InfiniTime/src/displayapp/screens/Screen.h

#pragma once

#include <cstdint>
#include "displayapp/TouchEvents.h"
#include <lvgl/lvgl.h>

namespace Pinetime {
  namespace Applications {
    class DisplayApp;

    namespace Screens {

      template <class T>
      class DirtyValue {
      public:
        DirtyValue() = default; // Use NSDMI

        explicit DirtyValue(T const& v) : value {v} {
        } // Use MIL and const-lvalue-ref

        bool IsUpdated() {
          if (this->isUpdated) {
            this->isUpdated = false;
            return true;
          }
          return false;
        }

        T const& Get() {
          this->isUpdated = false;
          return value;
        } // never expose a non-const lvalue-ref

        DirtyValue& operator=(const T& other) {
          if (this->value != other) {
            this->value = other;
            this->isUpdated = true;
          }
          return *this;
        }

      private:
        T value {};            // NSDMI - default initialise type
        bool isUpdated {true}; // NSDMI - use brace initialisation
      };

      class Screen {
      private:
        virtual void Refresh() {
        }

      public:
        explicit Screen(DisplayApp* app) : app {app} {
        }

        virtual ~Screen() = default;

        static void RefreshTaskCallback(lv_task_t* task);

        bool IsRunning() const {
          return running;
        }

        /** @return false if the button hasn't been handled by the app, true if it has been handled */
        virtual bool OnButtonPushed() {
          return false;
        }

        /** @return false if the event hasn't been handled by the app, true if it has been handled */
        // Returning true will cancel lvgl tap
        virtual bool OnTouchEvent(TouchEvents /*event*/) {
          return false;
        }

        virtual bool OnTouchEvent(uint16_t /*x*/, uint16_t /*y*/) {
          return false;
        }

      protected:
        DisplayApp* app;
        bool running = true;
      };
    }
  }
}