#5: F2 sub-project 2 - IMAP SEARCH, EXPUNGE, COPY, MOVE

Adds the second F2 sub-project on top of the merged IMAP core: full
SEARCH criteria matching (flags, dates, size, headers, body/text,
NOT/OR), EXPUNGE (soft-delete via expunged_at), COPY, and MOVE (RFC
6851, advertised via CapMove/CapUIDPlus). Verified end-to-end with a
real go-imap/v2 client against embedded Postgres.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

services/protocols/internal/infrastructure/postgres/copy_repository.go

@@ -0,0 +1,133 @@
+package postgres
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"lambdamail/protocols/internal/application/port"
+)
+
+// CopyRepository implements port.CopyRepository against Postgres. One
+// transaction per copied message, mirroring InboundMessageRepository's
+// established per-message transactional pattern (PLAN.md section 6.1).
+type CopyRepository struct {
+	pool *pgxpool.Pool
+}
+
+func NewCopyRepository(pool *pgxpool.Pool) *CopyRepository {
+	return &CopyRepository{pool: pool}
+}
+
+func (r *CopyRepository) CopyMessages(ctx context.Context, sourceFolderID string, uids []uint32, destFolderID string) ([]port.CopiedMessage, error) {
+	results := make([]port.CopiedMessage, 0, len(uids))
+	for _, uid := range uids {
+		destUID, err := r.copyOne(ctx, sourceFolderID, uid, destFolderID)
+		if err != nil {
+			return nil, fmt.Errorf("copy uid %d: %w", uid, err)
+		}
+		results = append(results, port.CopiedMessage{SourceUID: uid, DestUID: destUID})
+	}
+	return results, nil
+}
+
+func (r *CopyRepository) copyOne(ctx context.Context, sourceFolderID string, sourceUID uint32, destFolderID string) (uint32, error) {
+	tx, err := r.pool.Begin(ctx)
+	if err != nil {
+		return 0, fmt.Errorf("begin transaction: %w", err)
+	}
+	defer tx.Rollback(ctx)
+
+	var sourceMessageID string
+	var blobID, senderAddress string
+	var recipientAddresses []string
+	var sizeBytes int64
+	var spfResult, dkimResult, dmarcResult *string
+	var fromDisplayName, subject, snippet, messageIDHeader, inReplyTo *string
+	var threadID *uuid.UUID
+	var hasAttachments bool
+	var arcResult, daneStatus, tlsVersion, spamVerdict, virusName *string
+	var spamScore float64
+	err = tx.QueryRow(ctx, `
+		SELECT id, blob_id, sender_address, recipient_addresses, size_bytes, spf_result, dkim_result, dmarc_result,
+			from_display_name, subject, snippet, message_id_header, in_reply_to, thread_id, has_attachments,
+			arc_result, dane_status, tls_version, spam_score, spam_verdict, virus_name
+		FROM email_messages WHERE folder_id = $1 AND uid = $2 AND expunged_at IS NULL
+	`, sourceFolderID, sourceUID).Scan(&sourceMessageID, &blobID, &senderAddress, &recipientAddresses, &sizeBytes, &spfResult, &dkimResult, &dmarcResult,
+		&fromDisplayName, &subject, &snippet, &messageIDHeader, &inReplyTo, &threadID, &hasAttachments,
+		&arcResult, &daneStatus, &tlsVersion, &spamScore, &spamVerdict, &virusName)
+	if err != nil {
+		return 0, fmt.Errorf("find source message: %w", err)
+	}
+
+	// uid_next is BIGINT; the destination UID we allocate for this message
+	// is the folder's current uid_next value before advancing it.
+	var destUIDNext int64
+	if err := tx.QueryRow(ctx, `
+		SELECT uid_next FROM folders WHERE id = $1 FOR UPDATE
+	`, destFolderID).Scan(&destUIDNext); err != nil {
+		return 0, fmt.Errorf("lock destination folder: %w", err)
+	}
+	destUID := uint32(destUIDNext)
+
+	if _, err := tx.Exec(ctx, `UPDATE folders SET uid_next = uid_next + 1, total_count = total_count + 1 WHERE id = $1`, destFolderID); err != nil {
+		return 0, fmt.Errorf("advance destination uid_next: %w", err)
+	}
+
+	var wasSeen bool
+	if err := tx.QueryRow(ctx, `
+		SELECT EXISTS (SELECT 1 FROM message_flags WHERE message_id = $1 AND flag = '\Seen')
+	`, sourceMessageID).Scan(&wasSeen); err != nil {
+		return 0, fmt.Errorf("check source seen flag: %w", err)
+	}
+	if !wasSeen {
+		if _, err := tx.Exec(ctx, `UPDATE folders SET unread_count = unread_count + 1 WHERE id = $1`, destFolderID); err != nil {
+			return 0, fmt.Errorf("increment destination unread_count: %w", err)
+		}
+	}
+
+	var destMailboxID string
+	if err := tx.QueryRow(ctx, `SELECT mailbox_id FROM folders WHERE id = $1`, destFolderID).Scan(&destMailboxID); err != nil {
+		return 0, fmt.Errorf("find destination mailbox: %w", err)
+	}
+
+	var destMessageID string
+	var destReceivedAt any
+	err = tx.QueryRow(ctx, `
+		INSERT INTO email_messages (
+			mailbox_id, folder_id, uid, blob_id,
+			sender_address, recipient_addresses, size_bytes,
+			spf_result, dkim_result, dmarc_result,
+			from_display_name, subject, snippet, message_id_header, in_reply_to, thread_id, has_attachments,
+			arc_result, dane_status, tls_version, spam_score, spam_verdict, virus_name
+		) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16, $17, $18, $19, $20, $21, $22, $23)
+		RETURNING id, received_at
+	`, destMailboxID, destFolderID, destUID, blobID, senderAddress, recipientAddresses, sizeBytes, spfResult, dkimResult, dmarcResult,
+		fromDisplayName, subject, snippet, messageIDHeader, inReplyTo, threadID, hasAttachments,
+		arcResult, daneStatus, tlsVersion, spamScore, spamVerdict, virusName).Scan(&destMessageID, &destReceivedAt)
+	if err != nil {
+		return 0, fmt.Errorf("insert copied message: %w", err)
+	}
+
+	if _, err := tx.Exec(ctx, `UPDATE message_blobs SET ref_count = ref_count + 1 WHERE id = $1`, blobID); err != nil {
+		return 0, fmt.Errorf("increment blob ref_count: %w", err)
+	}
+
+	if _, err := tx.Exec(ctx, `UPDATE mailboxes SET used_bytes = used_bytes + $1 WHERE id = $2`, sizeBytes, destMailboxID); err != nil {
+		return 0, fmt.Errorf("increment destination mailbox used_bytes: %w", err)
+	}
+
+	if _, err := tx.Exec(ctx, `
+		INSERT INTO message_flags (message_id, received_at, flag)
+		SELECT $1, $2, flag FROM message_flags WHERE message_id = $3
+	`, destMessageID, destReceivedAt, sourceMessageID); err != nil {
+		return 0, fmt.Errorf("copy flags: %w", err)
+	}
+
+	if err := tx.Commit(ctx); err != nil {
+		return 0, fmt.Errorf("commit: %w", err)
+	}
+	return destUID, nil
+}