package main

import (
	"context"
	"flag"
	"io/fs"
	"log"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"time"

	"golang.org/x/sync/errgroup"
)

var (
	host   string
	listen string
	path   string
	ttl    time.Duration
)

func init() {
	flag.StringVar(&host, "host", "https://nixshare.ru/", "host of nixshare")
	flag.StringVar(&listen, "listen", ":8000", "port to listen")
	flag.StringVar(&path, "path", "./storage", "storage directory")
	flag.DurationVar(&ttl, "ttl", 24*time.Hour, "time to delete uploaded file")
}

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, os.Kill)
	defer cancel()

	flag.Parse()

	r := http.NewServeMux()

	r.Handle("POST /upload", http.HandlerFunc(uploadHandler))
	r.Handle("/", http.FileServer(http.Dir(path)))

	srv := http.Server{
		Addr:    listen,
		Handler: r,
	}

	eg, egCtx := errgroup.WithContext(ctx)

	eg.Go(func() error {
		<-egCtx.Done()
		srv.Close()

		return nil
	})

	eg.Go(func() error {
		if err := srv.ListenAndServe(); err != http.ErrServerClosed {
			return err
		}

		return nil
	})

	eg.Go(func() error {
		timer := time.NewTimer(1 * time.Minute)
		defer timer.Stop()
		for {
			select {
			case <-timer.C:
				now := time.Now()
				err := filepath.Walk(path, func(p string, info fs.FileInfo, err error) error {
					if info == nil {
						return nil
					}
					if info.IsDir() {
						return nil
					}
					if now.Sub(info.ModTime()).Seconds() > ttl.Seconds() {
						log.Println("delete old file:", p)
						if err := os.Remove(p); err != nil {
							return err
						}
					}
					return nil
				})
				if err != nil {
					log.Println(err)
				}
			case <-egCtx.Done():
				return nil
			}
		}
	})

	if err := eg.Wait(); err != nil {
		log.Fatal(err)
	}
}