package com.hx.mp.util;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import net.sf.json.JSONObject;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.UnsupportedEncodingException;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
 
 
public class WechatUtil {
	public static boolean initialized = false;

    //log4j日志
    private static Logger logger = LoggerFactory.getLogger(WechatUtil.class.getName());
	
	public static JSONObject encryptedData(String encryptedData, String session_key, String iv) throws Exception {
	    JSONObject encrypted_obj = null;
         byte[] resultByte  =decrypt(Base64.decode(encryptedData),
                 Base64.decode(session_key),
                 Base64.decode(iv));
             if(null != resultByte && resultByte.length > 0){
                 String userInfo = new String(resultByte, "UTF-8");
                 encrypted_obj = JSONObject.fromObject(userInfo);
             }else{
                 logger.error("获取unionid解密失败：encryptedData="+encryptedData+";session_key="+session_key+";iv="+iv);
             }
		return encrypted_obj;
	}


    /** 
     * AES解密 
     * @param content 密文 
     * @return 
     * @throws InvalidAlgorithmParameterException  
     * @throws NoSuchProviderException  
     */  
    public static byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws Exception {
        initialize();
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        Key sKeySpec = new SecretKeySpec(keyByte, "AES");

        cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
        byte[] result = cipher.doFinal(content);
        return result;
    }    

    public static void initialize(){
        if (initialized) return;
        Security.addProvider(new BouncyCastleProvider());
        initialized = true;
    }
    //生成iv    
    public static AlgorithmParameters generateIV(byte[] iv) throws Exception{    
        AlgorithmParameters params = AlgorithmParameters.getInstance("AES");    
        params.init(new IvParameterSpec(iv));    
        return params;    
    }     
 
 
}