// Copyright 2014 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 "ui/ozone/common/egl_util.h"

#include "base/files/file_path.h"
#include "base/path_service.h"
#include "ui/gl/egl_util.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_features.h"
#include "ui/gl/gl_implementation.h"

namespace ui {
namespace {

const base::FilePath::CharType kDefaultEglSoname[] =
    FILE_PATH_LITERAL("libEGL.so.1");
const base::FilePath::CharType kDefaultGlesSoname[] =
    FILE_PATH_LITERAL("libGLESv2.so.2");

#if BUILDFLAG(ENABLE_SWIFTSHADER)
const base::FilePath::CharType kGLESv2SwiftShaderLibraryName[] =
    FILE_PATH_LITERAL("libGLESv2.so");
const base::FilePath::CharType kEGLSwiftShaderLibraryName[] =
    FILE_PATH_LITERAL("libEGL.so");
#endif

bool LoadEGLGLES2Bindings(const base::FilePath& egl_library_path,
                          const base::FilePath& gles_library_path) {
  base::NativeLibraryLoadError error;
  base::NativeLibrary gles_library =
      base::LoadNativeLibrary(gles_library_path, &error);
  if (!gles_library) {
    LOG(ERROR) << "Failed to load GLES library: " << error.ToString();
    return false;
  }

  base::NativeLibrary egl_library =
      base::LoadNativeLibrary(base::FilePath(egl_library_path), &error);
  if (!egl_library) {
    LOG(ERROR) << "Failed to load EGL library: " << error.ToString();
    base::UnloadNativeLibrary(gles_library);
    return false;
  }

  gl::GLGetProcAddressProc get_proc_address =
      reinterpret_cast<gl::GLGetProcAddressProc>(
          base::GetFunctionPointerFromNativeLibrary(egl_library,
                                                    "eglGetProcAddress"));
  if (!get_proc_address) {
    LOG(ERROR) << "eglGetProcAddress not found.";
    base::UnloadNativeLibrary(egl_library);
    base::UnloadNativeLibrary(gles_library);
    return false;
  }

  gl::SetGLGetProcAddressProc(get_proc_address);
  gl::AddGLNativeLibrary(egl_library);
  gl::AddGLNativeLibrary(gles_library);

  return true;
}

}  // namespace

bool LoadDefaultEGLGLES2Bindings(gl::GLImplementation implementation) {
  base::FilePath glesv2_path;
  base::FilePath egl_path;

  if (implementation == gl::kGLImplementationSwiftShaderGL) {
#if BUILDFLAG(ENABLE_SWIFTSHADER)
    base::FilePath module_path;
    if (!PathService::Get(base::DIR_MODULE, &module_path))
      return false;
    module_path = module_path.Append(FILE_PATH_LITERAL("swiftshader/"));

    glesv2_path = module_path.Append(kGLESv2SwiftShaderLibraryName);
    egl_path = module_path.Append(kEGLSwiftShaderLibraryName);
#else
    return false;
#endif
  } else {
    glesv2_path = base::FilePath(kDefaultGlesSoname);
    egl_path = base::FilePath(kDefaultEglSoname);
  }

  return LoadEGLGLES2Bindings(egl_path, glesv2_path);
}

EGLConfig ChooseEGLConfig(EGLDisplay display, const int32_t* attributes) {
  int32_t num_configs;
  if (!eglChooseConfig(display, attributes, nullptr, 0, &num_configs)) {
    LOG(ERROR) << "eglChooseConfig failed with error "
               << GetLastEGLErrorString();
    return nullptr;
  }

  if (num_configs == 0) {
    LOG(ERROR) << "No suitable EGL configs found.";
    return nullptr;
  }

  EGLConfig config;
  if (!eglChooseConfig(display, attributes, &config, 1, &num_configs)) {
    LOG(ERROR) << "eglChooseConfig failed with error "
               << GetLastEGLErrorString();
    return nullptr;
  }
  return config;
}

}  // namespace ui