package dhcpv4

// This module defines the OptDomainSearch structure.
// https://tools.ietf.org/html/rfc3397

import (
	"fmt"

	"github.com/insomniacslk/dhcp/rfc1035label"
)

// OptDomainSearch represents an option encapsulating a domain search list.
type OptDomainSearch struct {
	DomainSearch *rfc1035label.Labels
}

// Code returns the option code.
func (op *OptDomainSearch) Code() OptionCode {
	return OptionDNSDomainSearchList
}

// ToBytes returns a serialized stream of bytes for this option.
func (op *OptDomainSearch) ToBytes() []byte {
	buf := []byte{byte(op.Code()), byte(op.Length())}
	buf = append(buf, op.DomainSearch.ToBytes()...)
	return buf
}

// Length returns the length of the data portion (excluding option code an byte
// length).
func (op *OptDomainSearch) Length() int {
	return op.DomainSearch.Length()
}

// String returns a human-readable string.
func (op *OptDomainSearch) String() string {
	return fmt.Sprintf("DNS Domain Search List -> %v", op.DomainSearch.Labels)
}

// ParseOptDomainSearch returns a new OptDomainSearch from a byte stream, or
// error if any.
func ParseOptDomainSearch(data []byte) (*OptDomainSearch, error) {
	if len(data) < 2 {
		return nil, ErrShortByteStream
	}
	code := OptionCode(data[0])
	if code != OptionDNSDomainSearchList {
		return nil, fmt.Errorf("expected code %v, got %v", OptionDNSDomainSearchList, code)
	}
	length := int(data[1])
	if len(data) < 2+length {
		return nil, ErrShortByteStream
	}
	labels, err := rfc1035label.FromBytes(data[2 : length+2])
	if err != nil {
		return nil, err
	}
	return &OptDomainSearch{DomainSearch: labels}, nil
}