package http

import (
	"fmt"
	"html/template"
	"io/ioutil"
	"net/http"
	"strings"

	"git.darknebu.la/emile/faila/src/structs"
	"github.com/gorilla/mux"
	"github.com/sirupsen/logrus"
	"github.com/spf13/viper"
)

// Server defines and runs an HTTP server
func Server() {
	r := mux.NewRouter()

	// static js / css hosting
	assets := r.PathPrefix("/assets/").Subrouter()
	fs := http.FileServer(http.Dir("./hosted/assets"))
	assets.PathPrefix("/").Handler(http.StripPrefix("/assets/", fs))

	r.HandleFunc("/download", downloadHandler).Methods("GET")

	t := r.PathPrefix("/").Subrouter()
	t.PathPrefix("/").HandlerFunc(pathHandler)

	// get the ip and port from the config
	bindIP := viper.GetString("server.bindip")
	listenPort := viper.GetString("server.listenport")

	// define the http server
	httpServer := http.Server{
		Addr:    fmt.Sprintf("%s:%s", bindIP, listenPort),
		Handler: r,
	}

	logrus.Warnf("HTTP server defined listening on %s:%s", bindIP, listenPort)
	logrus.Fatal(httpServer.ListenAndServe())
}

func downloadHandler(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query()

	file := query["file"][0]

	root := viper.GetString("server.root")
	logrus.Info(root)
	strippedFile := strings.Replace(file, root, "", -1)
	strippedFile = strings.Replace(strippedFile, "..", "", -1)

	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", strippedFile))
	w.Header().Set("Content-Type", r.Header.Get("Content-Type"))

	actualFile := fmt.Sprintf("%s%s", root, strippedFile)
	logrus.Infof("serving: %s", actualFile)
	http.ServeFile(w, r, actualFile)
}

func pathHandler(w http.ResponseWriter, r *http.Request) {
	var content map[string]interface{}
	content = make(map[string]interface{})

	root := viper.GetString("server.root")
	requestURI := fmt.Sprintf("%s%s", root, r.RequestURI)
	logrus.Tracef("root: %s", root)
	logrus.Tracef("requestURI: %s", root)

	query := r.URL.Query()

	if query["download"] != nil {

		// strip the file before and after the request
		strippedFile := strings.Replace(requestURI, root, "", -1)
		strippedFile = strings.Replace(strippedFile, "?download", "", -1)
		path := fmt.Sprintf("/download?file=%s", strippedFile)
		http.Redirect(w, r, path, http.StatusSeeOther)
		return
	}

	breadcrumbsList := breadcrumbs(r)
	content["Breadcrumbs"] = breadcrumbsList

	// get all files in the request dir
	files, err := ioutil.ReadDir(requestURI)
	if err != nil {
		logrus.Warn(err)
		return
	}

	// define the items (files and dirs)
	var items structs.Items
	var dirCount int = 0
	var fileCount int = 0
	for _, f := range files {
		if filterIsValid(f.Name()) == false {
			continue
		}

		// get the file or dirs modtime and format it in a readable way as
		// described in the config
		modTime := f.ModTime()
		if viper.GetString("time.format") == "" {
			logrus.Fatalf("Please insert a format for the time in the config (time.format), see the README for more information.")
		}
		humanModTime := modTime.Format(viper.GetString("time.format"))

		// define the file or dir's url
		var url string
		if r.RequestURI != "/" {
			url = fmt.Sprintf("%s/%s", r.RequestURI, f.Name())
		} else {
			url = fmt.Sprintf("/%s", f.Name())
		}

		// define the file or dir
		item := structs.Item{
			Name:         f.Name(),
			HumanSize:    f.Size(),
			URL:          url,
			HumanModTime: humanModTime,
			IsSymlink:    false,
			Size:         "0",
		}

		// if it is a dir, say so
		if f.IsDir() == true {
			item.IsDir = true
			dirCount++
		} else {
			item.Download = true
		}

		items = append(items, item)
	}

	// add the items to the content map
	content["Items"] = items

	// ad the file and dir count to the contents map
	content["NumDirs"] = dirCount
	content["NumFiles"] = fileCount
	logrus.Tracef("")
	logrus.Tracef("numDirs: %d", dirCount)
	logrus.Tracef("numFiles: %d", fileCount)

	// if there are more than one breadcrumb, define the uppath as the second
	// last breadcrumb
	// I did this, because somehow things broke when simply using ".." in
	// combination with hidden folders
	if len(breadcrumbsList) > 1 {
		content["UpPath"] = breadcrumbsList[len(breadcrumbsList)-2].Link
	} else {
		content["UpPath"] = ".."
	}

	// In the caddy
	content["ItemsLimitedTo"] = 100000000000

	// define the sort order manually
	// TODO: handle this correctly
	content["Sort"] = "namedirfirst"
	content["Order"] = "desc"

	// if we're not at the root, we can still go futher down!
	if r.RequestURI != "/" {
		content["CanGoUp"] = "true"
		logrus.Tracef("can go up")
	}

	// define a new template to render the challenges in
	t := template.New("")
	t, err = t.ParseGlob("./hosted/tmpl/*.html")
	if err != nil {
		logrus.Warn(err)
		return
	}

	err = t.ExecuteTemplate(w, "index", content)
	logrus.Warn(err)
	return
}

// breadcrumbs get's the breadcrumbs from the request
func breadcrumbs(r *http.Request) structs.Breadcrumbs {

	request := r.RequestURI

	// mitigate path traversals
	strippedRequest := strings.Replace(request, "..", "", -1)

	if request != "/" {
		strippedRequest = strings.TrimRight(strippedRequest, "/")
	}

	// continue without the first slash, as it produces an unused field that has
	// no use
	crumbs := strings.Split(strippedRequest[1:], "/")

	// build the breadcrumbs from the split RequestURI
	var breadcrumbs structs.Breadcrumbs
	for i, crumb := range crumbs {

		text := crumb

		// the link is defined as the text until the given crumb
		link := strings.Join(crumbs[:i+1], "/")

		resultCrumb := structs.Crumb{
			Text: text,
			Link: fmt.Sprintf("/%s", link),
		}
		breadcrumbs = append(breadcrumbs, resultCrumb)
	}

	return breadcrumbs
}

// filter filters files returning true if they should be displayed and false if
// not. The descision is made using the hide config from the config file
func filterIsValid(name string) bool {

	// hide files starting with a dot if the "hide.file" directive is set
	if viper.GetBool("hide.files") == true {
		if name[0] == '.' {
			return false
		}
	}

	extensions := viper.GetStringSlice("hide.extensions")
	for _, extension := range extensions {
		if strings.HasSuffix(name, extension) {
			return false
		}
	}

	return true
}