Add search filter to playlist list page

This allows power users who keep 100s of playlists to easily
find a playlist either by directory name, playlist name or by
searching for a song artist/title a playlist might contain

src/playlist/playlistlistcontainer.cpp

@@ -33,9 +33,17 @@
 #include <QSortFilterProxyModel>
 #include <QStandardItemModel>
 
-class PlaylistListSortFilterModel : public QSortFilterProxyModel {
+#include <iostream>
+
+/* This filter proxy will:
+ - Accept all ancestors if at least a single child matches
+ - Accept all children if at least a single ancestor matches
+
+   The tree is then expanded only to the level at which the match occurs
+*/
+class PlaylistListFilterProxyModel : public QSortFilterProxyModel {
  public:
-  explicit PlaylistListSortFilterModel(QObject* parent)
+  explicit PlaylistListFilterProxyModel(QObject* parent)
       : QSortFilterProxyModel(parent) {}
 
   bool lessThan(const QModelIndex& left, const QModelIndex& right) const {
@@ -49,6 +57,83 @@ class PlaylistListSortFilterModel : public QSortFilterProxyModel {
     // deterministic sorting even when two items are named the same.
     return left.row() < right.row();
   }
+
+  QList<QModelIndex> expandList;
+
+  void setFilterRegExp(const QRegExp & regExp) {
+    expandList.clear();
+    QSortFilterProxyModel::setFilterRegExp(regExp);
+  }
+
+  void refreshExpanded(QTreeView *tree) {
+    tree->collapseAll();
+    for(QModelIndex sourceIndex : expandList ) {
+      QModelIndex mappedIndex = mapFromSource( sourceIndex );
+      tree->setExpanded( mappedIndex, true );
+    }
+  }
+
+  // Depth first search of all the items
+  bool hasAcceptedChildren(int source_row, const QModelIndex &source_parent) const {
+    QModelIndex item = sourceModel()->index(source_row,0,source_parent);
+    if (!item.isValid()) {
+      return false;
+    }
+
+    //check if there are children
+    int childCount = item.model()->rowCount(item);
+    if (childCount == 0)
+      return false;
+
+    for (int i = 0; i < childCount; ++i) {
+      if (filterAcceptsRowItself(i, item))
+        return true;
+
+      if (hasAcceptedChildren(i, item))
+        return true;
+    }
+    return false;
+  }
+
+  bool filterAcceptsRowItself(int source_row, const QModelIndex &source_parent) const {
+    bool rv = QSortFilterProxyModel::filterAcceptsRow(source_row, source_parent);
+    if(rv) {
+      if(sourceModel()->hasIndex(source_row,0,source_parent)) {
+        QModelIndex idx = sourceModel()->index(source_row,0,source_parent);
+
+        // Bit of a hack to get around the const in this function
+        auto * me = const_cast<PlaylistListFilterProxyModel*>(this);
+
+        QModelIndex pidx = sourceModel()->parent(idx);
+        while(pidx.isValid()) {
+          me->expandList.append(pidx);
+          pidx = sourceModel()->parent(pidx);
+        }
+      }
+    }
+    return rv;
+  }
+
+  bool filterAcceptsRow(int source_row, const QModelIndex &source_parent) const {
+    if (filterAcceptsRowItself(source_row, source_parent)) {
+      return true;
+    }
+
+    //accept if any of the parents is accepted on it's own merits
+    QModelIndex parent = source_parent;
+    while (parent.isValid()) {
+      if (filterAcceptsRowItself(parent.row(), parent.parent()))
+        return true;
+      parent = parent.parent();
+    }
+
+    //accept if any of the children is accepted on it's own merits
+    if (hasAcceptedChildren(source_row, source_parent)) {
+      return true;
+    }
+
+    return false;
+  }
 };
 
 PlaylistListContainer::PlaylistListContainer(QWidget* parent)
@@ -60,11 +145,12 @@ PlaylistListContainer::PlaylistListContainer(QWidget* parent)
       action_remove_(new QAction(this)),
       action_save_playlist_(new QAction(this)),
       model_(new PlaylistListModel(this)),
-      proxy_(new PlaylistListSortFilterModel(this)),
+      proxy_(new PlaylistListFilterProxyModel(this)),
       loaded_icons_(false),
       active_playlist_id_(-1) {
   ui_->setupUi(this);
   ui_->tree->setAttribute(Qt::WA_MacShowFocusRect, false);
+  ui_->tree->SetAutoOpen(false);
 
   action_new_folder_->setText(tr("New folder"));
   action_remove_->setText(tr("Delete"));
@@ -91,6 +177,8 @@ PlaylistListContainer::PlaylistListContainer(QWidget* parent)
 
   model_->invisibleRootItem()->setData(PlaylistListModel::Type_Folder,
                                        PlaylistListModel::Role_Type);
+
+  connect(ui_->search, SIGNAL(textChanged(QString)), SLOT(SearchTextEdited(QString)));
 }
 
 PlaylistListContainer::~PlaylistListContainer() { delete ui_; }
@@ -128,6 +216,10 @@ void PlaylistListContainer::RecursivelySetIcons(QStandardItem* parent) const {
       case PlaylistListModel::Type_Playlist:
         child->setIcon(model_->playlist_icon());
         break;
+
+      case PlaylistListModel::Type_Track:
+        child->setIcon(model_->track_icon());
+        break;
     }
   }
 }
@@ -161,6 +253,10 @@ void PlaylistListContainer::SetApplication(Application* app) {
     QStandardItem* playlist_item = model_->NewPlaylist(p.name, p.id);
     QStandardItem* parent_folder = model_->FolderByPath(p.ui_path);
     parent_folder->appendRow(playlist_item);
+    for (const Song s : app->playlist_backend()->GetPlaylistSongs(p.id)) {
+      QStandardItem* track_item = model_->NewTrack(s);
+      playlist_item->appendRow(track_item);
+    }
   }
 }
 
@@ -267,6 +363,18 @@ void PlaylistListContainer::CurrentChanged(Playlist* new_playlist) {
   ui_->tree->scrollTo(index);
 }
 
+void PlaylistListContainer::SearchTextEdited(const QString& text) {
+    QRegExp regexp(text);
+    regexp.setCaseSensitivity(Qt::CaseInsensitive);
+
+    if(regexp.isEmpty()) {
+      ui_->tree->collapseAll();
+    } else {
+      proxy_->setFilterRegExp(regexp);
+      proxy_->refreshExpanded(ui_->tree);
+    }
+}
+
 void PlaylistListContainer::PlaylistPathChanged(int id,
                                                 const QString& new_path) {
   // Update the path in the database

src/playlist/playlistlistcontainer.h

@@ -31,6 +31,8 @@ class Playlist;
 class PlaylistListModel;
 class Ui_PlaylistListContainer;
 
+class PlaylistListFilterProxyModel;
+
 class PlaylistListContainer : public QWidget {
   Q_OBJECT
 
@@ -49,6 +51,7 @@ class PlaylistListContainer : public QWidget {
   void NewFolderClicked();
   void DeleteClicked();
   void ItemDoubleClicked(const QModelIndex& index);
+  void SearchTextEdited(const QString& text);
 
   // From the model
   void PlaylistPathChanged(int id, const QString& new_path);
@@ -87,7 +90,7 @@ class PlaylistListContainer : public QWidget {
   QAction* action_save_playlist_;
 
   PlaylistListModel* model_;
-  QSortFilterProxyModel* proxy_;
+  PlaylistListFilterProxyModel* proxy_;
 
   bool loaded_icons_;
   QIcon padded_play_icon_;

src/playlist/playlistlistcontainer.ui

@@ -41,6 +41,13 @@
       <property name="margin">
        <number>0</number>
       </property>
+      <item>
+       <widget class="QSearchField" name="search" native="true">
+        <property name="placeholderText" stdset="0">
+         <string>Search for anything</string>
+        </property>
+       </widget>
+      </item>
       <item>
        <widget class="QToolButton" name="new_folder">
         <property name="toolTip">
@@ -72,19 +79,6 @@
         </property>
        </widget>
       </item>
-      <item>
-       <spacer name="horizontalSpacer">
-        <property name="orientation">
-         <enum>Qt::Horizontal</enum>
-        </property>
-        <property name="sizeHint" stdset="0">
-         <size>
-          <width>70</width>
-          <height>20</height>
-         </size>
-        </property>
-       </spacer>
-      </item>
      </layout>
     </widget>
    </item>
@@ -125,6 +119,11 @@
   </layout>
  </widget>
  <customwidgets>
+  <customwidget>
+   <class>QSearchField</class>
+   <extends>QWidget</extends>
+   <header>3rdparty/qocoa/qsearchfield.h</header>
+  </customwidget>
   <customwidget>
    <class>AutoExpandingTreeView</class>
    <extends>QTreeView</extends>

src/playlist/playlistlistmodel.cpp

@@ -71,6 +71,12 @@ void PlaylistListModel::AddRowMappings(const QModelIndex& begin,
 void PlaylistListModel::AddRowItem(QStandardItem* item,
                                    const QString& parent_path) {
   switch (item->data(Role_Type).toInt()) {
+    case Type_Track: {
+      // const int id = item->data(Role_TrackId).toInt();
+      // TODO
+      break;
+    }
+
     case Type_Playlist: {
       const int id = item->data(Role_PlaylistId).toInt();
       playlists_by_id_[id] = item;
@@ -172,6 +178,16 @@ QStandardItem* PlaylistListModel::NewPlaylist(const QString& name,
   return ret;
 }
 
+QStandardItem* PlaylistListModel::NewTrack(const Song& song) const {
+  QStandardItem* ret = new QStandardItem;
+  ret->setText(song.artist() + " - " + song.title());
+  ret->setData(PlaylistListModel::Type_Track, PlaylistListModel::Role_Type);
+  ret->setData(song.id(), PlaylistListModel::Role_TrackId);
+  ret->setIcon(track_icon_);
+  ret->setFlags(Qt::ItemIsDragEnabled | Qt::ItemIsEnabled | Qt::ItemIsSelectable);
+  return ret;
+}
+
 bool PlaylistListModel::setData(const QModelIndex& index, const QVariant& value,
                                 int role) {
   if (!QStandardItemModel::setData(index, value, role)) {

src/playlist/playlistlistmodel.h

@@ -2,16 +2,16 @@
 #define PLAYLISTLISTMODEL_H
 
 #include <QStandardItemModel>
-
+#include "core/song.h"
 class PlaylistListModel : public QStandardItemModel {
   Q_OBJECT
 
  public:
   PlaylistListModel(QObject* parent = nullptr);
 
-  enum Types { Type_Folder, Type_Playlist };
+  enum Types { Type_Folder, Type_Playlist, Type_Track };
 
-  enum Roles { Role_Type = Qt::UserRole, Role_PlaylistId };
+  enum Roles { Role_Type = Qt::UserRole, Role_PlaylistId, Role_TrackId };
 
   bool dropMimeData(const QMimeData* data, Qt::DropAction action, int row,
                     int column, const QModelIndex& parent);
@@ -19,6 +19,7 @@ class PlaylistListModel : public QStandardItemModel {
   // These icons will be used for newly created playlists and folders.
   // The caller will need to set these icons on existing items if there are any.
   void SetIcons(const QIcon& playlist_icon, const QIcon& folder_icon);
+  const QIcon& track_icon() const { return track_icon_; }
   const QIcon& playlist_icon() const { return playlist_icon_; }
   const QIcon& folder_icon() const { return folder_icon_; }
 
@@ -41,6 +42,9 @@ class PlaylistListModel : public QStandardItemModel {
   // added to the model yet.
   QStandardItem* NewPlaylist(const QString& name, int id) const;
 
+  // Returns a new track item. The item isn't added to the model yet.
+  QStandardItem* NewTrack(const Song& song) const;
+
   // QStandardItemModel
   bool setData(const QModelIndex& index, const QVariant& value, int role);
 
@@ -61,6 +65,7 @@ signals:
  private:
   bool dropping_rows_;
 
+  QIcon track_icon_;
   QIcon playlist_icon_;
   QIcon folder_icon_;