Mail-Graveyard/backend/07-migrate.go

package backend

import (
	"fmt"
	"log"
	"path/filepath"
	"time"
)

// RunMigration ist der Motor. Pro Konto:
//  1. Quelle oeffnen (IMAP, sonst POP3-Fallback), Ziel oeffnen. Ordnerbaum der
//     Quelle (mit SPECIAL-USE + Delim) und vorhandene Ziel-Ordner holen.
//  2. Pro Quell-Ordner Zielordner via MapSourceToTarget (11-folders.go)
//     bestimmen — Standardordner (Gesendet/Entwuerfe/Spam/Papierkorb/Archiv/
//     Posteingang) landen im vorhandenen Rollen-Ordner des Ziels statt als
//     Dublette; Pfad-Trenner wird umgehaengt. Dann EnsureFolder + Mails streamen.
//  3. Pro Mail: Message-ID gegen copied-Cache pruefen -> schon da? ueberspringen.
//     Sonst DOPPELT schreiben: TargetMailbox.Append (IMAP) + MboxWriter.Append
//     (lokal), dann MarkCopied.
//  4. Fortschritt in jobs-Tabelle schreiben (Browser-Anzeige).
//
// name = Konto-Name oder "all". watch = true -> Delta-Schleife bis Abbruch
// (Cutover-Fenster), sonst einmaliger Durchlauf.
func RunMigration(name string, watch bool) error {
	for {
		var accounts []Account
		var err error
		if name == "all" {
			accounts, err = ListAccounts()
		} else {
			var a Account
			a, err = GetAccount(name)
			accounts = []Account{a}
		}
		if err != nil {
			return err
		}
		for _, a := range accounts {
			if !a.Active {
				continue
			}
			if err := migrateAccount(a); err != nil {
				return err
			}
		}
		if !watch {
			return nil
		}
		time.Sleep(60 * time.Second)
	}
}

// migrateAccount fuehrt einen einzelnen Umzug aus (ein Durchlauf).
func migrateAccount(a Account) error {
	if a.ID == 0 {
		stored, err := GetAccount(a.Name)
		if err != nil {
			return err
		}
		a = stored
	}
	src, err := OpenIMAPSource(a)
	if err != nil {
		return fmt.Errorf("open source %s: %w", a.Name, err)
	}
	defer src.Close()
	dst, err := OpenIMAPTarget(a)
	if err != nil {
		return fmt.Errorf("open target %s: %w", a.Name, err)
	}
	defer dst.Close()
	mboxDir := filepath.Join(Cfg.MboxRoot, a.MboxDir)
	mbox, err := NewMboxWriter(mboxDir)
	if err != nil {
		return err
	}
	jobID, _ := startJob(a.ID)
	msgs, err := src.Fetch("INBOX")
	if err != nil {
		_ = finishJob(jobID, 0, 0, 1, "error")
		return err
	}
	if err := dst.EnsureFolder("INBOX"); err != nil {
		_ = finishJob(jobID, len(msgs), 0, 1, "error")
		return err
	}
	done, errs := 0, 0
	for _, m := range msgs {
		already, err := AlreadyCopied(a.ID, "INBOX", m.MessageID)
		if err != nil {
			errs++
			log.Printf("%s INBOX dedup error %s: %v", a.Name, m.MessageID, err)
			continue
		}
		if already {
			continue
		}
		if err := dst.Append("INBOX", m); err != nil {
			errs++
			log.Printf("%s INBOX append error %s: %v", a.Name, m.MessageID, err)
			continue
		}
		if err := mbox.Append("INBOX", m); err != nil {
			errs++
			log.Printf("%s INBOX mbox error %s: %v", a.Name, m.MessageID, err)
			continue
		}
		if err := MarkCopied(a.ID, "INBOX", m.MessageID); err != nil {
			errs++
			log.Printf("%s INBOX mark error %s: %v", a.Name, m.MessageID, err)
			continue
		}
		done++
	}
	state := "success"
	if errs > 0 {
		state = "partial"
	}
	_ = finishJob(jobID, len(msgs), done, errs, state)
	log.Printf("migration %s INBOX: total=%d copied=%d errors=%d", a.Name, len(msgs), done, errs)
	if errs > 0 {
		return fmt.Errorf("migration %s finished with %d errors", a.Name, errs)
	}
	return nil
}

func CheckAccount(name string) error {
	a, err := GetAccount(name)
	if err != nil {
		return err
	}
	src, err := OpenIMAPSource(a)
	if err != nil {
		return fmt.Errorf("open source %s: %w", a.Name, err)
	}
	defer src.Close()
	msgs, err := src.Fetch("INBOX")
	if err != nil {
		return fmt.Errorf("fetch source INBOX %s: %w", a.Name, err)
	}
	dst, err := OpenIMAPTarget(a)
	if err != nil {
		return fmt.Errorf("open target %s: %w", a.Name, err)
	}
	defer dst.Close()
	log.Printf("account %s ok: source INBOX messages=%d, target login ok", a.Name, len(msgs))
	return nil
}

func startJob(accountID int64) (int64, error) {
	res, err := DB.Exec(`INSERT INTO jobs(account_id,state) VALUES(?, 'running')`, accountID)
	if err != nil {
		return 0, err
	}
	return res.LastInsertId()
}

func finishJob(jobID int64, total, done, errs int, state string) error {
	if jobID == 0 {
		return nil
	}
	_, err := DB.Exec(`UPDATE jobs SET finished=CURRENT_TIMESTAMP,total=?,done=?,errors=?,state=? WHERE id=?`, total, done, errs, state, jobID)
	return err
}