med-det-samme/app/src/main/java/no/naiv/meddetsamme/domain/ScheduleText.kt

package no.naiv.meddetsamme.domain

import no.naiv.meddetsamme.data.DoseTime

/**
 * Human-readable schedule descriptions (Norwegian, 24h) for the doctor
 * summary and the UI. Pure — unit-tested like the engine, since a wrong
 * description on a doctor's desk is a clinical communication error.
 */
object ScheduleText {

    /** Mask bit order matches ScheduleEngine: bit 0 = Sunday. */
    private val DAY_ABBREV = listOf("søn", "man", "tir", "ons", "tor", "fre", "lør")

    fun describe(doseTime: DoseTime): String {
        val time = "%02d:%02d".format(doseTime.minuteOfDay / 60, doseTime.minuteOfDay % 60)
        return "$time ${daysText(doseTime)}"
    }

    fun daysText(doseTime: DoseTime): String {
        if (doseTime.intervalDays > 1) {
            return "(hver ${doseTime.intervalDays}. dag)"
        }
        return when (val mask = doseTime.daysOfWeekMask and 0x7F) {
            0x7F -> "(daglig)"
            0x3E -> "(man–fre)"
            0x41 -> "(lør–søn)"
            0 -> "(aldri)"
            else -> {
                // Week listed Monday-first for humans, despite bit 0 = Sunday.
                val days = (1..7).map { it % 7 }
                    .filter { mask and (1 shl it) != 0 }
                    .map { DAY_ABBREV[it] }
                "(${days.joinToString(", ")})"
            }
        }
    }

    /** "1 dag", "3 dager" — norsk flertall. */
    fun daysCount(days: Int): String = if (days == 1) "1 dag" else "$days dager"

    /** "1 tablett", "2,5 ml" — norsk desimalkomma. */
    fun amountText(amount: Double, unit: String): String {
        val number = if (amount == amount.toLong().toDouble()) {
            amount.toLong().toString()
        } else {
            amount.toString().replace('.', ',')
        }
        return "$number $unit"
    }
}