chore: refresh gramsrv public release

internal/store/postgres/peer_username.go

@@ -0,0 +1,94 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgerrcode"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+
+	"telesrv/internal/domain"
+	"telesrv/internal/store/postgres/sqlcgen"
+)
+
+const (
+	peerUsernameTypeUser    = "user"
+	peerUsernameTypeChannel = "channel"
+)
+
+type peerUsernameOwner struct {
+	peerType string
+	peerID   int64
+}
+
+func (o peerUsernameOwner) matches(peerType string, peerID int64) bool {
+	return o.peerType == peerType && o.peerID == peerID
+}
+
+func getPeerUsernameOwner(ctx context.Context, db sqlcgen.DBTX, usernameLower string, forUpdate bool) (peerUsernameOwner, bool, error) {
+	if usernameLower == "" {
+		return peerUsernameOwner{}, false, nil
+	}
+	query := `SELECT peer_type, peer_id FROM peer_usernames WHERE username_lower = $1`
+	if forUpdate {
+		query += ` FOR UPDATE`
+	}
+	var owner peerUsernameOwner
+	err := db.QueryRow(ctx, query, usernameLower).Scan(&owner.peerType, &owner.peerID)
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return peerUsernameOwner{}, false, nil
+		}
+		return peerUsernameOwner{}, false, fmt.Errorf("get peer username owner: %w", err)
+	}
+	return owner, true, nil
+}
+
+func peerUsernameAvailable(ctx context.Context, db sqlcgen.DBTX, usernameLower, peerType string, peerID int64) (bool, error) {
+	owner, found, err := getPeerUsernameOwner(ctx, db, usernameLower, false)
+	if err != nil || !found {
+		return !found, err
+	}
+	return owner.matches(peerType, peerID), nil
+}
+
+func replacePeerUsernameTx(ctx context.Context, tx pgx.Tx, peerType string, peerID int64, usernameLower string) error {
+	if usernameLower != "" {
+		owner, found, err := getPeerUsernameOwner(ctx, tx, usernameLower, true)
+		if err != nil {
+			return err
+		}
+		if found && !owner.matches(peerType, peerID) {
+			return domain.ErrUsernameOccupied
+		}
+	}
+	if _, err := tx.Exec(ctx, `DELETE FROM peer_usernames WHERE peer_type = $1 AND peer_id = $2`, peerType, peerID); err != nil {
+		return fmt.Errorf("delete peer username: %w", err)
+	}
+	if usernameLower == "" {
+		return nil
+	}
+	if _, err := tx.Exec(ctx, `
+INSERT INTO peer_usernames (username_lower, peer_type, peer_id)
+VALUES ($1, $2, $3)`, usernameLower, peerType, peerID); err != nil {
+		if isUniqueViolation(err) {
+			return domain.ErrUsernameOccupied
+		}
+		return fmt.Errorf("insert peer username: %w", err)
+	}
+	return nil
+}
+
+func deletePeerUsernameTx(ctx context.Context, tx pgx.Tx, peerType string, peerID int64) error {
+	if _, err := tx.Exec(ctx, `DELETE FROM peer_usernames WHERE peer_type = $1 AND peer_id = $2`, peerType, peerID); err != nil {
+		return fmt.Errorf("delete peer username: %w", err)
+	}
+	return nil
+}
+
+func isUniqueConstraint(err error, constraintName string) bool {
+	var pgErr *pgconn.PgError
+	return errors.As(err, &pgErr) && pgErr.Code == pgerrcode.UniqueViolation && pgErr.ConstraintName == constraintName
+}