/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
/**
 * Copyright (C) 2013 Regents of the University of California.
 * @author: Yingdi Yu <yingdi@cs.ucla.edu>
 * See COPYING for copyright and distribution information.
 */

#ifndef NDN_OSX_PRIVATEKEY_STORAGE_H
#define NDN_OSX_PRIVATEKEY_STORAGE_H

// Only compile if ndn-cpp-config.h defines NDN_CPP_HAVE_OSX_SECURITY 1.
#include "../../ndn-cpp-config.h"
#if NDN_CPP_HAVE_OSX_SECURITY

#include "../../common.hpp"
#include "private-key-storage.hpp"

#include <CoreFoundation/CoreFoundation.h>
#include <Security/Security.h>
#include <CoreServices/CoreServices.h>

namespace ndn
{
  
class OSXPrivateKeyStorage : public PrivateKeyStorage {
public:
  /**
   * constructor of OSXPrivateKeyStorage
   * @param keychainName the name of keychain
   */
  OSXPrivateKeyStorage(const std::string & keychainName = "");

  /**
   * destructor of OSXPrivateKeyStore
   */    
  virtual 
  ~OSXPrivateKeyStorage();

  /**
   * Generate a pair of asymmetric keys.
   * @param keyName The name of the key pair.
   * @param keyType The type of the key pair, e.g. KEY_TYPE_RSA.
   * @param keySize The size of the key pair.
   */
  virtual void 
  generateKeyPair(const Name& keyName, KeyType keyType = KEY_TYPE_RSA, int keySize = 2048);

  /**
   * Get the public key
   * @param keyName The name of public key.
   * @return The public key.
   */
  virtual ptr_lib::shared_ptr<PublicKey> 
  getPublicKey(const Name& keyName);
  
  /**
   * Fetch the private key for keyName and sign the data, returning a signature Blob.
   * @param data Pointer to the input byte array.
   * @param dataLength The length of data.
   * @param keyName The name of the signing key.
   * @param digestAlgorithm the digest algorithm.
   * @return The signature, or a null pointer if signing fails.
   */  
  virtual Blob 
  sign(const uint8_t *data, size_t dataLength, const Name& keyName, DigestAlgorithm digestAlgorithm = DIGEST_ALGORITHM_SHA256);
      
  /**
   * Decrypt data.
   * @param keyName The name of the decrypting key.
   * @param data The byte to be decrypted.
   * @param dataLength the length of data.
   * @param isSymmetric If true symmetric encryption is used, otherwise asymmetric decryption is used.
   * @return The decrypted data.
   */
  virtual Blob 
  decrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric = false);

  /**
   * Encrypt data.
   * @param keyName The name of the encrypting key.
   * @param data The byte to be encrypted.
   * @param dataLength the length of data.
   * @param isSymmetric If true symmetric encryption is used, otherwise asymmetric decryption is used.
   * @return The encrypted data.
   */
  virtual Blob
  encrypt(const Name& keyName, const uint8_t* data, size_t dataLength, bool isSymmetric = false);

  /**
   * Generate a symmetric key.
   * @param keyName The name of the key.
   * @param keyType The type of the key, e.g. KEY_TYPE_AES.
   * @param keySize The size of the key.
   */
  virtual void 
  generateKey(const Name& keyName, KeyType keyType = KEY_TYPE_AES, int keySize = 256);

  /**
   * Check if a particular key exists.
   * @param keyName The name of the key.
   * @param keyClass The class of the key, e.g. KEY_CLASS_PUBLIC, KEY_CLASS_PRIVATE, or KEY_CLASS_SYMMETRIC.
   * @return True if the key exists, otherwise false.
   */
  virtual bool
  doesKeyExist(const Name& keyName, KeyClass keyClass);  

  /**
   * configure ACL of a particular key
   * @param keyName the name of key
   * @param keyClass the class of key, e.g. Private Key
   * @param acl the new acl of the key
   * @param appPath the absolute path to the application
   * @returns true if setting succeeds
   */
  bool 
  setACL(const Name & keyName, KeyClass keyClass, int acl, const std::string & appPath);

  /**
   * verify data (test only)
   * @param keyName the name of key
   * @param pData the data to be verified
   * @param pSig the signature associated with the data
   * @param digestAlgo digest algorithm
   * @return true if signature can be verified, otherwise false
   */
  bool 
  verifyData(const Name & keyName, const Blob & pData, const Blob & pSig, DigestAlgorithm digestAlgo = DIGEST_ALGORITHM_SHA256);

 private:
  /**
   * convert NDN name of a key to internal name of the key
   * @param keyName the NDN name of the key
   * @param keyClass the class of the key
   * @return the internal key name
   */
  std::string 
  toInternalKeyName(const Name & keyName, KeyClass keyClass);

  /**
   * Get key
   * @param keyName the name of the key
   * @param keyClass the class of the key
   * @returns pointer to the key
   */
  SecKeychainItemRef 
  getKey(const Name & keyName, KeyClass keyClass);
      
  /**
   * convert keyType to MAC OS symmetric key key type
   * @param keyType
   * @returns MAC OS key type
   */
  const CFTypeRef 
  getSymKeyType(KeyType keyType);

  /**
   * convert keyType to MAC OS asymmetirc key type
   * @param keyType
   * @returns MAC OS key type
   */
  const CFTypeRef 
  getAsymKeyType(KeyType keyType);

  /**
   * convert keyClass to MAC OS key class
   * @param keyClass
   * @returns MAC OS key class
   */
  const CFTypeRef 
  getKeyClass(KeyClass keyClass);

  /**
   * convert digestAlgo to MAC OS algorithm id
   * @param digestAlgo
   * @returns MAC OS algorithm id
   */
  const CFStringRef 
  getDigestAlgorithm(DigestAlgorithm digestAlgo);

  /**
   * convert format to MAC OS key format
   * @param format
   * @returns MAC OS keyformat
   */
  SecExternalFormat 
  getFormat(KeyFormat format);

  /**
   * get the digest size of the corresponding algorithm
   * @param digestAlgo the digest algorithm
   * @return digest size
   */
  long 
  getDigestSize(DigestAlgorithm digestAlgo);

  const std::string keyChainName_;
  SecKeychainRef keyChainRef_;
  SecKeychainRef originalDefaultKeyChain_;
};
  
}

#endif NDN_CPP_HAVE_OSX_SECURITY

#endif