electron/brightray/browser/win/win32_desktop_notifications/desktop_notification_controller.h

#pragma once
#include <Windows.h>
#include <deque>
#include <memory>
#include <string>
#include <vector>

namespace brightray {

struct NotificationData;

class DesktopNotificationController {
 public:
  explicit DesktopNotificationController(unsigned maximum_toasts = 3);
  ~DesktopNotificationController();

  class Notification;
  Notification AddNotification(std::wstring caption,
                               std::wstring body_text,
                               HBITMAP image);
  void CloseNotification(Notification& notification);

  // Event handlers -- override to receive the events
 private:
  virtual void OnNotificationClosed(Notification& notification) {}
  virtual void OnNotificationClicked(Notification& notification) {}
  virtual void OnNotificationDismissed(Notification& notification) {}

 private:
  static HINSTANCE RegisterWndClasses();
  void StartAnimation();
  HFONT GetCaptionFont();
  HFONT GetBodyFont();

 private:
  enum TimerID { TimerID_Animate = 1 };

  static constexpr int toast_margin_ = 20;

  // Wrapper around `NotificationData` which makes sure that
  // the `controller` member is cleared when the controller object
  // stops tracking the notification
  struct NotificationLink : std::shared_ptr<NotificationData> {
    explicit NotificationLink(DesktopNotificationController* controller);
    ~NotificationLink();

    NotificationLink(NotificationLink&&) = default;
    NotificationLink(const NotificationLink&) = delete;
    NotificationLink& operator=(NotificationLink&&) = default;
  };

  struct ToastInstance {
    HWND hwnd;
    NotificationLink data;
  };

  class Toast;

  static LRESULT CALLBACK WndProc(HWND hwnd,
                                  UINT message,
                                  WPARAM wparam,
                                  LPARAM lparam);
  static DesktopNotificationController* Get(HWND hwnd) {
    return reinterpret_cast<DesktopNotificationController*>(
        GetWindowLongPtr(hwnd, 0));
  }

  DesktopNotificationController(const DesktopNotificationController&) = delete;

  void InitializeFonts();
  void ClearAssets();
  void AnimateAll();
  void CheckQueue();
  void CreateToast(NotificationLink&& data);
  HWND GetToast(const NotificationData* data) const;
  void DestroyToast(ToastInstance& inst);

 private:
  static const TCHAR class_name_[];

  HWND hwnd_controller_ = NULL;
  HFONT caption_font_ = NULL, body_font_ = NULL;
  std::vector<ToastInstance> instances_;
  std::deque<NotificationLink> queue_;
  bool is_animating_ = false;
};

class DesktopNotificationController::Notification {
 public:
  Notification();
  explicit Notification(const std::shared_ptr<NotificationData>& data);
  Notification(const Notification&);
  ~Notification();

  bool operator==(const Notification& other) const;

  void Close();
  void Set(std::wstring caption, std::wstring body_text, HBITMAP image);

 private:
  std::shared_ptr<NotificationData> data_;

  friend class DesktopNotificationController;
};

}  // namespace brightray