package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"os"
	"strconv"
	"strings"
	"sync"
	"time"

	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
	"github.com/probakowski/go-satel"
)

const (
	MessageNotMoreOftenThanSeconds = 15
)

type TgSender struct {
	bot *tgbotapi.BotAPI
}

func (self TgSender) Send(msg GenericMessage) error {
	toSend := tgbotapi.NewMessage(msg.chatId, msg.msg)
	_, err := self.bot.Send(toSend)
	return err
}

func sendTgMessage(tgEvents chan GenericMessage, msg string, chatIds []int64) {
	for _, chatId := range chatIds {
		tgEvents <- GenericMessage{chatId, msg}
	}
}

type RealSleeper struct {
	duration time.Duration
}

func (self RealSleeper) Sleep(ch chan<- interface{}) {
	go func() {
		time.Sleep(self.duration)
		ch <- nil
	}()
}

func getCmdLineParams(logger *log.Logger) (string, []int64) {
	satelApiAddr := flag.String("satel-addr", "", "Address that should be used to connect to the SATEL device")
	satelApiPort := flag.String("satel-port", "7094", "Port that should be used to connect to the SATEL device")
	chatIdRaw := flag.String("tg-chat-id", "", "Telegram Chat ID where to send updates. Use \",\" to specify multiple IDs.")
	flag.Parse()

	if len(*satelApiAddr) == 0 || len(*satelApiPort) == 0 || len(*chatIdRaw) == 0 {
		logger.Fatal("Use --satel-addr=ADDR, --satel-port=PORT and --tg-chat-id=CHAT_ID command line flags to continue.")
	}
	chatIdsStrings := strings.Split(*chatIdRaw, ",")
	var chatIds []int64
	for _, chatIdStr := range chatIdsStrings {
		chatId, err := strconv.ParseInt(chatIdStr, 10, 64)
		if err != nil {
			logger.Fatalf("Tried to use a non-int value for one of tg_chatIds: %s. That's bad.", chatIdStr)
		}
		chatIds = append(chatIds, chatId)
	}

	satelAddr := fmt.Sprintf("%s:%s", *satelApiAddr, *satelApiPort)
	return satelAddr, chatIds
}

func makeSatel(satelAddr string) *satel.Satel {
	satelConn, err := net.Dial("tcp", satelAddr)
	if err != nil {
		panic(err)
	}
	return satel.NewConfig(satelConn, satel.Config{EventsQueueSize: 10})
}

func main() {
	var (
		wg       sync.WaitGroup
		tgEvents = make(chan GenericMessage, 100)
		sleeper  = RealSleeper{time.Second * MessageNotMoreOftenThanSeconds}
		logger   = log.New(os.Stderr, "Main", log.Lmicroseconds)
	)

	satelAddr, chatIds := getCmdLineParams(logger)

	s := makeSatel(satelAddr)
	logger.Printf("Connected to Satel: %s", satelAddr)

	bot, err := tgbotapi.NewBotAPI(os.Getenv("TELEGRAM_APITOKEN"))
	if err != nil {
		panic(err)
	}
	logger.Print("Created Telegram Bot API client")

	tgSender := TgSender{bot}
	go tgSenderWorker(tgEvents, tgSender, &wg, sleeper, log.New(os.Stderr, "TgSender", log.Lmicroseconds))
	for e := range s.Events {
		logger.Println("Received change from SATEL: ", e)
		sendTgMessage(tgEvents, fmt.Sprintln("Change from SATEL: ", "type", e.Type, "index", e.Index, "value", e.Value), chatIds)
	}

	close(tgEvents)
	wg.Wait()
}