//
//  AESUtils.m
//  YUMI
//
//  Created by YUMI on 2023/2/13.
//

#import "AESUtils.h"
#import <CommonCrypto/CommonCrypto.h>

#define GL_AES_KEY                  @"aef01238765abcdeaaageggbeggsded"
#define GL_AES_IV                      @"edgcdgrtc"
@implementation AESUtils
//MARK: AES加解密相关 start
+ (NSString *)aesEncrypt:(NSString *)sourceStr {
	if (!sourceStr) {
		return nil;
	}

	//秘钥
	char keyPtr[kCCKeySizeAES256 + 1];
	bzero(keyPtr, sizeof(keyPtr));
	[GL_AES_KEY getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

	//向量
	char ivPtr[kCCBlockSizeAES128 + 1];
	bzero(ivPtr, sizeof(ivPtr));
	[GL_AES_IV getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

	NSData *sourceData = [sourceStr dataUsingEncoding:NSUTF8StringEncoding];
	NSUInteger dataLength = [sourceData length];
	size_t buffersize = dataLength + kCCBlockSizeAES128;
	void *buffer = malloc(buffersize);
	size_t numBytesEncrypted = 0;
	/*
	 //CBC模式
	 kCCOptionPKCS7Padding
	 //ECB模式
	 kCCOptionPKCS7Padding | kCCOptionECBMode
	 */
	CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
										  kCCAlgorithmAES128,
										  kCCOptionPKCS7Padding,
										  keyPtr,
										  kCCBlockSizeAES128,
										  ivPtr,//ECB模式下可以为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];

		//转换为16进制字符串
		NSMutableString *output = [NSMutableString stringWithCapacity:encryptData.length * 2];
		if (encryptData && encryptData.length > 0) {
			Byte *datas = (Byte*)[encryptData bytes];
			for(int i = 0; i < encryptData.length; i++){
				[output appendFormat:@"%02x", datas[i]];
			}
		}
		return output;

	} else {
		free(buffer);
		return nil;
	}
}

+ (NSString *)aesDecrypt:(NSString *)secretStr {
	if (!secretStr) {
		return nil;
	}
//	//先对加密的字符串进行base64解码
	NSData *decodeData = [[NSData alloc] initWithBase64EncodedString:secretStr options:NSDataBase64DecodingIgnoreUnknownCharacters];
  //先对加密的字符串进行16进制解码
//	NSData *decodeData = [self convertHexStrToData:secretStr];

	//秘钥
	char keyPtr[kCCKeySizeAES256 + 1];
	bzero(keyPtr, sizeof(keyPtr));
	[GL_AES_KEY getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

	//向量
	char ivPtr[kCCBlockSizeAES128 + 1];
	bzero(ivPtr, sizeof(ivPtr));
	[GL_AES_IV getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

	NSUInteger dataLength = [decodeData length];
	size_t bufferSize = dataLength + kCCBlockSizeAES128;
	void *buffer = malloc(bufferSize);
	size_t numBytesDecrypted = 0;
	/*
	 //CBC模式
	 kCCOptionPKCS7Padding
	 //ECB模式
	 kCCOptionPKCS7Padding | kCCOptionECBMode
	 */
	CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
										  kCCAlgorithmAES128,
										  kCCOptionPKCS7Padding,
										  keyPtr,
										  kCCBlockSizeAES128,
										  ivPtr,//ECB模式下可以为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;
	}
}

// 16进制转NSData
+ (NSData *)convertHexStrToData:(NSString *)str {
	if (!str || [str length] == 0) {
		return nil;
	}

	NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:20];
	NSRange range;
	if ([str length] % 2 == 0) {
		range = NSMakeRange(0, 2);
	} else {
		range = NSMakeRange(0, 1);
	}
	for (NSInteger i = range.location; i < [str length]; i += 2) {
		unsigned int anInt;
		NSString *hexCharStr = [str 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;
	}
	return hexData;
}
@end