/*
The MIT License (MIT)

Copyright (c) 2014 DutchCoders [https://github.com/dutchcoders/]

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

package main

import (
	"flag"
	"fmt"
	"log"
	"math/rand"
	"mime"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"runtime"
	"syscall"
	"time"

	"github.com/PuerkitoBio/ghost/handlers"
	"github.com/gorilla/mux"

	_ "net/http/pprof"

	web "github.com/dutchcoders/transfer.sh-web"
	assetfs "github.com/elazarl/go-bindata-assetfs"
)

const SERVER_INFO = "transfer.sh"

// parse request with maximum memory of _24Kilobits
const _24K = (1 << 20) * 24

var storage Storage

type Server struct {
	AWS_ACCESS_KEY     string
	AWS_SECRET_KEY     string
	BUCKET             string
	VIRUSTOTAL_KEY     string
	CLAMAV_DAEMON_HOST string "/tmp/clamd.socket"
	Temp               string
	Path               string
}

func New() *Server {
	s := &Server{}
	s.AWS_ACCESS_KEY = os.Getenv("AWS_ACCESS_KEY_ID")
	s.AWS_SECRET_KEY = os.Getenv("AWS_SECRET_KEY")
	s.BUCKET = os.Getenv("BUCKET")

	s.VIRUSTOTAL_KEY = os.Getenv("VIRUSTOTAL_KEY")

	if os.Getenv("CLAMAV_DAEMON_HOST") != "" {
		s.CLAMAV_DAEMON_HOST = os.Getenv("CLAMAV_DAEMON_HOST")
	}

	s.Temp = os.TempDir()

	s.Path = "" // "../transfer.sh-web/dist/"

	return s
}

func (s *Server) Run() {
	rand.Seed(time.Now().UTC().UnixNano())

	nCPU := runtime.NumCPU()
	runtime.GOMAXPROCS(nCPU)
	fmt.Println("Number of CPUs: ", nCPU)

	go func() {
		fmt.Println("Profiled listening at: :6060")
		http.ListenAndServe(":6060", nil)
	}()

	r := mux.NewRouter()

	var fs http.FileSystem

	if config.Path != "" {
		log.Println("Using static file path: ", config.Path)

		fs = http.Dir(config.Path)
		html_templates, _ = html_templates.ParseGlob(config.Path + "*.html")
		text_templates, _ = text_templates.ParseGlob(config.Path + "*.txt")
	} else {
		fs = &assetfs.AssetFS{
			Asset:    web.Asset,
			AssetDir: web.AssetDir,
			AssetInfo: func(path string) (os.FileInfo, error) {
				return os.Stat(path)
			},
			Prefix: web.Prefix,
		}

		for _, path := range web.AssetNames() {
			bytes, err := web.Asset(path)
			if err != nil {
				log.Panicf("Unable to parse: path=%s, err=%s", path, err)
			}

			html_templates.New(stripPrefix(path)).Parse(string(bytes))
			text_templates.New(stripPrefix(path)).Parse(string(bytes))
		}
	}

	staticHandler := http.FileServer(fs)

	r.PathPrefix("/images/").Handler(staticHandler)
	r.PathPrefix("/styles/").Handler(staticHandler)
	r.PathPrefix("/scripts/").Handler(staticHandler)
	r.PathPrefix("/fonts/").Handler(staticHandler)
	r.PathPrefix("/ico/").Handler(staticHandler)
	r.PathPrefix("/favicon.ico").Handler(staticHandler)
	r.PathPrefix("/robots.txt").Handler(staticHandler)

	r.HandleFunc("/({files:.*}).zip", zipHandler).Methods("GET")
	r.HandleFunc("/({files:.*}).tar", tarHandler).Methods("GET")
	r.HandleFunc("/({files:.*}).tar.gz", tarGzHandler).Methods("GET")
	r.HandleFunc("/download/{token}/{filename}", getHandler).Methods("GET")

	r.HandleFunc("/{token}/{filename}", previewHandler).MatcherFunc(func(r *http.Request, rm *mux.RouteMatch) (match bool) {
		match = false

		// The file will show a preview page when opening the link in browser directly or
		// from external link. If the referer url path and current path are the same it will be
		// downloaded.
		if !acceptsHtml(r.Header) {
			return false
		}

		match = (r.Referer() == "")

		u, err := url.Parse(r.Referer())
		if err != nil {
			log.Fatal(err)
			return
		}

		match = match || (u.Path != r.URL.Path)
		return
	}).Methods("GET")

	r.HandleFunc("/{token}/{filename}", getHandler).Methods("GET")
	r.HandleFunc("/get/{token}/{filename}", getHandler).Methods("GET")
	r.HandleFunc("/{filename}/virustotal", virusTotalHandler).Methods("PUT")
	r.HandleFunc("/{filename}/scan", scanHandler).Methods("PUT")
	r.HandleFunc("/put/{filename}", putHandler).Methods("PUT")
	r.HandleFunc("/upload/{filename}", putHandler).Methods("PUT")
	r.HandleFunc("/{filename}", putHandler).Methods("PUT")
	r.HandleFunc("/health.html", healthHandler).Methods("GET")
	r.HandleFunc("/", postHandler).Methods("POST")
	// r.HandleFunc("/{page}", viewHandler).Methods("GET")
	r.HandleFunc("/", viewHandler).Methods("GET")

	r.NotFoundHandler = http.HandlerFunc(notFoundHandler)

	port := flag.String("port", "8080", "port number, default: 8080")
	temp := flag.String("temp", config.Temp, "")
	basedir := flag.String("basedir", "", "")
	logpath := flag.String("log", "", "")
	provider := flag.String("provider", "s3", "")

	flag.Parse()

	if *logpath != "" {
		f, err := os.OpenFile(*logpath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
		if err != nil {
			log.Fatalf("error opening file: %v", err)
		}

		defer f.Close()

		log.SetOutput(f)
	}

	config.Temp = *temp

	var err error

	switch *provider {
	case "s3":
		storage, err = NewS3Storage()
	case "local":
		if *basedir == "" {
			log.Panic("basedir not set")
		}

		storage, err = NewLocalStorage(*basedir)
	}

	if err != nil {
		log.Panic("Error while creating storage.", err)
	}

	mime.AddExtensionType(".md", "text/x-markdown")

	log.Printf("Transfer.sh server started. :\nlistening on port: %v\nusing temp folder: %s\nusing storage provider: %s", *port, config.Temp, *provider)
	log.Printf("---------------------------")

	s := &http.Server{
		Addr:    fmt.Sprintf(":%s", *port),
		Handler: handlers.PanicHandler(LoveHandler(RedirectHandler(handlers.LogHandler(r, handlers.NewLogOptions(log.Printf, "_default_")))), nil),
	}

	go func() {
		s.ListenAndServe()
	}()

	term := make(chan os.Signal, 1)
	signal.Notify(term, os.Interrupt)
	signal.Notify(term, syscall.SIGTERM)

	<-term

	log.Printf("Server stopped.")
}