package main

import (
	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
)

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

const asmPrivateKey = `
-----BEGIN PRIVATE KEY-----
MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAt5yrcHAAjhglnCEn
6yecMWPeUXcMyo0+itXrLlkpcKIIyqPw546bGThhlb1ppX1ySX/OUA4jSakHekNP
5eWPawIDAQABAkBbr9pUPTmpuxkcy9m5LYBrkWk02PQEOV/fyE62SEPPP+GRhv4Q
Fgsu+V2GCwPQ69E3LzKHPsSNpSosIHSO4g3hAiEA54JCn41fF8GZ90b9L5dtFQB2
/yIcGX4Xo7bCvl8DaPMCIQDLCUN8YiXppydqQ+uYkTQgvyq+47cW2wcGumRS46dd
qQIhAKp2v5e8AMj9ROFO5B6m4SsVrIkwFICw17c0WzDRxTEBAiAYDmftk990GLcF
0zhV4lZvztasuWRXE+p4NJtwasLIyQIgVKzknJe8VOt5a3shCMOyysoNEg+YAt02
O98RPCU0nJg=
-----END PRIVATE KEY-----`

var (
	privateKeyBlock, _    = pem.Decode([]byte(privateKey))
	asnPrivateKeyBlock, _ = pem.Decode([]byte(asmPrivateKey))
)

// 签名
func signWithSha1(data []byte) (signature []byte, err error) {
	priv, err := x509.ParsePKCS8PrivateKey(privateKeyBlock.Bytes)
	if err != nil {
		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
}

//TODO fix
func signWithMd5(data []byte) (signature []byte, err error) {
	priv, err := x509.ParsePKCS8PrivateKey(asnPrivateKeyBlock.Bytes)
	if err != nil {
		return
	}
	h := crypto.Hash.New(crypto.MD5)
	h.Write([]byte(data))
	hashed := h.Sum(nil)

	signature, err = rsa.SignPKCS1v15(rand.Reader, priv.(*rsa.PrivateKey), crypto.MD5, hashed)
	return
}