package com.example.medilightv2android.services

import android.app.NotificationChannel
import android.app.NotificationManager
import android.content.Context
import android.os.Build
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import com.example.medilightv2android.R
import com.example.medilightv2android.models.UrgencyLevel

class NotificationService private constructor(private val context: Context) {
    companion object {
        @Volatile
        private var instance: NotificationService? = null
        fun getInstance(context: Context): NotificationService =
            instance ?: synchronized(this) {
                instance ?: NotificationService(context.applicationContext).also { instance = it }
            }

        private const val CHANNEL_ID = "bladder_urgency"
        private const val CHANNEL_NAME = "Bladder Monitoring"
    }

    private var lastNotifiedUrgency: String? = null

    init {
        createNotificationChannel()
    }

    private fun createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                CHANNEL_ID,
                CHANNEL_NAME,
                NotificationManager.IMPORTANCE_HIGH
            ).apply {
                description = "Bladder level urgency notifications"
                enableVibration(true)
            }
            val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            notificationManager.createNotificationChannel(channel)
        }
    }

    fun sendUrgencyNotification(urgency: UrgencyLevel, volume: Int) {
        val urgencyKey = urgency.rawStringValue
        if (urgencyKey == "safe" || urgencyKey == lastNotifiedUrgency) return
        lastNotifiedUrgency = urgencyKey

        val (title, body) = when (urgency) {
            UrgencyLevel.WARNING -> "Bladder Level Rising" to "Estimated $volume ml. Prepare for catheterization."
            UrgencyLevel.URGENT -> "Catheterization Needed" to "Estimated $volume ml. Please catheterize now."
            UrgencyLevel.SAFE -> return
        }

        val priority = if (urgency == UrgencyLevel.URGENT)
            NotificationCompat.PRIORITY_MAX else NotificationCompat.PRIORITY_HIGH

        val notification = NotificationCompat.Builder(context, CHANNEL_ID)
            .setSmallIcon(R.drawable.ic_launcher_foreground)
            .setContentTitle(title)
            .setContentText(body)
            .setPriority(priority)
            .setAutoCancel(true)
            .build()

        try {
            NotificationManagerCompat.from(context).notify(urgencyKey.hashCode(), notification)
        } catch (_: SecurityException) { }
    }

    fun cancelAll() {
        lastNotifiedUrgency = null
        NotificationManagerCompat.from(context).cancelAll()
    }
}