/*
 * 86Box A hypervisor and IBM PC system emulator that specializes in
 *      running old operating systems and software designed for IBM
 *      PC systems and compatibles from 1981 through fairly recent
 *      system designs based on the PCI bus.
 *
 *      This file is part of the 86Box distribution.
 *
 *      Header file for OpenGL renderer
 *
 * Authors:
 *      Teemu Korhonen
 *
 *      Copyright 2022 Teemu Korhonen
 */

#ifndef QT_OPENGLRENDERER_HPP
#define QT_OPENGLRENDERER_HPP

#include <QOpenGLContext>
#include <QOpenGLFunctions_3_0>
#include <QResizeEvent>
#include <QTimer>
#include <QWidget>
#include <QWindow>
#include <QtOpenGLExtensions/QOpenGLExtensions>

#include <atomic>
#include <tuple>
#include <vector>

#include "qt_opengloptions.hpp"
#include "qt_renderercommon.hpp"

class OpenGLRenderer : public QWindow, protected QOpenGLFunctions_3_0, public RendererCommon {
    Q_OBJECT

public:
    QOpenGLContext *context;

    OpenGLRenderer(QWidget *parent = nullptr);
    ~OpenGLRenderer();

    std::vector<std::tuple<uint8_t *, std::atomic_flag *>> getBuffers() override;

    void     finalize() override final;
    bool     hasOptions() const override { return true; }
    QDialog *getOptions(QWidget *parent) override;

signals:
    void initialized();
    void errorInitializing();

public slots:
    void onBlit(int buf_idx, int x, int y, int w, int h);

protected:
    void exposeEvent(QExposeEvent *event) override;
    void resizeEvent(QResizeEvent *event) override;
    bool event(QEvent *event) override;

private:
    static constexpr int INIT_WIDTH   = 640;
    static constexpr int INIT_HEIGHT  = 400;
    static constexpr int ROW_LENGTH   = 2048;
    static constexpr int BUFFERPIXELS = 4194304;
    static constexpr int BUFFERBYTES  = 16777216; /* Pixel is 4 bytes. */
    static constexpr int BUFFERCOUNT  = 3;        /* How many buffers to use for pixel transfer (2-3 is commonly recommended). */

    OpenGLOptions *options;
    QTimer        *renderTimer;

    bool isInitialized = false;
    bool isFinalized   = false;

    GLuint unpackBufferID = 0;
    GLuint vertexArrayID  = 0;
    GLuint vertexBufferID = 0;
    GLuint textureID      = 0;
    int    frameCounter   = 0;

    void *unpackBuffer = nullptr;

    void initialize();
    void setupExtensions();
    void setupBuffers();
    void applyOptions();
    void applyShader(const OpenGLShaderPass &shader);
    bool notReady() const { return !isInitialized || isFinalized; }

    /* GL_ARB_buffer_storage */
    bool                   hasBufferStorage = false;
    PFNGLBUFFERSTORAGEPROC glBufferStorage  = nullptr;

    /* GL_ARB_debug_output */
    bool                             hasDebugOutput            = false;
    PFNGLDEBUGMESSAGECONTROLARBPROC  glDebugMessageControlARB  = nullptr;
    PFNGLDEBUGMESSAGEINSERTARBPROC   glDebugMessageInsertARB   = nullptr;
    PFNGLDEBUGMESSAGECALLBACKARBPROC glDebugMessageCallbackARB = nullptr;
    PFNGLGETDEBUGMESSAGELOGARBPROC   glGetDebugMessageLogARB   = nullptr;

    /* GL_ARB_sync */
    bool                    hasSync          = false;
    PFNGLFENCESYNCPROC      glFenceSync      = nullptr;
    PFNGLISSYNCPROC         glIsSync         = nullptr;
    PFNGLDELETESYNCPROC     glDeleteSync     = nullptr;
    PFNGLCLIENTWAITSYNCPROC glClientWaitSync = nullptr;
    PFNGLWAITSYNCPROC       glWaitSync       = nullptr;
    PFNGLGETINTEGER64VPROC  glGetInteger64v  = nullptr;
    PFNGLGETSYNCIVPROC      glGetSynciv      = nullptr;

private slots:
    void render();
    void updateOptions(OpenGLOptions *newOptions);
};

#endif