module.exports = {
  slug: "body-surface-area-mosteller",
  title: "Body surface area (Mosteller formula)",
  deck_category: "health",
  description: "Estimates body surface area in square meters from height and weight using the Mosteller formula.",
  inputs: [
    { name: "height_cm", type: "number", unit: "cm", required: true, description: "Height in centimeters", min: 0 },
    { name: "weight_kg", type: "number", unit: "kg", required: true, description: "Body weight in kilograms", min: 0 }
  ],
  outputs: [
    { name: "bsa", unit: "m^2", description: "Estimated body surface area" }
  ],
  steps: [
    "bsa = sqrt(height_cm * weight_kg / 3600).",
    "Round the result to 2 decimal places."
  ],
  constants: [
    { name: "divisor", value: 3600, unit: "cm*kg", source: 0 }
  ],
  sources: [
    { kind: "doi", value: "10.1056/NEJM198710223171717", title: "Simplified calculation of body-surface area", publisher: "New England Journal of Medicine, Mosteller RD, 1987;317(17):1098", retrieved_utc: "2026-09-30T19:20:00Z", note: "Source of the sqrt(height*weight/3600) formula." }
  ],
  disclaimer: "General formula only. Not medical advice. Dosing decisions belong to a licensed clinician and the product's label.",
  questionText(inputs) {
    return `What is the Mosteller body surface area for a person ${inputs.height_cm} cm tall weighing ${inputs.weight_kg} kg?`;
  },
  run(inputs) {
    const { height_cm, weight_kg } = inputs;
    if (typeof height_cm !== "number" || height_cm <= 0) throw new Error("height_cm must be a positive number");
    if (typeof weight_kg !== "number" || weight_kg <= 0) throw new Error("weight_kg must be a positive number");
    const bsaRaw = Math.sqrt((height_cm * weight_kg) / 3600);
    const bsa = Math.round(bsaRaw * 100) / 100;
    return { answer: `${bsa.toFixed(2)} m^2`, values: { bsa } };
  },
  examples: [
    {
      name: "worked example",
      inputs: { height_cm: 180, weight_kg: 80 },
      expected: { answer: "2.00 m^2" },
      check: "180*80 = 14400; 14400/3600 = 4; sqrt(4) = 2.00 exactly."
    },
    {
      name: "test vector: smaller adult",
      inputs: { height_cm: 160, weight_kg: 55 },
      expected: { answer: "1.56 m^2" },
      check: "160*55 = 8800; 8800/3600 = 2.44444; sqrt(2.44444) = 1.56347, rounds to 1.56."
    }
  ]
};