package main

import (
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"fmt"
	"log"
	"net/url"
	"os"
	"time"

	"github.com/go-acme/lego/v4/certcrypto"
	"github.com/go-acme/lego/v4/certificate"
	"github.com/go-acme/lego/v4/lego"
	"github.com/go-acme/lego/v4/providers/dns/pdns"
	"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
}

func GenCerts() {
	testMode := false
	testModeStr, exists := os.LookupEnv("TEST_MODE")
	if !exists {
		if testModeStr == "true" {
			testMode = true
		}
	}
	rootDomain, exists := os.LookupEnv("ROOT_DOMAIN")
	if !exists {
		rootDomain = "localhost"
	}
	pdnsKey, has := os.LookupEnv("PDNS_KEY")
	if !has {
		fmt.Println("must have PDNS_KEY")
		os.Exit(1)
	}
	pdnsHost, has := os.LookupEnv("PDNS_HOST")
	if !has {
		fmt.Println("must have PDNS_HOST ENV")
		os.Exit(1)
	}
	acmeEmail, has := os.LookupEnv("ACME_EMAIL")
	if !has {
		fmt.Println("must have ACME_EMAIL ENV")
		os.Exit(1)
	}
	fmt.Println("root domain is", rootDomain)
	// 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)
	}
	myUser := MyUser{
		Email: acmeEmail,
		key:   privateKey,
	}
	pdnsUrl, _ := url.Parse(pdnsHost)
	provider, err := pdns.NewDNSProviderConfig(&pdns.Config{
		Host:               pdnsUrl,
		APIKey:             pdnsKey,
		ServerName:         "localhost",
		TTL:                5,
		PropagationTimeout: time.Duration(time.Second * 30),
		PollingInterval:    time.Duration(time.Millisecond * 500),
	})
	if err != nil {
		log.Fatal(err)
	}

	config := lego.NewConfig(&myUser)
	// uncoment for tesing ->>
	if testMode {
		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)
	}
	client.Challenge.SetDNS01Provider(provider)

	// 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{rootDomain, "*." + rootDomain},
		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("./certs", 0777)
	os.WriteFile("./certs/cert.crt", certificates.Certificate, 0777)
	os.WriteFile("./certs/priv.key", certificates.PrivateKey, 0777)

	// ... all done.
}