itd/mpris/mpris.go

271 lines
6.0 KiB
Go

package mpris
import (
"context"
"strings"
"sync"
"github.com/godbus/dbus/v5"
"go.arsenm.dev/itd/internal/utils"
)
var (
method, monitor *dbus.Conn
monitorCh chan *dbus.Message
onChangeOnce sync.Once
)
// Init makes required connections to DBus and
// initializes change monitoring channel
func Init(ctx context.Context) error {
// Connect to session bus for monitoring
monitorConn, err := utils.NewSessionBusConn(ctx)
if err != nil {
return err
}
// Add match rule for PropertiesChanged on media player
monitorConn.AddMatchSignal(
dbus.WithMatchObjectPath("/org/mpris/MediaPlayer2"),
dbus.WithMatchInterface("org.freedesktop.DBus.Properties"),
dbus.WithMatchMember("PropertiesChanged"),
)
monitorCh = make(chan *dbus.Message, 10)
monitorConn.Eavesdrop(monitorCh)
// Connect to session bus for method calls
methodConn, err := utils.NewSessionBusConn(ctx)
if err != nil {
return err
}
method, monitor = methodConn, monitorConn
return nil
}
// Exit closes all connections and channels
func Exit() {
close(monitorCh)
method.Close()
monitor.Close()
}
// Play uses MPRIS to play media
func Play() error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
call := player.Call("org.mpris.MediaPlayer2.Player.Play", 0)
if call.Err != nil {
return call.Err
}
}
return nil
}
// Pause uses MPRIS to pause media
func Pause() error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
call := player.Call("org.mpris.MediaPlayer2.Player.Pause", 0)
if call.Err != nil {
return call.Err
}
}
return nil
}
// Next uses MPRIS to skip to next media
func Next() error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
call := player.Call("org.mpris.MediaPlayer2.Player.Next", 0)
if call.Err != nil {
return call.Err
}
}
return nil
}
// Prev uses MPRIS to skip to previous media
func Prev() error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
call := player.Call("org.mpris.MediaPlayer2.Player.Previous", 0)
if call.Err != nil {
return call.Err
}
}
return nil
}
func VolUp(percent uint) error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
currentVal, err := player.GetProperty("org.mpris.MediaPlayer2.Player.Volume")
if err != nil {
return err
}
newVal := currentVal.Value().(float64) + (float64(percent) / 100)
err = player.SetProperty("org.mpris.MediaPlayer2.Player.Volume", newVal)
if err != nil {
return err
}
}
return nil
}
func VolDown(percent uint) error {
player, err := getPlayerObj()
if err != nil {
return err
}
if player != nil {
currentVal, err := player.GetProperty("org.mpris.MediaPlayer2.Player.Volume")
if err != nil {
return err
}
newVal := currentVal.Value().(float64) - (float64(percent) / 100)
err = player.SetProperty("org.mpris.MediaPlayer2.Player.Volume", newVal)
if err != nil {
return err
}
}
return nil
}
type ChangeType int
const (
ChangeTypeTitle ChangeType = iota
ChangeTypeArtist
ChangeTypeAlbum
ChangeTypeStatus
)
func (ct ChangeType) String() string {
switch ct {
case ChangeTypeTitle:
return "Title"
case ChangeTypeAlbum:
return "Album"
case ChangeTypeArtist:
return "Artist"
case ChangeTypeStatus:
return "Status"
}
return ""
}
// OnChange runs cb when a value changes
func OnChange(cb func(ChangeType, string)) {
go onChangeOnce.Do(func() {
// For every message on channel
for msg := range monitorCh {
// Parse PropertiesChanged
iface, changed, ok := parsePropertiesChanged(msg)
if !ok || iface != "org.mpris.MediaPlayer2.Player" {
continue
}
// For every property changed
for name, val := range changed {
// If metadata changed
if name == "Metadata" {
// Get fields
fields := val.Value().(map[string]dbus.Variant)
// For every field
for name, val := range fields {
// Handle each field appropriately
if strings.HasSuffix(name, "title") {
title := val.Value().(string)
if title == "" {
title = "Unknown " + ChangeTypeTitle.String()
}
cb(ChangeTypeTitle, title)
} else if strings.HasSuffix(name, "album") {
album := val.Value().(string)
if album == "" {
album = "Unknown " + ChangeTypeAlbum.String()
}
cb(ChangeTypeAlbum, album)
} else if strings.HasSuffix(name, "artist") {
var artists string
switch artistVal := val.Value().(type) {
case string:
artists = artistVal
case []string:
artists = strings.Join(artistVal, ", ")
}
if artists == "" {
artists = "Unknown " + ChangeTypeArtist.String()
}
cb(ChangeTypeArtist, artists)
}
}
} else if name == "PlaybackStatus" {
// Handle status change
cb(ChangeTypeStatus, val.Value().(string))
}
}
}
})
}
// getPlayerNames gets all DBus MPRIS player bus names
func getPlayerNames(conn *dbus.Conn) ([]string, error) {
var names []string
err := conn.BusObject().Call("org.freedesktop.DBus.ListNames", 0).Store(&names)
if err != nil {
return nil, err
}
var players []string
for _, name := range names {
if strings.HasPrefix(name, "org.mpris.MediaPlayer2") {
players = append(players, name)
}
}
return players, nil
}
// GetPlayerObj gets the object corresponding to the first
// bus name found in DBus
func getPlayerObj() (dbus.BusObject, error) {
players, err := getPlayerNames(method)
if err != nil {
return nil, err
}
if len(players) == 0 {
return nil, nil
}
return method.Object(players[0], "/org/mpris/MediaPlayer2"), nil
}
// parsePropertiesChanged parses a DBus PropertiesChanged signal
func parsePropertiesChanged(msg *dbus.Message) (iface string, changed map[string]dbus.Variant, ok bool) {
if len(msg.Body) != 3 {
return "", nil, false
}
iface, ok = msg.Body[0].(string)
if !ok {
return
}
changed, ok = msg.Body[1].(map[string]dbus.Variant)
if !ok {
return
}
return
}