Prevent answer loop

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

@@ -396,6 +396,19 @@ public class EntityRule {
         if (answer == null)
             throw new IllegalArgumentException("Rule answer not found");
 
+        Address[] from = new InternetAddress[]{new InternetAddress(identity.email, identity.name)};
+
+        // Prevent loop
+        List<EntityMessage> messages = db.message().getMessagesByThread(
+                message.account, message.thread, null, message.folder);
+        for (EntityMessage threaded : messages)
+            if (!threaded.id.equals(message.id) &&
+                    MessageHelper.equal(threaded.from, from)) {
+                EntityLog.log(context, "Answer loop" +
+                        " name=" + answer.name +
+                        " from=" + MessageHelper.formatAddresses(from));
+                return false;
+            }
 
         EntityMessage reply = new EntityMessage();
         reply.account = message.account;
@@ -406,7 +419,7 @@ public class EntityRule {
         reply.inreplyto = message.msgid;
         reply.thread = message.thread;
         reply.to = (message.reply == null || message.reply.length == 0 ? message.from : message.reply);
-        reply.from = new InternetAddress[]{new InternetAddress(identity.email, identity.name)};
+        reply.from = from;
         if (cc)
             reply.cc = message.cc;
         reply.unsubscribe = "mailto:" + identity.email;

app/src/main/res/layout/fragment_rule.xml

@@ -656,6 +656,17 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/spAnswer" />
 
+                <eu.faircode.email.FixedTextView
+                    android:id="@+id/tvAnswerRemark"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="12dp"
+                    android:text="@string/title_rule_answer_remark"
+                    android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                    android:textStyle="italic"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/cbCc" />
+
                 <eu.faircode.email.FixedTextView
                     android:id="@+id/tvAutomation"
                     android:layout_width="wrap_content"
@@ -664,7 +675,7 @@
                     android:text="@string/title_rule_automation_hint"
                     android:textAppearance="@style/TextAppearance.AppCompat.Small"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@+id/cbCc" />
+                    app:layout_constraintTop_toBottomOf="@+id/tvAnswerRemark" />
 
                 <androidx.constraintlayout.widget.Group
                     android:id="@+id/grpReady"
@@ -720,7 +731,7 @@
                     android:id="@+id/grpAnswer"
                     android:layout_width="0dp"
                     android:layout_height="0dp"
-                    app:constraint_referenced_ids="tvAnswerIdentity,spIdent,tvAnswerTemplate,spAnswer,cbCc" />
+                    app:constraint_referenced_ids="tvAnswerIdentity,spIdent,tvAnswerTemplate,spAnswer,cbCc,tvAnswerRemark" />
 
                 <androidx.constraintlayout.widget.Group
                     android:id="@+id/grpAutomation"

app/src/main/res/values/strings.xml

@@ -1038,6 +1038,7 @@
     <string name="title_rule_identity">Identity</string>
     <string name="title_rule_template">Reply template</string>
     <string name="title_rule_cc">Reply to CC addresses</string>
+    <string name="title_rule_answer_remark">Only one reply will be sent for any conversation, to avoid reply loops</string>
     <string name="title_rule_name_missing">Rule name missing</string>
     <string name="title_rule_condition_missing">Condition missing</string>
     <string name="title_rule_automation_hint">This will send the intent \'%1$s\' with the extras \'%2$s\'</string>