// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "gpu/config/gpu_info_collector.h"

#include "base/android/build_info.h"
#include "base/command_line.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/native_library.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "ui/gl/egl_util.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_surface.h"

namespace {

std::pair<std::string, size_t> GetVersionFromString(
    const std::string& version_string,
    size_t begin = 0) {
  begin = version_string.find_first_of("0123456789", begin);
  if (begin == std::string::npos)
    return std::make_pair("", std::string::npos);

  size_t end = version_string.find_first_not_of("01234567890.", begin);
  std::string sub_string;
  if (end != std::string::npos)
    sub_string = version_string.substr(begin, end - begin);
  else
    sub_string = version_string.substr(begin);
  std::vector<std::string> pieces = base::SplitString(
      sub_string, ".", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
  if (pieces.size() >= 2)
    return std::make_pair(pieces[0] + "." + pieces[1], end);
  else
    return std::make_pair("", end);
}

std::string GetDriverVersionFromString(const std::string& version_string) {
  // We expect that android GL_VERSION strings will be of a form
  // similar to: "OpenGL ES 2.0 V@6.0 AU@ (CL@2946718)" where the
  // first match to [0-9][0-9.]* is the OpenGL ES version number, and
  // the second match to [0-9][0-9.]* is the driver version (in this
  // case, 6.0).
  // It is currently assumed that the driver version has at least one
  // period in it, and only the first two components are significant.
  size_t begin = GetVersionFromString(version_string).second;
  if (begin == std::string::npos)
    return "0";

  std::pair<std::string, size_t> driver_version =
      GetVersionFromString(version_string, begin);
  if (driver_version.first == "")
    return "0";

  return driver_version.first;
}

gpu::CollectInfoResult CollectDriverInfo(gpu::GPUInfo* gpu_info) {
  // Go through the process of loading GL libs and initializing an EGL
  // context so that we can get GL vendor/version/renderer strings.
  base::NativeLibrary gles_library, egl_library;
  base::NativeLibraryLoadError error;
  gles_library =
      base::LoadNativeLibrary(base::FilePath("libGLESv2.so"), &error);
  if (!gles_library)
    LOG(FATAL) << "Failed to load libGLESv2.so";

  egl_library = base::LoadNativeLibrary(base::FilePath("libEGL.so"), &error);
  if (!egl_library)
    LOG(FATAL) << "Failed to load libEGL.so";

  typedef void* (*eglGetProcAddressProc)(const char* name);

  auto eglGetProcAddressFn = reinterpret_cast<eglGetProcAddressProc>(
      base::GetFunctionPointerFromNativeLibrary(egl_library,
                                                "eglGetProcAddress"));
  if (!eglGetProcAddressFn)
    LOG(FATAL) << "eglGetProcAddress not found.";

  auto get_func = [eglGetProcAddressFn, gles_library, egl_library](
      const char* name) {
    void *proc;
    proc = base::GetFunctionPointerFromNativeLibrary(egl_library, name);
    if (proc)
      return proc;
    proc = base::GetFunctionPointerFromNativeLibrary(gles_library, name);
    if (proc)
      return proc;
    proc = eglGetProcAddressFn(name);
    if (proc)
      return proc;
    LOG(FATAL) << "Failed to look up " << name;
    return (void *)nullptr;
  };

#define LOOKUP_FUNC(x) auto x##Fn = reinterpret_cast<gfx::x##Proc>(get_func(#x))

  LOOKUP_FUNC(eglGetError);
  LOOKUP_FUNC(eglQueryString);
  LOOKUP_FUNC(eglGetCurrentContext);
  LOOKUP_FUNC(eglGetCurrentDisplay);
  LOOKUP_FUNC(eglGetCurrentSurface);
  LOOKUP_FUNC(eglGetDisplay);
  LOOKUP_FUNC(eglInitialize);
  LOOKUP_FUNC(eglChooseConfig);
  LOOKUP_FUNC(eglCreateContext);
  LOOKUP_FUNC(eglCreatePbufferSurface);
  LOOKUP_FUNC(eglMakeCurrent);
  LOOKUP_FUNC(eglDestroySurface);
  LOOKUP_FUNC(eglDestroyContext);

  LOOKUP_FUNC(glGetString);
  LOOKUP_FUNC(glGetIntegerv);

#undef LOOKUP_FUNC

  EGLDisplay curr_display = eglGetCurrentDisplayFn();
  EGLContext curr_context = eglGetCurrentContextFn();
  EGLSurface curr_draw_surface = eglGetCurrentSurfaceFn(EGL_DRAW);
  EGLSurface curr_read_surface = eglGetCurrentSurfaceFn(EGL_READ);

  EGLDisplay temp_display = EGL_NO_DISPLAY;
  EGLContext temp_context = EGL_NO_CONTEXT;
  EGLSurface temp_surface = EGL_NO_SURFACE;

  const EGLint kConfigAttribs[] = {
      EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
      EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
      EGL_NONE};
  const EGLint kContextAttribs[] = {
      EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_EXT,
          EGL_LOSE_CONTEXT_ON_RESET_EXT,
      EGL_CONTEXT_CLIENT_VERSION, 2,
      EGL_NONE};
  const EGLint kSurfaceAttribs[] = {
      EGL_WIDTH, 1,
      EGL_HEIGHT, 1,
      EGL_NONE};

  EGLint major, minor;

  EGLConfig config;
  EGLint num_configs;

  auto errorstr = [eglGetErrorFn]() {
    uint32_t err = eglGetErrorFn();
    return base::StringPrintf("%s (%x)", ui::GetEGLErrorString(err), err);
  };

  temp_display = eglGetDisplayFn(EGL_DEFAULT_DISPLAY);

  if (temp_display == EGL_NO_DISPLAY) {
    LOG(FATAL) << "failed to get display. " << errorstr();
  }

  eglInitializeFn(temp_display, &major, &minor);

  bool egl_create_context_robustness_supported =
      strstr(reinterpret_cast<const char*>(
                 eglQueryStringFn(temp_display, EGL_EXTENSIONS)),
             "EGL_EXT_create_context_robustness") != NULL;

  if (!eglChooseConfigFn(temp_display, kConfigAttribs, &config, 1,
                         &num_configs)) {
    LOG(FATAL) << "failed to choose an egl config. " << errorstr();
  }

  temp_context = eglCreateContextFn(
      temp_display, config, EGL_NO_CONTEXT,
      kContextAttribs + (egl_create_context_robustness_supported ? 0 : 2));
  if (temp_context == EGL_NO_CONTEXT) {
    LOG(FATAL)
        << "failed to create a temporary context for fetching driver strings. "
        << errorstr();
  }

  temp_surface =
      eglCreatePbufferSurfaceFn(temp_display, config, kSurfaceAttribs);

  if (temp_surface == EGL_NO_SURFACE) {
    eglDestroyContextFn(temp_display, temp_context);
    LOG(FATAL)
        << "failed to create a pbuffer surface for fetching driver strings. "
        << errorstr();
  }

  eglMakeCurrentFn(temp_display, temp_surface, temp_surface, temp_context);

  gpu_info->gl_vendor = reinterpret_cast<const char*>(glGetStringFn(GL_VENDOR));
  gpu_info->gl_version =
      reinterpret_cast<const char*>(glGetStringFn(GL_VERSION));
  gpu_info->gl_renderer =
      reinterpret_cast<const char*>(glGetStringFn(GL_RENDERER));
  gpu_info->gl_extensions =
      reinterpret_cast<const char*>(glGetStringFn(GL_EXTENSIONS));

  GLint max_samples = 0;
  glGetIntegervFn(GL_MAX_SAMPLES, &max_samples);
  gpu_info->max_msaa_samples = base::IntToString(max_samples);

  bool supports_robustness =
      gpu_info->gl_extensions.find("GL_EXT_robustness") != std::string::npos ||
      gpu_info->gl_extensions.find("GL_KHR_robustness") != std::string::npos ||
      gpu_info->gl_extensions.find("GL_ARB_robustness") != std::string::npos;

  if (supports_robustness) {
    glGetIntegervFn(
        GL_RESET_NOTIFICATION_STRATEGY_ARB,
        reinterpret_cast<GLint*>(&gpu_info->gl_reset_notification_strategy));
  }

  std::string glsl_version_string =
      reinterpret_cast<const char*>(glGetStringFn(GL_SHADING_LANGUAGE_VERSION));

  std::string glsl_version = GetVersionFromString(glsl_version_string).first;
  gpu_info->pixel_shader_version = glsl_version;
  gpu_info->vertex_shader_version = glsl_version;

  if (curr_display != EGL_NO_DISPLAY &&
      curr_context != EGL_NO_CONTEXT) {
    eglMakeCurrentFn(curr_display, curr_draw_surface, curr_read_surface,
                     curr_context);
  } else {
    eglMakeCurrentFn(temp_display, EGL_NO_SURFACE, EGL_NO_SURFACE,
                     EGL_NO_CONTEXT);
  }

  eglDestroySurfaceFn(temp_display, temp_surface);
  eglDestroyContextFn(temp_display, temp_context);

  return gpu::kCollectInfoSuccess;
}

}

namespace gpu {

CollectInfoResult CollectContextGraphicsInfo(GPUInfo* gpu_info) {
  /// TODO(tobiasjs) Check if CollectGraphicsInfo in gpu_main.cc
  /// really only needs basic graphics info on all platforms, and if
  /// so switch it to using that and make this the NOP that it really
  /// should be, to avoid potential double collection of info.
  return CollectBasicGraphicsInfo(gpu_info);
}

CollectInfoResult CollectGpuID(uint32* vendor_id, uint32* device_id) {
  DCHECK(vendor_id && device_id);
  *vendor_id = 0;
  *device_id = 0;
  return kCollectInfoNonFatalFailure;
}

CollectInfoResult CollectBasicGraphicsInfo(GPUInfo* gpu_info) {
  gpu_info->can_lose_context = false;

  gpu_info->machine_model_name =
      base::android::BuildInfo::GetInstance()->model();

  // Create a short-lived context on the UI thread to collect the GL strings.
  // Make sure we restore the existing context if there is one.
  CollectInfoResult result = CollectDriverInfo(gpu_info);
  if (result == kCollectInfoSuccess)
    result = CollectDriverInfoGL(gpu_info);
  gpu_info->basic_info_state = result;
  gpu_info->context_info_state = result;
  return result;
}

CollectInfoResult CollectDriverInfoGL(GPUInfo* gpu_info) {
  gpu_info->driver_version = GetDriverVersionFromString(
      gpu_info->gl_version);
  gpu_info->gpu.vendor_string = gpu_info->gl_vendor;
  gpu_info->gpu.device_string = gpu_info->gl_renderer;
  return kCollectInfoSuccess;
}

void MergeGPUInfo(GPUInfo* basic_gpu_info,
                  const GPUInfo& context_gpu_info) {
  MergeGPUInfoGL(basic_gpu_info, context_gpu_info);
}

}  // namespace gpu