Add logic to refresh library with monitor directory changes

To check if there have been any changes in monitor directory, we compare the files before and after followed by adding/removing them from the library

src/kiwixapp.cpp

@@ -275,6 +275,10 @@ bool KiwixApp::isCurrentArticleBookmarked()
 
 void KiwixApp::setMonitorDir(const QString &dir) {
     m_settingsManager.setMonitorDir(dir);
+    m_library.setMonitorDirZims(QStringList());
+    if (dir != "") {
+        m_library.asyncLoadMonitorDir(dir);
+    }
 }
 
 #define CREATE_ACTION(ID, TEXT) \

src/library.cpp

@@ -5,6 +5,8 @@
 #include <kiwix/tools.h>
 
 #include <QtDebug>
+#include <QtConcurrent/QtConcurrentRun>
+
 
 class LibraryManipulator: public kiwix::LibraryManipulator {
   public:
@@ -123,6 +125,45 @@ void Library::save()
     m_library.writeBookmarksToFile(kiwix::appendToDirectory(m_libraryDirectory.toStdString(), "library.bookmarks.xml"));
 }
 
+void Library::setMonitorDirZims(QStringList zimList)
+{
+    m_monitorDirZims = zimList;
+}
+
+void Library::loadMonitorDir(QString monitorDir)
+{
+    QMutex mutex;
+    QMutexLocker locker(&mutex);
+    const QDir dir(monitorDir);
+    QStringList newDirEntries = dir.entryList({"*.zim"});
+    for (auto &str : newDirEntries) {
+        str = monitorDir + QDir::separator() + str;
+    }
+    QSet<QString> newDir = QSet<QString>::fromList(newDirEntries);
+    QStringList oldDirEntries = m_monitorDirZims;
+    QSet<QString> oldDir = QSet<QString>::fromList(oldDirEntries);
+    QStringList addedZims = (newDir - oldDir).values();
+    QStringList removedZims = (oldDir - newDir).values();
+    setMonitorDirZims(newDir.values());
+    auto manipulator = LibraryManipulator(this);
+    auto manager = kiwix::Manager(&manipulator);
+    for (auto book : addedZims) {
+        manager.addBookFromPath(book.toStdString());
+    }
+    for (auto bookPath : removedZims) {
+        removeBookFromLibraryById(QString::fromStdString(m_library.getBookByPath(bookPath.toStdString()).getId()));
+    }
+    emit(booksChanged());
+    save();
+}
+
+void Library::asyncLoadMonitorDir(QString dir)
+{
+    QtConcurrent::run( [=]() {
+        loadMonitorDir(dir);
+    });
+}
+
 const kiwix::Book &Library::getBookById(QString id) const
 {
     return m_library.getBookById(id.toStdString());

src/library.h

@@ -33,11 +33,15 @@ public:
     QStringList getBookIds() const;
     QStringList listBookIds(const kiwix::Filter& filter, kiwix::supportedListSortBy sortBy, bool ascending) const;
     const std::vector<kiwix::Bookmark> getBookmarks(bool onlyValidBookmarks = false) const { return m_library.getBookmarks(onlyValidBookmarks); }
+    QStringList getLibraryZimsFromDir(QString dir) const;
+    void setMonitorDirZims(QStringList zimList);
     void addBookToLibrary(kiwix::Book& book);
     void removeBookFromLibraryById(const QString& id);
     void addBookmark(kiwix::Bookmark& bookmark);
     void removeBookmark(const QString& zimId, const QString& url);
     void save();
+    void loadMonitorDir(QString dir);
+    void asyncLoadMonitorDir(QString dir);
     kiwix::Library& getKiwixLibrary() { return m_library; }
 public slots:
     const kiwix::Book& getBookById(QString id) const;
@@ -49,6 +53,7 @@ signals:
 private:
     kiwix::Library m_library;
     QString m_libraryDirectory;
+    QStringList m_monitorDirZims;
 friend class LibraryManipulator;
 };