#pragma region CPL License
/*
Nuclex Native Framework
Copyright (C) 2002-2013 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#pragma endregion // CPL License

// If the library is compiled as a DLL, this ensures symbols are exported
#define NUCLEX_STORAGE_SOURCE 1

#include "SevenZipContainerFileCodec.h"
#include "SevenZipArchiveContainer.h"
#include "Format/SignatureHeaderSerializer.h"
#include "Nuclex/Storage/FileSystem/File.h"

namespace Nuclex { namespace Storage { namespace FileSystem { namespace SevenZip {

  // ------------------------------------------------------------------------------------------- //

  bool SevenZipContainerFileCodec::TryOpenAsContainer(
    const std::shared_ptr<ContainerFileCodec> &registeredCodecs,
    const std::shared_ptr<File> &file,
    std::shared_ptr<Container> &openedContainer
  ) {
    if(CanOpenAsContainer(file)) {
      openedContainer.reset(new SevenZipArchiveContainer(registeredCodecs, file));
      return true;
    } else {
      return false;
    }
  }

  // ------------------------------------------------------------------------------------------- //

  bool SevenZipContainerFileCodec::CanOpenAsContainer(const std::shared_ptr<File> &file) {
#if NUCLEX_STORAGE_IDENTIFY_ARCHIVES_BY_EXTENSION
    std::string fileName = file->GetName();

    std::size_t fileNameLength = fileName.length();
    if(fileNameLength < 3) {
      return false;
    }

    bool endsWithDotSevenZip = (fileName.substr(fileNameLength - 3) == ".7z");
    return endsWithDotSevenZip;
#else
    const std::uint64_t SmallestPossibleSevenZipArchive = 132; // bytes

    std::uint64_t size = file->GetSize();
    if(size < SmallestPossibleSevenZipArchive) {
      return false; // File is too small to be a 7-zip archive
    }

    // Check if this file starts with a signature header
    std::uint8_t signature[6];
    file->ReadAt(0, signature, sizeof(signature));

    return
      (signature[0] == SignatureHeaderSerializer::Signature[0]) &&
      (signature[1] == SignatureHeaderSerializer::Signature[1]) &&
      (signature[2] == SignatureHeaderSerializer::Signature[2]) &&
      (signature[3] == SignatureHeaderSerializer::Signature[3]) &&
      (signature[4] == SignatureHeaderSerializer::Signature[4]) &&
      (signature[5] == SignatureHeaderSerializer::Signature[5]);
#endif
  }

  // ------------------------------------------------------------------------------------------- //

}}}} // namespace Nuclex::Storage::FileSystem::SevenZip