103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
package radio
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import (
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"encoding/json"
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"sync"
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"time"
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)
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// Song stores artist and title of a song, a timestamp of when it started, its
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// duration, and a maximum number of listeners.
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type Song struct {
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Artist string
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Title string
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Duration time.Duration
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MaxListeners int
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StartAt time.Time
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}
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// DurationString returns song's duration as a string formatted as [H:]M:SS.
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func (s *Song) DurationString() string {
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if s.Duration.Hours() >= 1 {
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return time.UnixMilli(s.Duration.Milliseconds()).Format("3:4:05")
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}
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return time.UnixMilli(s.Duration.Milliseconds()).Format("4:05")
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}
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func (s *Song) MarshalJSON() ([]byte, error) {
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return json.Marshal(&struct {
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Artist string `json:"artist"`
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Title string `json:"title"`
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DurationMill int64 `json:"duration_msec"`
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MaxListeners int `json:"listeners"`
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StartAt string `json:"start_at"`
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}{
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Artist: s.Artist,
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Title: s.Title,
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DurationMill: s.Duration.Milliseconds(),
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MaxListeners: s.MaxListeners,
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StartAt: s.StartAt.UTC().Format(time.RFC3339)})
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}
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type SongList struct {
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sync.RWMutex
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current Song
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lastSongs []Song
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maxLen int
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}
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// NewSongList returns a new SongList with a maximal length set with maxLen.
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func NewSongList(maxLen int) *SongList {
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return &SongList{maxLen: maxLen, lastSongs: make([]Song, 0, maxLen)}
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}
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// Add a new song that is currently playing and update a list.
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func (sl *SongList) Add(newSong Song) {
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sl.Lock()
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defer sl.Unlock()
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if sl.current.StartAt.Year() == 1 {
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sl.current = newSong
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return
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}
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if len(sl.lastSongs) == sl.maxLen {
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sl.lastSongs = append(sl.lastSongs[1:], sl.current)
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} else {
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sl.lastSongs = append(sl.lastSongs, sl.current)
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}
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sl.current = newSong
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}
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// Current returns a currently playing song.
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func (sl *SongList) Current() *Song {
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sl.RLock()
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defer sl.RUnlock()
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if sl.current.StartAt.Year() == 1 {
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return nil
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}
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return &sl.current
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}
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// UpdateCurrentMaxListeners checks and updates a maximal number of listeners
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// for a current song.
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func (sl *SongList) UpdateCurrentMaxListeners(listeners int) {
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sl.Lock()
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defer sl.Unlock()
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if listeners > sl.current.MaxListeners {
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sl.current.MaxListeners = listeners
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}
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}
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// List returns a list of lastly played songs.
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func (sl *SongList) List() []Song {
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sl.RLock()
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defer sl.RUnlock()
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return sl.lastSongs
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}
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// MaxLen returns a maximal length of a list
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func (sl *SongList) MaxLen() int {
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return sl.maxLen
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}
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