//
//  GHNSString+HMAC.m
//
//  Permission is hereby granted, free of charge, to any person
//  obtaining a copy of this software and associated documentation
//  files (the "Software"), to deal in the Software without
//  restriction, including without limitation the rights to use,
//  copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the
//  Software is furnished to do so, subject to the following
//  conditions:
//
//  The above copyright notice and this permission notice shall be
//  included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//  OTHER DEALINGS IN THE SOFTWARE.
//
 
#import "GHNSString+HMAC.h"
 
#import "GTMBase64.h"
 
#import "hmac.h" 
 
@implementation NSString (GHHMAC)
 
/*!
 @method gh_hmacSha1
 @abstract Get HMAC SHA1 digest
 @param secret Secret key to sign with
 @result Base64 encoded HMAC SHA1 digest
 */
- (NSString *)gh_hmacSha1:(NSString *)secret {
  
  NSData *clearTextData = [self dataUsingEncoding:NSUTF8StringEncoding];
  NSData *secretData = [secret dataUsingEncoding:NSUTF8StringEncoding];  
  
  unsigned char digest[20];
  HMAC_SHA1(digest, (unsigned char *)[clearTextData bytes], (unsigned int)[clearTextData length], (unsigned char *)[secretData bytes], (unsigned int)[secretData length]);
  
  NSData *data = [GTMBase64 encodeBytes:digest length:20]; 
  return [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];
}
 
 
//  // Using OpenSSL
//
//#import <openssl/evp.h>
//#import <openssl/err.h>
//#import <openssl/hmac.h>
//#import <openssl/bio.h>
//
//- (NSString *)hmacSha1:(NSString *)secret {
// 
//  NSData *secretData = [secret dataUsingEncoding:NSUTF8StringEncoding];
//  NSData *clearTextData = [self dataUsingEncoding:NSUTF8StringEncoding];
//
//  //HMAC-SHA1
//  HMAC_CTX hmacContext;
//  unsigned char result[EVP_MAX_MD_SIZE];
//  unsigned int resultLength;
//
//  HMAC_CTX_init(&hmacContext);
//  HMAC_Init(&hmacContext, [secretData bytes], [secretData length], EVP_sha1());
//  HMAC_Update(&hmacContext, [clearTextData bytes], [clearTextData length]);
//  HMAC_Final(&hmacContext, result, &resultLength);
//
//  //Base64 Encoding
//  char *base64Result;
//
//  BIO *bio = BIO_new(BIO_s_mem());
//  BIO *b64Filter = BIO_new(BIO_f_base64());
//  bio = BIO_push(b64Filter, bio);
//  BIO_write(bio, result, resultLength);
//  BIO_flush(bio);
//
//  long base64ResultLength = BIO_get_mem_data(bio, &base64Result);
//  base64Result[base64ResultLength-1] = '\0'; // -1 is used to remove the "courtesy" newline added by this library
//
//  NSString *base64EncodedResult = [NSString stringWithCString:base64Result encoding:NSUTF8StringEncoding];
//
//  BIO_free_all(bio);
//  HMAC_CTX_cleanup(&hmacContext);
//
//  return base64EncodedResult;
//}
 
@end