1
0
dwelling-radio/internal/radio/playlist.go

97 lines
1.9 KiB
Go

package radio
import (
"dwelling-radio/pkg/watcher"
"log"
"os"
"strings"
"sync"
"syscall"
)
// Playlist holds a list of paths to a song files.
type Playlist struct {
mut sync.Mutex
filePath string
playlist []string
cur int
repeat bool
watcher *watcher.InotifyWatcher
changed chan uint32
}
// NewPlaylist returns an instance of a Playlist struct with a loaded playlist.
// Returns an error if failed to load a playlist file.
func NewPlaylist(filePath string, repeat bool) (*Playlist, error) {
p := &Playlist{filePath: filePath, repeat: repeat}
return p, p.load()
}
// Next returns the next song to play. Returns an empty string if repeat is
// false and the end of a playlist was reached.
func (p *Playlist) Next() (song string) {
p.mut.Lock()
defer p.mut.Unlock()
if p.cur == len(p.playlist) {
// If the end of a playlist was reached and repeat is set to true,
// then go back to the head of it, thus repeating it. Return an empty
// string otherwise.
if p.repeat {
p.cur = 0
} else {
return ""
}
}
song = p.playlist[p.cur]
p.cur++
return
}
// Load reads a playlist file.
func (p *Playlist) load() error {
data, err := os.ReadFile(p.filePath)
if err != nil {
return err
}
p.mut.Lock()
p.playlist = strings.Split(string(data), "\n")
p.cur = 0
p.mut.Unlock()
return nil
}
func (p *Playlist) Reload() error {
return p.load()
}
func (p *Playlist) Watch() (err error) {
p.watcher, err = watcher.NewInotifyWatcher()
if err != nil {
return err
}
err = p.watcher.AddWatch(p.filePath, watcher.ModIgnMask)
if err != nil {
return err
}
p.watcher.WatchForMask(p.changed, watcher.ModIgnMask)
go func() {
for {
mask := <-p.changed
if mask&syscall.IN_MODIFY > 0 {
if err := p.load(); err != nil {
log.Fatalln("cannot reload a changed playlist:", err)
}
} else if mask&syscall.IN_IGNORED > 0 {
p.watcher.Close()
p.Watch()
}
}
}()
return nil
}