//
//  Copyright © 2018年 dahua. All rights reserved.
//

#import "NSString+SHA256.h"
#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonCrypto.h>

@implementation NSString (SHA256)
- (NSString *)sha256 {
    const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
    NSData *data = [NSData dataWithBytes:cstr length:self.length];
    uint8_t digest[CC_SHA256_DIGEST_LENGTH];
    CC_SHA1(data.bytes, (CC_LONG)data.length, digest);
    NSMutableString* result = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH *2];
    for(int i =0; i < CC_SHA256_DIGEST_LENGTH; i++) {
        [result appendFormat:@"%02x", digest[i]];
    }
    return result;
}

- (NSData *)lc_MD5Data
{
    const char* input = [self UTF8String];
    unsigned char result[CC_MD5_DIGEST_LENGTH];
    CC_MD5(input, (CC_LONG)strlen(input), result);
    NSData *data = [NSData dataWithBytes:result length:CC_MD5_DIGEST_LENGTH];

    return data;
}

- (NSData *)lc_SHA256Data
{
    const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];
    NSData *data = [NSData dataWithBytes:cstr length:self.length];
    uint8_t digest[CC_SHA256_DIGEST_LENGTH];
    CC_SHA1(data.bytes, (CC_LONG)data.length, digest);
    NSData *result = [NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH];
    
    return result;
}

//将十六进制的字符串转换成NSString
- (NSString *)lc_convertHexStrToString {
    if (!self || [self length] == 0) {
        return nil;
    }
    
    NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];
    NSRange range;
    if ([self length] % 2 == 0) {
        range = NSMakeRange(0, 2);
    } else {
        range = NSMakeRange(0, 1);
    }
    for (NSInteger i = range.location; i < [self length]; i += 2) {
        unsigned int anInt;
        NSString *hexCharStr = [self substringWithRange:range];
        NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr];
        
        [scanner scanHexInt:&anInt];
        NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];
        [hexData appendData:entity];
        
        range.location += range.length;
        range.length = 2;
    }
    NSString *string = [[NSString alloc]initWithData:hexData encoding:NSUTF8StringEncoding];
    return string;
}

//将NSString转换成十六进制的字符串则可使用如下方式:
- (NSString *)lc_convertStringToHexString {
    if (!self || [self length] == 0) {
        return @"";
    }
    NSData *data = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableString *string = [[NSMutableString alloc] initWithCapacity:[data length]];
    
    [data enumerateByteRangesUsingBlock:^(const void *bytes, NSRange byteRange, BOOL *stop) {
        unsigned char *dataBytes = (unsigned char*)bytes;
        for (NSInteger i = 0; i < byteRange.length; i++) {
            NSString *hexStr = [NSString stringWithFormat:@"%x", (dataBytes[i]) & 0xff];
            if ([hexStr length] == 2) {
                [string appendString:hexStr];
            } else {
                [string appendFormat:@"0%@", hexStr];
            }
        }
    }];
    
    return string;
}
- (NSString *)lc_AESEncryptStringForkey:(NSString *)key {
    
    char keyPtr[kCCKeySizeAES256 + 1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSData *sourceData = [self dataUsingEncoding:NSUTF8StringEncoding];
    NSUInteger dataLength = [sourceData length];
    size_t buffersize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(buffersize);
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCBlockSizeAES128, NULL, [sourceData bytes], dataLength, buffer, buffersize, &numBytesEncrypted);
    
    if (cryptStatus == kCCSuccess) {
        NSData *encryptData = [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
        //对加密后的二进制数据进行base64转码
        return [encryptData base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithLineFeed];
    }else {
        free(buffer);
        return nil;
    }
}

- (NSString *)lc_AESDecryptStringForkey:(NSString *)key {
    
    //先对加密的字符串进行base64解码
    NSData *decodeData = [[NSData alloc] initWithBase64EncodedString:self options:NSDataBase64DecodingIgnoreUnknownCharacters];
    
    char keyPtr[kCCKeySizeAES256 + 1];
    bzero(keyPtr, sizeof(keyPtr));
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSUInteger dataLength = [decodeData length];
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding | kCCOptionECBMode, keyPtr, kCCBlockSizeAES128, NULL, [decodeData bytes], dataLength, buffer, bufferSize, &numBytesDecrypted);
    if (cryptStatus == kCCSuccess) {
        NSData *data = [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
        NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        return result;
    }else {
        free(buffer);
        return nil;
    }
}

@end