package main

import (
	"encoding/json"
	"fmt"
	"image/png"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"strings"

	"github.com/disintegration/imaging"
	"github.com/gorilla/mux"
)

var config = readConfig("./config.json")

type Configuration struct {
	Host    string
	Port    string
	IMGPath string
}

// our main function
func main() {

	fmt.Println("Version: 0.1")
	fmt.Println("Host: " + config.Host)
	fmt.Println("Post: " + config.Port)
	fmt.Println("ImgPath: " + config.IMGPath)

	router := mux.NewRouter()
	router.HandleFunc("/folder/{foldername:.*}", getFolderContent).Methods("GET")
	router.HandleFunc("/thumb/{imgname:.*}", getThumbNail).Methods("GET")
	router.HandleFunc("/imgdl/{imgname:.*}", getImageDownload).Methods("GET")
	router.PathPrefix("/img/").Handler(http.StripPrefix("/img/", http.FileServer(http.Dir(config.IMGPath)))).Methods("GET")
	router.PathPrefix("/").Handler(http.FileServer(http.Dir("web"))).Methods("GET")
	log.Fatal(http.ListenAndServe(":"+config.Port, router))

}

func getFolderContent(w http.ResponseWriter, r *http.Request) {

	params := mux.Vars(r)
	pFolder := params["foldername"]
	fmt.Println(path.Join(config.IMGPath, pFolder))
	files, err := ioutil.ReadDir(path.Join(config.IMGPath, pFolder))
	if err != nil {
		log.Fatal(err)
	}

	var dateien []string
	for _, f := range files {
		if !strings.HasSuffix(f.Name(), ".thumb.jpg") {
			dateien = append(dateien, f.Name())
		}
	}

	json.NewEncoder(w).Encode(dateien)
}

func getThumbNail(w http.ResponseWriter, r *http.Request) {

	// Variablen auswerten
	params := mux.Vars(r)
	pIMGName := params["imgname"]

	// Das Thumbnail soll nur generiert werden wenn es noch nicht existiert
	if !fileExists(config.IMGPath + "/" + pIMGName + ".thumb.jpg") {
		//  Originaldatei öffnen, welche angefragt wird
		src, err := imaging.Open(config.IMGPath + "/" + pIMGName)
		if err != nil {
			log.Fatalf("failed to open image: %v", err)
		}

		// Thumbanil von Foto auf 200px skalieren mit 50% Qualität
		src = imaging.Resize(src, 200, 0, imaging.NearestNeighbor)
		err = imaging.Save(src, config.IMGPath+"/"+pIMGName+".thumb.jpg", imaging.JPEGQuality(50))
		if err != nil {
			log.Fatalf("failed to save image: %v", err)
		}

		// Datei ausgeben
		png.Encode(w, src)
	} else {

		src, err := imaging.Open(config.IMGPath + "/" + pIMGName + ".thumb.jpg")
		if err != nil {
			log.Fatalf("failed to open image: %v", err)
		}

		// Datei ausgeben
		png.Encode(w, src)
	}
}

func getImageDownload(w http.ResponseWriter, r *http.Request) {

	// Variablen auswerten
	params := mux.Vars(r)
	pIMGName := params["imgname"]

	//  Originaldatei öffnen, welche angefragt wird
	src, err := imaging.Open(config.IMGPath + "/" + pIMGName)
	if err != nil {
		log.Fatalf("failed to open image: %v", err)
	}

	w.Header().Set("Content-Disposition", "attachment; filename=Fotobox_"+pIMGName)

	png.Encode(w, src)

}

//--------------------------------------------------------------------------
// Hilfsfunktionen
//--------------------------------------------------------------------------

func fileExists(filename string) bool {
	info, err := os.Stat(filename)
	if os.IsNotExist(err) {
		return false
	}
	return !info.IsDir()
}

func readConfig(filename string) *Configuration {
	// initialize conf with default values.
	conf := &Configuration{Host: "http://127.0.0.1", Port: "8000", IMGPath: "./Fotos"}

	b, err := ioutil.ReadFile(filename)
	if err != nil {
		return conf
	}
	if err = json.Unmarshal(b, conf); err != nil {
		return conf
	}
	return conf
}