////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2024 Laurent Gomila (laurent@sfml-dev.org)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
//    you must not claim that you wrote the original software.
//    If you use this software in a product, an acknowledgment
//    in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
//    and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////

#pragma once

////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Window/GlContext.hpp>
#include <SFML/Window/WindowEnums.hpp> // Prevent conflict with macro None from Xlib

#include <X11/Xlib.h>
#include <glad/glx.h>

#include <memory>


namespace sf::priv
{
////////////////////////////////////////////////////////////
/// \brief Linux (GLX) implementation of OpenGL contexts
///
////////////////////////////////////////////////////////////
class GlxContext : public GlContext
{
public:
    ////////////////////////////////////////////////////////////
    /// \brief Create a new default context
    ///
    /// \param shared Context to share the new one with (can be a null pointer)
    ///
    ////////////////////////////////////////////////////////////
    explicit GlxContext(GlxContext* shared);

    ////////////////////////////////////////////////////////////
    /// \brief Create a new context attached to a window
    ///
    /// \param shared       Context to share the new one with
    /// \param settings     Creation parameters
    /// \param owner        Pointer to the owner window
    /// \param bitsPerPixel Pixel depth, in bits per pixel
    ///
    ////////////////////////////////////////////////////////////
    GlxContext(GlxContext* shared, const ContextSettings& settings, const WindowImpl& owner, unsigned int bitsPerPixel);

    ////////////////////////////////////////////////////////////
    /// \brief Create a new context that embeds its own rendering target
    ///
    /// \param shared   Context to share the new one with
    /// \param settings Creation parameters
    /// \param size     Back buffer width and height, in pixels
    ///
    ////////////////////////////////////////////////////////////
    GlxContext(GlxContext* shared, const ContextSettings& settings, Vector2u size);

    ////////////////////////////////////////////////////////////
    /// \brief Destructor
    ///
    ////////////////////////////////////////////////////////////
    ~GlxContext() override;

    ////////////////////////////////////////////////////////////
    /// \brief Get the address of an OpenGL function
    ///
    /// \param name Name of the function to get the address of
    ///
    /// \return Address of the OpenGL function, 0 on failure
    ///
    ////////////////////////////////////////////////////////////
    static GlFunctionPointer getFunction(const char* name);

    ////////////////////////////////////////////////////////////
    /// \brief Activate the context as the current target for rendering
    ///
    /// \param current Whether to make the context current or no longer current
    ///
    /// \return `true` on success, `false` if any error happened
    ///
    ////////////////////////////////////////////////////////////
    bool makeCurrent(bool current) override;

    ////////////////////////////////////////////////////////////
    /// \brief Display what has been rendered to the context so far
    ///
    ////////////////////////////////////////////////////////////
    void display() override;

    ////////////////////////////////////////////////////////////
    /// \brief Enable or disable vertical synchronization
    ///
    /// Activating vertical synchronization will limit the number
    /// of frames displayed to the refresh rate of the monitor.
    /// This can avoid some visual artifacts, and limit the framerate
    /// to a good value (but not constant across different computers).
    ///
    /// \param enabled `true` to enable v-sync, `false` to deactivate
    ///
    ////////////////////////////////////////////////////////////
    void setVerticalSyncEnabled(bool enabled) override;

    ////////////////////////////////////////////////////////////
    /// \brief Select the best GLX visual for a given set of settings
    ///
    /// \param display      X display
    /// \param bitsPerPixel Pixel depth, in bits per pixel
    /// \param settings     Requested context settings
    ///
    /// \return The best visual
    ///
    ////////////////////////////////////////////////////////////
    static XVisualInfo selectBestVisual(::Display* display, unsigned int bitsPerPixel, const ContextSettings& settings);

private:
    ////////////////////////////////////////////////////////////
    /// \brief Update the context visual settings from XVisualInfo
    ///
    /// \param visualInfo XVisualInfo to update settings from
    ///
    ////////////////////////////////////////////////////////////
    void updateSettingsFromVisualInfo(XVisualInfo* visualInfo);

    ////////////////////////////////////////////////////////////
    /// \brief Update the context visual settings from the window
    ///
    ////////////////////////////////////////////////////////////
    void updateSettingsFromWindow();

    ////////////////////////////////////////////////////////////
    /// \brief Create the context's drawing surface
    ///
    /// \param shared       Context to share the new one with (can be a null pointer)
    /// \param size         Back buffer width and height, in pixels
    /// \param bitsPerPixel Pixel depth, in bits per pixel
    ///
    ////////////////////////////////////////////////////////////
    void createSurface(GlxContext* shared, Vector2u size, unsigned int bitsPerPixel);

    ////////////////////////////////////////////////////////////
    /// \brief Create the context's drawing surface from an existing window
    ///
    /// \param window Window ID of the owning window
    ///
    ////////////////////////////////////////////////////////////
    void createSurface(::Window window);

    ////////////////////////////////////////////////////////////
    /// \brief Create the context
    ///
    /// \param shared Context to share the new one with (can be a null pointer)
    ///
    ////////////////////////////////////////////////////////////
    void createContext(GlxContext* shared);

    ////////////////////////////////////////////////////////////
    // Member data
    ////////////////////////////////////////////////////////////
    std::shared_ptr<Display> m_display;      ///< Connection to the X server
    ::Window                 m_window{};     ///< Window to which the context is attached
    GLXContext               m_context{};    ///< OpenGL context
    GLXPbuffer               m_pbuffer{};    ///< GLX pbuffer ID if one was created
    bool                     m_ownsWindow{}; ///< Do we own the window associated to the context?
};

} // namespace sf::priv
