package main

import (
	"fmt"
	"strconv"
	"strings"
	"html/template"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"log"
	"runtime"
	"sync"
)

type Image struct {
	Name string
	Filename string
	Liked bool
}

var images []Image
var currIndex int = 0
var imagesPerPage int = 4

func openbrowser(url string) {
	var err error

	switch runtime.GOOS {
	case "linux":
		err = exec.Command("xdg-open", url).Start()
	case "windows":
		err = exec.Command("rundll32", "url.dll,FileProtocolHandler", url).Start()
	case "darwin":
		err = exec.Command("open", url).Start()
	default:
		err = fmt.Errorf("unsupported platform")
	}
	if err != nil {
		log.Fatal(err)
	}
}


var funcMap = template.FuncMap{
    "minus": minus,
}

func minus(a, b int) string {
    return strconv.FormatInt(int64(a-b), 10)
}

func main() {
	jpgs_path := "jpgs"

	http.HandleFunc("/", indexHandler)
	http.HandleFunc("/select", likeHandler)
	http.HandleFunc("/remove", removeHandler)
	http.HandleFunc("/removefav", removeFavsHandler)
	http.HandleFunc("/next", nextHandler)
	http.HandleFunc("/prev", prevHandler)
	http.HandleFunc("/favs", favsHandler)
	http.HandleFunc("/jpgs/", serveImage)
	http.Handle("/static/", http.FileServer(http.Dir(".")))


	filepath.Walk(jpgs_path, func(path string, info os.FileInfo, err error) error {
		if filepath.Ext(path) == ".jpg" || filepath.Ext(path) == ".JPG" {
			base := filepath.Base(path)
			name := base[:len(base)-len(filepath.Ext(base))]
			images = append(images, Image{name, filepath.ToSlash(path), false})
		}
		return nil
	})

	var wg sync.WaitGroup
	port := "42069"
	fmt.Println("Serving on http://localhost:" + port)
	wg.Add(1)
	go http.ListenAndServe(":" + port, nil)
	openbrowser("http://localhost:" + port)
	wg.Wait()
}

func serveImage(w http.ResponseWriter, r *http.Request) {
	filename := r.URL.Path[1:]
	http.ServeFile(w, r, filename)
}

func indexHandler(w http.ResponseWriter, r *http.Request) {
	tmpl, _ := template.ParseFiles("grid.html")
	idx := r.URL.Query().Get("idx")
	if len(idx) != 0 {
		tmp, _ := strconv.Atoi(idx)
		if tmp - 1 > len(images) {
			currIndex = len(images) - 1
		} else if tmp >= 1 {
			currIndex = tmp - 1
		} else {
			currIndex = 0
		}
	}
	name := r.URL.Query().Get("name")
	if len(name) != 0 {
		for idx, i := range images {
			if (strings.Contains(i.Name, name)) {
				currIndex = idx;
				reload(w, r)
				return
			}
		}
	}
	imagesToShow := images[currIndex:min(currIndex+imagesPerPage, len(images))]
	err := tmpl.Execute(w, imagesToShow)
	if err != nil { log.Fatal(err) }
}

func reload(w http.ResponseWriter, r *http.Request) {
	http.Redirect(w, r, "/?idx="+strconv.Itoa(currIndex + 1), http.StatusFound)
}
 
func likeHandler(w http.ResponseWriter, r *http.Request) {
	visibleImages := images[currIndex:min(currIndex+imagesPerPage, len(images))]
	index := r.URL.Query().Get("img_index")
	i, _ := strconv.Atoi(index)
	visibleImages[i].Liked = true
	reload(w, r)
}

func removeHandler(w http.ResponseWriter, r *http.Request) {
	visibleImages := images[currIndex:min(currIndex+imagesPerPage, len(images))]
	index := r.URL.Query().Get("img_index")
	i, _ := strconv.Atoi(index)
	visibleImages[i].Liked = false
	reload(w, r)
}

func nextHandler(w http.ResponseWriter, r *http.Request) {
	currIndex += imagesPerPage
	if currIndex >= len(images) {
		currIndex = len(images) - imagesPerPage
	}
	reload(w, r)
}

func prevHandler(w http.ResponseWriter, r *http.Request) {
	currIndex -= imagesPerPage
	if currIndex < 0 {
		currIndex = 0
	}
	reload(w, r)
}

func removeFavsHandler(w http.ResponseWriter, r *http.Request) {
	filename := r.URL.Query().Get("filename")
	for i := range images {
		if images[i].Filename == filename {
			images[i].Liked = false
		}
	}
	http.Redirect(w, r, "/favs", http.StatusFound)
}

func favsHandler(w http.ResponseWriter, r *http.Request) {
	tmpl, _ := template.New("favs.html").Funcs(funcMap).ParseFiles("favs.html")

	var liked []Image

	for _, i := range images {
		if i.Liked {
			liked = append(liked, i)
		}
	}
	
	err := 	tmpl.Execute(w, liked)
	if err != nil { log.Fatal(err) }
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}