Add OS Lyrics extension (#2656)

* draft commit

* time to fight pipeline

* round 2 changes

* remove unnecessary line

* fight taglib. again

* make taglib work again???

* add id3 tags

* taglib 1.12 vs 1.13

* use int instead for windows

* store as json now

* add migration, more tests

* support repeated line, multiline

* fix ms and support .m, .mm, .mmm

* address some concerns, make cpp a bit safer

* separate responses from model

* remove [:]

* Add trace log

* Try to unblock pipeline

* Fix merge errors

* Fix SIGSEGV error (proper handling of empty frames)

* Add fallback artist/title to structured lyrics

* Rename conflicting named vars

* Fix tests

* Do we still need ffmpeg in the pipeline?

* Revert "Do we still need ffmpeg in the pipeline?"

Yes we do.

This reverts commit 87df7f6df79bccee83f48c4b7a8118a7636a5e66.

* Does this passes now, with a newer ffmpeg version?

* Revert "Does this passes now, with a newer ffmpeg version?"

No, it does not :(

This reverts commit 372eb4b0ae05d9ffe98078e9bc4e56a9b2921f32.

* My OCD made me do it :P

---------

Co-authored-by: Deluan Quintão <deluan@navidrome.org>

server/subsonic/responses/responses.go

@@ -58,6 +58,7 @@ type Subsonic struct {
 	JukeboxPlaylist *JukeboxPlaylist `xml:"jukeboxPlaylist,omitempty"                     json:"jukeboxPlaylist,omitempty"`
 
 	OpenSubsonicExtensions *OpenSubsonicExtensions `xml:"openSubsonicExtensions,omitempty"  json:"openSubsonicExtensions,omitempty"`
+	LyricsList             *LyricsList             `xml:"lyricsList,omitempty" json:"lyricsList,omitempty"`
 }
 
 type JsonWrapper struct {
@@ -446,6 +447,26 @@ type JukeboxPlaylist struct {
 	JukeboxStatus
 	Entry []Child `xml:"entry,omitempty"         json:"entry,omitempty"`
 }
+
+type Line struct {
+	Start *int64 `xml:"start,attr,omitempty" json:"start,omitempty"`
+	Value string `xml:"value"                json:"value"`
+}
+
+type StructuredLyric struct {
+	DisplayArtist string `xml:"displayArtist,attr,omitempty" json:"displayArtist,omitempty"`
+	DisplayTitle  string `xml:"displayTitle,attr,omitempty"  json:"displayTitle,omitempty"`
+	Lang          string `xml:"lang,attr"                    json:"lang"`
+	Line          []Line `xml:"line"                         json:"line"`
+	Offset        *int64 `xml:"offset,attr,omitempty"        json:"offset,omitempty"`
+	Synced        bool   `xml:"synced,attr"                  json:"synced"`
+}
+
+type StructuredLyrics []StructuredLyric
+type LyricsList struct {
+	StructuredLyrics []StructuredLyric `xml:"structuredLyrics,omitempty" json:"structuredLyrics,omitempty"`
+}
+
 type OpenSubsonicExtension struct {
 	Name     string  `xml:"name,attr" json:"name"`
 	Versions []int32 `xml:"versions"  json:"versions"`