package eu.brassepc.fitnessdroid.data

import java.time.LocalDate

/**
 * Basalmetabolism (kcal/dygn) enligt Mifflin–St Jeor:
 * 10·vikt + 6.25·längd − 5·ålder + 5 (man) / −161 (kvinna).
 * null om något av underlagen saknas.
 */
fun bmrKcalPerDay(
    weightKg: Double?,
    heightCm: Double?,
    birthYear: Int?,
    isFemale: Boolean?,
): Double? {
    if (weightKg == null || heightCm == null || birthYear == null || isFemale == null) return null
    val age = (LocalDate.now().year - birthYear).coerceIn(0, 120)
    val k = if (isFemale) -161.0 else 5.0
    return 10.0 * weightKg + 6.25 * heightCm - 5.0 * age + k
}