/*
 * Copyright (c) Advanced Micro Devices, Inc., or its affiliates.
 *
 * SPDX-License-Identifier: MIT
 */

#include "OCLGLCommon.h"

struct OCLGLHandle_ {
  static Display* display;
  static XVisualInfo* vInfo;
  static int referenceCount;
  GLXContext context;
  Window window;
  Colormap cmap;
};

Display* OCLGLHandle_::display = NULL;
XVisualInfo* OCLGLHandle_::vInfo = NULL;
int OCLGLHandle_::referenceCount = 0;

OCLGLCommon::OCLGLCommon() {
  hGL_ = new OCLGLHandle_;

  hGL_->context = NULL;
  hGL_->window = 0;
  hGL_->cmap = 0;
}

OCLGLCommon::~OCLGLCommon() { destroyGLContext(hGL_); }

void OCLGLCommon::destroyGLContext(OCLGLHandle& hGL) {
  deleteGLContext(hGL);
  delete hGL;
  hGL = NULL;
}

void OCLGLCommon::deleteGLContext(OCLGLHandle& hGL) {
  if (hGL->display != NULL) {
    glXMakeCurrent(hGL->display, None, NULL);
    if (hGL->cmap) {
      XFreeColormap(hGL->display, hGL->cmap);
      hGL->cmap = 0;
    }
    if (hGL->window) {
      XDestroyWindow(hGL->display, hGL->window);
      hGL->window = 0;
    }
    if (hGL->context) {
      glXDestroyContext(hGL->display, hGL->context);
      hGL->context = NULL;
    }

    hGL->referenceCount--;
    if (hGL->referenceCount == 0) {
      XCloseDisplay(hGL->display);
      hGL->display = NULL;

      XFree(hGL->vInfo);
      hGL->vInfo = NULL;
    }
  }
}

bool OCLGLCommon::createGLContext(OCLGLHandle& hGL) {
  hGL = new OCLGLHandle_;
  return initializeGLContext(hGL);
}

bool OCLGLCommon::initializeGLContext(OCLGLHandle& hGL) {
  if (hGL->display == NULL) {
    hGL->display = XOpenDisplay(NULL);
    if (hGL->display == NULL) {
      printf("XOpenDisplay() failed\n");
      return false;
    }
  }
  if (hGL->vInfo == NULL) {
    int dblBuf[] = {GLX_RGBA, GLX_RED_SIZE,   1,  GLX_GREEN_SIZE,   1,   GLX_BLUE_SIZE,
                    1,        GLX_DEPTH_SIZE, 12, GLX_DOUBLEBUFFER, None};

    hGL->vInfo = glXChooseVisual(hGL->display, DefaultScreen(hGL->display), dblBuf);
    if (hGL->vInfo == NULL) {
      printf("glXChooseVisual() failed\n");
      return false;
    }
  }
  hGL->referenceCount++;

  hGL->context = glXCreateContext(hGL->display, hGL->vInfo, None, True);
  if (hGL->context == NULL) {
    printf("glXCreateContext() failed\n");
    return false;
  }

  XSetWindowAttributes swa = {0};
  hGL->cmap = XCreateColormap(hGL->display, RootWindow(hGL->display, hGL->vInfo->screen),
                              hGL->vInfo->visual, AllocNone);
  swa.colormap = hGL->cmap;
  hGL->window = XCreateWindow(hGL->display, RootWindow(hGL->display, hGL->vInfo->screen), 0, 0, 640,
                              480, 0, hGL->vInfo->depth, InputOutput, hGL->vInfo->visual,
                              CWBorderPixel | CWColormap | CWEventMask, &swa);

  Bool glErr = glXMakeCurrent(hGL->display, hGL->window, hGL->context);
  if (False == glErr) {
    return false;
  }

  if (!checkAssociationDeviceWithGLContext(hGL)) {
    deleteGLContext(hGL);
    return false;
  }
  return true;
}

bool OCLGLCommon::checkAssociationDeviceWithGLContext(OCLGLHandle& hGL) {
  bool ret = false;
  size_t devicesSize = 0;
  cl_context_properties properties[] = {CL_CONTEXT_PLATFORM,
                                        (cl_context_properties)platform_,
                                        CL_GL_CONTEXT_KHR,
                                        (cl_context_properties)hGL->context,
                                        CL_GLX_DISPLAY_KHR,
                                        (cl_context_properties)hGL->display,
                                        0};

  error_ = _wrapper->clGetGLContextInfoKHR(properties, CL_DEVICES_FOR_GL_CONTEXT_KHR, 0, NULL,
                                           &devicesSize);
  if (error_ != CL_SUCCESS) {
    printf("clGetGLContextInfoKHR failed (%d)\n", error_);
    return false;
  }

  cl_uint numDevices = (cl_uint)devicesSize / sizeof(cl_device_id);
  cl_device_id* interopDevices = (cl_device_id*)malloc(devicesSize);

  error_ = _wrapper->clGetGLContextInfoKHR(properties, CL_DEVICES_FOR_GL_CONTEXT_KHR, devicesSize,
                                           interopDevices, NULL);
  if (error_ != CL_SUCCESS) {
    printf("clGetGLContextInfoKHR failed (%d)\n", error_);
    free(interopDevices);
    return false;
  }

  // Check that current device can be associated with OpenGL context
  for (unsigned int i = 0; i < numDevices; i++) {
    if (interopDevices[i] == devices_[_deviceId]) {
      ret = true;
      break;
    }
  }

  // If the current device id does not work for CL GL interop,
  // fall back to other devices.
  if (!ret) {
    for (unsigned int i = 0; i < numDevices; i++) {
      for (unsigned int j = 0; j < deviceCount_; j++) {
        if (interopDevices[i] == devices_[j]) {
          // Found an OpenCL device work with current GL context.
          _deviceId = j;
          ret = true;
          break;
        }
      }
    }
  }

  free(interopDevices);
  return ret;
}

void OCLGLCommon::createCLContextFromGLContext(OCLGLHandle& hGL) {
  cl_context_properties properties[] = {CL_CONTEXT_PLATFORM,
                                        (cl_context_properties)platform_,
                                        CL_GL_CONTEXT_KHR,
                                        (cl_context_properties)hGL->context,
                                        CL_GLX_DISPLAY_KHR,
                                        (cl_context_properties)hGL->display,
                                        0};

  // Release current command queue
  if (cmdQueues_[_deviceId]) {
    error_ = _wrapper->clReleaseCommandQueue(cmdQueues_[_deviceId]);
    CHECK_RESULT_NO_RETURN((error_ != CL_SUCCESS), "clReleaseCommandQueue() failed");
  }

  // Release current context
  if (context_) {
    error_ = _wrapper->clReleaseContext(context_);
    CHECK_RESULT_NO_RETURN((error_ != CL_SUCCESS), "clReleaseContext() failed");
  }

  // Create new CL context from GL context
  context_ = clCreateContext(properties, 1, &devices_[_deviceId], NULL, NULL, &error_);
  CHECK_RESULT((error_ != CL_SUCCESS), "clCreateContext() failed (%d)", error_);

  // Create command queue for new context
  cmdQueues_[_deviceId] = _wrapper->clCreateCommandQueue(context_, devices_[_deviceId], 0, &error_);
  CHECK_RESULT((error_ != CL_SUCCESS), "clCreateCommandQueue() failed (%d)", error_);

  // GLEW versions 1.13.0 and earlier do not fetch all GL function pointers
  // without glewExperimental set.
  glewExperimental = GL_TRUE;
  GLenum glErr = glewInit();
  CHECK_RESULT((glErr != GLEW_OK), "glewInit() failed: %s", glewGetErrorString(glErr));
}

void OCLGLCommon::makeCurrent(OCLGLHandle hGL) {
  if (hGL == NULL) {
    if (hGL_ != NULL) {
      glXMakeCurrent(hGL_->display, None, NULL);
    }
  } else {
    bool ret = glXMakeCurrent(hGL->display, hGL->window, hGL->context);
    assert(ret && "glXMakeCurrent failed!");
  }
}

void OCLGLCommon::getCLContextPropertiesFromGLContext(const OCLGLHandle hGL,
                                                      cl_context_properties properties[7]) {
  if (!properties) return;

  properties[0] = CL_CONTEXT_PLATFORM;
  properties[1] = (cl_context_properties)platform_;
  properties[2] = CL_GL_CONTEXT_KHR;
  properties[3] = (cl_context_properties)hGL->context;
  properties[4] = CL_GLX_DISPLAY_KHR;
  properties[5] = (cl_context_properties)hGL->display;
  properties[6] = 0;
}
