Make waybar-mpris more flexible customizable

Instead of customizing by indicating just the order and using flags for
other customization options (e.g. separator), read a C-like format
string with tokens/verbs that are replaced with their respective
information (e.g. `%a` for artist).

Also made it possible to customize the tooltip. The principle is the
same as with the module's text.

2 files changed, 130 insertions, 124 deletions

diff --git a/README.md b/README.md
index 87eca47..0a8712c 100644
--- a/README.md
+++ b/README.md
@@ -57,21 +57,29 @@ When running, the program will pipe out json in waybar's format. Add something l
 
 
 ```
-Usage of waybar-mpris:
-      --autofocus          Auto switch to currently playing music players.
-      --interpolate        Interpolate track position (helpful for players that don't update regularly, e.g mpDris2)
-      --order string       Element order. (default "SYMBOL:ARTIST:ALBUM:TITLE:POSITION")
-      --pause string       Pause symbol/text to use. (default "\uf8e3")
-      --play string        Play symbol/text to use. (default "▶")
-      --position           Show current position between brackets, e.g (04:50/05:00)
-      --replace            Replace any running instances
-      --send string        send command to already runnning waybar-mpris instance. (options: player-next/player-prev/next/prev/toggle)
-      --separator string   Separator string to use between artist, album, and title. (default " - ")
+Usage of ./waybar-mpris:
+      --autofocus               Auto switch to currently playing music players.
+      --interpolate             Interpolate track position (helpful for players that don't update regularly, e.g mpDris2)
+      --pause string            Pause symbol/text to use. (default "\uf8e3")
+      --play string             Play symbol/text to use. (default "▶")
+      --replace                 Replace existing waybar-mpris if found. When false, new instance will clone the original instances output.
+      --send string             send command to already runnning waybar-mpris instance. (options: player-next/player-prev/next/prev/toggle/list)
+      --text-format string      Format of the waybar module text. (default "%i %a - %t (%p/%d)")
+      --tooltip-format string   Format of the waybar module tooltip. (default "%t by %a from %A\n(%P)")
 ```
 
-* Modify the order of components with `--order`. `SYMBOL` is the play/paused icon or text, `POSITION` is the track position (if enabled), other options are self explanatory.
+* `--text-format` specifies in what format to display the module's text in
+  waybar; the accepted tokens are as follows:
+  - `%i` play/pause icon
+  - `%a` track artist
+  - `%A` album
+  - `%t` track title
+  - `%p` current position
+  - `%l` track length
+  - `%P` current media player
+* `--tooltip-format` same as `text-format` but for the tooltip; same rules
+  apply.
 * `--play/--pause` specify the symbols or text to display when music is paused/playing respectively.
-* `--separator` specifies a string to separate the artist, album and title text.
 * `--autofocus` makes waybar-mpris automatically focus on currently playing music players.
 * `--position` enables the display of the track position.
 * `--interpolate` increments the track position every second. This is useful for players (e.g mpDris2) that don't regularly update the position.
diff --git a/main.go b/main.go
index 206ea44..4593ca2 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -28,20 +29,32 @@ const (
 
 // Mostly default values for flag options.
 var (
-	PLAY      = "▶"
-	PAUSE     = ""
-	SEP       = " - "
-	ORDER     = "SYMBOL:ARTIST:ALBUM:TITLE:POSITION"
-	AUTOFOCUS = false
+	playIcon      = "▶"
+	pauseIcon     = ""
+	textFormat    = "%i %a - %t (%p/%d)"
+	tooltipFormat = "%t by %a from %A\n(%P)"
+	autofocus     = false
 	// Available commands that can be sent to running instances.
-	COMMANDS                          = []string{"player-next", "player-prev", "next", "prev", "toggle", "list"}
-	SHOW_POS                          = false
-	INTERPOLATE                       = false
-	REPLACE                           = false
+	commands                          = []string{"player-next", "player-prev", "next", "prev", "toggle", "list"}
+	showPos                           = false
+	interpolate                       = false
+	replace                           = false
 	isSharing                         = false
 	isDataSharing                     = false
-	WRITER                  io.Writer = os.Stdout
-	SHAREWRITER, DATAWRITER io.Writer
+	writer                  io.Writer = os.Stdout
+	shareWriter, dataWriter io.Writer
+)
+
+// Format tokens `%<character>`
+const (
+	tokIcon     = 'i'
+	tokArtist   = 'a'
+	tokAlbum    = 'A'
+	tokTitle    = 't'
+	tokPosition = 'p'
+	tokLength   = 'd'
+	tokPlayer   = 'P'
+	tokPercent  = '%'
 )
 
 const (
@@ -142,97 +155,78 @@ type player struct {
 	Duplicate bool
 }
 
+// This represents the output in JSON format that waybar is expecting
+type waybarData struct {
+	Class   string `json:"class"`
+	Text    string `json:"text"`
+	Tooltip string `json:"tooltip"`
+}
+
 func secondsToString(seconds int) string {
 	minutes := int(seconds / 60)
 	seconds -= int(minutes * 60)
 	return fmt.Sprintf("%02d:%02d", minutes, seconds)
 }
 
-// JSON returns json for waybar to consume.
-func playerJSON(p *player) string {
-	artist := strings.ReplaceAll(p.Artist, "\"", "\\\"")
-	album := strings.ReplaceAll(p.Album, "\"", "\\\"")
-	title := strings.ReplaceAll(p.Title, "\"", "\\\"")
-	name := strings.ReplaceAll(p.Name, "\"", "\\\"")
-	symbol := PLAY
-	out := "{\"class\": \""
-	if p.Playing {
-		symbol = PAUSE
-		out += "playing"
-	} else {
-		out += "paused"
-	}
-	var pos string
-	if SHOW_POS {
-		if !p.Duplicate {
-			pos = p.StringPosition()
-			if pos != "" {
-				pos = "(" + pos + ")"
-			}
-		} else {
-			pos = "(" + secondsToString(int(p.Position/1000000)) + "/" + secondsToString(p.Length) + ")"
-
-		}
-	}
-	var items []string
-	order := strings.Split(ORDER, ":")
-	for _, v := range order {
-		switch v {
-		case "SYMBOL":
-			items = append(items, symbol)
-		case "ARTIST":
-			if artist != "" {
-				items = append(items, artist)
+func formatOutput(p *player, icon string, fstr string) string {
+	var buf []byte
+	for i := 0; i < len(fstr); i++ {
+		if fstr[i] == '%' {
+			i++
+			if i >= len(fstr) {
+				break
 			}
-		case "ALBUM":
-			if album != "" {
-				items = append(items, album)
+			switch fstr[i] {
+			case tokIcon:
+				buf = append(buf, []byte(icon)...)
+			case tokArtist:
+				buf = append(buf, []byte(p.Artist)...)
+			case tokAlbum:
+				buf = append(buf, []byte(p.Album)...)
+			case tokTitle:
+				buf = append(buf, []byte(p.Title)...)
+			case tokPosition:
+				position := secondsToString(int(p.Position / 1000000))
+				buf = append(buf, []byte(position)...)
+			case tokLength:
+				length := secondsToString(p.Length)
+				buf = append(buf, []byte(length)...)
+			case tokPlayer:
+				buf = append(buf, []byte(p.Name)...)
+			default:
+				buf = append(buf, fstr[i])
 			}
-		case "TITLE":
-			if title != "" {
-				items = append(items, title)
-			}
-		case "POSITION":
-			if pos != "" && SHOW_POS {
-				items = append(items, pos)
-			}
-		case "PLAYER":
-			if name != "" {
-				items = append(items, name)
-			}
-		}
-	}
-	if len(items) == 0 {
-		return "{}"
-	}
-	text := ""
-	for i, v := range items {
-		right := ""
-		if (v == symbol || v == pos) && i != len(items)-1 {
-			right = " "
-		} else if i != len(items)-1 && items[i+1] != symbol && items[i+1] != pos {
-			right = SEP
 		} else {
-			right = " "
+			buf = append(buf, fstr[i])
 		}
-		text += v + right
 	}
-	out += "\",\"text\":\"" + text + "\","
-	out += "\"tooltip\":\"" + strings.ReplaceAll(title, "&", "&amp;") + "\\n"
-	if artist != "" {
-		out += "by " + strings.ReplaceAll(artist, "&", "&amp;") + "\\n"
+
+	out := strings.ReplaceAll(string(buf), `"`, `\"`)
+	out = strings.ReplaceAll(out, "&", "&amp;")
+
+	return out
+}
+
+// Returns JSON for waybar to consume.
+func playerJSON(p *player) string {
+	data := waybarData{}
+
+	icon := playIcon
+	if p.Playing {
+		icon = pauseIcon
+		data.Class = "playing"
+	} else {
+		data.Class = "paused"
 	}
-	if album != "" {
-		out += "from " + strings.ReplaceAll(album, "&", "&amp;") + "\\n"
+
+	data.Text = formatOutput(p, icon, textFormat)
+	data.Tooltip = formatOutput(p, icon, tooltipFormat)
+
+	out, err := json.Marshal(data)
+	if err != nil {
+		return "{}"
 	}
-	out += "(" + name + ")\"}"
-	return out
-	// return fmt.Sprintf("{\"class\":\"%s\",\"text\":\"%s\",\"tooltip\":\"%s\"}", data["class"], data["text"], data["tooltip"])
-	// out, err := json.Marshal(data)
-	// if err != nil {
-	// 	return "{}"
-	// }
-	// return string(out)
+	return string(out)
 }
 
 type players struct {
@@ -407,7 +401,7 @@ func duplicateOutput() error {
 						}
 						str := string(l)
 						fromData(p, str)
-						fmt.Fprintln(WRITER, playerJSON(p))
+						fmt.Fprintln(writer, playerJSON(p))
 						f.Seek(0, 0)
 					}
 				}
@@ -483,14 +477,14 @@ func listenForCommands(players *players) {
 				if err != nil {
 					fmt.Fprintf(con, "Failed: %v", err)
 				}
-				DATAWRITER = dataWrite{
+				dataWriter = dataWrite{
 					emptyEveryWrite{file: f},
 					players,
 				}
 				if isSharing {
-					WRITER = io.MultiWriter(os.Stdout, SHAREWRITER, DATAWRITER)
+					writer = io.MultiWriter(os.Stdout, shareWriter, dataWriter)
 				} else {
-					WRITER = io.MultiWriter(os.Stdout, DATAWRITER)
+					writer = io.MultiWriter(os.Stdout, dataWriter)
 				}
 				isDataSharing = true
 			}
@@ -502,11 +496,11 @@ func listenForCommands(players *players) {
 				if err != nil {
 					fmt.Fprintf(con, "Failed: %v", err)
 				}
-				SHAREWRITER = emptyEveryWrite{file: f}
+				shareWriter = emptyEveryWrite{file: f}
 				if isDataSharing {
-					WRITER = io.MultiWriter(SHAREWRITER, DATAWRITER, os.Stdout)
+					writer = io.MultiWriter(shareWriter, dataWriter, os.Stdout)
 				} else {
-					WRITER = io.MultiWriter(SHAREWRITER, os.Stdout)
+					writer = io.MultiWriter(shareWriter, os.Stdout)
 				}
 				isSharing = true
 			}
@@ -565,16 +559,20 @@ func main() {
 	}
 	mw := io.MultiWriter(logfile, os.Stdout)
 	log.SetOutput(mw)
-	flag.StringVar(&PLAY, "play", PLAY, "Play symbol/text to use.")
-	flag.StringVar(&PAUSE, "pause", PAUSE, "Pause symbol/text to use.")
-	flag.StringVar(&SEP, "separator", SEP, "Separator string to use between artist, album, and title.")
-	flag.StringVar(&ORDER, "order", ORDER, "Element order. An extra \"PLAYER\" element is also available.")
-	flag.BoolVar(&AUTOFOCUS, "autofocus", AUTOFOCUS, "Auto switch to currently playing music players.")
-	flag.BoolVar(&SHOW_POS, "position", SHOW_POS, "Show current position between brackets, e.g (04:50/05:00)")
-	flag.BoolVar(&INTERPOLATE, "interpolate", INTERPOLATE, "Interpolate track position (helpful for players that don't update regularly, e.g mpDris2)")
-	flag.BoolVar(&REPLACE, "replace", REPLACE, "replace existing waybar-mpris if found. When false, new instance will clone the original instances output.")
+	flag.StringVar(&playIcon, "play", playIcon, "Play symbol/text to use.")
+	flag.StringVar(&pauseIcon, "pause", pauseIcon, "Pause symbol/text to use.")
+	flag.StringVar(&textFormat, "text-format", textFormat,
+		"Format of the waybar module text.")
+	flag.StringVar(&tooltipFormat, "tooltip-format", tooltipFormat,
+		"Format of the waybar module tooltip.")
+	flag.BoolVar(&autofocus, "autofocus", autofocus,
+		"Auto switch to currently playing music players.")
+	flag.BoolVar(&interpolate, "interpolate", interpolate,
+		"Interpolate track position (helpful for players that don't update regularly, e.g mpDris2)")
+	flag.BoolVar(&replace, "replace", replace,
+		"Replace existing waybar-mpris if found. When false, new instance will clone the original instances output.")
 	var command string
-	flag.StringVar(&command, "send", "", "send command to already runnning waybar-mpris instance. (options: "+strings.Join(COMMANDS, "/")+")")
+	flag.StringVar(&command, "send", "", "send command to already runnning waybar-mpris instance. (options: "+strings.Join(commands, "/")+")")
 
 	flag.Parse()
 	os.Stderr = logfile
@@ -585,7 +583,7 @@ func main() {
 	// fmt.Println("New array", players)
 	// Start command listener
 	if _, err := os.Stat(SOCK); err == nil {
-		if REPLACE {
+		if replace {
 			fmt.Printf("Socket %s already exists, this could mean waybar-mpris is already running.\nStarting this instance will overwrite the file, possibly stopping other instances from accepting commands.\n", SOCK)
 			var input string
 			ignoreChoice := false
@@ -614,34 +612,34 @@ func main() {
 		log.Fatalln("Error connecting to DBus:", err)
 	}
 	players := &players{
-		mpris2: mpris2.NewMpris2(conn, INTERPOLATE, POLL, AUTOFOCUS),
+		mpris2: mpris2.NewMpris2(conn, interpolate, POLL, autofocus),
 	}
 	players.mpris2.Reload()
 	players.mpris2.Sort()
 	lastLine := ""
 	go listenForCommands(players)
 	go players.mpris2.Listen()
-	if SHOW_POS {
+	if showPos {
 		go func() {
 			for {
 				time.Sleep(POLL * time.Second)
 				if len(players.mpris2.List) != 0 {
 					if players.mpris2.List[players.mpris2.Current].Playing {
-						go fmt.Fprintln(WRITER, players.JSON())
+						go fmt.Fprintln(writer, players.JSON())
 					}
 				}
 			}
 		}()
 	}
-	fmt.Fprintln(WRITER, players.JSON())
+	fmt.Fprintln(writer, players.JSON())
 	for v := range players.mpris2.Messages {
 		if v.Name == "refresh" {
-			if AUTOFOCUS {
+			if autofocus {
 				players.mpris2.Sort()
 			}
 			if l := players.JSON(); l != lastLine {
 				lastLine = l
-				fmt.Fprintln(WRITER, l)
+				fmt.Fprintln(writer, l)
 			}
 		}
 	}