write code frame

imap.go

@@ -0,0 +1,220 @@
+package main
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/client"
+	"github.com/sirupsen/logrus"
+	bolt "go.etcd.io/bbolt"
+)
+
+// IMAPConfig holds connection details
+type IMAPConfig struct {
+	Host     string
+	Port     int
+	Username string
+	Password string
+	UseTLS   bool
+}
+
+// parseIMAPURL parses "user:pass@host:port" format
+func parseIMAPURL(rawURL string) (*IMAPConfig, error) {
+	if !strings.Contains(rawURL, "://") {
+		rawURL = "imap://" + rawURL
+	}
+
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return nil, err
+	}
+
+	port := 993 // default IMAPS
+	if u.Port() != "" {
+		port, err = strconv.Atoi(u.Port())
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	password, _ := u.User.Password()
+
+	return &IMAPConfig{
+		Host:     u.Hostname(),
+		Port:     port,
+		Username: u.User.Username(),
+		Password: password,
+		UseTLS:   port == 993 || u.Scheme == "imaps",
+	}, nil
+}
+
+// connectIMAP creates IMAP client connection
+func connectIMAP(cfg *IMAPConfig, insecure bool) (*client.Client, error) {
+	addr := fmt.Sprintf("%s:%d", cfg.Host, cfg.Port)
+
+	var c *client.Client
+	var err error
+
+	if cfg.UseTLS {
+		tlsConfig := &tls.Config{
+			ServerName:         cfg.Host,
+			InsecureSkipVerify: insecure,
+		}
+		c, err = client.DialTLS(addr, tlsConfig)
+	} else {
+		c, err = client.Dial(addr)
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("dial failed: %w", err)
+	}
+
+	if err := c.Login(cfg.Username, cfg.Password); err != nil {
+		c.Close()
+		return nil, fmt.Errorf("login failed: %w", err)
+	}
+
+	logrus.Infof("Connected to %s as %s", addr, cfg.Username)
+	return c, nil
+}
+
+// listMailboxes returns all mailboxes
+func listMailboxes(c *client.Client) ([]*imap.MailboxInfo, error) {
+	mailboxes := make(chan *imap.MailboxInfo, 10)
+	done := make(chan error, 1)
+
+	go func() {
+		done <- c.List("", "*", mailboxes)
+	}()
+
+	var result []*imap.MailboxInfo
+	for m := range mailboxes {
+		result = append(result, m)
+	}
+
+	if err := <-done; err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}
+
+func copyMessages(srcClient, dstClient *client.Client, srcMbox, dstMbox string, stateKey string, db *bolt.DB) error {
+	// Select source mailbox
+	srcStatus, err := srcClient.Select(srcMbox, true) // read-only
+	if err != nil {
+		return fmt.Errorf("select source %s: %w", srcMbox, err)
+	}
+
+	// Select destination mailbox
+	_, err = dstClient.Select(dstMbox, false)
+	if err != nil {
+		// Try to create mailbox if it doesn't exist
+		if err := dstClient.Create(dstMbox); err != nil {
+			return fmt.Errorf("create dest %s: %w", dstMbox, err)
+		}
+		if _, err := dstClient.Select(dstMbox, false); err != nil {
+			return fmt.Errorf("select dest %s: %w", dstMbox, err)
+		}
+	}
+
+	// Get last migrated UID for resume
+	var lastUID uint32 = 0
+	if db != nil {
+		lastUID, _ = getLastUID(db, stateKey)
+	}
+
+	logrus.Infof("Migrating %s: %d messages (resume from UID %d)", srcMbox, srcStatus.Messages, lastUID)
+
+	// Search for messages to copy
+	criteria := &imap.SearchCriteria{}
+	if lastUID > 0 {
+		criteria.Uid = &imap.SeqSet{}
+		criteria.Uid.AddRange(lastUID+1, 0) // from lastUID+1 to end
+	} else {
+		criteria.Uid = &imap.SeqSet{}
+		criteria.Uid.AddRange(1, 0) // all messages
+	}
+
+	uids, err := srcClient.UidSearch(criteria)
+	if err != nil {
+		return fmt.Errorf("search failed: %w", err)
+	}
+
+	if len(uids) == 0 {
+		logrus.Infof("No new messages to migrate in %s", srcMbox)
+		return nil
+	}
+
+	logrus.Infof("Found %d messages to migrate", len(uids))
+
+	// Copy messages in batches
+	batchSize := 50
+	for i := 0; i < len(uids); i += batchSize {
+		end := i + batchSize
+		if end > len(uids) {
+			end = len(uids)
+		}
+
+		batch := uids[i:end]
+		seqSet := &imap.SeqSet{}
+		for _, uid := range batch {
+			seqSet.AddNum(uid)
+		}
+
+		// Fetch messages
+		messages := make(chan *imap.Message, batchSize)
+		done := make(chan error, 1)
+
+		go func() {
+			done <- srcClient.UidFetch(seqSet, []imap.FetchItem{imap.FetchRFC822}, messages)
+		}()
+
+		// Process each message
+		for msg := range messages {
+			if len(msg.Body) == 0 {
+				logrus.Warnf("Empty message body for UID %d", msg.Uid)
+				continue
+			}
+
+			// Get message content
+			var msgContent []byte
+			for _, body := range msg.Body {
+				buf := make([]byte, 1024*1024) // 1MB buffer
+				n, err := body.Read(buf)
+				if err != nil && err.Error() != "EOF" {
+					logrus.Errorf("Read message UID %d: %v", msg.Uid, err)
+					continue
+				}
+				msgContent = append(msgContent, buf[:n]...)
+			}
+
+			// Append to destination
+			if err := dstClient.Append(dstMbox, nil, time.Time{}, strings.NewReader(string(msgContent))); err != nil {
+				logrus.Errorf("Append message UID %d: %v", msg.Uid, err)
+				continue
+			}
+
+			// Update state
+			if db != nil {
+				// TODO: implement setLastUID from state.go
+				// setLastUID(db.(*bolt.DB), stateKey, msg.Uid)
+			}
+
+			logrus.Debugf("Copied message UID %d", msg.Uid)
+		}
+
+		if err := <-done; err != nil {
+			return fmt.Errorf("fetch batch failed: %w", err)
+		}
+
+		logrus.Infof("Migrated batch %d-%d/%d", i+1, end, len(uids))
+	}
+
+	return nil
+}