Limit thread search range

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

@@ -2909,7 +2909,7 @@ class Core {
                         message.references = TextUtils.join(" ", helper.getReferences());
                         message.inreplyto = helper.getInReplyTo();
                         message.deliveredto = helper.getDeliveredTo();
-                        message.thread = helper.getThreadId(context, account.id, folder.id, 0);
+                        message.thread = helper.getThreadId(context, account.id, folder.id, 0, received);
                         message.priority = helper.getPriority();
                         message.sensitivity = helper.getSensitivity();
                         message.auto_submitted = helper.getAutoSubmitted();
@@ -3807,7 +3807,7 @@ class Core {
                     have = true;
 
                 if (dup.folder.equals(folder.id)) {
-                    String thread = helper.getThreadId(context, account.id, folder.id, uid);
+                    String thread = helper.getThreadId(context, account.id, folder.id, uid, dup.received);
                     Log.i(folder.name + " found as id=" + dup.id +
                             " uid=" + dup.uid + "/" + uid +
                             " msgid=" + msgid + " thread=" + thread);
@@ -3886,7 +3886,7 @@ class Core {
             message.inreplyto = helper.getInReplyTo();
             // Local address contains control or whitespace in string ``mailing list someone@example.org''
             message.deliveredto = helper.getDeliveredTo();
-            message.thread = helper.getThreadId(context, account.id, folder.id, uid);
+            message.thread = helper.getThreadId(context, account.id, folder.id, uid, received);
             if (BuildConfig.DEBUG && message.thread.startsWith("outlook:"))
                 message.warning = message.thread;
             message.priority = helper.getPriority();

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

@@ -424,8 +424,9 @@ public interface DaoMessage {
 
     @Query("SELECT thread, msgid, hash, inreplyto FROM message" +
             " WHERE account = :account" +
-            " AND (msgid IN (:msgids) OR inreplyto IN (:msgids))")
-    List<TupleThreadInfo> getThreadInfo(long account, List<String> msgids);
+            " AND (msgid IN (:msgids) OR inreplyto IN (:msgids))" +
+            " AND (:range IS NULL || received > :range)")
+    List<TupleThreadInfo> getThreadInfo(long account, List<String> msgids, Long range);
 
     @Query("SELECT * FROM message" +
             " WHERE account = :account" +

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

@@ -141,6 +141,7 @@ public class MessageHelper {
     static final int DEFAULT_DOWNLOAD_SIZE = 4 * 1024 * 1024; // bytes
     static final String HEADER_CORRELATION_ID = "X-Correlation-ID";
     static final int MAX_SUBJECT_AGE = 48; // hours
+    static final long MAX_THREAD_AGE = 180; // days
 
     static final List<String> RECEIVED_WORDS = Collections.unmodifiableList(Arrays.asList(
             "from", "by", "via", "with", "id", "for"
@@ -1334,10 +1335,10 @@ public class MessageHelper {
         return reportHeaders;
     }
 
-    String getThreadId(Context context, long account, long folder, long uid) throws MessagingException {
+    String getThreadId(Context context, long account, long folder, long uid, long received) throws MessagingException {
         if (threadId == null)
             if (true)
-                threadId = _getThreadIdAlt(context, account, folder, uid);
+                threadId = _getThreadIdAlt(context, account, folder, uid, received);
             else
                 threadId = _getThreadId(context, account, folder, uid);
         return threadId;
@@ -1429,7 +1430,7 @@ public class MessageHelper {
         return thread;
     }
 
-    private String _getThreadIdAlt(Context context, long account, long folder, long uid) throws MessagingException {
+    private String _getThreadIdAlt(Context context, long account, long folder, long uid, long received) throws MessagingException {
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
 
         if (imessage instanceof GmailMessage) {
@@ -1483,9 +1484,10 @@ public class MessageHelper {
 
         List<String> all = new ArrayList<>(refs);
         all.add(msgid);
+        Long range = (received == 0 ? null : received - MAX_THREAD_AGE * 24 * 3600L);
         List<TupleThreadInfo> infos = (all.size() == 0
                 ? new ArrayList<>()
-                : db.message().getThreadInfo(account, all));
+                : db.message().getThreadInfo(account, all, range));
 
         // References, In-Reply-To (sent before)
         for (TupleThreadInfo info : infos)