package no.naiv.meddetsamme.alarm

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import java.time.LocalDate
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import no.naiv.meddetsamme.data.MedDatabase
import no.naiv.meddetsamme.domain.ScheduleEngine
import no.naiv.meddetsamme.notify.Notifications

/**
 * Daily derived-state check: low stock (inventory ÷ scheduled rate) and
 * prescription renewal (rx expiry, independent of stock — decision #9).
 * One digest notification, not one per med.
 */
class SupplyCheckReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        val pending = goAsync()
        CoroutineScope(Dispatchers.IO).launch {
            try {
                check(context)
            } finally {
                AlarmScheduler(context).armSupplyCheck() // chain the next daily check
                pending.finish()
            }
        }
    }

    private suspend fun check(context: Context) {
        val db = MedDatabase.get(context)
        val today = LocalDate.now()
        val lines = mutableListOf<String>()

        // Per inventory item: consumption is the SUM across all active regimens
        // drawing from it — one shared box drains faster than either alone.
        val byItem = db.medicationDao().getActive().groupBy { it.item.id }
        for ((_, meds) in byItem) {
            val item = meds.first().item
            var rate = 0.0
            for (med in meds) rate += ScheduleEngine.dailyConsumption(db.doseTimeDao().getForMed(med.med.id))
            if (ScheduleEngine.needsRefill(item.stockUnits, rate, item.lowStockLeadDays)) {
                val days = ScheduleEngine.daysOfSupply(item.stockUnits, rate)
                lines += "${item.name}: lager for ${days?.toInt() ?: 0} dager"
            }
            if (ScheduleEngine.needsRenewal(item.rxExpiryEpochDay, today)) {
                val expired = item.rxExpiryEpochDay!! < today.toEpochDay()
                lines += if (expired) "${item.name}: resept utløpt" else "${item.name}: resept må fornyes"
            }
        }

        if (lines.isNotEmpty()) {
            Notifications.post(
                context,
                Notifications.SUPPLY_NOTIFICATION_ID,
                Notifications.buildSupplyNotification(context, lines),
            )
        }
    }
}