package parser

import (
	"bufio"
	"io"
	"net"
	"strings"
)

func init() {
	RegisterDomainsParser(hostsParser{})
}

type hostsParser struct{}

func (hostsParser) CanHandle(line string) bool {
	part := strings.Fields(line)
	return len(part) >= 2 && net.ParseIP(part[0]) != nil
}

func (hostsParser) ParseDomains(r io.Reader) (domains []string, ignored int, err error) {
	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if isComment(line) {
			continue
		}

		part := strings.Fields(line)
		if len(part) >= 2 && net.ParseIP(part[0]) != nil {
			domains = append(domains, part[1:]...)
			continue
		}

		ignored++
	}
	if err = scanner.Err(); err != nil {
		return
	}
	return unique(domains), ignored, nil
}