package errors

import "fmt"

type withCode struct {
	err   error
	code  int
	cause error
	*stack
}

func WithCode(code int, format string, args ...interface{}) error {
	return &withCode{
		err:   fmt.Errorf(format, args...),
		code:  code,
		stack: callers(),
	}
}

func Wrap(err error, message string) error {
	if err == nil {
		return nil
	}
	if e, ok := err.(*withCode); ok {
		return &withCode{
			err:   fmt.Errorf(message),
			code:  e.code,
			cause: err,
			stack: callers(),
		}
	}

	return &withCode{
		err:   fmt.Errorf(message),
		code:  unknownCoder.Code(),
		cause: err,
		stack: callers(),
	}
}

func WrapC(err error, code int, format string, args ...interface{}) error {
	if err == nil {
		return nil
	}

	return &withCode{
		err:   fmt.Errorf(format, args...),
		code:  code,
		cause: err,
		stack: callers(),
	}
}

func (w *withCode) Error() string { return fmt.Sprintf("%v", w) }

// Cause 返回根因
func (w *withCode) Cause() error { return w.cause }

// Unwrap 返回根因
func (w *withCode) Unwrap() error { return w.cause }

func Cause(err error) error {
	type causer interface {
		Cause() error
	}

	for err != nil {
		cause, ok := err.(causer)
		if !ok {
			break
		}

		if cause.Cause() == nil {
			break
		}

		err = cause.Cause()
	}
	return err
}