#ifndef DISPLAY_HH

#define DISPLAY_HH

#include "RenderSettings.hh"

#include "Command.hh"

#include "EventListener.hh"

#include "InfoTopic.hh"

#include "OSDGUI.hh"

#include "RTSchedulable.hh"

#include "CircularBuffer.hh"

#include "Observer.hh"

#include <cstdint>

#include <memory>

#include <optional>

#include <vector>

namespace openmsx {

class Layer;

class Reactor;

class VideoSystem;

class CliComm;

class VideoSystemChangeListener;

class Setting;

class OutputSurface;

/** Represents the output window/screen of openMSX.

  * A display contains several layers.

  */

class Display final : public EventListener, private Observer<Setting>

                    , private RTSchedulable

{

public:

	static constexpr std::string_view SCREENSHOT_DIR = "screenshots";

	static constexpr std::string_view SCREENSHOT_EXTENSION = ".png";

public:

	using Layers = std::vector<Layer*>;

	explicit Display(Reactor& reactor);

	~Display();

	void createVideoSystem();

	[[nodiscard]] VideoSystem& getVideoSystem();

	[[nodiscard]] CliComm& getCliComm() const;

	[[nodiscard]] RenderSettings& getRenderSettings() { return renderSettings; }

	[[nodiscard]] auto getRenderer() const { return currentRenderer; }

	[[nodiscard]] OSDGUI& getOSDGUI() { return osdGui; }

	/** Redraw the display.

	  * The repaintImpl() methods are for internal and VideoSystem/VisibleSurface use only.

	  */

	void repaint();

	void repaintDelayed(uint64_t delta);

	void repaintImpl();

	void repaintImpl(OutputSurface& surface);

	void addLayer(Layer& layer);

	void removeLayer(Layer& layer);

	void updateZ(Layer& layer);

	void attach(VideoSystemChangeListener& listener);

	void detach(VideoSystemChangeListener& listener);

	[[nodiscard]] Layer* findActiveLayer() const;

	[[nodiscard]] const Layers& getAllLayers() const { return layers; }

	[[nodiscard]] OutputSurface* getOutputSurface();

	/** Returns the size of a single MSX pixel as it is currently drawn on

	  * screen, expressed in the same units as the host mouse coordinates.

	  * Returns std::nullopt when there's no window to draw on. */

	[[nodiscard]] std::optional<gl::vec2> getMsxPixelSize();

	[[nodiscard]] std::string getWindowTitle();

	/** Get/set x,y coordinates of top-left window corner.

	    Either the actual, or the last known coordinates. */

	[[nodiscard]] gl::ivec2 getWindowPosition();

	void setWindowPosition(gl::ivec2 pos);

	// should only be called from VisibleSurface

	void storeWindowPosition(gl::ivec2 pos);

	[[nodiscard]] gl::ivec2 retrieveWindowPosition();

	[[nodiscard]] gl::ivec2 getWindowSize() const;

	// Get the latest fps value

	[[nodiscard]] float getFps() const;

private:

	void resetVideoSystem();

	// EventListener interface

	bool signalEvent(const Event& event) override;

	// RTSchedulable

	void executeRT() override;

	// Observer<Setting> interface

	void update(const Setting& setting) noexcept override;

	void checkRendererSwitch();

	void doRendererSwitch(RenderSettings::RendererID newRenderer);

	void doRendererSwitch2(RenderSettings::RendererID newRenderer);

	/** Find front most opaque layer.

	  */

	[[nodiscard]] Layers::iterator baseLayer();

private:

	Layers layers; // sorted on z

	std::unique_ptr<VideoSystem> videoSystem;

	std::vector<VideoSystemChangeListener*> listeners; // unordered

	// fps related data

	static constexpr unsigned NUM_FRAME_DURATIONS = 50;

	CircularBuffer<uint64_t, NUM_FRAME_DURATIONS> frameDurations;

	uint64_t frameDurationSum;

	uint64_t prevTimeStamp;

	struct ScreenShotCmd final : Command {

		explicit ScreenShotCmd(CommandController& commandController);

		void execute(std::span<const TclObject> tokens, TclObject& result) override;

		[[nodiscard]] std::string help(std::span<const TclObject> tokens) const override;

	} screenShotCmd;

	struct FpsInfoTopic final : InfoTopic {

		explicit FpsInfoTopic(InfoCommand& openMSXInfoCommand);

		void execute(std::span<const TclObject> tokens,

			     TclObject& result) const override;

		[[nodiscard]] std::string help(std::span<const TclObject> tokens) const override;

	} fpsInfo;

	OSDGUI osdGui;

	Reactor& reactor;

	RenderSettings renderSettings;

	// the current renderer

	RenderSettings::RendererID currentRenderer = RenderSettings::RendererID::UNINITIALIZED;

	bool renderFrozen = false;

	bool switchInProgress = false;

};

} // namespace openmsx

#endif