// Copyright 2019 Google LLC.
//
// Licensed 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 TINK_PYTHON_CC_CC_KEY_MANAGER_H_
#define TINK_PYTHON_CC_CC_KEY_MANAGER_H_

#include <algorithm>
#include <vector>

#include "tink/key_manager.h"
#include "tink/util/errors.h"
#include "tink/util/status.h"
#include "tink/util/statusor.h"
#include "proto/tink.pb.h"
#include "tink/registry.h"

namespace crypto {
namespace tink {

/**
 * CcKeyManager is a thin wrapper of KeyManager in
 * third_party/tink/cc/key_manager.h
 * It only implements the methods currently needed in Python, and slightly
 * changes the interface to ease usage of CLIF.
 */
template<class P>
class CcKeyManager {
 public:
  // Returns a key manager from the registry.
  static util::StatusOr<std::unique_ptr<CcKeyManager<P>>>
  GetFromCcRegistry(const std::string& type_url) {
    auto key_manager_result = Registry::get_key_manager<P>(type_url);
    if (!key_manager_result.ok()) {
      return ToStatusF(util::error::FAILED_PRECONDITION,
                       "No manager for key type '%s' found in the registry.",
                       type_url.c_str());
    }
    return absl::make_unique<CcKeyManager<P>>(
        key_manager_result.ValueOrDie());
  }

  explicit CcKeyManager(const KeyManager<P>* key_manager)
      : key_manager_(key_manager) {}

  // Constructs an instance of P for the given 'key_data'.
  crypto::tink::util::StatusOr<std::unique_ptr<P>> GetPrimitive(
      const google::crypto::tink::KeyData& key_data) {
    return key_manager_->GetPrimitive(key_data);
  }

  // Creates a new random key, based on the specified 'key_format'.
  crypto::tink::util::StatusOr<std::unique_ptr<google::crypto::tink::KeyData>>
      NewKeyData(const google::crypto::tink::KeyTemplate& key_template) {
    if (key_manager_->get_key_type() != key_template.type_url()) {
      return ToStatusF(util::error::INVALID_ARGUMENT,
                       "Key type '%s' is not supported by this manager.",
                       key_template.type_url().c_str());
    }
    return key_manager_->get_key_factory().NewKeyData(key_template.value());
  }

  // Returns public key data extracted from the given private_key_data.
  crypto::tink::util::StatusOr<std::unique_ptr<google::crypto::tink::KeyData>>
  GetPublicKeyData(
      const google::crypto::tink::KeyData& private_key_data) const {
    const PrivateKeyFactory* factory = dynamic_cast<const PrivateKeyFactory*>(
        &key_manager_->get_key_factory());
    if (factory == nullptr) {
      return ToStatusF(util::error::INVALID_ARGUMENT,
                       "KeyManager for type '%s' does not have "
                       "a PrivateKeyFactory.",
                       key_manager_->get_key_type().c_str());
    }
    auto result = factory->GetPublicKeyData(private_key_data.value());
    return result;
  }

  // Returns the type_url identifying the key type handled by this manager.
  std::string KeyType() {
    return key_manager_->get_key_type();
  }

 private:
  const KeyManager<P>* key_manager_;
};

}  // namespace tink
}  // namespace crypto
#endif  // TINK_PYTHON_CC_CC_KEY_MANAGER_H_