remove secret chat from database

src/main/java/eu/siacs/conversations/persistance/DatabaseBackend.java

@@ -1112,6 +1112,37 @@ public class DatabaseBackend extends SQLiteOpenHelper {
         return null;
     }
 
+    public boolean deleteConversation(final Account account, final Jid contactJid, final Jid counterpart) {
+        SQLiteDatabase db = this.getWritableDatabase();
+
+        if (counterpart != null) {
+            String[] selectionArgs = {account.getUuid(),
+                    contactJid.asBareJid().toString() + "/%",
+                    contactJid.asBareJid().toString(),
+                    counterpart.toString()
+            };
+
+            int rows = db.delete(Conversation.TABLENAME,
+                    Conversation.ACCOUNT + "=? AND (" + Conversation.CONTACTJID
+                            + " like ? OR " + Conversation.CONTACTJID + "=?) AND " + Conversation.NEXT_COUNTERPART + "=?", selectionArgs);
+
+            return rows == 1;
+        } else {
+            String[] selectionArgs = new String[]{
+                    account.getUuid(),
+                    contactJid.asBareJid().toString() + "/%",
+                    contactJid.asBareJid().toString()
+            };
+
+            int rows = db.delete(Conversation.TABLENAME,
+                    Conversation.ACCOUNT + "=? AND (" + Conversation.CONTACTJID
+                            + " like ? OR " + Conversation.CONTACTJID + "=?) AND " + Conversation.NEXT_COUNTERPART + " =NULL", selectionArgs);
+
+            return rows == 1;
+
+        }
+    }
+
     public void updateConversation(final Conversation conversation) {
         final SQLiteDatabase db = this.getWritableDatabase();
         final String[] args = {conversation.getUuid()};