From 4a4f6990773f988892ea9a112b62731a5b39fca7 Mon Sep 17 00:00:00 2001
From: Philipp Wolfer <ph.wolfer@gmail.com>
Date: Sat, 22 Feb 2020 19:13:26 +0000
Subject: [PATCH] PICARD-1760: Prevent duplicates in top tags editor

---
 picard/ui/ui_widget_taglisteditor.py  |  4 +--
 picard/ui/widgets/editablelistview.py | 45 +++++++++++++++++++++++++--
 ui/widget_taglisteditor.ui            |  4 +--
 3 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/picard/ui/ui_widget_taglisteditor.py b/picard/ui/ui_widget_taglisteditor.py
index b4c38e6fd..03aa58eff 100644
--- a/picard/ui/ui_widget_taglisteditor.py
+++ b/picard/ui/ui_widget_taglisteditor.py
@@ -17,7 +17,7 @@ class Ui_TagListEditor(object):
         self.horizontalLayout.setObjectName("horizontalLayout")
         self.verticalLayout = QtWidgets.QVBoxLayout()
         self.verticalLayout.setObjectName("verticalLayout")
-        self.tag_list_view = EditableListView(TagListEditor)
+        self.tag_list_view = UniqueEditableListView(TagListEditor)
         self.tag_list_view.setDragDropMode(QtWidgets.QAbstractItemView.InternalMove)
         self.tag_list_view.setSelectionMode(QtWidgets.QAbstractItemView.ExtendedSelection)
         self.tag_list_view.setObjectName("tag_list_view")
@@ -74,4 +74,4 @@ class Ui_TagListEditor(object):
         self.tags_remove_btn.setToolTip(_("Remove selected tags"))
         self.tags_remove_btn.setAccessibleName(_("Remove selected tags"))
         self.tags_remove_btn.setText(_("Remove tags"))
-from picard.ui.widgets.editablelistview import EditableListView
+from picard.ui.widgets.editablelistview import UniqueEditableListView
diff --git a/picard/ui/widgets/editablelistview.py b/picard/ui/widgets/editablelistview.py
index 4726f5fb4..2b4dd5d16 100644
--- a/picard/ui/widgets/editablelistview.py
+++ b/picard/ui/widgets/editablelistview.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 #
 # Picard, the next-generation MusicBrainz tagger
-# Copyright (C) 2019 Philipp Wolfer
+# Copyright (C) 2019-2020 Philipp Wolfer
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -113,7 +113,7 @@ class EditableListView(QtWidgets.QListView):
 
     def select_key(self, value):
         model = self.model()
-        for row in range(0, model.rowCount() - 1):
+        for row in range(0, model.rowCount()):
             index = model.createIndex(row, 0)
             if value == index.data(QtCore.Qt.EditRole):
                 self.setCurrentIndex(index)
@@ -134,6 +134,46 @@ class EditableListView(QtWidgets.QListView):
                 selection.setCurrentIndex(new_index, QtCore.QItemSelectionModel.Current)
 
 
+class UniqueEditableListView(EditableListView):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._is_drag_drop = False
+
+    def setModel(self, model):
+        current_model = self.model()
+        if current_model:
+            current_model.dataChanged.disconnect(self.on_data_changed)
+        super().setModel(model)
+        model.dataChanged.connect(self.on_data_changed)
+
+    def dropEvent(self, event):
+        self._is_drag_drop = True
+        super().dropEvent(event)
+        self._is_drag_drop = False
+
+    def on_data_changed(self, top_left, bottom_right, roles):
+        # Do not drop duplicates during drag and drop as there is always
+        # a duplicate in the list for a short time in this case.
+        if self._is_drag_drop:
+            return
+        model = self.model()
+        if QtCore.Qt.EditRole in roles:
+            value = model.data(top_left, QtCore.Qt.EditRole)
+            if not value:
+                return
+            # Remove duplicate entries from the model
+            changed_row = top_left.row()
+            row = 0
+            for item in model.items:
+                if item == value and row != changed_row:
+                    model.removeRow(row)
+                    row -= 1
+                    if changed_row > row:
+                        changed_row -= 1
+                row += 1
+            self.select_row(changed_row)
+
+
 class EditableListModel(QtCore.QAbstractListModel):
     user_sortable_changed = QtCore.pyqtSignal(bool)
 
@@ -184,6 +224,7 @@ class EditableListModel(QtCore.QAbstractListModel):
             elif role == QtCore.Qt.DisplayRole:
                 current = self._items[i]
                 self._items[i] = (current[0], value)
+            self.dataChanged.emit(index, index, [role])
             return True
         except IndexError:
             return False
diff --git a/ui/widget_taglisteditor.ui b/ui/widget_taglisteditor.ui
index 02aff2baa..877b174ba 100644
--- a/ui/widget_taglisteditor.ui
+++ b/ui/widget_taglisteditor.ui
@@ -32,7 +32,7 @@
    <item>
     <layout class="QVBoxLayout" name="verticalLayout">
      <item>
-      <widget class="EditableListView" name="tag_list_view">
+      <widget class="UniqueEditableListView" name="tag_list_view">
        <property name="dragDropMode">
         <enum>QAbstractItemView::InternalMove</enum>
        </property>
@@ -150,7 +150,7 @@
  </widget>
  <customwidgets>
   <customwidget>
-   <class>EditableListView</class>
+   <class>UniqueEditableListView</class>
    <extends>QListView</extends>
    <header>picard.ui.widgets.editablelistview</header>
    <slots>