module.exports = {
  slug: "pediatric-dose-per-kg-per-day-divided",
  title: "Pediatric per-dose amount from mg/kg/day divided",
  deck_category: "health",
  description: "Computes the per-dose amount when a total daily mg/kg/day dose is divided into a number of doses per day, general formula only.",
  inputs: [
    { name: "weight_kg", type: "number", unit: "kg", required: true, description: "Body weight in kilograms", min: 0 },
    { name: "mg_per_kg_per_day", type: "number", unit: "mg/kg/day", required: true, description: "Total daily dose per kilogram of body weight", min: 0 },
    { name: "doses_per_day", type: "integer", required: true, description: "Number of equally divided doses given per day", min: 1 }
  ],
  outputs: [
    { name: "daily_total_mg", unit: "mg", description: "Total daily dose" },
    { name: "per_dose_mg", unit: "mg", description: "Amount per individual dose" }
  ],
  steps: [
    "daily_total_mg = weight_kg * mg_per_kg_per_day.",
    "per_dose_mg = daily_total_mg / doses_per_day.",
    "Round both results to 2 decimal places."
  ],
  constants: [],
  sources: [
    { kind: "edition_page", value: "Standard pediatric weight-based dosing arithmetic (total daily dose = weight x mg/kg/day, then divided evenly across the number of daily doses)", title: "General pediatric dosing-by-weight-and-frequency method", publisher: "Standard pharmacology reference practice (e.g. Harriet Lane Handbook, dosing chapter)", retrieved_utc: "2026-09-30T19:30:00Z", note: "This card performs only the general arithmetic; the mg/kg/day figure and dose frequency are supplied as inputs, never baked in." }
  ],
  disclaimer: "General formula only. Not medical advice. Dosing decisions belong to a licensed clinician and the product's label.",
  questionText(inputs) {
    return `Using this general formula, for a ${inputs.weight_kg} kg child at ${inputs.mg_per_kg_per_day} mg/kg/day divided into ${inputs.doses_per_day} doses per day, what is the amount per dose?`;
  },
  run(inputs) {
    const { weight_kg, mg_per_kg_per_day, doses_per_day } = inputs;
    if (typeof weight_kg !== "number" || weight_kg <= 0) throw new Error("weight_kg must be a positive number");
    if (typeof mg_per_kg_per_day !== "number" || mg_per_kg_per_day < 0) throw new Error("mg_per_kg_per_day must be a non-negative number");
    if (!Number.isInteger(doses_per_day) || doses_per_day < 1) throw new Error("doses_per_day must be a positive integer");
    const dailyTotalRaw = weight_kg * mg_per_kg_per_day;
    const perDoseRaw = dailyTotalRaw / doses_per_day;
    const dailyTotal = Math.round(dailyTotalRaw * 100) / 100;
    const perDose = Math.round(perDoseRaw * 100) / 100;
    return { answer: `${perDose.toFixed(2)} mg per dose`, values: { daily_total_mg: dailyTotal, per_dose_mg: perDose } };
  },
  examples: [
    {
      name: "worked example",
      inputs: { weight_kg: 20, mg_per_kg_per_day: 30, doses_per_day: 3 },
      expected: { answer: "200.00 mg per dose" },
      check: "20 * 30 = 600 mg/day total; 600 / 3 = 200.00 mg per dose."
    },
    {
      name: "test vector: non-integer split",
      inputs: { weight_kg: 15, mg_per_kg_per_day: 40, doses_per_day: 4 },
      expected: { answer: "150.00 mg per dose" },
      check: "15 * 40 = 600 mg/day total; 600 / 4 = 150.00 mg per dose."
    }
  ]
};