package de.data_it_solution.netdiag

import android.app.Notification
import android.app.NotificationChannel
import android.app.NotificationManager
import android.app.Service
import android.content.Context
import android.content.Intent
import android.content.pm.ServiceInfo
import android.os.Build
import android.os.IBinder
import androidx.core.app.NotificationCompat

/**
 * Schlanker Vordergrund-Dienst für den Geräte-Monitor.
 *
 * Er hält den App-Prozess am Leben, solange die Überwachung läuft — damit
 * Android die Mess-Schleife bei ausgeschaltetem Display oder App-Wechsel nicht
 * beendet. Die eigentliche Ping-Logik läuft im NetDiagScannerPlugin; dieser
 * Dienst zeigt nur die dauerhafte Benachrichtigung.
 */
class MonitorService : Service() {

    override fun onBind(intent: Intent?): IBinder? = null

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        val text = intent?.getStringExtra(EXTRA_TEXT) ?: "Geräte-Überwachung läuft"
        val notification = buildNotification(text)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
            startForeground(NOTIF_ID, notification, ServiceInfo.FOREGROUND_SERVICE_TYPE_DATA_SYNC)
        } else {
            startForeground(NOTIF_ID, notification)
        }
        return START_STICKY
    }

    private fun buildNotification(text: String): Notification {
        ensureChannel(this)
        return NotificationCompat.Builder(this, CHANNEL_ID)
            .setContentTitle("NetDiag — Geräte-Monitor")
            .setContentText(text)
            .setSmallIcon(android.R.drawable.ic_menu_compass)
            .setOngoing(true)
            .setPriority(NotificationCompat.PRIORITY_LOW)
            .build()
    }

    companion object {
        const val CHANNEL_ID = "netdiag-monitor"
        const val NOTIF_ID = 4711
        const val EXTRA_TEXT = "text"

        /** Benachrichtigungskanal anlegen (idempotent) */
        fun ensureChannel(ctx: Context) {
            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return
            val mgr = ctx.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            if (mgr.getNotificationChannel(CHANNEL_ID) == null) {
                mgr.createNotificationChannel(
                    NotificationChannel(
                        CHANNEL_ID,
                        "Geräte-Monitor",
                        NotificationManager.IMPORTANCE_LOW,
                    ),
                )
            }
        }

        fun start(ctx: Context, text: String) {
            val i = Intent(ctx, MonitorService::class.java).putExtra(EXTRA_TEXT, text)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                ctx.startForegroundService(i)
            } else {
                ctx.startService(i)
            }
        }

        fun stop(ctx: Context) {
            ctx.stopService(Intent(ctx, MonitorService::class.java))
        }
    }
}