package main

import (
	"log"
	"net/http"
	"os"

	"golang.org/x/net/webdav"
)

const (
	envPrefix = "WEBDAV_PREFIX"
	pathRoot  = "/webdav/root"
	pathLog   = "/dev/stdout"
)

func logger() func(*http.Request, error) {
	return func(r *http.Request, err error) {
		if err != nil {
			log.Printf("ERROR %v\n", err)
		}
	}
}

func filesystem() webdav.FileSystem {
	if err := os.Mkdir(pathRoot, os.ModePerm); !os.IsExist(err) {
		log.Fatalf("FATAL %v", err)
	}
	log.Printf("INFO using local filesystem at %s", pathRoot)
	return webdav.Dir(pathRoot)
}

func main() {
	logFile, err := os.OpenFile(pathLog, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
	if err != nil {
		log.Fatalf("FATAL %v", err)
	}
	defer logFile.Close()
	log.SetOutput(logFile)

	h := &webdav.Handler{
		Prefix:     os.Getenv(envPrefix),
		FileSystem: filesystem(),
		LockSystem: webdav.NewMemLS(),
		Logger:     logger(),
	}

	http.HandleFunc("/", h.ServeHTTP)
	http.ListenAndServe(":8080", h)
}