package VMSConnection.Security.SM2;

import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.CryptoException;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.signers.SM2Signer;

import java.math.BigInteger;
import java.security.SecureRandom;

/*
 * @Author: hongyu guo
 * @Description: 国密sm2 非对称加密私钥
 * @Version: 1.0.0
 * @Date: 19:40 2021/03/03
 * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
 */
public class SM2PrivateKey implements PrivateKeyInterface {

    public SM2PrivateKey(){}

    /*
     * @param d
     * @return
     * @author hongyu guo
     * @date 2021/3/7
    **/

    /*
     * @param d 大数
     * @return
     * @author hongyu guo
     * @date 2021/3/7
    **/
    public SM2PrivateKey(byte[] d) {
        privateKey = new ECPrivateKeyParameters(new BigInteger(d), SM2Base.DOMAIN_PARAMS);
    }
    public SM2PrivateKey(byte[] d, ECDomainParameters parameters){
        if(d.length == 32 || d.length == 33)
            privateKey = new ECPrivateKeyParameters(new BigInteger(d), parameters);
        else {
            try {
                throw new SM2Exception("SM2私钥中，参数d长度应为32/33");
            } catch (SM2Exception e) {
                e.printStackTrace();
            }
        }
    }
    
    @Override
    public byte[] getBytes() {
        byte[] bytes = privateKey.getD().toByteArray();
        return SM2Base.byteArraytoHexByteArray(bytes);
    }

    @Override
//    public boolean setBytes(byte[] d) {
//        // TODO 待与go版本进行兼容 目前版本无法使用
//        if(d.length != 32 && d.length != 33)
//            return false;
//        privateKey = new ECPrivateKeyParameters(new BigInteger(d), SM2Base.DOMAIN_PARAMS);
//        return true;
//    }

    /**
     * @description 与external_amd64同步
     * @params d {byte[]}
     * @return boolean
     */
    // TODO 实现不同
    public boolean setBytes(byte[] d){
        if (d.length != 64 && d.length != 66 && d.length != 32 && d.length != 33)
            return false;
        switch (d.length){
            case 32:
            case 33:
                privateKey = new ECPrivateKeyParameters(new BigInteger(d), SM2Base.DOMAIN_PARAMS);
                break;
            case 64:
            case 66:
                d = SM2Base.hexByteArrayToByteArray(d);
                privateKey = new ECPrivateKeyParameters(new BigInteger(d), SM2Base.DOMAIN_PARAMS);
                break;
        }
        return true;
    }

    @Override
    public byte[] decrypt(byte[] cipher) throws InvalidCipherTextException {
        SM2Engine engine = new SM2Engine(SM2Engine.Mode.C1C2C3);
        engine.init(false, privateKey);
        return engine.processBlock(cipher, 0, cipher.length);
    }

    @Override
    public byte[] sign(byte[] content) throws CryptoException {
        SM2Signer signer = new SM2Signer();
        CipherParameters param = null;
        ParametersWithRandom pwr = new ParametersWithRandom(privateKey, new SecureRandom());
        param = pwr;
        signer.init(true, param);
        signer.update(content, 0, content.length);
        return signer.generateSignature();
    }

    private ECPrivateKeyParameters privateKey;
}