// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include <cstddef>
#include <cstring>
#include <map>
#include <mbedtls/aes.h>
#include <mbedtls/sha1.h>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "Common/CommonFuncs.h"
#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
#include "DiscIO/Blob.h"
#include "DiscIO/FileMonitor.h"
#include "DiscIO/Filesystem.h"
#include "DiscIO/Volume.h"
#include "DiscIO/VolumeCreator.h"
#include "DiscIO/VolumeGC.h"
#include "DiscIO/VolumeWiiCrypted.h"

namespace DiscIO
{
CVolumeWiiCrypted::CVolumeWiiCrypted(std::unique_ptr<IBlobReader> reader, u64 _VolumeOffset,
                                     const unsigned char* _pVolumeKey)
    : m_pReader(std::move(reader)), m_AES_ctx(std::make_unique<mbedtls_aes_context>()),
      m_VolumeOffset(_VolumeOffset), m_dataOffset(0x20000), m_LastDecryptedBlockOffset(-1)
{
  mbedtls_aes_setkey_dec(m_AES_ctx.get(), _pVolumeKey, 128);
}

bool CVolumeWiiCrypted::ChangePartition(u64 offset)
{
  m_VolumeOffset = offset;
  m_LastDecryptedBlockOffset = -1;

  u8 volume_key[16];
  DiscIO::VolumeKeyForPartition(*m_pReader, offset, volume_key);
  mbedtls_aes_setkey_dec(m_AES_ctx.get(), volume_key, 128);
  return true;
}

CVolumeWiiCrypted::~CVolumeWiiCrypted()
{
}

bool CVolumeWiiCrypted::Read(u64 _ReadOffset, u64 _Length, u8* _pBuffer, bool decrypt) const
{
  if (m_pReader == nullptr)
    return false;

  if (!decrypt)
    return m_pReader->Read(_ReadOffset, _Length, _pBuffer);

  FileMon::FindFilename(_ReadOffset);

  std::vector<u8> read_buffer(s_block_total_size);
  while (_Length > 0)
  {
    // Calculate block offset
    u64 Block = _ReadOffset / s_block_data_size;
    u64 Offset = _ReadOffset % s_block_data_size;

    if (m_LastDecryptedBlockOffset != Block)
    {
      // Read the current block
      if (!m_pReader->Read(m_VolumeOffset + m_dataOffset + Block * s_block_total_size,
                           s_block_total_size, read_buffer.data()))
        return false;

      // Decrypt the block's data.
      // 0x3D0 - 0x3DF in m_pBuffer will be overwritten,
      // but that won't affect anything, because we won't
      // use the content of m_pBuffer anymore after this
      mbedtls_aes_crypt_cbc(m_AES_ctx.get(), MBEDTLS_AES_DECRYPT, s_block_data_size,
                            &read_buffer[0x3D0], &read_buffer[s_block_header_size],
                            m_LastDecryptedBlock);
      m_LastDecryptedBlockOffset = Block;

      // The only thing we currently use from the 0x000 - 0x3FF part
      // of the block is the IV (at 0x3D0), but it also contains SHA-1
      // hashes that IOS uses to check that discs aren't tampered with.
      // http://wiibrew.org/wiki/Wii_Disc#Encrypted
    }

    // Copy the decrypted data
    u64 MaxSizeToCopy = s_block_data_size - Offset;
    u64 CopySize = (_Length > MaxSizeToCopy) ? MaxSizeToCopy : _Length;
    memcpy(_pBuffer, &m_LastDecryptedBlock[Offset], (size_t)CopySize);

    // Update offsets
    _Length -= CopySize;
    _pBuffer += CopySize;
    _ReadOffset += CopySize;
  }

  return true;
}

bool CVolumeWiiCrypted::GetTitleID(u64* buffer) const
{
  // Tik is at m_VolumeOffset size 0x2A4
  // TitleID offset in tik is 0x1DC
  if (!Read(m_VolumeOffset + 0x1DC, sizeof(u64), reinterpret_cast<u8*>(buffer), false))
    return false;

  *buffer = Common::swap64(*buffer);
  return true;
}

std::vector<u8> CVolumeWiiCrypted::GetTMD() const
{
  u32 tmd_size;
  u32 tmd_address;

  Read(m_VolumeOffset + 0x2a4, sizeof(u32), (u8*)&tmd_size, false);
  Read(m_VolumeOffset + 0x2a8, sizeof(u32), (u8*)&tmd_address, false);
  tmd_size = Common::swap32(tmd_size);
  tmd_address = Common::swap32(tmd_address) << 2;

  if (tmd_size > 1024 * 1024 * 4)
  {
    // The size is checked so that a malicious or corrupt ISO
    // can't force Dolphin to allocate up to 4 GiB of memory.
    // 4 MiB should be much bigger than the size of TMDs and much smaller
    // than the amount of RAM in a computer that can run Dolphin.
    PanicAlert("TMD > 4 MiB");
    tmd_size = 1024 * 1024 * 4;
  }

  std::vector<u8> buffer(tmd_size);
  Read(m_VolumeOffset + tmd_address, tmd_size, buffer.data(), false);

  return buffer;
}

std::string CVolumeWiiCrypted::GetUniqueID() const
{
  if (m_pReader == nullptr)
    return std::string();

  char ID[6];

  if (!Read(0, 6, (u8*)ID, false))
    return std::string();

  return DecodeString(ID);
}

IVolume::ECountry CVolumeWiiCrypted::GetCountry() const
{
  if (!m_pReader)
    return COUNTRY_UNKNOWN;

  u8 country_byte;
  if (!m_pReader->Read(3, 1, &country_byte))
  {
    return COUNTRY_UNKNOWN;
  }

  IVolume::ECountry country_value = CountrySwitch(country_byte);

  u32 region_code;
  if (!ReadSwapped(0x4E000, &region_code, false))
  {
    return country_value;
  }

  switch (region_code)
  {
  case 0:
    switch (country_value)
    {
    case IVolume::COUNTRY_TAIWAN:
      return IVolume::COUNTRY_TAIWAN;
    default:
      return IVolume::COUNTRY_JAPAN;
    }
  case 1:
    return IVolume::COUNTRY_USA;
  case 2:
    switch (country_value)
    {
    case IVolume::COUNTRY_FRANCE:
    case IVolume::COUNTRY_GERMANY:
    case IVolume::COUNTRY_ITALY:
    case IVolume::COUNTRY_NETHERLANDS:
    case IVolume::COUNTRY_RUSSIA:
    case IVolume::COUNTRY_SPAIN:
    case IVolume::COUNTRY_AUSTRALIA:
      return country_value;
    default:
      return IVolume::COUNTRY_EUROPE;
    }
  case 4:
    return IVolume::COUNTRY_KOREA;
  default:
    return country_value;
  }
}

std::string CVolumeWiiCrypted::GetMakerID() const
{
  if (m_pReader == nullptr)
    return std::string();

  char makerID[2];

  if (!Read(0x4, 0x2, (u8*)&makerID, false))
    return std::string();

  return DecodeString(makerID);
}

u16 CVolumeWiiCrypted::GetRevision() const
{
  if (!m_pReader)
    return 0;

  u8 revision;
  if (!m_pReader->Read(7, 1, &revision))
    return 0;

  return revision;
}

std::string CVolumeWiiCrypted::GetInternalName() const
{
  char name_buffer[0x60];
  if (m_pReader != nullptr && Read(0x20, 0x60, (u8*)&name_buffer, false))
    return DecodeString(name_buffer);

  return "";
}

std::map<IVolume::ELanguage, std::string> CVolumeWiiCrypted::GetLongNames() const
{
  std::unique_ptr<IFileSystem> file_system(CreateFileSystem(this));
  std::vector<u8> opening_bnr(NAMES_TOTAL_BYTES);
  opening_bnr.resize(
      file_system->ReadFile("opening.bnr", opening_bnr.data(), opening_bnr.size(), 0x5C));
  return ReadWiiNames(opening_bnr);
}

std::vector<u32> CVolumeWiiCrypted::GetBanner(int* width, int* height) const
{
  *width = 0;
  *height = 0;

  u64 title_id;
  if (!GetTitleID(&title_id))
    return std::vector<u32>();

  return GetWiiBanner(width, height, title_id);
}

u64 CVolumeWiiCrypted::GetFSTSize() const
{
  if (m_pReader == nullptr)
    return 0;

  u32 size;

  if (!Read(0x428, 0x4, (u8*)&size, true))
    return 0;

  return (u64)Common::swap32(size) << 2;
}

std::string CVolumeWiiCrypted::GetApploaderDate() const
{
  if (m_pReader == nullptr)
    return std::string();

  char date[16];

  if (!Read(0x2440, 0x10, (u8*)&date, true))
    return std::string();

  return DecodeString(date);
}

IVolume::EPlatform CVolumeWiiCrypted::GetVolumeType() const
{
  return WII_DISC;
}

u8 CVolumeWiiCrypted::GetDiscNumber() const
{
  u8 disc_number;
  m_pReader->Read(6, 1, &disc_number);
  return disc_number;
}

BlobType CVolumeWiiCrypted::GetBlobType() const
{
  return m_pReader ? m_pReader->GetBlobType() : BlobType::PLAIN;
}

u64 CVolumeWiiCrypted::GetSize() const
{
  if (m_pReader)
    return m_pReader->GetDataSize();
  else
    return 0;
}

u64 CVolumeWiiCrypted::GetRawSize() const
{
  if (m_pReader)
    return m_pReader->GetRawSize();
  else
    return 0;
}

bool CVolumeWiiCrypted::CheckIntegrity() const
{
  // Get partition data size
  u32 partSizeDiv4;
  Read(m_VolumeOffset + 0x2BC, 4, (u8*)&partSizeDiv4, false);
  u64 partDataSize = (u64)Common::swap32(partSizeDiv4) * 4;

  u32 nClusters = (u32)(partDataSize / 0x8000);
  for (u32 clusterID = 0; clusterID < nClusters; ++clusterID)
  {
    u64 clusterOff = m_VolumeOffset + m_dataOffset + (u64)clusterID * 0x8000;

    // Read and decrypt the cluster metadata
    u8 clusterMDCrypted[0x400];
    u8 clusterMD[0x400];
    u8 IV[16] = {0};
    if (!m_pReader->Read(clusterOff, 0x400, clusterMDCrypted))
    {
      NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: could not read metadata", clusterID);
      return false;
    }
    mbedtls_aes_crypt_cbc(m_AES_ctx.get(), MBEDTLS_AES_DECRYPT, 0x400, IV, clusterMDCrypted,
                          clusterMD);

    // Some clusters have invalid data and metadata because they aren't
    // meant to be read by the game (for example, holes between files). To
    // try to avoid reporting errors because of these clusters, we check
    // the 0x00 paddings in the metadata.
    //
    // This may cause some false negatives though: some bad clusters may be
    // skipped because they are *too* bad and are not even recognized as
    // valid clusters. To be improved.
    bool meaningless = false;
    for (u32 idx = 0x26C; idx < 0x280; ++idx)
      if (clusterMD[idx] != 0)
        meaningless = true;

    if (meaningless)
      continue;

    u8 clusterData[0x7C00];
    if (!Read((u64)clusterID * 0x7C00, 0x7C00, clusterData, true))
    {
      NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: could not read data", clusterID);
      return false;
    }

    for (u32 hashID = 0; hashID < 31; ++hashID)
    {
      u8 hash[20];

      mbedtls_sha1(clusterData + hashID * 0x400, 0x400, hash);

      // Note that we do not use strncmp here
      if (memcmp(hash, clusterMD + hashID * 20, 20))
      {
        NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: hash %d is invalid", clusterID,
                   hashID);
        return false;
      }
    }
  }

  return true;
}

}  // namespace
