package main

import (
	"io/ioutil"
	"log"
	"net/http"
	"regexp"

	"github.com/miekg/dns"
)

func loadBlacklist(config []configBlacklist) map[string]bool {
	list := make([]string, 0)
	for _, element := range config {
		raw, err := requestBacklist(element)

		if err != nil {
			log.Printf("Failed to load blacklist %s reason: %s", element.URL, err.Error())
			continue
		}

		domains := parseRawBlacklist(element, *raw)
		list = append(list, domains...)
	}

	// list = removeDuplicates(list)
	// sort.Strings(list)

	domainMap := make(map[string]bool)
	for _, e := range list {
		domainMap[e] = true
	}

	return domainMap
}

func removeDuplicates(elements []string) []string {
	encountered := map[string]bool{}
	result := []string{}

	for v := range elements {
		if !encountered[elements[v]] {
			encountered[elements[v]] = true

			result = append(result, elements[v])
		}
	}

	return result
}

func requestBacklist(blacklist configBlacklist) (*string, error) {
	// Request list
	resp, err := http.Get(blacklist.URL)
	if err != nil {
		return nil, err
	}

	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	bodyString := string(body)

	log.Printf("Downloaded blacklist %s", blacklist.URL)

	return &bodyString, err
}

func parseRawBlacklist(blacklist configBlacklist, raw string) []string {
	finalList := make([]string, 0)
	reg := regexp.MustCompile(`(?mi)^\s*(#*)\s*(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+([a-zA-Z0-9\.\- ]+)$`)
	matches := reg.FindAllStringSubmatch(raw, -1)
	for _, match := range matches {
		if match[1] != "#" {
			finalList = append(finalList, dns.Fqdn(match[3]))
		}
	}

	return finalList
}