waybar-mpris/main.go

package main

import (
	"encoding/json"
	"fmt"
	"sort"
	"strings"

	"github.com/godbus/dbus/v5"
)

var knownPlayers = map[string]string{
	"plasma-browser-integration": "Browser",
	"noson":                      "Noson",
}

type Player struct {
	player                               dbus.BusObject
	fullName, name, title, artist, album string
	playing, stopped                     bool
	metadata                             map[string]dbus.Variant
	conn                                 *dbus.Conn
}

const (
	INTERFACE = "org.mpris.MediaPlayer2"
	PATH      = "/org/mpris/MediaPlayer2"
	PLAY      = "▶"
	PAUSE     = ""
	// NameOwnerChanged
	MATCH_NOC = "type='signal',path='/org/freedesktop/DBus',interface='org.freedesktop.DBus',member='NameOwnerChanged'"
	// PropertiesChanged
	MATCH_PC = "type='signal',path='/org/mpris/MediaPlayer2',interface='org.freedesktop.DBus.Properties'"
)

// NewPlayer returns a new player object.
func NewPlayer(conn *dbus.Conn, name string) (p *Player) {
	playerName := strings.ReplaceAll(name, INTERFACE+".", "")
	for key, val := range knownPlayers {
		if strings.Contains(name, key) {
			playerName = val
			break
		}
	}
	p = &Player{
		player:   conn.Object(name, PATH),
		conn:     conn,
		name:     playerName,
		fullName: name,
	}
	p.Refresh()
	return
}

// Refresh grabs playback info.
func (p *Player) Refresh() (err error) {
	val, err := p.player.GetProperty(INTERFACE + ".Player.PlaybackStatus")
	if err != nil {
		p.playing = false
		p.stopped = false
		p.metadata = map[string]dbus.Variant{}
		p.title = ""
		p.artist = ""
		p.album = ""
		return
	}
	strVal := val.String()
	if strings.Contains(strVal, "Playing") {
		p.playing = true
		p.stopped = false
	} else if strings.Contains(strVal, "Paused") {
		p.playing = false
		p.stopped = false
	} else {
		p.playing = false
		p.stopped = true
	}
	metadata, err := p.player.GetProperty(INTERFACE + ".Player.Metadata")
	if err != nil {
		p.metadata = map[string]dbus.Variant{}
		p.title = ""
		p.artist = ""
		p.album = ""
		return
	}
	p.metadata = metadata.Value().(map[string]dbus.Variant)
	switch artist := p.metadata["xesam:artist"].Value().(type) {
	case []string:
		p.artist = strings.Join(artist, ", ")
	case string:
		p.artist = artist
	default:
		p.artist = ""
	}
	switch title := p.metadata["xesam:title"].Value().(type) {
	case string:
		p.title = title
	default:
		p.title = ""
	}
	switch album := p.metadata["xesam:album"].Value().(type) {
	case string:
		p.album = album
	default:
		p.album = ""
	}
	return nil
}

func (p *Player) JSON() string {
	var items []string
	for _, v := range []string{p.artist, p.album, p.title} {
		if v != "" {
			items = append(items, v)
		}
	}
	if len(items) == 0 {
		return "{}"
	}
	data := map[string]string{}
	data["tooltip"] = fmt.Sprintf(
		"%s\nby %s\n",
		p.title,
		p.artist)
	if p.album != "" {
		data["tooltip"] += "from " + p.album + "\n"
	}
	data["tooltip"] += "(" + p.name + ")"
	symbol := PLAY
	data["class"] = "paused"
	if p.playing {
		symbol = PAUSE
		data["class"] = "playing"
	}
	data["text"] = symbol + " " + strings.Join(items, " - ")
	text, err := json.Marshal(data)
	if err != nil {
		return "{}"
	}
	return string(text)
}

type PlayerList struct {
	list List
	conn *dbus.Conn
}

type List []*Player

func (ls List) Len() int {
	return len(ls)
}

func (ls List) Less(i, j int) bool {
	var states [2]uint8
	for i, p := range []bool{ls[i].playing, ls[j].playing} {
		if p {
			states[i] = 1
		}
	}
	// Reverse order
	return states[0] > states[1]
}

func (ls List) Swap(i, j int) {
	ls[i], ls[j] = ls[j], ls[i]
}

// Doesn't retain order since sorting if constantly done anyway
func (pl *PlayerList) Remove(fullName string) {
	var i int
	found := false
	for ind, p := range pl.list {
		if p.fullName == fullName {
			i = ind
			found = true
			break
		}
	}
	if found {
		pl.list[0], pl.list[i] = pl.list[i], pl.list[0]
		pl.list = pl.list[1:]
	}
	// ls[len(ls)-1], ls[i] = ls[i], ls[len(ls)-1]
	// ls = ls[:len(ls)-1]
}

func (pl *PlayerList) Reload() error {
	var buses []string
	err := pl.conn.BusObject().Call("org.freedesktop.DBus.ListNames", 0).Store(&buses)
	if err != nil {
		return err
	}
	for _, name := range buses {
		if strings.HasPrefix(name, INTERFACE) {
			pl.New(name)
		}
	}
	return nil
}

func (pl *PlayerList) New(name string) {
	pl.list = append(pl.list, NewPlayer(pl.conn, name))
}

func (pl *PlayerList) Sort() {
	sort.Sort(pl.list)
}

func (pl *PlayerList) Refresh() {
	for i := range pl.list {
		pl.list[i].Refresh()
	}
}

func (pl *PlayerList) JSON() string {
	if len(pl.list) != 0 {
		return pl.list[0].JSON()
	}
	return "{}"
}

func main() {
	conn, err := dbus.SessionBus()
	if err != nil {
		panic(err)
	}
	players := &PlayerList{
		conn: conn,
	}
	players.Reload()
	players.Sort()
	fmt.Println("New array", players)
	conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0, MATCH_NOC)
	conn.BusObject().Call("org.freedesktop.DBus.AddMatch", 0, MATCH_PC)
	c := make(chan *dbus.Signal, 10)
	conn.Signal(c)
	for v := range c {
		// fmt.Printf("SIGNAL: Sender %s, Path %s, Name %s, Body %s\n", v.Sender, v.Path, v.Name, v.Body)
		if strings.Contains(v.Name, "NameOwnerChanged") {
			switch name := v.Body[0].(type) {
			case string:
				var pid uint32
				conn.BusObject().Call("org.freedesktop.DBus.GetConnectionUnixProcessID", 0, name).Store(&pid)
				if strings.Contains(name, INTERFACE) {
					if pid == 0 {
						fmt.Println("Removing", name)
						players.Remove(name)
					} else {
						fmt.Println("Adding", name)
						players.New(name)
					}
				}
			}
		} else if strings.Contains(v.Name, "PropertiesChanged") && strings.Contains(v.Body[0].(string), INTERFACE+".Player") {
			players.Refresh()
			players.Sort()
			fmt.Println(players.JSON())
		}
		fmt.Println("New array", players)
	}
}