// Copyright 2012 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <string>

#include "Common/GL/GLInterface/GLX.h"
#include "Common/Logging/Log.h"

#define GLX_CONTEXT_MAJOR_VERSION_ARB 0x2091
#define GLX_CONTEXT_MINOR_VERSION_ARB 0x2092

typedef GLXContext (*PFNGLXCREATECONTEXTATTRIBSPROC)(Display*, GLXFBConfig, GLXContext, Bool,
                                                     const int*);
typedef int (*PFNGLXSWAPINTERVALSGIPROC)(int interval);

static PFNGLXCREATECONTEXTATTRIBSPROC glXCreateContextAttribs = nullptr;
static PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalSGI = nullptr;

static bool s_glxError;
static int ctxErrorHandler(Display* dpy, XErrorEvent* ev)
{
  s_glxError = true;
  return 0;
}

void cInterfaceGLX::SwapInterval(int Interval)
{
  if (glXSwapIntervalSGI)
    glXSwapIntervalSGI(Interval);
  else
    ERROR_LOG(VIDEO, "No support for SwapInterval (framerate clamped to monitor refresh rate).");
}
void* cInterfaceGLX::GetFuncAddress(const std::string& name)
{
  return (void*)glXGetProcAddress((const GLubyte*)name.c_str());
}

void cInterfaceGLX::Swap()
{
  glXSwapBuffers(dpy, win);
}

// Create rendering window.
// Call browser: Core.cpp:EmuThread() > main.cpp:Video_Initialize()
bool cInterfaceGLX::Create(void* window_handle, bool core)
{
  dpy = XOpenDisplay(nullptr);
  int screen = DefaultScreen(dpy);

  // checking glx version
  int glxMajorVersion, glxMinorVersion;
  glXQueryVersion(dpy, &glxMajorVersion, &glxMinorVersion);
  if (glxMajorVersion < 1 || (glxMajorVersion == 1 && glxMinorVersion < 4))
  {
    ERROR_LOG(VIDEO, "glX-Version %d.%d detected, but need at least 1.4", glxMajorVersion,
              glxMinorVersion);
    return false;
  }

  // loading core context creation function
  glXCreateContextAttribs =
      (PFNGLXCREATECONTEXTATTRIBSPROC)GetFuncAddress("glXCreateContextAttribsARB");
  if (!glXCreateContextAttribs)
  {
    ERROR_LOG(VIDEO,
              "glXCreateContextAttribsARB not found, do you support GLX_ARB_create_context?");
    return false;
  }

  // choosing framebuffer
  int visual_attribs[] = {GLX_X_RENDERABLE,
                          True,
                          GLX_DRAWABLE_TYPE,
                          GLX_WINDOW_BIT,
                          GLX_X_VISUAL_TYPE,
                          GLX_TRUE_COLOR,
                          GLX_RED_SIZE,
                          8,
                          GLX_GREEN_SIZE,
                          8,
                          GLX_BLUE_SIZE,
                          8,
                          GLX_DEPTH_SIZE,
                          0,
                          GLX_STENCIL_SIZE,
                          0,
                          GLX_DOUBLEBUFFER,
                          True,
                          None};
  int fbcount = 0;
  GLXFBConfig* fbc = glXChooseFBConfig(dpy, screen, visual_attribs, &fbcount);
  if (!fbc || !fbcount)
  {
    ERROR_LOG(VIDEO, "Failed to retrieve a framebuffer config");
    return false;
  }
  fbconfig = *fbc;
  XFree(fbc);

  // Get an appropriate visual
  XVisualInfo* vi = glXGetVisualFromFBConfig(dpy, fbconfig);

  s_glxError = false;
  XErrorHandler oldHandler = XSetErrorHandler(&ctxErrorHandler);

  // Create a GLX context.
  // We try to get a 4.0 core profile, else we try 3.3, else try it with anything we get.
  int context_attribs[] = {GLX_CONTEXT_MAJOR_VERSION_ARB,
                           4,
                           GLX_CONTEXT_MINOR_VERSION_ARB,
                           0,
                           GLX_CONTEXT_PROFILE_MASK_ARB,
                           GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
                           GLX_CONTEXT_FLAGS_ARB,
                           GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
                           None};
  ctx = nullptr;
  if (core)
  {
    ctx = glXCreateContextAttribs(dpy, fbconfig, 0, True, context_attribs);
    XSync(dpy, False);
  }
  if (core && (!ctx || s_glxError))
  {
    int context_attribs_33[] = {GLX_CONTEXT_MAJOR_VERSION_ARB,
                                3,
                                GLX_CONTEXT_MINOR_VERSION_ARB,
                                3,
                                GLX_CONTEXT_PROFILE_MASK_ARB,
                                GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
                                GLX_CONTEXT_FLAGS_ARB,
                                GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
                                None};
    s_glxError = false;
    ctx = glXCreateContextAttribs(dpy, fbconfig, 0, True, context_attribs_33);
    XSync(dpy, False);
  }
  if (!ctx || s_glxError)
  {
    int context_attribs_legacy[] = {GLX_CONTEXT_MAJOR_VERSION_ARB, 1, GLX_CONTEXT_MINOR_VERSION_ARB,
                                    0, None};
    s_glxError = false;
    ctx = glXCreateContextAttribs(dpy, fbconfig, 0, True, context_attribs_legacy);
    XSync(dpy, False);
  }
  if (!ctx || s_glxError)
  {
    ERROR_LOG(VIDEO, "Unable to create GL context.");
    return false;
  }
  XSetErrorHandler(oldHandler);

  XWindow.Initialize(dpy);

  Window parent = (Window)window_handle;

  XWindowAttributes attribs;
  if (!XGetWindowAttributes(dpy, parent, &attribs))
  {
    ERROR_LOG(VIDEO, "Window attribute retrieval failed");
    return false;
  }

  s_backbuffer_width = attribs.width;
  s_backbuffer_height = attribs.height;

  win = XWindow.CreateXWindow(parent, vi);
  XFree(vi);

  return true;
}

bool cInterfaceGLX::MakeCurrent()
{
  bool success = glXMakeCurrent(dpy, win, ctx);
  if (success)
  {
    // load this function based on the current bound context
    glXSwapIntervalSGI =
        (PFNGLXSWAPINTERVALSGIPROC)GLInterface->GetFuncAddress("glXSwapIntervalSGI");
  }
  return success;
}

bool cInterfaceGLX::ClearCurrent()
{
  return glXMakeCurrent(dpy, None, nullptr);
}

// Close backend
void cInterfaceGLX::Shutdown()
{
  XWindow.DestroyXWindow();
  if (ctx)
  {
    glXDestroyContext(dpy, ctx);
    XCloseDisplay(dpy);
    ctx = nullptr;
  }
}
