package ddwrt

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

	"github.com/pkg/errors"
	"gitlab.lehouerou.net/laurent/dnsupdater/internal/outboundip"
)

const (
	DefaultUrl = "http://192.168.1.1/Status_Internet.live.asp"
	WanIpRegex = "wan_ipaddr::([0-9.]*)}"
)

type IpRequester struct {
	StatusUrl string

	client   *http.Client
	login    string
	password string
}

func NewIpRequester(client *http.Client, statusUrl string, login string, password string) *IpRequester {
	return &IpRequester{client: client, StatusUrl: statusUrl, login: login, password: password}
}

func (r IpRequester) GetOutboundIp() <-chan outboundip.IpRequestResult {
	result := make(chan outboundip.IpRequestResult)
	go func() {
		defer close(result)
		url := r.StatusUrl
		if url == "" {
			url = DefaultUrl
		}
		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			result <- outboundip.IpRequestResult{
				Error: errors.Wrap(err, "creating http request"),
			}
			return
		}

		if r.login != "" && r.password != "" {
			req.SetBasicAuth(r.login, r.password)
		}

		res, err := r.client.Do(req)
		if err != nil {
			result <- outboundip.IpRequestResult{
				Error: errors.Wrap(err, "executing http request"),
			}
			return
		}
		defer res.Body.Close()

		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			result <- outboundip.IpRequestResult{
				Error: errors.Wrap(err, "reading response body"),
			}
			return
		}

		matches := regexp.MustCompile(WanIpRegex).FindStringSubmatch(string(body))
		if len(matches) < 2 {
			result <- outboundip.IpRequestResult{
				Error: errors.Errorf("unable to find WAN IP with regex %s in %s", WanIpRegex, string(body)),
			}
			return
		}
		result <- outboundip.IpRequestResult{Ip: matches[1]}
	}()
	return result
}