package sources

import "errors"

type streamRetryableError struct {
	err error
}

func (e *streamRetryableError) Error() string {
	if e.err == nil {
		return "retryable stream error"
	}
	return e.err.Error()
}

func (e *streamRetryableError) Unwrap() error { return e.err }

type streamFatalError struct {
	err error
}

func (e *streamFatalError) Error() string {
	if e.err == nil {
		return "fatal stream error"
	}
	return e.err.Error()
}

func (e *streamFatalError) Unwrap() error { return e.err }

// StreamRetryable marks a stream-source exit as retryable.
func StreamRetryable(err error) error {
	if err == nil {
		return nil
	}
	return &streamRetryableError{err: err}
}

// StreamFatal marks a stream-source exit as fatal.
func StreamFatal(err error) error {
	if err == nil {
		return nil
	}
	return &streamFatalError{err: err}
}

// IsStreamRetryable reports whether err contains a retryable stream marker.
func IsStreamRetryable(err error) bool {
	if err == nil {
		return false
	}
	var target *streamRetryableError
	return errors.As(err, &target)
}

// IsStreamFatal reports whether err contains a fatal stream marker.
func IsStreamFatal(err error) bool {
	if err == nil {
		return false
	}
	var target *streamFatalError
	return errors.As(err, &target)
}