package main

import (
	"fmt"
	"strings"
	"time"

	"github.com/go-errors/errors"
	tele "gopkg.in/telebot.v3"

	"git.gensokyo.cafe/kkyy/tgbot_misaka_5882f7/stats"
)

func isFromAdmin(sender *tele.User) bool {
	if sender == nil {
		return false
	}

	_, ok := config.AdminUIDs[sender.ID]
	return ok
}

func initBot() (*tele.Bot, error) {
	pref := tele.Settings{
		Token:  config.TGBotToken,
		Poller: &tele.LongPoller{Timeout: 15 * time.Second},
	}

	b, err := tele.NewBot(pref)
	if err != nil {
		return nil, errors.Wrap(err, 0)
	}

	// command routing
	b.Handle("/start", handleStartCmd)
	b.Handle("/traffic", handleTrafficCmd)

	return b, nil
}

func handleStartCmd(c tele.Context) error {
	if !isFromAdmin(c.Sender()) {
		return c.Send("Hello, stranger :)")
	}

	return c.Send("Hi :)")
}

func handleTrafficCmd(c tele.Context) error {
	if !isFromAdmin(c.Sender()) {
		return nil
	}

	dailyTraffic, err := stats.VnstatDailyTraffic(config.WatchedInterface)
	if err != nil {
		_ = c.Reply("im die, thank you forever")
		return err
	}
	monthlyTraffic, err := stats.VnstatMonthlyTraffic(config.WatchedInterface)
	if err != nil {
		_ = c.Reply("im die, thank you forever")
		return err
	}

	var responseParts = []string{"*Traffic Usage Summaries*\n"}
	// Yesterday's traffic if present
	if len(dailyTraffic) > 1 {
		row := dailyTraffic[len(dailyTraffic)-2]
		day := fmt.Sprintf("%d-%02d-%02d", row.Date.Year, row.Date.Month, row.Date.Day)
		responseParts = append(
			responseParts,
			fmt.Sprintf("Yesterday (%s):` %s`", day, fmtTraffic(row)),
		)
	}
	// Today's traffic if present
	if len(dailyTraffic) > 0 {
		row := dailyTraffic[len(dailyTraffic)-1]
		responseParts = append(
			responseParts,
			fmt.Sprintf("Today so far:` %s`\n", fmtTraffic(row)),
		)
	}

	// Last month's traffic, if present
	if len(monthlyTraffic) > 1 {
		row := monthlyTraffic[len(monthlyTraffic)-2]
		month := fmt.Sprintf("%d-%02d", row.Date.Year, row.Date.Month)
		responseParts = append(
			responseParts,
			fmt.Sprintf("Last month (%s):` %s`", month, fmtTraffic(row)),
		)
	}
	// This month's traffic, if present
	if len(monthlyTraffic) > 0 {
		row := monthlyTraffic[len(monthlyTraffic)-1]

		responseParts = append(
			responseParts,
			fmt.Sprintf("This month so far:` %s`", fmtTraffic(row)),
		)
	}

	var respText string
	if len(responseParts) == 1 {
		respText = "No traffic data available."
	} else {
		respText = strings.Join(responseParts, "\n")
	}

	return c.Reply(respText, &tele.SendOptions{ParseMode: tele.ModeMarkdown})
}

func fmtTraffic(r stats.VnstatTrafficRecord) string {
	biggest := r.Rx
	if r.Tx > biggest {
		biggest = r.Tx
	}

	return fmt.Sprintf("%.2f GiB", float64(biggest)/1024/1024/1024)
}