dwelling-radio/internal/http/dj_handlers.go

package http

import (
	"dwelling-radio/internal/radio"
	"dwelling-radio/pkg/oggtag"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"strings"
	"time"
)

type DJHandlers struct {
	listeners    *radio.ListenerCounter
	playlist     *radio.Playlist
	songList     *radio.SongList
	mostLSong    *radio.MostListenedSong
	fallbackSong string
}

func NewDJHandlers(l *radio.ListenerCounter, p *radio.Playlist,
	sl *radio.SongList, mls *radio.MostListenedSong, fS string) *DJHandlers {
	return &DJHandlers{listeners: l, playlist: p, songList: sl,
		mostLSong: mls, fallbackSong: fS}
}

func (dj *DJHandlers) ListenersGet(w http.ResponseWriter, _ *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	json.NewEncoder(w).Encode(dj.listeners)
}

func (dj *DJHandlers) ListenersInc(w http.ResponseWriter, _ *http.Request) {
	l := dj.listeners.Inc()
	go dj.songList.UpdateCurrentMaxListeners(l)
	w.WriteHeader(http.StatusCreated)
	w.Header().Add("Content-Type", "text/plain")
	fmt.Fprint(w, l)
}

func (dj *DJHandlers) ListenersDec(w http.ResponseWriter, _ *http.Request) {
	l, err := dj.listeners.Dec()
	if err != nil {
		log.Print(err)
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	w.WriteHeader(http.StatusOK)
	w.Header().Add("Content-Type", "text/plain")
	fmt.Fprint(w, l)
}

func (dj *DJHandlers) PlaylistNext(w http.ResponseWriter, _ *http.Request) {
	w.Header().Add("Content-Type", "text/plain")
	nxt := dj.playlist.Next()
	if nxt == "" {
		log.Println("the end of a playlist has been reached")
		if nxt = dj.fallbackSong; nxt == "" {
			log.Println("a fallback song is not set")
			http.Error(w, "a playlist is empty and a fallback song is not set", http.StatusNotFound)
			return
		}
	}

	go func() {
		oggf, err := oggtag.NewOggFile(nxt)
		if err != nil {
			log.Println("cannot read an OGG file", nxt, ":", err)
			http.Error(w, "cannot read an OGG file", http.StatusInternalServerError)
			return
		}

		song := radio.Song{
			Artist:       oggf.GetTag("artist"),
			Title:        oggf.GetTag("title"),
			Duration:     oggf.GetDuration(),
			MaxListeners: dj.listeners.Current(),
			StartAt:      time.Now()}

		if strings.HasSuffix(nxt, "/fallback.ogg") {
			song.Artist = "Nothing to play. Playing a fallback: " + song.Artist
		}

		if dj.songList.Current() != nil {
			dj.mostLSong.Update(*dj.songList.Current())
		}

		dj.songList.Add(song)
	}()
	fmt.Fprintln(w, nxt)
}

func (dj *DJHandlers) Song(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	err := json.NewEncoder(w).Encode(dj.songList.Current())
	if err != nil {
		log.Println("DJHandlers.Song:", err)
		http.Error(w, "cannot obtain current song", http.StatusInternalServerError)
	}
}

func (dj *DJHandlers) Songs(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	err := json.NewEncoder(w).Encode(dj.songList.List())
	if err != nil {
		log.Println("DJHandlers.Songs:", err)
		http.Error(w, "cannot obtain list of last songs", http.StatusInternalServerError)
	}
}

func (dj *DJHandlers) Status(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	var curSong *radio.Song = nil
	if dj.songList.Current() != nil {
		curSong = &radio.Song{}
		*curSong = *dj.songList.Current()
	}
	err := json.NewEncoder(w).Encode(&struct {
		Current   *radio.Song             `json:"current_song,omitempty"`
		Listeners *radio.ListenerCounter  `json:"listeners"`
		List      []radio.Song            `json:"last_songs,omitempty"`
		Mls       *radio.MostListenedSong `json:"most_listened_song,omitempty"`
	}{
		Current:   curSong,
		Listeners: dj.listeners,
		List:      dj.songList.List(),
		Mls:       dj.mostLSong.Get()})
	if err != nil {
		log.Println("DJHandlers.Status:", err)
		http.Error(w, "status parsing failed", http.StatusInternalServerError)
	}
}

func (dj *DJHandlers) MostListenedSong(w http.ResponseWriter, r *http.Request) {
	w.Header().Add("Content-Type", "application/json")
	mls := dj.mostLSong.Get()
	if mls == nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}
	err := json.NewEncoder(w).Encode(mls)
	if err != nil {
		log.Println("DJHandlers.MostListenedSong:", err)
		http.Error(w, "MostListenedSong parsing failed", http.StatusInternalServerError)
	}
}