plane/email/pkg/services/session.go

package services

import (
	"bytes"
	"errors"
	"io"
	"log"
	"plane/email/pkg/utils/parser"
	"strings"

	"github.com/emersion/go-message/mail"
	"github.com/emersion/go-smtp"
)

type Session struct {
	From string
	To   []string
}

func (s *Session) AuthPlain(username, password string) error {
	// log.Println("Authenticating user", username)
	if AuthenticateUser(username, password) {
		return nil
	}
	return errors.New("invalid username or password")
}

func (s *Session) Mail(from string, opts *smtp.MailOptions) error {
	s.From = from
	// log.Printf("Mail from: %s", from)
	return nil
}

func (s *Session) Rcpt(to string, opts *smtp.RcptOptions) error {
	// log.Printf("Rcpt to: %s", to)
	s.To = append(s.To, to)
	return nil
}

func (s *Session) Data(r io.Reader) error {
	// log.Println("Receiving message")
	if s.From == "" || len(s.To) == 0 {
		return errors.New("missing from or to address")
	}
	// Read email data
	var buf bytes.Buffer
	if _, err := io.Copy(&buf, r); err != nil {
		return err
	}
	data := buf.Bytes()

	// Basic spam check
	if parser.IsBacklistedDomain(string(s.From)) {
		log.Printf("Detected spam domain from %s", s.From)
		return errors.New("message rejected")
	}
	if parser.IsSpam(string(data)) {
		log.Printf("Detected spam from %s", s.From)
		return errors.New("message rejected")
	}

	// Parse the email
	mr, err := mail.CreateReader(bytes.NewReader(data))
	if err != nil {
		return err
	}

	header := mr.Header
	subject, _ := header.Subject()
	// log.Printf("Subject: %v", subject)

	var body string
	for {
		p, err := mr.NextPart()
		if err == io.EOF {
			break
		} else if err != nil {
			return err
		}

		switch h := p.Header.(type) {
		case *mail.InlineHeader:
			// This is the message's text (can be plain-text or HTML)
			b, _ := io.ReadAll(p.Body)
			body += string(b)
		case *mail.AttachmentHeader:
			// This is an attachment
			filename, _ := h.Filename()
			log.Printf("Got attachment: %v", filename)
		}
	}

	// Store the email
	if err := SaveEmail(s.From, strings.Join(s.To, ", "), subject, body); err != nil {
		return err
	}
	log.Printf("Email processed successfully: %s", s.From)
	return nil
}

func (s *Session) Reset() {
	s.From = ""
	s.To = nil
}

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