Limit number of snoozed/delayed messages

app/src/main/java/eu/faircode/email/DaoMessage.java

@@ -647,6 +647,9 @@ public interface DaoMessage {
             " AND NOT ui_snoozed IS NULL")
     List<EntityMessage> getSnoozed(Long folder);
 
+    @Query("SELECT COUNT(*) FROM message WHERE NOT ui_snoozed IS NULL")
+    int getSnoozedCount();
+
     @Query("SELECT id AS _id, subject AS suggestion FROM message" +
             " WHERE (:account IS NULL OR message.account = :account)" +
             " AND (:folder IS NULL OR message.folder = :folder)" +

app/src/main/java/eu/faircode/email/EntityMessage.java

@@ -121,6 +121,8 @@ public class EntityMessage implements Serializable {
     static final Long SWIPE_ACTION_JUNK = -8L;
     static final Long SWIPE_ACTION_REPLY = -9L;
 
+    private static final int MAX_SNOOZED = 300;
+
     @PrimaryKey(autoGenerate = true)
     public Long id;
     @NonNull
@@ -354,7 +356,7 @@ public class EntityMessage implements Serializable {
                 EntityMessage.SMIME_SIGNENCRYPT.equals(ui_encrypt));
     }
 
-    boolean isVerifiable(){
+    boolean isVerifiable() {
         return (EntityMessage.PGP_SIGNONLY.equals(encrypt) ||
                 EntityMessage.SMIME_SIGNONLY.equals(encrypt));
     }
@@ -582,6 +584,30 @@ public class EntityMessage implements Serializable {
     }
 
     static void snooze(Context context, long id, Long wakeup) {
+        if (wakeup != null) {
+            /*
+                java.lang.IllegalStateException: Maximum limit of concurrent alarms 500 reached for uid: u0a601, callingPackage: eu.faircode.email
+                    at android.os.Parcel.createExceptionOrNull(Parcel.java:2433)
+                    at android.os.Parcel.createException(Parcel.java:2409)
+                    at android.os.Parcel.readException(Parcel.java:2392)
+                    at android.os.Parcel.readException(Parcel.java:2334)
+                    at android.app.IAlarmManager$Stub$Proxy.set(IAlarmManager.java:359)
+                    at android.app.AlarmManager.setImpl(AlarmManager.java:947)
+                    at android.app.AlarmManager.setImpl(AlarmManager.java:907)
+                    at android.app.AlarmManager.setExactAndAllowWhileIdle(AlarmManager.java:1175)
+                    at androidx.core.app.AlarmManagerCompat$Api23Impl.setExactAndAllowWhileIdle(Unknown Source:0)
+                    at androidx.core.app.AlarmManagerCompat.setExactAndAllowWhileIdle(SourceFile:2)
+                    at eu.faircode.email.AlarmManagerCompatEx.setAndAllowWhileIdle(SourceFile:2)
+                    at eu.faircode.email.EntityMessage.snooze(SourceFile:7)
+             */
+            DB db = DB.getInstance(context);
+            int count = db.message().getSnoozedCount();
+            Log.i("Snoozed=" + count + "/" + MAX_SNOOZED);
+            if (count > MAX_SNOOZED)
+                throw new IllegalArgumentException(
+                        String.format("Due to Android limitations, no more than %d messages can be snoozed or delayed", MAX_SNOOZED));
+        }
+
         Intent snoozed = new Intent(context, ServiceSynchronize.class);
         snoozed.setAction("unsnooze:" + id);
         PendingIntent pi = PendingIntentCompat.getForegroundService(

app/src/main/java/eu/faircode/email/ServiceSend.java

@@ -500,6 +500,8 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             }
 
             db.setTransactionSuccessful();
+        } catch (IllegalArgumentException ex) {
+            Log.w(ex);
         } finally {
             db.endTransaction();
         }

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -3002,6 +3002,8 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
                             EntityMessage.snooze(context, message.id, message.ui_snoozed);
 
                         db.setTransactionSuccessful();
+                    } catch (IllegalArgumentException ex) {
+                        Log.w(ex);
                     } finally {
                         db.endTransaction();
                     }

app/src/main/java/eu/faircode/email/WorkerCleanup.java

@@ -154,8 +154,12 @@ public class WorkerCleanup extends Worker {
                 }
 
                 // Restore alarms
+                try {
                     for (EntityMessage message : db.message().getSnoozed(null))
                         EntityMessage.snooze(context, message.id, message.ui_snoozed);
+                } catch (IllegalArgumentException ex) {
+                    Log.w(ex);
+                }
 
                 ServiceSynchronize.reschedule(context);