package acme

import (
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"io/ioutil"
	"log"

	"github.com/go-acme/lego/v4/certcrypto"
	"github.com/go-acme/lego/v4/certificate"
	"github.com/go-acme/lego/v4/challenge/http01"
	"github.com/go-acme/lego/v4/lego"
	"github.com/go-acme/lego/v4/registration"
)

// You'll need a user or account type that implements acme.User
type MyUser struct {
	Email        string
	Registration *registration.Resource
	key          crypto.PrivateKey
}

func (u *MyUser) GetEmail() string {
	return u.Email
}
func (u MyUser) GetRegistration() *registration.Resource {
	return u.Registration
}
func (u *MyUser) GetPrivateKey() crypto.PrivateKey {
	return u.key
}

type ACMEHandler struct {
	email   string
	domains []string
}

func NewACME(email string, domains []string) *ACMEHandler {

	return &ACMEHandler{
		email:   email,
		domains: domains,
	}
}

func (a *ACMEHandler) ObtainCert() {
	log.Println("Obtaining certificate...")
	// Create a user. New accounts need an email and private key to start.
	privateKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		log.Fatal(err)
	}

	adminUser := MyUser{
		Email: a.email,
		key:   privateKey,
	}

	config := lego.NewConfig(&adminUser)

	config.CADirURL = "https://acme-staging-v02.api.letsencrypt.org/directory"
	config.Certificate.KeyType = certcrypto.RSA2048

	client, err := lego.NewClient(config)
	if err != nil {
		log.Println(err)
	}

	err = client.Challenge.SetHTTP01Provider(http01.NewProviderServer("", "5002"))
	if err != nil {
		log.Println(err)
	}

	// New users will need to register
	reg, err := client.Registration.Register(registration.RegisterOptions{TermsOfServiceAgreed: true})
	if err != nil {
		log.Println(err)
	}
	adminUser.Registration = reg

	request := certificate.ObtainRequest{
		Domains: a.domains,
		Bundle:  true,
	}
	certificates, err := client.Certificate.Obtain(request)
	if err != nil {
		log.Println(err)
	}

	// Each certificate comes back with the cert bytes, the bytes of the client's
	// private key, and a certificate URL. SAVE THESE TO DISK.
	err = ioutil.WriteFile("./certs/"+certificates.Domain+".crt", certificates.Certificate, 0777)
	err = ioutil.WriteFile("./certs/"+certificates.Domain+".key", certificates.PrivateKey, 0777)

	if err != nil {
		log.Println(err)
	}

	// ... all done.
}