Use a namedtuple for display values, with fields text and is_grouped

- it makes things a bit clearer
- it will be easier to add new fields

Author: zas

picard/ui/edittagdialog.py

@@ -240,9 +240,17 @@ def tag_changed(self, tag):
         values = self.modified_tags.get(self.tag, None)
         if values is None:
             new_tags = self.metadata_box.tag_diff.new
-            display_value, self.different = new_tags.display_value(self.tag)
-            values = [display_value] if self.different else new_tags[self.tag]
-            self.ui.add_value.setEnabled(not self.different)
+            display_value = new_tags.display_value(self.tag)
+            if display_value.is_grouped:
+                # grouped values have a special text, which isn't a valid tag value
+                self.different = True
+                values = [display_value.text]
+                self.ui.add_value.setEnabled(False)
+            else:
+                # normal tag values
+                self.different = False
+                values = new_tags[self.tag]
+                self.ui.add_value.setEnabled(True)
 
         self.value_list.model().rowsInserted.disconnect(self.on_rows_inserted)
         self._add_value_items(values)

picard/ui/metadatabox.py

@@ -34,6 +34,7 @@
 from collections import (
     Counter,
     defaultdict,
+    namedtuple,
 )
 from functools import partial
 
@@ -83,6 +84,9 @@ class TagStatus:
     READONLY = 32
 
 
+TagCounterDisplayValue = namedtuple('TagCounterDisplayValue', ('text', 'is_grouped'))
+
+
 class TagCounter(dict):
 
     __slots__ = ('parent', 'counts', 'different')
@@ -109,17 +113,22 @@ def display_value(self, tag):
         missing = self.parent.objects - count
 
         if tag in self.different:
-            return (ngettext("(different across %d item)", "(different across %d items)", count) % count, True)
+            text = ngettext("(different across %d item)", "(different across %d items)", count) % count
+            is_grouped = True
         else:
             if tag == '~length':
                 msg = format_time(self.get(tag, 0))
             else:
                 msg = MULTI_VALUED_JOINER.join(self[tag])
 
             if count > 0 and missing > 0:
-                return (msg + " " + (ngettext("(missing from %d item)", "(missing from %d items)", missing) % missing), True)
+                text = msg + " " + (ngettext("(missing from %d item)", "(missing from %d items)", missing) % missing)
+                is_grouped = True
             else:
-                return (msg, False)
+                text = msg
+                is_grouped = False
+
+        return TagCounterDisplayValue(text, is_grouped)
 
 
 class TagDiff(object):
@@ -714,11 +723,11 @@ def _update_items(self, result=None, error=None):
             self.setRowHeight(i, self.sizeHintForRow(i))
 
     def _set_item_value(self, item, tags, tag):
-        text, italic = tags.display_value(tag)
+        display_value = tags.display_value(tag)
         item.setData(QtCore.Qt.ItemDataRole.UserRole, tag)
-        item.setText(text)
+        item.setText(display_value.text)
         font = item.font()
-        font.setItalic(italic)
+        font.setItalic(display_value.is_grouped)
         item.setFont(font)
 
     @restore_method