package magna

import (
	"fmt"
)

// BufferOverflowError represents an error when there is a buffer overflow.
type BufferOverflowError struct {
	Length int
	Offset int
}

func (e *BufferOverflowError) Error() string {
	return fmt.Sprintf("buffer overflow: attempted to read past buffer length %d at offset %d", e.Length, e.Offset)
}

func (e *BufferOverflowError) Is(target error) bool {
	_, ok := target.(*BufferOverflowError)
	return ok
}

// InvalidLabelError represents an error when an invalid label length is encountered.
type InvalidLabelError struct {
	Length int
}

func (e *InvalidLabelError) Error() string {
	if e.Length > 63 {
		return fmt.Sprintf("invalid domain label: length %d exceeds maximum 63", e.Length)
	}
	if e.Length == 0 {
		return "invalid domain label: zero length label encountered"
	}

	// XXX: this should be unreachable
	return fmt.Sprintf("invalid domain label: unexpected length %d", e.Length)
}

func (e *InvalidLabelError) Is(target error) bool {
	_, ok := target.(*InvalidLabelError)
	return ok
}

// DomainCompressionError represents an error related to domain compression.
type DomainCompressionError struct{}

func (e *DomainCompressionError) Error() string {
	return "invalid domain compression: pointer loop detected"
}

func (e *DomainCompressionError) Is(target error) bool {
	_, ok := target.(*DomainCompressionError)
	return ok
}