/* -*- 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>
 * @author: Jeff Thompson <jefft0@remap.ucla.edu>
 * See COPYING for copyright and distribution information.
 */

#ifndef NDN_KEY_CHAIN_HPP
#define NDN_KEY_CHAIN_HPP

#include "certificate/identity-certificate.hpp"
#include "certificate/public-key.hpp"
#include "identity/identity-storage.hpp"
#include "identity/private-key-storage.hpp"


namespace ndn {

/**
 * KeyChain is one of the main classes of the security library.
 *
 * The KeyChain class provides a set of interfaces of identity management and private key related operations.
 */
class KeyChain {
public:
  struct Error : public std::runtime_error { Error(const std::string &what) : std::runtime_error(what) {} };

  KeyChain(const ptr_lib::shared_ptr<IdentityStorage>   &identityStorage   = DefaultIdentityStorage,
           const ptr_lib::shared_ptr<PrivateKeyStorage> &privateKeyStorage = DefaultPrivateKeyStorage);
  
  inline IdentityStorage&
  info();

  inline const IdentityStorage&
  info() const;

  inline PrivateKeyStorage&
  tpm();

  inline const PrivateKeyStorage&
  tpm() const;

  
  /**
   * Create an identity by creating a pair of Key-Signing-Key (KSK) for this identity and a self-signed certificate of the KSK.
   * @param identityName The name of the identity.
   * @return The key name of the auto-generated KSK of the identity.
   */
  Name
  createIdentity(const Name& identityName);
    
  /**
   * Generate a pair of RSA keys for the specified identity.
   * @param identityName The name of the identity.
   * @param isKsk true for generating a Key-Signing-Key (KSK), false for a Data-Signing-Key (KSK).
   * @param keySize The size of the key.
   * @return The generated key name.
   */
  Name
  generateRSAKeyPair(const Name& identityName, bool isKsk = false, int keySize = 2048);

  /**
   * Set a key as the default key of an identity.
   * @param keyName The name of the key.
   * @param identityName the name of the identity. If not specified, the identity name is inferred from the keyName.
   */
  void
  setDefaultKeyForIdentity(const Name& keyName, const Name& identityName = Name())
  {
    info().setDefaultKeyNameForIdentity(keyName, identityName);
    defaultCertificate_.reset();
  }
  
  /**
   * Generate a pair of RSA keys for the specified identity and set it as default key for the identity.
   * @param identityName The name of the identity.
   * @param isKsk true for generating a Key-Signing-Key (KSK), false for a Data-Signing-Key (KSK).
   * @param keySize The size of the key.
   * @return The generated key name.
   */
  Name
  generateRSAKeyPairAsDefault(const Name& identityName, bool isKsk = false, int keySize = 2048);

  /**
   * Create an identity certificate for a public key managed by this IdentityManager.
   * @param certificatePrefix The name of public key to be signed.
   * @param signerCertificateName The name of signing certificate.
   * @param notBefore The notBefore value in the validity field of the generated certificate.
   * @param notAfter The notAfter vallue in validity field of the generated certificate.
   * @return The name of generated identity certificate.
   */
  ptr_lib::shared_ptr<IdentityCertificate>
  createIdentityCertificate
    (const Name& certificatePrefix,
     const Name& signerCertificateName,
     const MillisecondsSince1970& notBefore, 
     const MillisecondsSince1970& notAfter);

  /**
   * Create an identity certificate for a public key supplied by the caller.
   * @param certificatePrefix The name of public key to be signed.
   * @param publickey The public key to be signed.
   * @param signerCertificateName The name of signing certificate.
   * @param notBefore The notBefore value in the validity field of the generated certificate.
   * @param notAfter The notAfter vallue in validity field of the generated certificate.
   * @return The generated identity certificate.
   */
  ptr_lib::shared_ptr<IdentityCertificate>
  createIdentityCertificate
    (const Name& certificatePrefix,
     const PublicKey& publickey,
     const Name& signerCertificateName, 
     const MillisecondsSince1970& notBefore,
     const MillisecondsSince1970& notAfter); 
    
  /**
   * Set the certificate as the default for its corresponding key.
   * @param certificateName The certificate.
   */
  void
  setDefaultCertificateForKey(const IdentityCertificate& certificate);

  /**
   * Add a certificate into the public key identity storage and set the certificate as the default for its corresponding identity.
   * @param certificate The certificate to be added.  This makes a copy of the certificate.
   */
  void
  addCertificateAsIdentityDefault(const IdentityCertificate& certificate);

  /**
   * Add a certificate into the public key identity storage and set the certificate as the default of its corresponding key.
   * @param certificate The certificate to be added.  This makes a copy of the certificate.
   */
  void
  addCertificateAsDefault(const IdentityCertificate& certificate);
        
  /**
   * Get the default certificate name of the default identity, which will be used when signing is based on identity and 
   * the identity is not specified.
   * @return The requested certificate name.
   */
  Name
  getDefaultCertificateName()
  {
    return info().getDefaultCertificateNameForIdentity(info().getDefaultIdentity());
  }

  void
  sign(Data &data);
  
  /**
   * Wire encode the Data object, sign it and set its signature.
   * @param data The Data object to be signed.  This updates its signature and key locator field and wireEncoding.
   * @param certificateName The certificate name of the key to use for signing.  If omitted, infer the signing identity from the data packet name.
   */
  void 
  sign(Data& data, const Name& certificateName);

  void
  sign(Data& data, const IdentityCertificate& certificate);
  
  /**
   * Sign the byte array using a certificate name and return a Signature object.
   * @param buffer The byte array to be signed.
   * @param bufferLength the length of buffer.
   * @param certificateName The certificate name used to get the signing key and which will be put into KeyLocator.
   * @return The Signature.
   */
  Signature
  sign(const uint8_t* buffer, size_t bufferLength, const Name& certificateName);

  /**
   * Wire encode the Data object, sign it and set its signature.
   * @param data The Data object to be signed.  This updates its signature and key locator field and wireEncoding.
   * @param identityName The identity name for the key to use for signing.  If omitted, infer the signing identity from the data packet name.
   */
  void 
  signByIdentity(Data& data, const Name& identityName = Name());

  /**
   * Sign the byte array using an identity name and return a Signature object.
   * @param buffer The byte array to be signed.
   * @param bufferLength the length of buffer.
   * @param identityName The identity name.
   * @return The Signature.
   */
  Signature
  signByIdentity(const uint8_t* buffer, size_t bufferLength, const Name& identityName = Name());

  /**
   * Generate a self-signed certificate for a public key.
   * @param keyName The name of the public key.
   * @return The generated certificate.
   */
  ptr_lib::shared_ptr<IdentityCertificate>
  selfSign(const Name& keyName);

  /**
   * @brief Self-sign the supplied identity certificate
   */
  void
  selfSign (IdentityCertificate& cert);

private:
  /**
   * Generate a key pair for the specified identity.
   * @param identityName The name of the specified identity.
   * @param isKsk true for generating a Key-Signing-Key (KSK), false for a Data-Signing-Key (KSK).
   * @param keyType The type of the key pair, e.g. KEY_TYPE_RSA.
   * @param keySize The size of the key pair.
   * @return The name of the generated key.
   */
  Name
  generateKeyPair(const Name& identityName, bool isKsk = false, KeyType keyType = KEY_TYPE_RSA, int keySize = 2048);

  static Name
  getKeyNameFromCertificatePrefix(const Name& certificatePrefix);

public:
  static const ptr_lib::shared_ptr<IdentityStorage>   DefaultIdentityStorage;
  static const ptr_lib::shared_ptr<PrivateKeyStorage> DefaultPrivateKeyStorage;
    
private:
  ptr_lib::shared_ptr<IdentityStorage>   publicInfoStorage_;
  ptr_lib::shared_ptr<PrivateKeyStorage> privateKeyStorage_;

  ptr_lib::shared_ptr<IdentityCertificate> defaultCertificate_;
};


inline IdentityStorage&
KeyChain::info()
{
  if (!publicInfoStorage_)
    throw Error("IdentityStorage is not assigned to IdentityManager");

  return *publicInfoStorage_;
}

inline const IdentityStorage&
KeyChain::info() const
{
  if (!publicInfoStorage_)
    throw Error("IdentityStorage is not assigned to IdentityManager");
  
  return *publicInfoStorage_;
}

inline PrivateKeyStorage&
KeyChain::tpm()
{
  if (!privateKeyStorage_)
    throw Error("PrivateKeyStorage is not assigned to IdentityManager");
  
  return *privateKeyStorage_;
}

inline const PrivateKeyStorage&
KeyChain::tpm() const
{
  if (!privateKeyStorage_)
    throw Error("PrivateKeyStorage is not assigned to IdentityManager");
  return *privateKeyStorage_;
}

}

#endif