initialize paraclub-ai-mailer project with core components and configuration

internal/imap/imap.go

@@ -0,0 +1,187 @@
+package imap
+
+import (
+	"fmt"
+	"io"
+	"paraclub-ai-mailer/config"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/client"
+)
+
+type IMAPClient struct {
+	client    *client.Client
+	config    config.IMAPConfig
+	processed map[string]bool
+}
+
+// MessageLiteral implements imap.Literal for draft messages
+type MessageLiteral struct {
+	content []byte
+}
+
+func (m *MessageLiteral) Read(p []byte) (n int, err error) {
+	return copy(p, m.content), io.EOF
+}
+
+func (m *MessageLiteral) Len() int {
+	return len(m.content)
+}
+
+func New(cfg config.IMAPConfig) (*IMAPClient, error) {
+	addr := fmt.Sprintf("%s:%d", cfg.Server, cfg.Port)
+	var c *client.Client
+	var err error
+
+	if cfg.UseTLS {
+		c, err = client.DialTLS(addr, nil)
+	} else {
+		c, err = client.Dial(addr)
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to connect to IMAP server: %v", err)
+	}
+
+	if err := c.Login(cfg.Username, cfg.Password); err != nil {
+		return nil, fmt.Errorf("failed to login: %v", err)
+	}
+
+	return &IMAPClient{
+		client:    c,
+		config:    cfg,
+		processed: make(map[string]bool),
+	}, nil
+}
+
+type Email struct {
+	ID      string
+	Subject string
+	From    string
+	Body    string
+}
+
+func (ic *IMAPClient) FetchUnprocessedEmails() ([]Email, error) {
+	_, err := ic.client.Select(ic.config.MailboxIn, false)
+	if err != nil {
+		return nil, err
+	}
+
+	criteria := imap.NewSearchCriteria()
+	criteria.WithoutFlags = []string{"\\Seen", "Processed"}
+
+	uids, err := ic.client.Search(criteria)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(uids) == 0 {
+		return nil, nil
+	}
+
+	seqSet := new(imap.SeqSet)
+	seqSet.AddNum(uids...)
+
+	messages := make(chan *imap.Message, 10)
+	section := &imap.BodySectionName{Peek: true}
+
+	done := make(chan error, 1)
+	go func() {
+		done <- ic.client.Fetch(seqSet, []imap.FetchItem{section.FetchItem()}, messages)
+	}()
+
+	var emails []Email
+	for msg := range messages {
+		if ic.processed[msg.Envelope.MessageId] {
+			continue
+		}
+
+		r := msg.GetBody(section)
+		if r == nil {
+			continue
+		}
+
+		var bodyBuilder strings.Builder
+		_, err := io.Copy(&bodyBuilder, r)
+		if err != nil {
+			continue
+		}
+
+		emails = append(emails, Email{
+			ID:      msg.Envelope.MessageId,
+			Subject: msg.Envelope.Subject,
+			From:    msg.Envelope.From[0].Address(),
+			Body:    bodyBuilder.String(),
+		})
+
+		ic.processed[msg.Envelope.MessageId] = true
+	}
+
+	if err := <-done; err != nil {
+		return nil, err
+	}
+
+	return emails, nil
+}
+
+func (ic *IMAPClient) SaveDraft(email Email, response string) error {
+	_, err := ic.client.Select(ic.config.DraftBox, false)
+	if err != nil {
+		return err
+	}
+
+	// Format the draft message
+	draft := fmt.Sprintf("From: %s\r\n"+
+		"To: %s\r\n"+
+		"Subject: Re: %s\r\n"+
+		"Content-Type: text/plain; charset=UTF-8\r\n"+
+		"\r\n%s",
+		ic.config.Username,
+		email.From,
+		email.Subject,
+		response)
+
+	// Create literal message
+	literal := &MessageLiteral{content: []byte(draft)}
+
+	// Save the draft
+	flags := []string{"\\Draft"}
+	if err := ic.client.Append(ic.config.DraftBox, flags, time.Now(), literal); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (ic *IMAPClient) MarkAsProcessed(email Email) error {
+	_, err := ic.client.Select(ic.config.MailboxIn, false)
+	if err != nil {
+		return err
+	}
+
+	criteria := imap.NewSearchCriteria()
+	criteria.Header.Set("Message-Id", email.ID)
+
+	uids, err := ic.client.Search(criteria)
+	if err != nil {
+		return err
+	}
+
+	if len(uids) == 0 {
+		return fmt.Errorf("email not found")
+	}
+
+	seqSet := new(imap.SeqSet)
+	seqSet.AddNum(uids...)
+
+	return ic.client.Store(seqSet, imap.FormatFlagsOp(imap.AddFlags, true), []interface{}{"Processed"}, nil)
+}
+
+func (ic *IMAPClient) Close() error {
+	if ic.client != nil {
+		ic.client.Logout()
+	}
+	return nil
+}