// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <stdlib.h>

#include <filesystem>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "lodepng_sapi.sapi.h"
#include "sandbox.h"
#include "sandboxed_api/util/flag.h"
#include "sandboxed_api/util/status_matchers.h"

using sapi::IsOk;
using testing::Eq;
using testing::NotNull;

namespace {

constexpr unsigned int img_len(unsigned int width, unsigned int height) {
  return width * height * 4;
}

// use the current path
std::string images_path = std::filesystem::current_path().string();

TEST(initSandbox, basic) {
  SapiLodepngSandbox sandbox(images_path);
  ASSERT_THAT(sandbox.Init(), IsOk());
}

// generate an image, encode it, decode it and compare the pixels with the
// initial values
TEST(generate_image, encode_decode_compare_one_step) {
  SapiLodepngSandbox sandbox(images_path);
  ASSERT_THAT(sandbox.Init(), IsOk());
  LodepngApi api(&sandbox);

  // generate the values
  unsigned int width = 512, height = 512;
  std::vector<unsigned char> image(img_len(width, height));

  for (int y = 0; y < height; ++y) {
    for (int x = 0; x < width; ++x) {
      image[4 * width * y + 4 * x + 0] = 255 * !(x & y);
      image[4 * width * y + 4 * x + 1] = x ^ y;
      image[4 * width * y + 4 * x + 2] = x | y;
      image[4 * width * y + 4 * x + 3] = 255;
    }
  }

  // encode the image
  sapi::v::Array<unsigned char> sapi_image(image.data(),
                                           img_len(width, height));
  sapi::v::UInt sapi_width(width), sapi_height(height);
  std::string filename = "/output/out_generated1.png";
  sapi::v::ConstCStr sapi_filename(filename.c_str());

  SAPI_ASSERT_OK_AND_ASSIGN(
      unsigned int result,
      api.lodepng_encode32_file(sapi_filename.PtrBefore(),
                                sapi_image.PtrBefore(), sapi_width.GetValue(),
                                sapi_height.GetValue()));

  ASSERT_THAT(result, Eq(0));
  // after the image has been encoded, decode it to check that the
  // pixel values are the same

  sapi::v::UInt sapi_width2, sapi_height2;
  sapi::v::IntBase<unsigned char *> sapi_image_ptr(0);

  SAPI_ASSERT_OK_AND_ASSIGN(
      result, api.lodepng_decode32_file(
                  sapi_image_ptr.PtrBoth(), sapi_width2.PtrBoth(),
                  sapi_height2.PtrBoth(), sapi_filename.PtrBefore()));

  ASSERT_THAT(result, Eq(0));

  EXPECT_THAT(sapi_width2.GetValue(), Eq(width));
  EXPECT_THAT(sapi_height2.GetValue(), Eq(height));

  // the pixels have been allocated inside the sandboxed process
  // memory, so we need to transfer them to this process.
  // Transferring the memory has the following steps:
  // 1) define a RemotePtr variable that holds the memory location from
  // the sandboxed process
  // 2) define an array with the required length
  // 3) set the remote pointer for the array to specify where the memory
  // that will be transferred is located
  // 4) transfer the memory to this process (this step is why we need
  // the pointer and the length)
  sapi::v::RemotePtr sapi_remote_out_ptr(sapi_image_ptr.GetValue());
  sapi::v::Array<unsigned char> sapi_pixels(
      img_len(sapi_width2.GetValue(), sapi_height2.GetValue()));
  sapi_pixels.SetRemote(sapi_remote_out_ptr.GetValue());

  ASSERT_THAT(sandbox.TransferFromSandboxee(&sapi_pixels), IsOk());

  // after the memory has been transferred, we can access it
  // using the GetData function
  unsigned char *pixels_ptr = sapi_pixels.GetData();

  // now, we can compare the values
  for (size_t i = 0; i < img_len(width, height); ++i) {
    EXPECT_THAT(pixels_ptr[i], Eq(image[i]));
  }
}

// similar to the previous test, only that we use encoding by saving the data in
// memory and then writing it to the file and decoding by first decoding in
// memory and then getting the actual pixel values.
TEST(generate_image, encode_decode_compare_two_steps) {
  SapiLodepngSandbox sandbox(images_path);
  ASSERT_THAT(sandbox.Init(), IsOk());
  LodepngApi api(&sandbox);

  // generate the values
  unsigned int width = 512, height = 512;
  std::vector<unsigned char> image(img_len(width, height));

  for (int y = 0; y < height; ++y) {
    for (int x = 0; x < width; ++x) {
      image[4 * width * y + 4 * x + 0] = 255 * !(x & y);
      image[4 * width * y + 4 * x + 1] = x ^ y;
      image[4 * width * y + 4 * x + 2] = x | y;
      image[4 * width * y + 4 * x + 3] = 255;
    }
  }

  // encode the image into memory first
  sapi::v::Array<unsigned char> sapi_image(image.data(),
                                           img_len(width, height));
  sapi::v::UInt sapi_width(width), sapi_height(height);
  std::string filename = "/output/out_generated2.png";
  sapi::v::ConstCStr sapi_filename(filename.c_str());

  sapi::v::ULLong sapi_pngsize;
  sapi::v::IntBase<unsigned char *> sapi_png_ptr(0);

  // encode it into memory
  SAPI_ASSERT_OK_AND_ASSIGN(
      unsigned int result,
      api.lodepng_encode32(sapi_png_ptr.PtrBoth(), sapi_pngsize.PtrBoth(),
                           sapi_image.PtrBefore(), sapi_width.GetValue(),
                           sapi_height.GetValue()));

  ASSERT_THAT(result, Eq(0));

  // the new array (pointed to by sapi_png_ptr) is allocated
  // inside the sandboxed process so we need to transfer it to this
  // process

  sapi::v::RemotePtr sapi_remote_out_ptr(sapi_png_ptr.GetValue());
  sapi::v::Array<unsigned char> sapi_png_array(sapi_pngsize.GetValue());

  sapi_png_array.SetRemote(sapi_remote_out_ptr.GetValue());

  ASSERT_THAT(sandbox.TransferFromSandboxee(&sapi_png_array), IsOk());

  // write the image into the file (from memory)
  SAPI_ASSERT_OK_AND_ASSIGN(
      result,
      api.lodepng_save_file(sapi_png_array.PtrBefore(), sapi_pngsize.GetValue(),
                            sapi_filename.PtrBefore()));

  ASSERT_THAT(result, Eq(0));

  // now, decode the image using the 2 steps in order to compare the values
  sapi::v::UInt sapi_width2, sapi_height2;
  sapi::v::IntBase<unsigned char *> sapi_png_ptr2(0);
  sapi::v::ULLong sapi_pngsize2;

  // load the file in memory
  SAPI_ASSERT_OK_AND_ASSIGN(
      result,
      api.lodepng_load_file(sapi_png_ptr2.PtrBoth(), sapi_pngsize2.PtrBoth(),
                            sapi_filename.PtrBefore()));

  ASSERT_THAT(result, Eq(0));

  EXPECT_THAT(sapi_pngsize.GetValue(), Eq(sapi_pngsize2.GetValue()));

  // transfer the png array
  sapi::v::RemotePtr sapi_remote_out_ptr2(sapi_png_ptr2.GetValue());
  sapi::v::Array<unsigned char> sapi_png_array2(sapi_pngsize2.GetValue());

  sapi_png_array2.SetRemote(sapi_remote_out_ptr2.GetValue());

  ASSERT_THAT(sandbox.TransferFromSandboxee(&sapi_png_array2), IsOk());

  // after the file is loaded, decode it so we have access to the values
  // directly
  sapi::v::IntBase<unsigned char *> sapi_png_ptr3(0);
  SAPI_ASSERT_OK_AND_ASSIGN(
      result,
      api.lodepng_decode32(sapi_png_ptr3.PtrBoth(), sapi_width2.PtrBoth(),
                           sapi_height2.PtrBoth(), sapi_png_array2.PtrBefore(),
                           sapi_pngsize2.GetValue()));

  ASSERT_THAT(result, Eq(0));

  EXPECT_THAT(sapi_width2.GetValue(), Eq(width));
  EXPECT_THAT(sapi_height2.GetValue(), Eq(height));

  // transfer the pixels so they can be used
  sapi::v::RemotePtr sapi_remote_out_ptr3(sapi_png_ptr3.GetValue());
  sapi::v::Array<unsigned char> sapi_pixels(
      img_len(sapi_width2.GetValue(), sapi_height2.GetValue()));

  sapi_pixels.SetRemote(sapi_remote_out_ptr3.GetValue());

  ASSERT_THAT(sandbox.TransferFromSandboxee(&sapi_pixels), IsOk());

  unsigned char *pixels_ptr = sapi_pixels.GetData();

  // compare values
  for (size_t i = 0; i < img_len(width, height); ++i) {
    EXPECT_THAT(pixels_ptr[i], Eq(image[i]));
  }
}

}  // namespace