// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#ifndef INTERNAL_FILE_DECRYPTOR_H
#define INTERNAL_FILE_DECRYPTOR_H

#include <map>
#include <memory>
#include <string>
#include <vector>

#include "parquet/schema.h"

namespace parquet {

namespace encryption {
class AesDecryptor;
class AesEncryptor;
}  // namespace encryption

class FileDecryptionProperties;

class PARQUET_EXPORT Decryptor {
 public:
  Decryptor(encryption::AesDecryptor* decryptor, const std::string& key,
            const std::string& file_aad, const std::string& aad,
            ::arrow::MemoryPool* pool);

  const std::string& file_aad() const { return file_aad_; }
  void UpdateAad(const std::string& aad) { aad_ = aad; }
  ::arrow::MemoryPool* pool() { return pool_; }

  int CiphertextSizeDelta();
  int Decrypt(const uint8_t* ciphertext, int ciphertext_len, uint8_t* plaintext);

 private:
  encryption::AesDecryptor* aes_decryptor_;
  std::string key_;
  std::string file_aad_;
  std::string aad_;
  ::arrow::MemoryPool* pool_;
};

class InternalFileDecryptor {
 public:
  explicit InternalFileDecryptor(FileDecryptionProperties* properties,
                                 const std::string& file_aad,
                                 ParquetCipher::type algorithm,
                                 const std::string& footer_key_metadata,
                                 ::arrow::MemoryPool* pool);

  std::string& file_aad() { return file_aad_; }

  std::string GetFooterKey();

  ParquetCipher::type algorithm() { return algorithm_; }

  std::string& footer_key_metadata() { return footer_key_metadata_; }

  FileDecryptionProperties* properties() { return properties_; }

  void WipeOutDecryptionKeys();

  ::arrow::MemoryPool* pool() { return pool_; }

  std::shared_ptr<Decryptor> GetFooterDecryptor();
  std::shared_ptr<Decryptor> GetFooterDecryptorForColumnMeta(const std::string& aad = "");
  std::shared_ptr<Decryptor> GetFooterDecryptorForColumnData(const std::string& aad = "");
  std::shared_ptr<Decryptor> GetColumnMetaDecryptor(
      const std::string& column_path, const std::string& column_key_metadata,
      const std::string& aad = "");
  std::shared_ptr<Decryptor> GetColumnDataDecryptor(
      const std::string& column_path, const std::string& column_key_metadata,
      const std::string& aad = "");

 private:
  FileDecryptionProperties* properties_;
  // Concatenation of aad_prefix (if exists) and aad_file_unique
  std::string file_aad_;
  std::map<std::string, std::shared_ptr<Decryptor>> column_data_map_;
  std::map<std::string, std::shared_ptr<Decryptor>> column_metadata_map_;

  std::shared_ptr<Decryptor> footer_metadata_decryptor_;
  std::shared_ptr<Decryptor> footer_data_decryptor_;
  ParquetCipher::type algorithm_;
  std::string footer_key_metadata_;
  std::vector<encryption::AesDecryptor*> all_decryptors_;

  /// Key must be 16, 24 or 32 bytes in length. Thus there could be up to three
  // types of meta_decryptors and data_decryptors.
  std::unique_ptr<encryption::AesDecryptor> meta_decryptor_[3];
  std::unique_ptr<encryption::AesDecryptor> data_decryptor_[3];

  ::arrow::MemoryPool* pool_;

  std::shared_ptr<Decryptor> GetFooterDecryptor(const std::string& aad, bool metadata);
  std::shared_ptr<Decryptor> GetColumnDecryptor(const std::string& column_path,
                                                const std::string& column_key_metadata,
                                                const std::string& aad,
                                                bool metadata = false);

  encryption::AesDecryptor* GetMetaAesDecryptor(size_t key_size);
  encryption::AesDecryptor* GetDataAesDecryptor(size_t key_size);

  int MapKeyLenToDecryptorArrayIndex(int key_len);
};

}  // namespace parquet

#endif  // INTERNAL_FILE_ENCRYPTORS_H
