Implement playing station visual feedback, track desktop notifications, and local cover caching

src/notificationmanager.h

@@ -0,0 +1,50 @@
+#ifndef NOTIFICATIONMANAGER_H
+#define NOTIFICATIONMANAGER_H
+
+#include <QObject>
+#include <QString>
+#include <QTimer>
+#include <QNetworkAccessManager>
+#include <QNetworkReply>
+
+class RadioBackend;
+class BearPlayer;
+
+class NotificationManager : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit NotificationManager(RadioBackend *backend, QObject *parent = nullptr);
+    ~NotificationManager();
+
+private slots:
+    void onTrackInfoChanged();
+    void onDownloadFinished();
+    void onNotifyTimeout();
+
+private:
+    void showNotification(const QString &station, const QString &artist, const QString &title, const QString &coverPath);
+    void closeNotification();
+    void downloadCover(const QString &url);
+    void triggerNotification();
+
+    RadioBackend *m_backend = nullptr;
+    BearPlayer *m_player = nullptr;
+    QNetworkAccessManager *m_networkManager = nullptr;
+    QNetworkReply *m_currentReply = nullptr;
+    QTimer m_notifyTimer;
+
+    quint32 m_lastNotificationId = 0;
+    QString m_coversDir;
+
+    QString m_lastArtist;
+    QString m_lastTitle;
+    QString m_lastStation;
+    QString m_notifiedCoverUrl;
+    QString m_pendingCoverUrl;
+    QString m_activeCoverPath;
+    bool m_notificationShown = false;
+};
+
+#endif // NOTIFICATIONMANAGER_H