// Copyright (C) 2003-2026, Foxit Software Inc..
// All Rights Reserved.
//
// http://www.foxitsoftware.com
//
// The following code is copyrighted and contains proprietary information and trade secrets of Foxit Software Inc..
// You cannot distribute any part of Foxit PDF SDK to any third party or general public,
// unless there is a separate license agreement with Foxit Software Inc. which explicitly grants you such rights.
//
// This file contains an example to demonstrate how to use Foxit PDF SDK to loading PDF document asynchronously.

// Include Foxit SDK header files.
#include <time.h>
#include <iostream>
#if defined(_WIN32) || defined(_WIN64)
#include<direct.h>
#else
#include <sys/stat.h>
#endif

#include "../../../include/common/fs_common.h"
#include "../../../include/common/fs_render.h"
#include "../../../include/pdf/fs_pdfdoc.h"
#include "../../../include/pdf/fs_pdfpage.h"

using namespace std;
using namespace foxit;
using namespace foxit::common;
using foxit::common::Library;
using namespace pdf;

static const char* sn = "bPxThFlBAYifO3yiW0C51bKbjPap1zHaf5aG5sX378TjFvB7Q0802A==";
static const char* key = "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";

#if defined(_WIN32) || defined(_WIN64)
static WString output_path = WString::FromLocal("../output_files/");
static WString input_path = WString::FromLocal("../input_files/");
#else
static WString output_path = WString::FromLocal("./output_files/");
static WString input_path = WString::FromLocal("./input_files/");
#endif

class SdkLibMgr {
public:
  SdkLibMgr() : is_initialize_(false){};
  ErrorCode Initialize() {
    ErrorCode error_code = Library::Initialize(sn, key);
    if (error_code != foxit::e_ErrSuccess) {
      printf("Library Initialize Error: %d\n", error_code);
    } else {
      is_initialize_ = true;
    }
    return error_code;

  }
  ~SdkLibMgr(){
    if(is_initialize_)
      Library::Release();
  }
private:
  bool is_initialize_;
};

// Data of asynchronous loader callback object.
struct DownloadHintDataInfo {
  DownloadHintDataInfo() {
    offset = 0;
    size = 0;
    is_downloaded = false;
  }
  DownloadHintDataInfo(int64 offset, int64 size, bool is_downloaded) {
    this->offset = offset;
    this->size = size;
    this->is_downloaded = is_downloaded;
  }
  int64 offset;
  int64 size;
  bool is_downloaded;
};

// This callback just simulates the downloading progress by DownloadHintDataInfo::is_downloaded,
// not really to download data.
class AsyncFileRead : public foxit::common::file::AsyncReaderCallback {
public:
  AsyncFileRead()
    : file_(NULL)
    , is_large_file_(false) {}

  ~AsyncFileRead() {
    hint_data_record_.clear();
  }

  bool LoadFile(const wchar_t* file_path, bool is_large_file = false) {
#if defined(_WIN32) || (_WIN64)
    fopen_s(&file_, String::FromUnicode(file_path), "rb");
#else
    file_ = fopen(String::FromUnicode(file_path), "rb");
#endif
    if (!file_)
      return false;

    is_large_file_ = is_large_file;
    return true;
  }

  FILESIZE GetSize() {
    if (is_large_file_) {
#if defined(_WIN32) || defined(_WIN64)
      _fseeki64(file_, 0, SEEK_END);
      long long size_long = _ftelli64(file_);
#elif defined(__linux__) || defined(__APPLE__)
      fseeko(file_, 0, SEEK_END);
      long long size_long = ftello(file_);
#endif
      return size_long;
    } else {
      fseek(file_, 0, SEEK_END);
      return (int64)ftell(file_);
    }
    return 0;
  }

  FX_BOOL      ReadBlock(void* buffer, FILESIZE offset, size_t size) {
    if (is_large_file_) {
#if defined(_WIN32) || defined(_WIN64)
      _fseeki64(file_, offset, SEEK_SET);
#elif defined(__linux__) || defined(__APPLE__)
      fseeko(file_, offset, SEEK_SET);
#endif
      long long read_size = fread(buffer, 1, size, file_);
      return read_size == size ? true : false;
    } else {
      if (!file_)
        return false;
      if (0 != fseek(file_, static_cast<long>(offset), 0))
        return false;
      if (0 == fread(buffer, size, 1, file_))
        return false;
      return true;
    }
    return false;
  }

  void Release() {
    if (file_)
      fclose(file_);
    file_ = NULL;
    delete this;
  }

  virtual bool IsDataAvail(int64 offset, size_t size) {
    return CheckRecordDownloaded(offset, size, false);
  }
  virtual bool AddDownloadHint(int64 offset, size_t size) {
    // Record the range and downloaded data.
    return CheckRecordDownloaded(offset, size, true);
  }

protected:
  bool CheckRecordDownloaded(int64 offset, int64 size, bool to_download) {
    size_t record_count = hint_data_record_.size();
    for (size_t i = 0; i < record_count; i++) {
      DownloadHintDataInfo data_info = hint_data_record_[i];

      // If (offset+size) is out of current data_info, just continue to check other record in hint_data_record_.
      if (offset > (data_info.offset + data_info.size))
        continue;
      if (offset + size < data_info.offset)
        continue;

      // If data defined by <offset, size> has been in/within current data info, just download the data.
      if (offset >= data_info.offset && (offset + size) <= (data_info.offset + data_info.size)) {
        if (to_download)
          data_info.is_downloaded = true;
        return data_info.is_downloaded;
      }

      // If only part of data defined by <offset, size> is in current data_info, download current data_info and
      // also check and download rest data.
      if (offset >= data_info.offset && offset < (data_info.offset + data_info.size) &&
        (offset + size) > (data_info.offset + data_info.size)) {
          if (to_download)
            data_info.is_downloaded = true;
          if (!data_info.is_downloaded)
            return data_info.is_downloaded;
          int64 new_offset = data_info.offset + data_info.size + 1;
          int64 new_size = size - 1 - (data_info.offset + data_info.size - offset);
          return CheckRecordDownloaded(new_offset, new_size, to_download);
      }

      if (offset < data_info.offset && (offset + size) >= data_info.offset &&
        (offset + size) <= (data_info.offset + data_info.size)) {
          if (to_download)
            data_info.is_downloaded = true;
          if (!data_info.is_downloaded)
            return data_info.is_downloaded;
          int64 new_offset = offset;
          int64 new_size = data_info.offset - 1 - offset;
          return CheckRecordDownloaded(new_offset, new_size, to_download);
      }
      if (offset < data_info.offset && (offset + size) > (data_info.offset + data_info.size)) {
        if (to_download)
          data_info.is_downloaded = true;
        if (!data_info.is_downloaded)
          return data_info.is_downloaded;
        int64 new_offset = offset;
        int64 new_size = data_info.offset - 1 - offset;
        if (CheckRecordDownloaded(new_offset, new_size, to_download)) {
          new_offset = data_info.offset + data_info.size + 1;
          new_size = size - 1 - (data_info.offset - offset + data_info.size);
          return CheckRecordDownloaded(new_offset, new_size, to_download);
        } else
          return false;
      }
    }
    if (to_download) {
      return DownloadData(offset, size);
    }
    return false;
  }
  bool DownloadData(int64 offset, int64 size) {
    DownloadHintDataInfo new_info(offset, size, true);
    hint_data_record_.push_back(new_info);
    return true;
  }

private:
  // Used to record added hint range and if the range is downloaded.
  std::vector<DownloadHintDataInfo> hint_data_record_;
  FILE* file_;
  bool is_large_file_;
};

int main(int argc, char *argv[])
{
  int err_ret = 0;

  WString input_file = input_path + L"AboutFoxit.pdf";
  WString output_directory = output_path + L"async_load/";
#if defined(_WIN32) || defined(_WIN64)
  _mkdir(String::FromUnicode(output_directory));
#else
  mkdir(String::FromUnicode(output_directory), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
#endif

  WString output_file = output_directory + L"page0.bmp";
  SdkLibMgr sdk_lib_mgr;
  // Initialize library
  ErrorCode error_code = sdk_lib_mgr.Initialize();
  if (error_code != foxit::e_ErrSuccess) {
    return 1;
  }

  try {

    AsyncFileRead* file_read = new AsyncFileRead();
    file_read->LoadFile(input_file);
    PDFDoc doc(file_read, true);

    // Actually, here, application should download needed data which specified by AsyncFileRead::AddDownloadHint().
    // But here, for simple example, we just "download" these data inside AsyncFileRead::AddDownloadHint().
    // So, just continue to check the ready state here, which will trigger AsyncFileRead::AddDownloadHint() to
    // "download" data.
    ErrorCode code = foxit::e_ErrDataNotReady;
    while (code == foxit::e_ErrDataNotReady)
      code = doc.Load();
    if (code != foxit::e_ErrSuccess) {
      printf("The Doc [%s] Error: %d\n", (const char*)String::FromUnicode(input_file), error_code);
      return 1;
    }

    // Actually, here, application should download needed data which specified by AsyncFileRead::AddDownloadHint().
    // But here, for simple example, we just "download" these data inside AsyncFileRead::AddDownloadHint().
    // So, just continue to check the ready state here, which will trigger AsyncFileRead::AddDownloadHint() to
    // "download" data.
    PDFPage page;
    code = foxit::e_ErrDataNotReady;
    while (code == foxit::e_ErrDataNotReady) {
      try {
        page = doc.GetPage(0);
        break;
      }
      catch (Exception e) {
        code = e.GetErrCode();
      }
      catch (...) {
        throw;
      }
    }
    // Parse page.
    page.StartParse(foxit::pdf::PDFPage::e_ParsePageNormal, NULL, false);

    int width = static_cast<int>(page.GetWidth());
    int height = static_cast<int>(page.GetHeight());
    foxit::Matrix matrix = page.GetDisplayMatrix(0, 0, width, height, page.GetRotation());

    // Prepare a bitmap for rendering.
    foxit::common::Bitmap bitmap(width, height, foxit::common::Bitmap::e_DIBArgb, NULL, 0);
    bitmap.FillRect(0xFFFFFFFF, NULL);
    // Render page
    foxit::common::Renderer render(bitmap, false);
    render.StartRender(page, matrix, NULL);

    foxit::common::Image image;
    image.AddFrame(bitmap);
    image.SaveAs(output_file);

    cout << "async-load demo finished." << endl;

  } catch (const Exception& e) {
    cout << e.GetMessage() << endl;
    err_ret = 1;
  }
  catch(...)
  {
    cout << "Unknown Exception" << endl;
    err_ret = 1;
  }

  return err_ret;
}

