support reordering notes in file list panel

Signed-off-by: Le Tan <tamlokveer@gmail.com>

src/vdirectory.cpp

@@ -582,3 +582,59 @@ void VDirectory::setExpanded(bool p_expanded)
     m_expanded = p_expanded;
 }
 
+void VDirectory::reorderFiles(int p_first, int p_last, int p_destStart)
+{
+    Q_ASSERT(m_opened);
+    Q_ASSERT(p_first <= p_last);
+    Q_ASSERT(p_last < m_files.size());
+    Q_ASSERT(p_destStart < p_first || p_destStart > p_last);
+    Q_ASSERT(p_destStart >= 0 && p_destStart <= m_files.size());
+
+    if (!reorderFilesInConfig(p_first, p_last, p_destStart)) {
+        qWarning() << "failed to reorder files in config" << p_first << p_last << p_destStart;
+        return;
+    }
+
+    // Reorder m_files.
+    if (p_destStart > p_last) {
+        int to = p_destStart - 1;
+        for (int i = p_first; i <= p_last; ++i) {
+            // Move p_first to p_destStart every time.
+            m_files.move(p_first, to);
+        }
+    } else {
+        int to = p_destStart;
+        for (int i = p_first; i <= p_last; ++i) {
+            m_files.move(i, to++);
+        }
+    }
+}
+
+bool VDirectory::reorderFilesInConfig(int p_first, int p_last, int p_destStart)
+{
+    QString path = retrivePath();
+    QJsonObject dirJson = VConfigManager::readDirectoryConfig(path);
+    Q_ASSERT(!dirJson.isEmpty());
+    QJsonArray fileArray = dirJson["files"].toArray();
+    Q_ASSERT(fileArray.size() == m_files.size());
+
+    if (p_destStart > p_last) {
+        int to = p_destStart - 1;
+        for (int i = p_first; i <= p_last; ++i) {
+            // Move p_first to p_destStart every time.
+            QJsonValue ele = fileArray.takeAt(p_first);
+            fileArray.insert(to, ele);
+        }
+    } else {
+        int to = p_destStart;
+        for (int i = p_first; i <= p_last; ++i) {
+            QJsonValue ele = fileArray.takeAt(i);
+            fileArray.insert(to++, ele);
+        }
+    }
+    dirJson["files"] = fileArray;
+    if (!VConfigManager::writeDirectoryConfig(path, dirJson)) {
+        return false;
+    }
+    return true;
+}

src/vdirectory.h

@@ -59,6 +59,8 @@ public:
     inline QString getNotebookName() const;
     inline bool isExpanded() const;
     void setExpanded(bool p_expanded);
+    void reorderFiles(int p_first, int p_last, int p_destStart);
+    bool reorderFilesInConfig(int p_first, int p_last, int p_destStart);
 
     static QJsonObject createDirectoryJson();
 

src/vfilelist.cpp

@@ -21,6 +21,7 @@ void VFileList::setupUI()
     fileList = new QListWidget(this);
     fileList->setContextMenuPolicy(Qt::CustomContextMenu);
     fileList->setSelectionMode(QAbstractItemView::ExtendedSelection);
+    fileList->setDragDropMode(QAbstractItemView::InternalMove);
     fileList->setObjectName("FileList");
 
     QVBoxLayout *mainLayout = new QVBoxLayout;
@@ -31,6 +32,8 @@ void VFileList::setupUI()
             this, &VFileList::contextMenuRequested);
     connect(fileList, &QListWidget::itemClicked,
             this, &VFileList::handleItemClicked);
+    connect(fileList->model(), &QAbstractItemModel::rowsMoved,
+            this, &VFileList::handleRowsMoved);
 
     setLayout(mainLayout);
 }
@@ -140,8 +143,9 @@ QListWidgetItem* VFileList::insertFileListItem(VFile *file, bool atFront)
 {
     Q_ASSERT(file);
     QListWidgetItem *item = new QListWidgetItem(file->getName());
-    item->setData(Qt::UserRole, QVariant::fromValue(file));
-
+    unsigned long long ptr = (long long)file;
+    item->setData(Qt::UserRole, ptr);
+    Q_ASSERT(sizeof(file) <= sizeof(ptr));
     if (atFront) {
         fileList->insertItem(0, item);
     } else {
@@ -469,3 +473,27 @@ bool VFileList::locateFile(const VFile *p_file)
     }
     return false;
 }
+
+void VFileList::handleRowsMoved(const QModelIndex &p_parent, int p_start, int p_end, const QModelIndex &p_destination, int p_row)
+{
+    if (p_parent == p_destination) {
+        // Items[p_start, p_end] are moved to p_row.
+        m_directory->reorderFiles(p_start, p_end, p_row);
+        Q_ASSERT(identicalListWithDirectory());
+    }
+}
+
+bool VFileList::identicalListWithDirectory() const
+{
+    const QVector<VFile *> files = m_directory->getFiles();
+    int nrItems = fileList->count();
+    if (nrItems != files.size()) {
+        return false;
+    }
+    for (int i = 0; i < nrItems; ++i) {
+        if (getVFile(fileList->item(i)) != files.at(i)) {
+            return false;
+        }
+    }
+    return true;
+}

src/vfilelist.h

@@ -44,6 +44,7 @@ private slots:
     void cutSelectedFiles();
     void pasteFilesInCurDir();
     void deleteFile();
+    void handleRowsMoved(const QModelIndex &p_parent, int p_start, int p_end, const QModelIndex &p_destination, int p_row);
 
 public slots:
     void setDirectory(VDirectory *p_directory);
@@ -64,7 +65,9 @@ private:
     bool copyFile(VDirectory *p_destDir, const QString &p_destName, VFile *p_file, bool p_cut);
     // New items have been added to direcotry. Update file list accordingly.
     QVector<QListWidgetItem *> updateFileListAdded();
-    inline QPointer<VFile> getVFile(QListWidgetItem *p_item);
+    inline QPointer<VFile> getVFile(QListWidgetItem *p_item) const;
+    // Check if the list items match exactly the contents of the directory.
+    bool identicalListWithDirectory() const;
 
     VEditArea *editArea;
     QListWidget *fileList;
@@ -85,10 +88,10 @@ inline void VFileList::setEditArea(VEditArea *editArea)
     this->editArea = editArea;
 }
 
-inline QPointer<VFile> VFileList::getVFile(QListWidgetItem *p_item)
+inline QPointer<VFile> VFileList::getVFile(QListWidgetItem *p_item) const
 {
     Q_ASSERT(p_item);
-    return p_item->data(Qt::UserRole).value<VFile *>();
+    return (VFile *)p_item->data(Qt::UserRole).toULongLong();
 }
 
 inline const VDirectory *VFileList::currentDirectory() const