// Copyright 2017 PDFium 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 <cstring>
#include <memory>
#include <string>
#include <vector>

#include "core/fxcrt/fx_system.h"
#include "public/cpp/fpdf_scopers.h"
#include "public/fpdf_annot.h"
#include "public/fpdf_edit.h"
#include "public/fpdfview.h"
#include "testing/embedder_test.h"
#include "testing/fake_file_access.h"
#include "testing/gmock/include/gmock/gmock-matchers.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/utils/file_util.h"
#include "testing/utils/path_service.h"

namespace {

class FileAccess final : public FPDF_FILEACCESS {
 public:
  explicit FileAccess(const std::string& file_name) {
    std::string file_path;
    if (!PathService::GetTestFilePath(file_name, &file_path))
      return;

    file_contents_ = GetFileContents(file_path.c_str(), &file_length_);
    if (!file_contents_)
      return;

    m_FileLen = static_cast<unsigned long>(file_length_);
    m_GetBlock = SGetBlock;
    m_Param = this;
  }

 private:
  int GetBlockImpl(unsigned long pos, unsigned char* pBuf, unsigned long size) {
    memcpy(pBuf, file_contents_.get() + pos, size);
    return size;
  }

  static int SGetBlock(void* param,
                       unsigned long pos,
                       unsigned char* pBuf,
                       unsigned long size) {
    return static_cast<FileAccess*>(param)->GetBlockImpl(pos, pBuf, size);
  }

  size_t file_length_;
  std::unique_ptr<char, pdfium::FreeDeleter> file_contents_;
};

}  // namespace

class CPDF_CreatorEmbedderTest : public EmbedderTest {};

TEST_F(CPDF_CreatorEmbedderTest, SavedDocsAreEqualAfterParse) {
  ASSERT_TRUE(OpenDocument("annotation_stamp_with_ap.pdf"));
  // Save without additional data reading.
  EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));
  const std::string saved_doc_1 = GetString();
  ClearString();

  {
    // Do some read only operations.
    ASSERT_GE(1, FPDF_GetPageCount(document()));
    FPDF_PAGE page = LoadPage(0);
    ASSERT_TRUE(page);
    ScopedFPDFBitmap bitmap = RenderLoadedPageWithFlags(page, FPDF_ANNOT);
    EXPECT_EQ(595, FPDFBitmap_GetWidth(bitmap.get()));
    EXPECT_EQ(842, FPDFBitmap_GetHeight(bitmap.get()));
    UnloadPage(page);
  }

  // Save when we have additional loaded data.
  EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));
  const std::string saved_doc_2 = GetString();
  ClearString();

  // The sizes of saved docs should be equal.
  EXPECT_EQ(saved_doc_1.size(), saved_doc_2.size());
}

TEST_F(CPDF_CreatorEmbedderTest, BUG_873) {
  EXPECT_TRUE(OpenDocument("embedded_attachments.pdf"));
  EXPECT_TRUE(FPDF_SaveAsCopy(document(), this, 0));

  // Cannot match second part of the ID since it is randomly generated.
  std::string saved_data = GetString();
  const char kTrailerBeforeSecondID[] =
      "trailer\r\n<</Info 9 0 R /Root 11 0 R /Size "
      "36/ID[<D889EB6B9ADF88E5EDA7DC08FE85978B><";
  ASSERT_THAT(saved_data, testing::HasSubstr(kTrailerBeforeSecondID));
  size_t trailer_start = saved_data.find(kTrailerBeforeSecondID);
  constexpr size_t kIdLen = 32;
  size_t trailer_continuation =
      trailer_start + strlen(kTrailerBeforeSecondID) + kIdLen;
  std::string data_after_second_id = saved_data.substr(trailer_continuation);
  EXPECT_THAT(data_after_second_id, testing::StartsWith(">]>>\r\n"));
}

TEST_F(CPDF_CreatorEmbedderTest, SaveLinearizedInfo) {
  FileAccess file_acc("linearized.pdf");
  FakeFileAccess fake_acc(&file_acc);

  avail_ = FPDFAvail_Create(fake_acc.GetFileAvail(), fake_acc.GetFileAccess());
  while (PDF_DATA_AVAIL !=
         FPDFAvail_IsDocAvail(avail_, fake_acc.GetDownloadHints())) {
    fake_acc.SetRequestedDataAvailable();
  }

  document_ = FPDFAvail_GetDocument(avail_, nullptr);
  ASSERT_TRUE(document_);

  // Load second page, to parse additional crossref sections.
  while (PDF_DATA_AVAIL !=
         FPDFAvail_IsPageAvail(avail_, 1, fake_acc.GetDownloadHints())) {
    fake_acc.SetRequestedDataAvailable();
  }
  // Simulate downloading of whole file.
  fake_acc.SetWholeFileAvailable();
  // Save document.
  EXPECT_TRUE(FPDF_SaveAsCopy(document_, this, 0));
  const std::string saved_doc = GetString();

  EXPECT_THAT(saved_doc, ::testing::HasSubstr("/Info"));
}