package main

import (
	"context"
	"os"
	"os/exec"
	"os/signal"
	"sync"
	"syscall"

	"git.milar.in/milarin/channel"
	"git.milar.in/nyaanime/logic"
	"github.com/fsnotify/fsnotify"
)

var (
	// AppCtx notifies all threads to finish their work and shutdown
	AppCtx, cancelAppCtx = context.WithCancel(context.Background())
	// AppExitWg is waiting for all threads until they are done
	AppExitWg = &sync.WaitGroup{}

	Runner = InitializeRunner()
)

func main() {
	signalChan := make(chan os.Signal, 1)
	signal.Notify(signalChan, syscall.SIGTERM, syscall.SIGINT)
	go func() {
		<-signalChan
		exit()
	}()

	// check for ffprobe in PATH
	if _, err := exec.LookPath("ffprobe"); err != nil {
		panic(err) // TODO error handling
	}

	// get access token once at startup to be sure that an access token is obtainable at all
	if _, err := logic.GetAnilistAccessToken(); err != nil {
		panic(err) // TODO error handling
	}

	if err := InitTelegramBot(); err != nil {
		panic(err) // TODO error handling
	}

	logic.PrintPriorityTables()

	fileChan, err := WatchDirectory(fsnotify.Create, DownloadPath)
	if err != nil {
		panic(err) // TODO error handling
	}

	fileHandleChan := channel.Map(fileChan, NewFileHandle)
	workChan, logChan := channel.Tee(fileHandleChan)

	AppExitWg.Add(1)
	go func() {
		defer AppExitWg.Done()
		channel.Each(workChan, HandleFileInRunner)
	}()

	channel.Each(logChan, PrintFileHandle)
}

func HandleFileInRunner(fh *FileHandle) {
	Runner.Run(func() { HandleFile(fh) })
}

func exit() {
	cancelAppCtx()   // notify all threads to shutdown
	AppExitWg.Wait() // wait for threads until shutdown
}