//go:build fetch_public_ip

package config

import (
	"encoding/json"
	"io"
	"net"
	"net/http"
	"strings"
	"time"
)

func FetchPublicIPAddress() string {
	client := &http.Client{Timeout: 5 * time.Second}
	resp, err := client.Get("https://api.ipify.org?format=json")
	if err != nil {
		return ""
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return ""
	}
	body, err := io.ReadAll(io.LimitReader(resp.Body, 256))
	if err != nil {
		return ""
	}
	var payload struct {
		IP string `json:"ip"`
	}
	if err := json.Unmarshal(body, &payload); err != nil {
		return ""
	}
	ip := strings.TrimSpace(payload.IP)
	if net.ParseIP(ip) == nil {
		return ""
	}
	return ip
}