Use FTS if enabled for external search, cleanup

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

@@ -1094,9 +1094,17 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
             String search = (csearch == null ? null : csearch.toString());
             if (!TextUtils.isEmpty(search)) {
                 searching = true;
+
+                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+                boolean fts = prefs.getBoolean("fts", false);
+
+                BoundaryCallbackMessages.SearchCriteria criteria = new BoundaryCallbackMessages.SearchCriteria();
+                criteria.query = search;
+                criteria.fts = fts;
+
                 FragmentMessages.search(
                         ActivityView.this, ActivityView.this, getSupportFragmentManager(),
-                        -1, -1, false, new BoundaryCallbackMessages.SearchCriteria(search));
+                        -1, -1, false, criteria);
             }
 
             intent.removeExtra(Intent.EXTRA_PROCESS_TEXT);

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

@@ -657,24 +657,6 @@ public class BoundaryCallbackMessages extends PagedList.BoundaryCallback<TupleMe
         Long after = null;
         Long before = null;
 
-        SearchCriteria() {
-        }
-
-        SearchCriteria(String query) {
-            this.query = query;
-        }
-
-        boolean isExpression() {
-            if (this.query == null)
-                return false;
-
-            for (String w : this.query.trim().split("\\s+"))
-                if (w.length() > 1 && "+-?".indexOf(w.charAt(0)) >= 0)
-                    return true;
-
-            return false;
-        }
-
         SearchTerm getTerms(boolean utf8, Flags flags, String[] keywords) {
             List<SearchTerm> or = new ArrayList<>();
             List<SearchTerm> and = new ArrayList<>();