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dwelling-radio/internal/radio/song.go

78 lines
1.6 KiB
Go

package radio
import (
"encoding/json"
"sync"
"time"
)
// Song_ stores artist and title of a song, a timestamp of when it started, and
// a maximum number of listeners.
type Song_ struct {
Artist string
Title string
MaxListeners int
StartAt time.Time
}
func (s *Song_) ArtistTitle() string {
return s.Artist + " - " + s.Title
}
func (s *Song_) MarshalJSON() ([]byte, error) {
return json.Marshal(&struct {
Artist string `json:"artist"`
Title string `json:"title"`
MaxListeners int `json:"listeners"`
StartAt string `json:"start_at"`
}{
Artist: s.Artist,
Title: s.Title,
MaxListeners: s.MaxListeners,
StartAt: s.StartAt.UTC().Format(time.RFC3339)})
}
type SongList struct {
mut sync.Mutex
current Song_
lastSongs []Song_
listMaxLen int
}
func NewSongList(length int) *SongList {
return &SongList{listMaxLen: length, lastSongs: make([]Song_, 0, length)}
}
// Add a new song that is currently playing and update a list.
func (sl *SongList) Add(newSong Song_) {
sl.mut.Lock()
defer sl.mut.Unlock()
if sl.current.StartAt.Year() == 1 {
sl.current = newSong
return
}
if len(sl.lastSongs) == sl.listMaxLen {
sl.lastSongs = append(sl.lastSongs[1:], sl.current)
} else {
sl.lastSongs = append(sl.lastSongs, sl.current)
}
sl.current = newSong
}
// Current returns a current playing song.
func (sl *SongList) Current() *Song_ {
sl.mut.Lock()
defer sl.mut.Unlock()
return &sl.current
}
// List returns a list of lastly played songs.
func (sl *SongList) List() []Song_ {
sl.mut.Lock()
defer sl.mut.Unlock()
return sl.lastSongs
}