package main

import (
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"fmt"
	"log"
	"os"

	"github.com/go-acme/lego/v4/certcrypto"
	"github.com/go-acme/lego/v4/certificate"
	"github.com/go-acme/lego/v4/challenge/dns01"
	"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 DNSProviderBestDNS struct {
	apiAuthToken string
}

func NewDNSProviderBestDNS(apiAuthToken string) (*DNSProviderBestDNS, error) {
	return &DNSProviderBestDNS{apiAuthToken: apiAuthToken}, nil
}
func (d *DNSProviderBestDNS) Present(domain, token, keyAuth string) error {
	info := dns01.GetChallengeInfo(domain, keyAuth)
	fmt.Println()
	fmt.Println("------")
	fmt.Println()
	fmt.Println("Please create DNS TXT record, for domain", info.FQDN, "with these content:")
	fmt.Println()
	fmt.Println(info.Value)
	fmt.Println()
	fmt.Println("------")
	fmt.Scanln()
	// make API request to set a TXT record on fqdn with value and TTL
	return nil
}
func (d *DNSProviderBestDNS) CleanUp(domain, token, keyAuth string) error {
	// clean up any state you created in Present, like removing the TXT record
	fmt.Println("------")
	fmt.Println()
	fmt.Println("you can delete the TXT record, and press enter to continue")
	fmt.Println()
	fmt.Println("------")
	fmt.Scanln()
	return nil
}

func main() {
	if len(os.Args) != 2 {
		fmt.Println("usage: ./cert root.domain")
		os.Exit(1)
	}
	fmt.Println("root domain is", os.Args[1])
	// 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)
	}
	var email string
	fmt.Print("enter you email > ")
	fmt.Scanln(&email)
	myUser := MyUser{
		Email: email,
		key:   privateKey,
	}

	config := lego.NewConfig(&myUser)

	//config.CADirURL = lego.LEDirectoryStaging
	config.Certificate.KeyType = certcrypto.RSA2048

	// A client facilitates communication with the CA server.
	client, err := lego.NewClient(config)
	if err != nil {
		log.Fatal(err)
	}

	bestDNS, err := NewDNSProviderBestDNS("my-auth-token")
	if err != nil {
		log.Fatal(err)
	}
	err = client.Challenge.SetDNS01Provider(bestDNS)
	if err != nil {
		log.Fatal(err)
	}

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

	request := certificate.ObtainRequest{
		Domains: []string{os.Args[1], "*." + os.Args[1]},
		Bundle:  true,
	}
	certificates, err := client.Certificate.Obtain(request)
	if err != nil {
		log.Fatal(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.
	os.Mkdir("/etc/ssl", 0777)
	os.WriteFile("/etc/ssl/cert.crt", certificates.Certificate, 0777)
	os.WriteFile("/etc/ssl/priv.key", certificates.PrivateKey, 0777)

	// ... all done.
}