package com.nova.sankuai.domain.api.rongduoduo;

import org.springframework.stereotype.Component;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

@Component
public class SecurityCore {

    private static SecurityCore instance = null;


    private SecurityCore() {

    }

    public static SecurityCore getInstance() {
        if (instance == null)
            instance = new SecurityCore();
        return instance;
    }

    /*
     * 加密用的Key 可以用26个字母和数字组成 此处使用AES-128-CBC加密模式，key需要为16位。
     */
    public static String webSafeBase64StringEncoding(byte[] sSrc,boolean padded) throws Exception {
        String encodeString= Base64.getEncoder().encodeToString(sSrc);// 此处使用BASE64做转码。

        //websafe base64
        encodeString=encodeString.replace("+","-");
        encodeString=encodeString.replace("/","_");

        //nopadding base64
        if (!padded) {
            if (encodeString.endsWith("=")) {
                encodeString = encodeString.substring(0, encodeString.length() - 1);
                if (encodeString.endsWith("=")) {
                    encodeString = encodeString.substring(0, encodeString.length() - 1);
                }
            }
        }
        return encodeString;
    }

    public static byte[] webSafeBase64StringDecoding(String sSrc) throws Exception {
        //websafe base64
        sSrc=sSrc.replace("-","+");
        sSrc=sSrc.replace("_","/");

        return Base64.getDecoder().decode(sSrc);
    }

    public static String base64StringEncoding(byte[] sSrc,boolean padded) throws Exception {
        String encodeString=Base64.getEncoder().encodeToString(sSrc);// 此处使用BASE64做转码。

        //nopadding base64
        if (!padded) {
            if (encodeString.endsWith("=")) {
                encodeString = encodeString.substring(0, encodeString.length() - 1);
                if (encodeString.endsWith("=")) {
                    encodeString = encodeString.substring(0, encodeString.length() - 1);
                }
            }
        }
        return encodeString;
    }

    public static byte[] base64StringDecoding(String sSrc) throws Exception {
        return Base64.getDecoder().decode(sSrc);
    }

    public byte[] AES128CBCStringEncoding(String encData ,String secretKey,String vector) throws Exception {
        if(secretKey == null) {
            return null;
        }
        if(secretKey.length() != 16) {
            return null;
        }
        if (vector != null && vector.length() != 16) {
            return null;
        }
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        byte[] raw = secretKey.getBytes();
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        IvParameterSpec iv = new IvParameterSpec(vector.getBytes());// 使用CBC模式，需要一个向量iv，可增加加密算法的强度
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
        byte[] encrypted = cipher.doFinal(encData.getBytes("utf-8"));

        return encrypted;
    }

    public String AES128CBCStringDecoding(byte[] sSrc,String key,String ivs){
        try {
            if(key == null) {
                return null;
            }
            if(key.length() != 16) {
                return null;
            }
            if (ivs != null && ivs.length() != 16) {
                return null;
            }
            byte[] raw = key.getBytes("ASCII");
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            IvParameterSpec iv = new IvParameterSpec(ivs.getBytes());
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
            byte[] original = cipher.doFinal(sSrc);
            String originalString = new String(original, "utf-8");
            return originalString;
        } catch (Exception ex) {
            return null;
        }
    }


    // 加密
    public String encrypt(String sSrc){
        try {
            String encodeString=base64StringEncoding(AES128CBCStringEncoding(sSrc,"dxjf18129979469s","dxjf18129979469s"),false);

            return encodeString;
        } catch (Exception ex) {
            ex.printStackTrace();
            return null;
        }
    }

    // 解密
    public String decrypt(String sSrc){
        try {
            String decodeString=AES128CBCStringDecoding(base64StringDecoding(sSrc),"dxjf18129979469s","dxjf18129979469s");
            return decodeString;
        } catch (Exception ex) {
            return null;
        }
    }
}