package mycrypto

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/base64"
	"service/library/configcenter"
	"service/library/logger"
)

type RsaCrypto struct {
	rsaPubKey *rsa.PublicKey
	rsaPriKey *rsa.PrivateKey
}

func NewRsaCrypto(cryptoConfig *configcenter.CryptoConfig) (rsaCrypto *RsaCrypto, err error) {
	rsaCrypto = &RsaCrypto{}

	//读取私钥
	if rsaCrypto.readRSAPriKey(cryptoConfig) != nil {
		logger.Error("read rsa primary key failed!", err)
		return
	}

	//读取公钥
	rsaCrypto.readRSAPubKey()
	return
}

func NewRsaCryptoFromString(rsaPrivateKeyStr string) (rsaCrypto *RsaCrypto, err error) {
	rsaCrypto = &RsaCrypto{}

	//读取私钥
	rsaPriKey, err := readRSAPriKeyFromString(rsaPrivateKeyStr)
	if err != nil {
		logger.Error("read rsa primary key failed!", err)
		return
	}

	//读取公钥
	rsaPubKey := &rsaPriKey.PublicKey

	rsaCrypto.rsaPriKey = rsaPriKey
	rsaCrypto.rsaPubKey = rsaPubKey
	return
}

func (rsaCrypto *RsaCrypto) Encrypt(msg []byte) (encryptedBytes []byte, err error) {
	//公钥加密
	encryptedBytes, err = rsa.EncryptPKCS1v15(rand.Reader, rsaCrypto.rsaPubKey, msg)
	if err != nil {
		logger.Error("EncryptByRSA failed!, err: %v", err)
		return
	}
	return
}

func (rsaCrypto *RsaCrypto) Decrypt(encryptedBytes []byte) (decryptedBytes []byte, err error) {
	if len(encryptedBytes) == 0 {
		return
	}
	//私钥解密
	decryptedBytes, err = rsa.DecryptPKCS1v15(rand.Reader, rsaCrypto.rsaPriKey, encryptedBytes)
	if err != nil {
		logger.Error("DecryptByRSA failed!, err: %v", err)
		return
	}

	return
}

func (rsaCrypto *RsaCrypto) readRSAPubKey() (err error) {
	//读取公钥
	rsaCrypto.rsaPubKey = &rsaCrypto.rsaPriKey.PublicKey
	return
}

func (rsaCrypto *RsaCrypto) readRSAPriKey(cryptoConfig *configcenter.CryptoConfig) (err error) {
	//读取私钥
	rsaPriKeyBytes, _ := base64.StdEncoding.DecodeString(cryptoConfig.RSAPrivateKey)
	rsaCrypto.rsaPriKey, err = x509.ParsePKCS1PrivateKey(rsaPriKeyBytes)
	if err != nil {
		logger.Error("Decoding rsa primary key failed, check your config, please!, err: %v", err)
		return
	}
	return
}

func readRSAPriKeyFromString(rsaPrivateKeyStr string) (rsaPriKey *rsa.PrivateKey, err error) {
	//读取私钥
	rsaPriKeyBytes, _ := base64.StdEncoding.DecodeString(rsaPrivateKeyStr)
	rsaPriKey, err = x509.ParsePKCS1PrivateKey(rsaPriKeyBytes)
	if err != nil {
		logger.Error("Decoding rsa primary key failed, check your config, please!, err: %v", err)
		return
	}
	return
}