeMonths(-1)).toBeNull();
  });
});

describe('calculateMostellerBsa', () => {
  it('matches the legacy 20 kg, 110 cm smoke-test value', () => {
    expect(calculateMostellerBsa(20, 110)?.toFixed(3)).toBe('0.782');
  });

  it('rejects invalid measurements', () => {
    expect(calculateMostellerBsa(0, 110)).toBeNull();
    expect(calculateMostellerBsa(20, 0)).toBeNull();
  });
});

describe('calculateWeightBasedDose', () => {
  it('calculates a single dose and daily total', () => {
    const result = calculateWeightBasedDose({ weightKg: 15, dosePerKg: 10, frequencyPerDay: 3 });
    expect(result).toEqual({
      singleDoseMg: 150,
      dailyDoseMg: 450,
      frequencyPerDay: 3,
      capped: false,
      volumeMl: null,
    });
  });

  it('respects a max single-dose cap', () => {
    const result = calculateWeightBasedDose({ weightKg: 15, dosePerKg: 100, maxSingleDoseMg: 500 });
    expect(result?.singleDoseMg).toBe(500);
    expect(result?.capped).toBe(true);
  });

  it('calculates dose volume when concentration is supplied', () => {
    const result = calculateWeightBasedDose({
      weightKg: 20,
      dosePerKg: 12.5,
      concentrationMgPerMl: 50,
    });
    expect(result?.singleDoseMg).toBe(250);
    expect(result?.volumeMl).toBe(5);
  });

  it('rejects invalid dose inputs', () => {
    expect(calculateWeightBasedDose({ weightKg: 0, dosePerKg: 10 })).toBeNull();
    expect(calculateWeightBasedDose({ weightKg: 15, dosePerKg: 0 })).toBeNull();
    expect(calculateWeightBasedDose({ weightKg: 15, dosePerKg: 10, frequencyPerDay: 0 })).toBeNull();
  });
});

describe('calculateGcs', () => {
  it('scores maximum child/adult defaults as mild GCS 15', () => {
    expect(calculateGcs(4, 5, 6)).toEqual({ total: 15, severity: 'Mild' });
  });

  it('scores 4/5/1 as moderate GCS 10', () => {
    expect(calculateGcs(4, 5, 1)).toEqual({ total: 10, severity: 'Moderate' });
  });

  it('scores 1/1/1 as severe coma', () => {
    expect(calculateGcs(1, 1, 1)).toEqual({ total: 3, severity: 'Severe (Coma)' });
  });

  it('rejects invalid component scores', () => {
    expect(calculateGcs(0, 5, 6)).toBeNull();
    expect(calculateGcs(5, 5, 6)).toBeNull();
    expect(calculateGcs(4, 6, 6)).toBeNull();
    expect(calculateGcs(4, 5, 7)).toBeNull();
  });
});