package utils

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

// IPVersion specifies the IP version (IPv4 or IPv6).
type IPVersion int

const (
	IPv4 IPVersion = 4
	IPv6 IPVersion = 6
)

// fetchWebpage fetches the content of a URL and returns it as a string.
// It uses the specified IP version for the HTTP request.
func fetchWebpage(url string, version IPVersion) string {
	client := &http.Client{
		Transport: &http.Transport{
			DialContext: (&net.Dialer{}).DialContext,
			Dial: func(network, addr string) (net.Conn, error) {
				if version == IPv6 {
					addr = "[" + addr + "]"
				}
				return net.Dial(network, addr)
			},
		},
	}

	resp, err := client.Get(url)
	if err != nil {
		return ""
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return ""
	}

	return string(body)
}

// extractIPAddress extracts the IP address from the given string.
func extractIPAddress(input string) string {
	re := regexp.MustCompile(`(?m)Your IP Address:</strong> ([^<]+)`)
	matches := re.FindStringSubmatch(input)
	if len(matches) < 1 {
		return ""
	}
	return matches[0]
}

// GetPublicIPAddress returns the public IP address of the machine.
func GetPublicIPAddress() (string, string) {
	ipv4 := fetchWebpage("https://real-debrid.com/vpn", IPv4)
	ipv4address := extractIPAddress(ipv4)
	ipv6 := fetchWebpage("https://real-debrid.com/vpn", IPv6)
	ipv6address := extractIPAddress(ipv6)

	return ipv4address, ipv6address
}