package mysql

import (
	"database/sql"
	"errors"

	mysqldrv "github.com/go-sql-driver/mysql"

	"code.nochebuena.dev/einherjar/core/xerrors"
)

// HandleError maps MySQL driver and database/sql errors to typed [xerrors] values.
// Returns nil when err is nil. Also available as [Provider.HandleError].
//
// Mapped codes:
//   - 1062 (ER_DUP_ENTRY)                → ErrAlreadyExists
//   - 1216, 1217, 1451, 1452 (FK errors) → ErrInvalidInput
//   - sql.ErrNoRows                       → ErrNotFound
//   - all others                          → ErrInternal
func HandleError(err error) error {
	if err == nil {
		return nil
	}
	var mysqlErr *mysqldrv.MySQLError
	if errors.As(err, &mysqlErr) {
		switch mysqlErr.Number {
		case 1062:
			return xerrors.New(xerrors.ErrAlreadyExists, "record already exists").WithError(err)
		case 1216, 1217, 1451, 1452:
			return xerrors.New(xerrors.ErrInvalidInput, "data integrity violation").WithError(err)
		}
	}
	if errors.Is(err, sql.ErrNoRows) {
		return xerrors.New(xerrors.ErrNotFound, "record not found").WithError(err)
	}
	return xerrors.New(xerrors.ErrInternal, "unexpected database error").WithError(err)
}