implemented access token refreshing - untested

internal/domains/authentication/store.go

@@ -113,3 +113,39 @@ func (a *Authenticator) GetAccessTokenClaimsAndExpiration(ctx context.Context, a
 
 	return claims, r.Expiry, nil
 }
+
+func (a *Authenticator) getRefreshTokenForAccessToken(ctx context.Context, accessToken string) (refreshToken, tokenType string, err error) {
+	rows, err := a.db.Query(
+		ctx,
+		`
+			SELECT
+				refresh_token,
+				token_type
+			FROM
+				oauth_tokens
+			WHERE
+				access_token = @access_token
+		`,
+		pgx.NamedArgs{
+			"access_token": accessToken,
+		},
+	)
+	if err != nil {
+		return "", "", fmt.Errorf("failed to perform query: %w", err)
+	}
+
+	type Row struct {
+		Refresh_token string
+		Token_type    string
+	}
+
+	r, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByNameLax[Row])
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return "", "", consts.ErrNotFound
+		}
+		return "", "", fmt.Errorf("failed to scan row: %w", err)
+	}
+
+	return r.Refresh_token, r.Token_type, nil
+}