// Copyright 2017 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include "DiscIO/DiscExtractor.h"

#include <algorithm>
#include <cinttypes>
#include <optional>

#include "Common/CommonTypes.h"
#include "DiscIO/Enums.h"
#include "DiscIO/Filesystem.h"
#include "DiscIO/Volume.h"

namespace DiscIO
{
u64 ReadFile(const Volume& volume, const Partition& partition, const FileInfo* file_info,
             u8* buffer, u64 max_buffer_size, u64 offset_in_file)
{
  if (!file_info || file_info->IsDirectory() || offset_in_file >= file_info->GetSize())
    return 0;

  const u64 read_length = std::min(max_buffer_size, file_info->GetSize() - offset_in_file);

  DEBUG_LOG(DISCIO, "Reading %" PRIx64 " bytes at %" PRIx64 " from file %s. Offset: %" PRIx64
                    " Size: %" PRIx32,
            read_length, offset_in_file, file_info->GetPath().c_str(), file_info->GetOffset(),
            file_info->GetSize());

  if (!volume.Read(file_info->GetOffset() + offset_in_file, read_length, buffer, partition))
    return 0;

  return read_length;
}

bool ExportData(const Volume& volume, const Partition& partition, u64 offset, u64 size,
                const std::string& export_filename)
{
  File::IOFile f(export_filename, "wb");
  if (!f)
    return false;

  while (size)
  {
    // Limit read size to 128 MB
    const size_t read_size = static_cast<size_t>(std::min<u64>(size, 0x08000000));

    std::vector<u8> buffer(read_size);

    if (!volume.Read(offset, read_size, buffer.data(), partition))
      return false;

    if (!f.WriteBytes(buffer.data(), read_size))
      return false;

    size -= read_size;
    offset += read_size;
  }

  return true;
}

bool ExportFile(const Volume& volume, const Partition& partition, const FileInfo* file_info,
                const std::string& export_filename)
{
  if (!file_info || file_info->IsDirectory())
    return false;

  return ExportData(volume, partition, file_info->GetOffset(), file_info->GetSize(),
                    export_filename);
}

void ExportDirectory(const Volume& volume, const Partition partition, const FileInfo& directory,
                     bool recursive, const std::string& filesystem_path,
                     const std::string& export_folder,
                     const std::function<bool(const std::string& path)>& update_progress)
{
  for (const FileInfo& file_info : directory)
  {
    const std::string path =
        filesystem_path + file_info.GetName() + (file_info.IsDirectory() ? "/" : "");
    const std::string export_path = export_folder + '/' + path;

    if (update_progress(path))
      return;

    DEBUG_LOG(DISCIO, "%s", export_path.c_str());

    if (!file_info.IsDirectory())
    {
      if (File::Exists(export_path))
        NOTICE_LOG(DISCIO, "%s already exists", export_path.c_str());
      else if (!ExportFile(volume, partition, &file_info, export_path))
        ERROR_LOG(DISCIO, "Could not export %s", export_path.c_str());
    }
    else if (recursive)
    {
      File::CreateFullPath(export_path);
      ExportDirectory(volume, partition, file_info, recursive, path, export_folder,
                      update_progress);
    }
  }
}

bool ExportApploader(const Volume& volume, const Partition& partition,
                     const std::string& export_filename)
{
  if (!IsDisc(volume.GetVolumeType()))
    return false;

  std::optional<u32> apploader_size = volume.ReadSwapped<u32>(0x2440 + 0x14, partition);
  const std::optional<u32> trailer_size = volume.ReadSwapped<u32>(0x2440 + 0x18, partition);
  constexpr u32 header_size = 0x20;
  if (!apploader_size || !trailer_size)
    return false;
  *apploader_size += *trailer_size + header_size;
  DEBUG_LOG(DISCIO, "Apploader size -> %x", *apploader_size);

  return ExportData(volume, partition, 0x2440, *apploader_size, export_filename);
}

std::optional<u64> GetBootDOLOffset(const Volume& volume, const Partition& partition)
{
  const Platform volume_type = volume.GetVolumeType();
  if (!IsDisc(volume_type))
    return {};

  const std::optional<u32> offset = volume.ReadSwapped<u32>(0x420, partition);
  const u8 offset_shift = volume_type == Platform::WII_DISC ? 2 : 0;
  return offset ? static_cast<u64>(*offset) << offset_shift : std::optional<u64>();
}

std::optional<u32> GetBootDOLSize(const Volume& volume, const Partition& partition, u64 dol_offset)
{
  if (!IsDisc(volume.GetVolumeType()))
    return {};

  u32 dol_size = 0;

  // Iterate through the 7 code segments
  for (u8 i = 0; i < 7; i++)
  {
    const std::optional<u32> offset = volume.ReadSwapped<u32>(dol_offset + 0x00 + i * 4, partition);
    const std::optional<u32> size = volume.ReadSwapped<u32>(dol_offset + 0x90 + i * 4, partition);
    if (!offset || !size)
      return {};
    dol_size = std::max(*offset + *size, dol_size);
  }

  // Iterate through the 11 data segments
  for (u8 i = 0; i < 11; i++)
  {
    const std::optional<u32> offset = volume.ReadSwapped<u32>(dol_offset + 0x1c + i * 4, partition);
    const std::optional<u32> size = volume.ReadSwapped<u32>(dol_offset + 0xac + i * 4, partition);
    if (!offset || !size)
      return {};
    dol_size = std::max(*offset + *size, dol_size);
  }

  return dol_size;
}

bool ExportDOL(const Volume& volume, const Partition& partition, const std::string& export_filename)
{
  if (!IsDisc(volume.GetVolumeType()))
    return false;

  const std::optional<u64> dol_offset = GetBootDOLOffset(volume, partition);
  if (!dol_offset)
    return false;
  const std::optional<u32> dol_size = GetBootDOLSize(volume, partition, *dol_offset);
  if (!dol_size)
    return false;

  return ExportData(volume, partition, *dol_offset, *dol_size, export_filename);
}

}  // namespace DiscIO