Added support for Outlook categories (read only)

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

@@ -96,6 +96,7 @@ public class AdapterKeyword extends RecyclerView.Adapter<AdapterKeyword.ViewHold
         }
 
         private void bindTo(TupleKeyword keyword) {
+            cbKeyword.setEnabled(!keyword.name.startsWith(MessageHelper.CATEGORY_PREFIX));
             cbKeyword.setText(getTitle(keyword.name));
             cbKeyword.setChecked(keyword.selected);
             if (keyword.partial)
@@ -168,7 +169,7 @@ public class AdapterKeyword extends RecyclerView.Adapter<AdapterKeyword.ViewHold
             if (itemId == R.id.ibEdit) {
                 String key = "kwtitle." + keyword.name;
                 etKeyword.setText(prefs.getString(key, null));
-                etKeyword.setHint(keyword.name);
+                etKeyword.setHint(keyword.name.replace(MessageHelper.CATEGORY_PREFIX, ""));
                 grpNotEdit.setVisibility(View.GONE);
                 grpEdit.setVisibility(View.VISIBLE);
                 etKeyword.post(new Runnable() {

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

@@ -4619,7 +4619,7 @@ class Core {
         boolean flagged = helper.getFlagged();
         boolean deleted = helper.getDeleted();
         String flags = helper.getFlags();
-        String[] keywords = helper.getKeywords();
+        String[] keywords = helper.getKeywords(account.isOutlook());
         String[] labels = helper.getLabels();
         boolean update = false;
         boolean process = false;

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

@@ -253,6 +253,7 @@ public class MessageHelper {
     static final String FLAG_LOW_IMPORTANCE = "$LowImportance";
     static final String FLAG_HIGH_IMPORTANCE = "$HighImportance";
     static final String FLAG_PHISHING = "$Phishing"; // Gmail
+    static final String CATEGORY_PREFIX = "$category:";
 
     // https://www.iana.org/assignments/imap-jmap-keywords/imap-jmap-keywords.xhtml
     // Not black listed: Gmail $Phishing
@@ -1544,10 +1545,19 @@ public class MessageHelper {
     }
 
     @NonNull
-    String[] getKeywords() throws MessagingException {
+    String[] getKeywords(boolean outlook) throws MessagingException {
         List<String> keywords = new ArrayList<>(Arrays.asList(imessage.getFlags().getUserFlags()));
+
+        if (outlook) {
+            String categories = imessage.getHeader("Keywords", null);
+            if (!TextUtils.isEmpty(categories))
+                for (String category : categories.split(","))
+                    keywords.add(CATEGORY_PREFIX + category);
+        }
+
         while (keywords.size() > MAX_KEYWORDS)
             keywords.remove(keywords.size() - 1);
+
         Collections.sort(keywords);
         return keywords.toArray(new String[0]);
     }

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

@@ -168,6 +168,9 @@ public class TupleKeyword {
     }
 
     static String getDefaultKeywordAlias(Context context, String keyword) {
+        if (keyword.startsWith(MessageHelper.CATEGORY_PREFIX))
+            return keyword.substring(MessageHelper.CATEGORY_PREFIX.length());
+
         switch (keyword) {
             case "$label1": // Important
                 return context.getString(R.string.title_keyword_label1);