fix: should now be able to show property dialog for all supported files

app/playlistmanager.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <QObject>
+
+class PlaylistManager : public QObject
+{
+    Q_OBJECT
+public:
+    enum PlaylistType {
+        PL_USERPLAYLIST, // Regular playlist, managed by user.
+        PL_SAMEFOLDER // PlaylistManager managed playlist, loaded from files from same folder.
+    };
+
+    explicit PlaylistManager(PlaylistType type = PL_USERPLAYLIST, QObject *parent = nullptr);
+    ~PlaylistManager();
+
+    void setPlaylistType(PlaylistType type);
+    PlaylistType playlistType() const;
+
+    void clear();
+
+    void setPlaylist(const QList<QUrl> & urls);
+    void setCurrentFile(const QString & filePath);
+    void setCurrentIndex(int index);
+    int appendFile(const QString & filePath);
+    int indexOf(const QString & filePath);
+
+    std::tuple<int, QString> previousFile() const;
+    std::tuple<int, QString> nextFile() const;
+    std::tuple<int, QString> currentFile() const;
+    std::tuple<int, QUrl> currentFileUrl() const;
+
+    static QList<QUrl> convertToUrlList(const QStringList & files);
+
+signals:
+    void loaded(int length);
+
+private:
+    QList<QUrl> m_playlist;
+    PlaylistType m_type;
+    QString m_currentDir;
+    int m_currentIndex = -1;
+};
+