package parser

import (
	"bufio"
	"io"
	"net/netip"
	"strings"

	"git.maze.io/maze/styx/internal/sliceutil"
)

func init() {
	RegisterDomainsParser(hostsDomainsParser{})
	RegisterNetworksParser(hostsNetworksParser{})
}

type hostsDomainsParser struct{}

func (hostsDomainsParser) CanHandle(line string) bool {
	part := strings.Fields(line)
	return len(part) >= 2 && isIP(part[0])
}

func (hostsDomainsParser) 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 && isIP(part[0]) {
			domains = append(domains, part[1:]...)
			continue
		}

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

type hostsNetworksParser struct{}

func (hostsNetworksParser) CanHandle(line string) bool {
	part := strings.Fields(line)
	return len(part) >= 2 && isIP(part[0])
}

func (hostsNetworksParser) ParseNetworks(r io.Reader) (prefixes []netip.Prefix, 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 && isIP(part[0]) {
			if addr, err := netip.ParseAddr(part[0]); err == nil && !addr.IsUnspecified() && addr.IsValid() {
				prefixes = append(prefixes, addrToPrefix(addr))
			}
			continue
		}

		ignored++
	}
	if err = scanner.Err(); err != nil {
		return
	}
	return sliceutil.Unique(prefixes), ignored, nil
}