package main

import (
	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"github.com/pkg/errors"
)

// pem private key
const privateKey = `-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----`

func testSign(data []byte) (signature []byte, err error) {
	block, _ := pem.Decode([]byte(privateKey))
	if block == nil {
		return nil, errors.New("Decode key error, current block is null")
	}
	priv, err := x509.ParsePKCS8PrivateKey(block.Bytes)
	if err != nil {
		fmt.Println(err)
		return
	}
	h := crypto.Hash.New(crypto.SHA1)
	h.Write([]byte(data))
	hashed := h.Sum(nil)

	signature, err = rsa.SignPKCS1v15(rand.Reader, priv.(*rsa.PrivateKey), crypto.SHA1, hashed)

	return
}

type SHA1withRSA struct {
	privateKey *rsa.PrivateKey
}

func sign(privateKey []byte, encryptData []byte) (res []byte, err error) {

	//rsa, err := x509.ParsePKCS8PrivateKey(privateKey)

	return
}