repertory/support/include/utils/encrypting_reader.hpp

/*
  Copyright <2018-2025> <scott.e.graves@protonmail.com>

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
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  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
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  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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*/
#ifndef REPERTORY_INCLUDE_UTILS_ENCRYPTING_READER_HPP_
#define REPERTORY_INCLUDE_UTILS_ENCRYPTING_READER_HPP_
#if defined(PROJECT_ENABLE_LIBSODIUM) && defined(PROJECT_ENABLE_BOOST)

#include "utils/config.hpp"

#include "utils/encryption.hpp"
#include "utils/hash.hpp"
#include "utils/types/file/i_file.hpp"

namespace repertory::utils::encryption {
class encrypting_reader final {
public:
  encrypting_reader(std::string_view file_name, std::string_view source_path,
                    stop_type_callback stop_requested_cb,
                    std::string_view token,
                    std::optional<std::string> relative_parent_path,
                    std::size_t error_return = 0U);

  encrypting_reader(stop_type_callback stop_requested_cb,
                    std::string_view encrypted_file_path,
                    std::string_view source_path, std::string_view token,
                    std::size_t error_return = 0U);

  encrypting_reader(
      stop_type_callback stop_requested_cb,
      std::string_view encrypted_file_path, std::string_view source_path,
      std::string_view token,
      std::vector<std::array<unsigned char,
                             crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>>
          iv_list,
      std::size_t error_return = 0U);

  encrypting_reader(std::string_view file_name, std::string_view source_path,
                    stop_type_callback stop_requested_cb,
                    std::string_view token, kdf_config cfg,
                    std::optional<std::string> relative_parent_path,
                    std::size_t error_return = 0U);

  encrypting_reader(stop_type_callback stop_requested_cb,
                    std::string_view encrypted_file_path,
                    std::string_view source_path, std::string_view token,
                    kdf_config cfg, std::size_t error_return = 0U);

  encrypting_reader(
      stop_type_callback stop_requested_cb,
      std::string_view encrypted_file_path, std::string_view source_path,
      std::string_view token, kdf_config cfg,
      std::vector<std::array<unsigned char,
                             crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>>
          iv_list,
      std::size_t error_return = 0U);

  encrypting_reader(std::string_view file_name, std::string_view source_path,
                    stop_type_callback stop_requested_cb,
                    const utils::hash::hash_256_t &master_key,
                    const kdf_config &cfg,
                    std::optional<std::string> relative_parent_path,
                    std::size_t error_return = 0U);

  encrypting_reader(std::string_view file_name, std::string_view source_path,
                    stop_type_callback stop_requested_cb,
                    const utils::hash::hash_256_t &master_key,
                    const std::pair<kdf_config, kdf_config> &configs,
                    std::optional<std::string> relative_parent_path,
                    std::size_t error_return = 0U);

  encrypting_reader(stop_type_callback stop_requested_cb,
                    std::string_view encrypted_file_path,
                    std::string_view source_path,
                    const utils::hash::hash_256_t &master_key,
                    const kdf_config &cfg, std::size_t error_return = 0U);

  encrypting_reader(
      stop_type_callback stop_requested_cb,
      std::string_view encrypted_file_path, std::string_view source_path,
      const utils::hash::hash_256_t &master_key, const kdf_config &cfg,
      std::vector<std::array<unsigned char,
                             crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>>
          iv_list,
      std::size_t error_return = 0U);

  encrypting_reader(
      stop_type_callback stop_requested_cb,
      std::string_view encrypted_file_path, std::string_view source_path,
      const utils::hash::hash_256_t &master_key,
      const std::pair<kdf_config, kdf_config> &configs,
      std::vector<std::array<unsigned char,
                             crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>>
          iv_list,
      std::size_t error_return = 0U);

  encrypting_reader(const encrypting_reader &reader);
  encrypting_reader(encrypting_reader &&) = delete;

  auto operator=(const encrypting_reader &) -> encrypting_reader & = delete;
  auto operator=(encrypting_reader &&) -> encrypting_reader & = delete;

  ~encrypting_reader() noexcept = default;

public:
  using iostream = std::basic_iostream<char, std::char_traits<char>>;
  using kdf_pair_t = std::pair<data_buffer, data_buffer>;
  using key_pair_t =
      std::pair<utils::hash::hash_256_t, utils::hash::hash_256_t>;
  using streambuf = std::basic_streambuf<char, std::char_traits<char>>;

private:
  key_pair_t keys_;
  stop_type_callback stop_requested_cb_;
  size_t error_return_;
  std::unique_ptr<utils::file::i_file> source_file_;
  std::string encrypted_file_name_;
  std::string encrypted_file_path_;
  std::vector<
      std::array<unsigned char, crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>>
      iv_list_;

private:
  std::unordered_map<std::size_t, data_buffer> chunk_buffers_;
  std::optional<kdf_pair_t> kdf_headers_;
  std::size_t last_data_chunk_{};
  std::size_t last_data_chunk_size_{};
  std::uint64_t read_offset_{};
  std::uint64_t total_size_{};

private:
  static const std::size_t header_size_;
  static const std::size_t data_chunk_size_;
  static const std::size_t encrypted_chunk_size_;

private:
  auto reader_function(char *buffer, size_t size, size_t nitems) -> size_t;

  void common_initialize(bool procces_iv_list);

  void common_initialize_kdf_data(const kdf_config &cfg,
                                  const utils::hash::hash_256_t &master_key);

  void common_initialize_kdf_keys(std::string_view token, kdf_config &cfg);

  void common_initialize_kdf_path(const utils::hash::hash_256_t &master_key);

  void create_encrypted_paths(std::string_view file_name,
                              std::optional<std::string> relative_parent_path);

public:
  [[nodiscard]] static auto calculate_decrypted_size(std::uint64_t total_size,
                                                     bool uses_kdf)
      -> std::uint64_t;

  [[nodiscard]] static auto
  calculate_encrypted_size(std::string_view source_path, bool uses_kdf)
      -> std::uint64_t;

  [[nodiscard]] auto create_iostream() const -> std::shared_ptr<iostream>;

  [[nodiscard]] static constexpr auto get_encrypted_chunk_size()
      -> std::size_t {
    return encrypted_chunk_size_;
  }

  [[nodiscard]] static constexpr auto get_data_chunk_size() -> std::size_t {
    return data_chunk_size_;
  }

  [[nodiscard]] auto get_encrypted_file_name() const -> std::string {
    return encrypted_file_name_;
  }

  [[nodiscard]] auto get_encrypted_file_path() const -> std::string {
    return encrypted_file_path_;
  }

  [[nodiscard]] auto get_error_return() const -> std::size_t {
    return error_return_;
  }

  [[nodiscard]] static constexpr auto get_header_size() -> std::size_t {
    return header_size_;
  }

  [[nodiscard]] auto get_iv_list() -> std::vector<
      std::array<unsigned char, crypto_aead_xchacha20poly1305_IETF_NPUBBYTES>> {
    return iv_list_;
  }

  [[nodiscard]] auto get_kdf_config_for_data() const
      -> std::optional<kdf_config>;

  [[nodiscard]] auto get_kdf_config_for_path() const
      -> std::optional<kdf_config>;

  [[nodiscard]] auto get_stop_requested() const -> bool {
    return stop_requested_cb_();
  }

  [[nodiscard]] auto get_total_size() const -> std::uint64_t {
    return total_size_;
  }

  [[nodiscard]] static auto reader_function(char *buffer, size_t size,
                                            size_t nitems, void *instream)
      -> size_t {
    return reinterpret_cast<encrypting_reader *>(instream)->reader_function(
        buffer, size, nitems);
  }

  void set_read_position(std::uint64_t position) { read_offset_ = position; }
};
} // namespace repertory::utils::encryption

#endif // defined(PROJECT_ENABLE_LIBSODIUM) && defined(PROJECT_ENABLE_BOOST)
#endif // REPERTORY_INCLUDE_UTILS_ENCRYPTING_READER_HPP_