package jsonkit

// DecodeError wraps an underlying decode error with optional diagnostics.
type DecodeError struct {
	err         error
	diagnostics []Diagnostic
}

// Error implements error.
func (e *DecodeError) Error() string {
	if e == nil || e.err == nil {
		return ""
	}
	return e.err.Error()
}

// Unwrap returns the underlying decode error.
func (e *DecodeError) Unwrap() error {
	if e == nil {
		return nil
	}
	return e.err
}

// Diagnostics returns a copy of attached diagnostics.
func (e *DecodeError) Diagnostics() []Diagnostic {
	if e == nil {
		return nil
	}
	out := make([]Diagnostic, len(e.diagnostics))
	copy(out, e.diagnostics)
	return out
}

func wrapDecodeError(err error, res DecodeResult) error {
	if err == nil {
		return nil
	}
	diags := res.Diagnostics()
	if len(diags) == 0 {
		return err
	}
	return &DecodeError{
		err:         err,
		diagnostics: diags,
	}
}