package main

import (
	"html/template"
	"net/http"
	"strconv"
)

var (
	cachedTemplates = template.Must(template.ParseFiles("web/index.html"))
	songsChan       chan *SongEntry
)

func indexHandler(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.Error(w, "Not Found", http.StatusNotFound)
		return
	}

	alsoEmptySongs := SongsFile{
		Songs: make([]*SongEntry, 52),
	}
	for week := 1; week <= 52; week++ {
		alsoEmptySongs.Songs[week-1] = &SongEntry{Week: week}
	}
	username := ""
	session, err := getSession(r)
	if session != nil {
		songs, err := loadDb()
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		for _, song := range songs.Songs {
			alsoEmptySongs.Songs[song.Week-1] = song
		}
		username = session.username
	}

	var templates = cachedTemplates
	if true {
		templates = template.Must(template.ParseFiles("web/index.html"))
	}

	data := struct {
		Username string
		Songs    []*SongEntry
	}{
		username,
		alsoEmptySongs.Songs,
	}
	err = templates.ExecuteTemplate(w, "index.html", data)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

func updateHandler(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/update" {
		http.Error(w, "Forbidden", http.StatusForbidden)
		return
	}

	err := r.ParseForm()
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	week, err := strconv.Atoi(r.Form.Get("week"))
	if err != nil {
		http.Error(w, "week parameter not provided", http.StatusBadRequest)
		return
	}
	artist := r.Form.Get("artist")
	title := r.Form.Get("title")
	url := r.Form.Get("url")
	sync := r.Form.Get("sync")

	songs, err := loadDb()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	matched := false
	for _, song := range songs.Songs {
		if song.Week == week {
			song.Artist = artist
			song.Title = title
			song.URL = url
			if song.Sync && sync != "on" {
				song.Sync = false
			}
			songsChan <- song
			matched = true
		}
	}
	if !matched {
		song := &SongEntry{
			Artist: artist,
			Title:  title,
			URL:    url,
			Week:   week,
		}
		songs.Songs = append(songs.Songs, song)
		songsChan <- song
	}

	err = saveDb(songs)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
}

func loginHandler(w http.ResponseWriter, r *http.Request) {
	err := r.ParseForm()
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	username := r.Form.Get("username")
	password := r.Form.Get("password")
	remember := r.Form.Get("remember")
	longer := remember == "remember-me"

	cookie, err := tryLogin(username, password, longer)

	if err != nil {
		http.Error(w, err.Error(), http.StatusForbidden)
		return
	}

	http.SetCookie(w, &cookie)
	http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
}

func webStart(modifiedSongChan chan *SongEntry) {
	songsChan = modifiedSongChan

	mux := http.NewServeMux()

	fs := http.FileServer(http.Dir("web"))
	mux.Handle("/css/", fs)
	mux.Handle("/fonts/", fs)
	mux.Handle("/js/", fs)
	mux.Handle("/favicon.ico", fs)
	mux.HandleFunc("/", indexHandler)
	mux.HandleFunc("/update", updateHandler)
	mux.HandleFunc("/login", loginHandler)

	http.ListenAndServe("localhost:8080", mux)
}