fix(alarms): fallback native scheduling

android/app/src/main/kotlin/es/freetimelab/pluriwave/AlarmScheduler.kt

@@ -41,13 +41,13 @@ class AlarmScheduler(private val context: Context) {
             PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
         )
 
-        alarmManager.setAlarmClock(
+        val mainScheduled = scheduleMainAlarm(id, triggerAtMillis, showIntent, alarmIntent)
-            AlarmManager.AlarmClockInfo(triggerAtMillis, showIntent),
-            alarmIntent
-        )
-        Log.d(tag, "alarm.schedule setAlarmClock OK id=$id")
 
         val now = System.currentTimeMillis()
+        if (!mainScheduled) {
+            Log.w(tag, "alarm.schedule main alarm fallback failed or degraded id=$id")
+        }
+
         if (preNoticeAtMillis > now) {
             try {
                 alarmManager.setExactAndAllowWhileIdle(
@@ -83,6 +83,55 @@ class AlarmScheduler(private val context: Context) {
         }
     }
 
+    private fun scheduleMainAlarm(
+        id: String,
+        triggerAtMillis: Long,
+        showIntent: PendingIntent,
+        alarmIntent: PendingIntent
+    ): Boolean {
+        try {
+            alarmManager.setAlarmClock(
+                AlarmManager.AlarmClockInfo(triggerAtMillis, showIntent),
+                alarmIntent
+            )
+            Log.d(tag, "alarm.schedule setAlarmClock OK id=$id")
+            return true
+        } catch (error: SecurityException) {
+            Log.e(tag, "alarm.schedule setAlarmClock SecurityException id=$id", error)
+        } catch (error: Throwable) {
+            Log.e(tag, "alarm.schedule setAlarmClock ERROR id=$id", error)
+        }
+
+        return try {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S && alarmManager.canScheduleExactAlarms()) {
+                alarmManager.setExactAndAllowWhileIdle(
+                    AlarmManager.RTC_WAKEUP,
+                    triggerAtMillis,
+                    alarmIntent
+                )
+                Log.d(tag, "alarm.schedule setExactAndAllowWhileIdle fallback OK id=$id")
+            } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+                alarmManager.setAndAllowWhileIdle(
+                    AlarmManager.RTC_WAKEUP,
+                    triggerAtMillis,
+                    alarmIntent
+                )
+                Log.d(tag, "alarm.schedule setAndAllowWhileIdle fallback OK id=$id")
+            } else {
+                alarmManager.set(
+                    AlarmManager.RTC_WAKEUP,
+                    triggerAtMillis,
+                    alarmIntent
+                )
+                Log.d(tag, "alarm.schedule set fallback OK id=$id")
+            }
+            true
+        } catch (error: Throwable) {
+            Log.e(tag, "alarm.schedule fallback ERROR id=$id", error)
+            false
+        }
+    }
+
     fun cancelAlarm(id: String) {
         Log.d(tag, "alarm.cancel id=$id")
         for (slot in 1..3) {