package main

import (
	"os"
	"strconv"
	"strings"

	"github.com/go-errors/errors"
	"github.com/samber/lo"
)

type Config struct {
	AdminUIDs  map[int64]struct{}
	TGBotToken string

	WatchedInterface       string
	MonthlyTrafficLimitGiB int
}

var config *Config

func LoadCfg() error {
	cfg := Config{}

	token := os.Getenv("TG_TOKEN")
	if token == "" {
		return errors.New("TG_TOKEN env not set")
	}
	cfg.TGBotToken = token

	adminUIDsEnv := os.Getenv("TG_ADMIN_UIDS")
	adminUIDs := lo.FilterMap(strings.Split(adminUIDsEnv, ","), func(s string, _ int) (string, bool) {
		trimmed := strings.TrimSpace(s)
		return trimmed, trimmed != ""
	})
	cfg.AdminUIDs = make(map[int64]struct{}, len(adminUIDs))
	for _, uidStr := range adminUIDs {
		uid, err := strconv.ParseInt(uidStr, 10, 64)
		if err != nil {
			return errors.New("invalid admin UID: " + uidStr)
		}
		cfg.AdminUIDs[uid] = struct{}{}
	}

	cfg.WatchedInterface = "eth0"
	if iface := os.Getenv("TG_WATCHED_INTERFACE"); iface != "" {
		cfg.WatchedInterface = iface
	}

	cfg.MonthlyTrafficLimitGiB = 1000
	if trafficLimitStr := os.Getenv("TG_MONTHLY_TRAFFIC_LIMIT_GIB"); trafficLimitStr != "" {
		var err error
		if cfg.MonthlyTrafficLimitGiB, err = strconv.Atoi(trafficLimitStr); err != nil {
			return errors.New("invalid traffic limit: " + trafficLimitStr)
		}
	}

	config = &cfg
	return nil
}