package main

import (
	"fmt"
	"math"
	"strings"
	"time"

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

	b.Handle("/me", handleUserInfoCmd)
	b.Handle("/chat", handleChatInfoCmd)

	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)),
		)
		bar := fmt.Sprintf("\n```\n%s\n```", drawBarForTrafficRecord(row))
		responseParts = append(responseParts, bar)
	}

	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 {
	effective := lo.Max([]uint64{r.Rx, r.Tx})
	return fmt.Sprintf("%.2f GiB", float64(effective)/1024/1024/1024)
}

func handleUserInfoCmd(c tele.Context) error {
	u := c.Sender()
	if u == nil {
		return c.Reply("Unknown.")
	}

	replyText := []string{
		`*User Info*`,
		"```",
		fmt.Sprintf(`ID:           %d`, u.ID),
		fmt.Sprintf(`Username:     %s`, u.Username),
		fmt.Sprintf(`FirstName:    %s`, u.FirstName),
		fmt.Sprintf(`LastName:     %s`, u.LastName),
		fmt.Sprintf(`LanguageCode: %s`, u.LanguageCode),
		fmt.Sprintf(`IsBot:        %t`, u.IsBot),
		fmt.Sprintf(`IsPremium:    %t`, u.IsPremium),
		"```",
	}
	return c.Reply(strings.Join(replyText, "\n"), &tele.SendOptions{ParseMode: tele.ModeMarkdown})
}

func handleChatInfoCmd(c tele.Context) error {
	chat := c.Chat()
	if chat == nil {
		return c.Reply("Unknown.")
	}
	loc := ""
	if chat.ChatLocation != nil {
		loc = chat.ChatLocation.Address
	}

	replyText := []string{
		`*Chat Info*`,
		"```",
		fmt.Sprintf(`ID:               %d`, chat.ID),
		fmt.Sprintf(`Type:             %s`, chat.Type),
		fmt.Sprintf(`Title:            %s`, chat.Title),
		fmt.Sprintf(`FirstName:        %s`, chat.FirstName),
		fmt.Sprintf(`LastName:         %s`, chat.LastName),
		fmt.Sprintf(`Username:         %s`, chat.Username),
		fmt.Sprintf(`SlowMode:         %d`, chat.SlowMode),
		fmt.Sprintf(`StickerSet:       %s`, chat.StickerSet),
		fmt.Sprintf(`CanSetStickerSet: %t`, chat.CanSetStickerSet),
		fmt.Sprintf(`LinkedChatID:     %d`, chat.LinkedChatID),
		fmt.Sprintf(`ChatLocation:     %s`, loc),
		fmt.Sprintf(`Private:          %t`, chat.Private),
		fmt.Sprintf(`Protected:        %t`, chat.Protected),
		fmt.Sprintf(`NoVoiceAndVideo:  %t`, chat.NoVoiceAndVideo),
		"```",
	}
	return c.Reply(strings.Join(replyText, "\n"), &tele.SendOptions{ParseMode: tele.ModeMarkdown})
}

func drawBar(progress float64, length int) string {
	barChars := []rune("░▒▓█")

	if length <= 0 {
		return ""
	}
	step := 1 / float64(length)
	buf := make([]rune, length)
	for i := 0; i < length; i++ {
		fill := (progress - float64(i)*step) / step
		fill = math.Min(math.Max(fill, 0), 1)
		idx := int(math.Round(fill * float64(len(barChars)-1)))
		buf[i] = barChars[idx]
	}
	return string(buf)
}

func drawBarForTrafficRecord(r stats.VnstatTrafficRecord) string {
	effective := lo.Max([]uint64{r.Rx, r.Tx})
	max := config.MonthlyTrafficLimitGiB
	ratio := float64(effective) / 1024 / 1024 / 1024 / float64(max)
	return fmt.Sprintf("%s %2.0f%%", drawBar(ratio, 16), ratio*100)
}