package main

import (
	"fmt"
	"io/fs"
	"net"
	"path/filepath"
	"strings"

	"gopkg.in/ini.v1"
)

func parseUsedIPsFromConfigs(dir string) ([]net.IP, error) {
	var usedIPs []net.IP

	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
		if err != nil || d.IsDir() || !strings.HasSuffix(d.Name(), ".conf") {
			return nil
		}

		cfg, err := ini.Load(path)
		if err != nil {
			return fmt.Errorf("failed to parse config %s: %w", path, err)
		}

		// Check [Interface] section
		if iface := cfg.Section("Interface"); iface != nil {
			if addr := iface.Key("Address").String(); addr != "" {
				ip := strings.Split(addr, "/")[0]
				usedIPs = append(usedIPs, net.ParseIP(ip))
			}
		}

		return nil
	})

	if err != nil {
		return nil, err
	}

	return usedIPs, nil
}