package history

import (
	"context"
	"database/sql"
	"fmt"

	"reanimator/internal/idgen"
)

func (s *Service) generateID(ctx context.Context, tx *sql.Tx, entityType idgen.EntityType) (string, error) {
	if tx == nil {
		return s.idgen.Generate(ctx, entityType)
	}
	var nextValue int64
	if err := tx.QueryRowContext(ctx, `SELECT next_value FROM id_sequences WHERE entity_type = ? FOR UPDATE`, string(entityType)).Scan(&nextValue); err != nil {
		if err == sql.ErrNoRows {
			return "", fmt.Errorf("sequence not found for entity type: %s", entityType)
		}
		return "", err
	}
	if _, err := tx.ExecContext(ctx, `UPDATE id_sequences SET next_value = next_value + 1 WHERE entity_type = ?`, string(entityType)); err != nil {
		return "", err
	}
	prefix, err := idgen.GetPrefix(entityType)
	if err != nil {
		return "", err
	}
	return idgen.FormatID(prefix, nextValue), nil
}