/* -*- 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.
 */

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

#include <fstream>
#include <sstream>
#include <CoreFoundation/CoreFoundation.h>

#include "../../util/logging.hpp"
#include "osx-private-key-storage.hpp"
#include "../security-exception.hpp"

using namespace std;
using namespace ndn::ptr_lib;

INIT_LOGGER("ndn.OSXPrivateKeyStorage");

namespace ndn
{
  OSXPrivateKeyStorage::OSXPrivateKeyStorage(const string & keychainName)
    : keyChainName_("" == keychainName ?  "NDN.keychain" : keychainName)
  {
    OSStatus res = SecKeychainCreate(keyChainName_.c_str(), //Keychain path
                                      0,                       //Keychain password length
                                      NULL,                    //Keychain password
                                      true,                    //User prompt
                                      NULL,                    //Initial access of Keychain
                                      &keyChainRef_);         //Keychain reference

    if (res == errSecDuplicateKeychain)
      res = SecKeychainOpen(keyChainName_.c_str(),
                             &keyChainRef_);

    if (res != errSecSuccess){
      _LOG_DEBUG("Fail to initialize keychain ref: " << res);
      throw SecurityException("Fail to initialize keychain ref");
    }

    res = SecKeychainCopyDefault(&originalDefaultKeyChain_);

    res = SecKeychainSetDefault(keyChainRef_);
    if (res != errSecSuccess){
      _LOG_DEBUG("Fail to set default keychain: " << res);
      throw SecurityException("Fail to set default keychain");
    }
  }

  OSXPrivateKeyStorage::~OSXPrivateKeyStorage(){
    //TODO: implement
  }

  void 
  OSXPrivateKeyStorage::generateKeyPair(const Name & keyName, KeyType keyType, int keySize)
  { 
    
    if(doesKeyExist(keyName, KEY_CLASS_PUBLIC)){
      _LOG_DEBUG("keyName has existed");
      throw SecurityException("keyName has existed");
    }

    string keyNameUri = toInternalKeyName(keyName, KEY_CLASS_PUBLIC);

    SecKeyRef publicKey, privateKey;

    CFStringRef keyLabel = CFStringCreateWithCString(NULL, 
                                                      keyNameUri.c_str(), 
                                                      keyNameUri.size());
    
    CFMutableDictionaryRef attrDict = CFDictionaryCreateMutable(NULL,
                                                             3,
                                                             &kCFTypeDictionaryKeyCallBacks,
                                                             NULL);

    CFDictionaryAddValue(attrDict, kSecAttrKeyType, getAsymKeyType(keyType));
    CFDictionaryAddValue(attrDict, kSecAttrKeySizeInBits, CFNumberCreate(NULL, kCFNumberIntType, &keySize));
    CFDictionaryAddValue(attrDict, kSecAttrLabel, keyLabel);

    OSStatus res = SecKeyGeneratePair((CFDictionaryRef)attrDict, &publicKey, &privateKey);

    CFRelease(publicKey);
    CFRelease(privateKey);

    if (res != errSecSuccess){
      _LOG_DEBUG("Fail to create a key pair: " << res);
      throw SecurityException("Fail to create a key pair");
    }
  }

  void 
  OSXPrivateKeyStorage::generateKey(const Name & keyName, KeyType keyType, int keySize)
  {

    if(doesKeyExist(keyName, KEY_CLASS_SYMMETRIC))
        throw SecurityException("keyName has existed!");

    string keyNameUri =  toInternalKeyName(keyName, KEY_CLASS_SYMMETRIC);

    CFMutableDictionaryRef attrDict = CFDictionaryCreateMutable(kCFAllocatorDefault,
                                                                0,
                                                                &kCFTypeDictionaryKeyCallBacks,
                                                                &kCFTypeDictionaryValueCallBacks);

    CFStringRef keyLabel = CFStringCreateWithCString(NULL, 
                                                      keyNameUri.c_str(), 
                                                      keyNameUri.size());

    CFDictionaryAddValue(attrDict, kSecAttrKeyType, getSymKeyType(keyType));
    CFDictionaryAddValue(attrDict, kSecAttrKeySizeInBits, CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &keySize));
    CFDictionaryAddValue(attrDict, kSecAttrIsPermanent, kCFBooleanTrue);
    CFDictionaryAddValue(attrDict, kSecAttrLabel, keyLabel);

    CFErrorRef error = NULL;

    SecKeyRef symmetricKey = SecKeyGenerateSymmetric(attrDict, &error);

    if (error) 
        throw SecurityException("Fail to create a symmetric key");
  }

  shared_ptr<PublicKey> OSXPrivateKeyStorage::getPublicKey(const Name & keyName)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::getPublickey");

    SecKeychainItemRef publicKey = getKey(keyName, KEY_CLASS_PUBLIC);

    CFDataRef exportedKey;

    OSStatus res = SecItemExport(publicKey,
                                  kSecFormatOpenSSL,
                                  0,
                                  NULL,
                                  &exportedKey);
    
    Blob blob(CFDataGetBytePtr(exportedKey), CFDataGetLength(exportedKey));

    return PublicKey::fromDer(blob);
  }

  Blob OSXPrivateKeyStorage::sign(const uint8_t *data, size_t dataLength, const Name & keyName, DigestAlgorithm digestAlgo)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::Sign");
    
    CFDataRef dataRef = CFDataCreate(NULL,
                                      reinterpret_cast<const unsigned char*>(data),
                                      dataLength
                                      );

    SecKeyRef privateKey = (SecKeyRef)getKey(keyName, KEY_CLASS_PRIVATE);
    
    CFErrorRef error;
    SecTransformRef signer = SecSignTransformCreate((SecKeyRef)privateKey, &error);
    if (error) throw SecurityException("Fail to create signer");
    
    Boolean set_res = SecTransformSetAttribute(signer,
                                               kSecTransformInputAttributeName,
                                               dataRef,
                                               &error);
    if (error) throw SecurityException("Fail to configure input of signer");

    set_res = SecTransformSetAttribute(signer,
                                       kSecDigestTypeAttribute,
                                       getDigestAlgorithm(digestAlgo),
                                       &error);
    if (error) throw SecurityException("Fail to configure digest algorithm of signer");

    long digestSize = getDigestSize(digestAlgo);

    set_res = SecTransformSetAttribute(signer,
                                       kSecDigestLengthAttribute,
                                       CFNumberCreate(NULL, kCFNumberLongType, &digestSize),
                                       &error);
    if (error) throw SecurityException("Fail to configure digest size of signer");

    CFDataRef signature = (CFDataRef) SecTransformExecute(signer, &error);
    if (error) {
      CFShow(error);
      throw SecurityException("Fail to sign data");
    }

    if (!signature) throw SecurityException("Signature is NULL!\n");

    return Blob(CFDataGetBytePtr(signature), CFDataGetLength(signature));
  }

  Blob OSXPrivateKeyStorage::decrypt(const Name & keyName, const uint8_t* data, size_t dataLength, bool sym)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::Decrypt");

    KeyClass keyClass;
    if(sym)
        keyClass = KEY_CLASS_SYMMETRIC;
    else
        keyClass = KEY_CLASS_PRIVATE;

    CFDataRef dataRef = CFDataCreate(NULL,
                                      reinterpret_cast<const unsigned char*>(data),
                                      dataLength
                                      );

    // _LOG_DEBUG("CreateData");
    
    SecKeyRef decryptKey = (SecKeyRef)getKey(keyName, keyClass);

    // _LOG_DEBUG("GetKey");

    CFErrorRef error;
    SecTransformRef decrypt = SecDecryptTransformCreate(decryptKey, &error);
    if (error) throw SecurityException("Fail to create decrypt");

    Boolean set_res = SecTransformSetAttribute(decrypt,
                                               kSecTransformInputAttributeName,
                                               dataRef,
                                               &error);
    if (error) throw SecurityException("Fail to configure decrypt");

    CFDataRef output = (CFDataRef) SecTransformExecute(decrypt, &error);
    if (error)
      {
        CFShow(error);
        throw SecurityException("Fail to decrypt data");
      }
    if (!output) throw SecurityException("Output is NULL!\n");

    return Blob(CFDataGetBytePtr(output), CFDataGetLength(output));
  }
  
  bool OSXPrivateKeyStorage::setACL(const Name & keyName, KeyClass keyClass, int acl, const string & appPath)
  {
    SecKeychainItemRef privateKey = getKey(keyName, keyClass);
    
    SecAccessRef accRef;
    OSStatus acc_res = SecKeychainItemCopyAccess(privateKey, &accRef);

    CFArrayRef signACL = SecAccessCopyMatchingACLList(accRef,
                                                       kSecACLAuthorizationSign);

    SecACLRef aclRef = (SecACLRef) CFArrayGetValueAtIndex(signACL, 0);

    CFArrayRef appList;
    CFStringRef description;
    SecKeychainPromptSelector promptSelector;
    OSStatus acl_res = SecACLCopyContents(aclRef,
                                           &appList,
                                           &description,
                                           &promptSelector);

    CFMutableArrayRef newAppList = CFArrayCreateMutableCopy(NULL,
                                                            0,
                                                            appList);

    SecTrustedApplicationRef trustedApp;
    acl_res = SecTrustedApplicationCreateFromPath(appPath.c_str(),
                                                   &trustedApp);
    
    CFArrayAppendValue(newAppList, trustedApp);


    CFArrayRef authList = SecACLCopyAuthorizations(aclRef);
    
    acl_res = SecACLRemove(aclRef);

    SecACLRef newACL;
    acl_res = SecACLCreateWithSimpleContents(accRef,
                                              newAppList,
                                              description,
                                              promptSelector,
                                              &newACL);

    acl_res = SecACLUpdateAuthorizations(newACL, authList);

    acc_res = SecKeychainItemSetAccess(privateKey, accRef);

    return true;
  }

  bool OSXPrivateKeyStorage::verifyData(const Name & keyName, const Blob & pData, const Blob & pSig, DigestAlgorithm digestAlgo)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::Verify");
    
    CFDataRef dataRef = CFDataCreate(NULL,
                                      reinterpret_cast<const unsigned char*>(pData.buf()),
                                      pData.size());

    CFDataRef sigRef = CFDataCreate(NULL,
                                     reinterpret_cast<const unsigned char*>(pSig.buf()),
                                     pSig.size());

    SecKeyRef publicKey = (SecKeyRef)getKey(keyName, KEY_CLASS_PUBLIC);
    
    CFErrorRef error;
    SecTransformRef verifier = SecVerifyTransformCreate(publicKey, sigRef, &error);
    if (error) throw SecurityException("Fail to create verifier");
    
    Boolean set_res = SecTransformSetAttribute(verifier,
                                               kSecTransformInputAttributeName,
                                               dataRef,
                                               &error);
    if (error) throw SecurityException("Fail to configure input of verifier");

    set_res = SecTransformSetAttribute(verifier,
                                       kSecDigestTypeAttribute,
                                       getDigestAlgorithm(digestAlgo),
                                       &error);
    if (error) throw SecurityException("Fail to configure digest algorithm of verifier");

    long digestSize = getDigestSize(digestAlgo);
    set_res = SecTransformSetAttribute(verifier,
                                       kSecDigestLengthAttribute,
                                       CFNumberCreate(NULL, kCFNumberLongType, &digestSize),
                                       &error);
    if (error) throw SecurityException("Fail to configure digest size of verifier");

    CFBooleanRef result = (CFBooleanRef) SecTransformExecute(verifier, &error);
    if (error) throw SecurityException("Fail to verify data");

    if (result == kCFBooleanTrue)
      return true;
    else
      return false;
  }

  Blob OSXPrivateKeyStorage::encrypt(const Name & keyName, const uint8_t* data, size_t dataLength, bool sym)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::Encrypt");

    KeyClass keyClass;
    if(sym)
        keyClass = KEY_CLASS_SYMMETRIC;
    else
        keyClass = KEY_CLASS_PUBLIC;
    
    CFDataRef dataRef = CFDataCreate(NULL,
                                      reinterpret_cast<const unsigned char*>(data),
                                      dataLength
                                      );
    
    SecKeyRef encryptKey = (SecKeyRef)getKey(keyName, keyClass);

    CFErrorRef error;
    SecTransformRef encrypt = SecEncryptTransformCreate(encryptKey, &error);
    if (error) throw SecurityException("Fail to create encrypt");

    Boolean set_res = SecTransformSetAttribute(encrypt,
                                               kSecTransformInputAttributeName,
                                               dataRef,
                                               &error);
    if (error) throw SecurityException("Fail to configure encrypt");

    CFDataRef output = (CFDataRef) SecTransformExecute(encrypt, &error);
    if (error) throw SecurityException("Fail to encrypt data");

    if (!output) throw SecurityException("Output is NULL!\n");

    return Blob(CFDataGetBytePtr(output), CFDataGetLength(output));
  }

  bool OSXPrivateKeyStorage::doesKeyExist(const Name & keyName, KeyClass keyClass)
  {
    _LOG_TRACE("OSXPrivateKeyStorage::doesKeyExist");

    string keyNameUri = toInternalKeyName(keyName, keyClass);

    CFStringRef keyLabel = CFStringCreateWithCString(NULL, 
                                                      keyNameUri.c_str(), 
                                                      keyNameUri.size());
    
    CFMutableDictionaryRef attrDict = CFDictionaryCreateMutable(NULL,
                                                                3,
                                                                &kCFTypeDictionaryKeyCallBacks,
                                                                NULL);

    CFDictionaryAddValue(attrDict, kSecAttrKeyClass, getKeyClass(keyClass));
    CFDictionaryAddValue(attrDict, kSecAttrLabel, keyLabel);
    CFDictionaryAddValue(attrDict, kSecReturnRef, kCFBooleanTrue);
    
    SecKeychainItemRef itemRef;
    OSStatus res = SecItemCopyMatching((CFDictionaryRef)attrDict, (CFTypeRef*)&itemRef);
    
    if(res == errSecItemNotFound)
      return true;
    else
      return false;

  }

  SecKeychainItemRef OSXPrivateKeyStorage::getKey(const Name & keyName, KeyClass keyClass)
  {
    string keyNameUri = toInternalKeyName(keyName, keyClass);

    CFStringRef keyLabel = CFStringCreateWithCString (NULL, 
                                                      keyNameUri.c_str(), 
                                                      keyNameUri.size());
    
    CFMutableDictionaryRef attrDict = CFDictionaryCreateMutable(NULL,
                                                             5,
                                                             &kCFTypeDictionaryKeyCallBacks,
                                                             NULL);

    CFDictionaryAddValue(attrDict, kSecClass, kSecClassKey);
    CFDictionaryAddValue(attrDict, kSecAttrLabel, keyLabel);
    CFDictionaryAddValue(attrDict, kSecAttrKeyClass, getKeyClass(keyClass));
    CFDictionaryAddValue(attrDict, kSecReturnRef, kCFBooleanTrue);
    
    SecKeychainItemRef keyItem;

    OSStatus res = SecItemCopyMatching((CFDictionaryRef) attrDict, (CFTypeRef*)&keyItem);
    
    if(res != errSecSuccess){
      _LOG_DEBUG("Fail to find the key!");
      return NULL;
    }
    else
      return keyItem;
  }
  
  string OSXPrivateKeyStorage::toInternalKeyName(const Name & keyName, KeyClass keyClass)
  {
    string keyUri = keyName.toUri();

    if(KEY_CLASS_SYMMETRIC == keyClass)
      return keyUri + "/symmetric";
    else
      return keyUri;
  }

  const CFTypeRef OSXPrivateKeyStorage::getAsymKeyType(KeyType keyType)
  {
    switch(keyType){
    case KEY_TYPE_RSA:
      return kSecAttrKeyTypeRSA;
    default:
      _LOG_DEBUG("Unrecognized key type!")
      return NULL;
    }
  }

  const CFTypeRef OSXPrivateKeyStorage::getSymKeyType(KeyType keyType)
  {
    switch(keyType){
    case KEY_TYPE_AES:
      return kSecAttrKeyTypeAES;
    default:
      _LOG_DEBUG("Unrecognized key type!")
      return NULL;
    }
  }

  const CFTypeRef OSXPrivateKeyStorage::getKeyClass(KeyClass keyClass)
  {
    switch(keyClass){
    case KEY_CLASS_PRIVATE:
      return kSecAttrKeyClassPrivate;
    case KEY_CLASS_PUBLIC:
      return kSecAttrKeyClassPublic;
    case KEY_CLASS_SYMMETRIC:
      return kSecAttrKeyClassSymmetric;
    default:
      _LOG_DEBUG("Unrecognized key class!");
      return NULL;
    }
  }

  SecExternalFormat OSXPrivateKeyStorage::getFormat(KeyFormat format)
  {
    switch(format){
    case KEY_FORMAT_PUBLIC_OPENSSL:
      return kSecFormatOpenSSL;
    default:
      _LOG_DEBUG("Unrecognized output format!");
      return 0;
    }
  }

  const CFStringRef OSXPrivateKeyStorage::getDigestAlgorithm(DigestAlgorithm digestAlgo)
  {
    switch(digestAlgo){
    // case DIGEST_MD2:
    //   return kSecDigestMD2;
    // case DIGEST_MD5:
    //   return kSecDigestMD5;
    // case DIGEST_SHA1:
    //   return kSecDigestSHA1;
    case DIGEST_ALGORITHM_SHA256:
      return kSecDigestSHA2;
    default:
      _LOG_DEBUG("Unrecognized digest algorithm!");
      return NULL;
    }
  }

  long OSXPrivateKeyStorage::getDigestSize(DigestAlgorithm digestAlgo)
  {
    switch(digestAlgo){
    case DIGEST_ALGORITHM_SHA256:
      return 256;
    // case DIGEST_SHA1:
    // case DIGEST_MD2:
    // case DIGEST_MD5:
    //   return 0;
    default:
      _LOG_DEBUG("Unrecognized digest algorithm! Unknown digest size");
      return -1;
    }
  }
  
}

#endif NDN_CPP_HAVE_OSX_SECURITY