package main

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"io"
	"log"
	"os"

	"github.com/emersion/go-smtp"
	"github.com/rabbitmq/amqp091-go"
)

type Mail struct {
	From    *string `json:"from"`
	To      *string `json:"to"`
	Body    *string `json:"body"`
	UTF8 *bool `json:"UTF8"`
}

type backend struct{
	Queue *amqp091.Queue
	Channel *amqp091.Channel
}

func (bkd *backend) NewSession(c *smtp.Conn) (smtp.Session, error) {
	return &session{
		Queue: bkd.Queue,
		Channel: bkd.Channel,
		MailBuilder: Mail{},
	}, nil
}

type session struct{
	Queue *amqp091.Queue
	MailBuilder Mail
	Channel *amqp091.Channel
}

func (s *session) AuthPlain(username, password string) error {
	return nil
}

func (s *session) Mail(from string, opts *smtp.MailOptions) error {
	s.MailBuilder.From = &from
	s.MailBuilder.UTF8 = &opts.UTF8
	return nil
}

func (s *session) Rcpt(to string, opts *smtp.RcptOptions) error {
	s.MailBuilder.To = &to
	return nil
}

func (s *session) Data(r io.Reader) error {
	buf := new(bytes.Buffer)
	if _, err := buf.ReadFrom(r); err != nil {
		log.Fatal(err)
	}
	body := base64.StdEncoding.EncodeToString(buf.Bytes())
	s.MailBuilder.Body = &body
	return nil
}

func (s *session) Reset() {
	submitMail(s.MailBuilder, s.Channel, s.Queue)
}

func (s *session) Logout() error {
	return nil
}

func submitMail(mail Mail, ch *amqp091.Channel, q *amqp091.Queue) {
	mb, err := json.Marshal(mail)
	if err != nil {
		log.Fatal(err)
	}
	err = ch.Publish(
		"",
		q.Name,
		false,
		false,
		amqp091.Publishing{
			ContentType: "application/octet-stream",
			Body: []byte(base64.StdEncoding.EncodeToString(mb)),
		},
	)
	if err != nil {
		log.Println("oh uh")
		log.Fatal(err)
	}
	log.Println("Submited mail to rabbitmq")
}


func main() {
	conn, err := amqp091.Dial("amqp://d:8o9HGX!CFx!2sg!@dUqN@localhost:5672/")
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	ch, err := conn.Channel()
	if err != nil {
		log.Fatal(err)
	}
	defer ch.Close()

	q, err := ch.QueueDeclare("mail", true, false, false, false, nil)
	if err != nil {
		log.Fatal(err)
	}

	s := smtp.NewServer(&backend{
		Queue: &q,
		Channel: ch,
	})

	s.Addr = "0.0.0.0:8700"
	s.AllowInsecureAuth = true
	s.Debug = os.Stderr

	log.Println("Starting smtp server")
	log.Fatal(s.ListenAndServe())

}