From 4d07a39b64ce9d2a9926e46a78652a78a2dd9fd2 Mon Sep 17 00:00:00 2001
From: Philipp Wolfer <ph.wolfer@gmail.com>
Date: Sun, 10 Dec 2023 00:24:39 +0100
Subject: [PATCH] jspf: implement append mode

---
 config.example.toml            |  3 ++
 internal/backends/jspf/jspf.go | 90 +++++++++++++++++++++++-----------
 2 files changed, 65 insertions(+), 28 deletions(-)

diff --git a/config.example.toml b/config.example.toml
index b7b82fc..11930a2 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -59,6 +59,9 @@ append          = true
 backend    = "jspf"
 # The file path to the XSPF file
 file-path  = "data/playlist.jspf"
+# If true (default), new listens will be appended to the existing file. Set to
+# false to overwrite the file and create a new JSPF playlist on every run.
+append     = true
 # Title of the playlist
 title      = "My Playlist"
 # Creator of the playlist (only informational)
diff --git a/internal/backends/jspf/jspf.go b/internal/backends/jspf/jspf.go
index 944c6e6..b87b86a 100644
--- a/internal/backends/jspf/jspf.go
+++ b/internal/backends/jspf/jspf.go
@@ -28,11 +28,9 @@ import (
 )
 
 type JSPFBackend struct {
-	filePath   string
-	title      string
-	creator    string
-	identifier string
-	tracks     []jspf.Track
+	filePath string
+	playlist jspf.Playlist
+	append   bool
 }
 
 func (b *JSPFBackend) Name() string { return "jspf" }
@@ -42,6 +40,11 @@ func (b *JSPFBackend) Options() []models.BackendOption {
 		Name:  "file-path",
 		Label: i18n.Tr("File path"),
 		Type:  models.String,
+	}, {
+		Name:    "append",
+		Label:   i18n.Tr("Append to file"),
+		Type:    models.Bool,
+		Default: "true",
 	}, {
 		Name:  "title",
 		Label: i18n.Tr("Playlist title"),
@@ -59,23 +62,37 @@ func (b *JSPFBackend) Options() []models.BackendOption {
 
 func (b *JSPFBackend) FromConfig(config *config.ServiceConfig) models.Backend {
 	b.filePath = config.GetString("file-path")
-	b.title = config.GetString("title")
-	b.creator = config.GetString("username")
-	b.identifier = config.GetString("identifier")
-	b.tracks = make([]jspf.Track, 0)
+	b.append = true
+	if config.IsSet("append") {
+		b.append = config.GetBool("append")
+	}
+	b.playlist = jspf.Playlist{
+		Title:      config.GetString("title"),
+		Creator:    config.GetString("username"),
+		Identifier: config.GetString("identifier"),
+		Tracks:     make([]jspf.Track, 0),
+		Extension: map[string]any{
+			jspf.MusicBrainzPlaylistExtensionId: jspf.MusicBrainzPlaylistExtension{
+				LastModifiedAt: time.Now(),
+				Public:         true,
+			},
+		},
+	}
 	return b
 }
 
-func (b *JSPFBackend) StartImport() error { return nil }
+func (b *JSPFBackend) StartImport() error {
+	return b.readJSPF()
+}
+
 func (b *JSPFBackend) FinishImport() error {
-	err := b.writeJSPF(b.tracks)
-	return err
+	return b.writeJSPF()
 }
 
 func (b *JSPFBackend) ImportListens(export models.ListensResult, importResult models.ImportResult, progress chan models.Progress) (models.ImportResult, error) {
 	for _, listen := range export.Items {
 		track := listenAsTrack(listen)
-		b.tracks = append(b.tracks, track)
+		b.playlist.Tracks = append(b.playlist.Tracks, track)
 		importResult.ImportCount += 1
 		importResult.UpdateTimestamp(listen.ListenedAt)
 	}
@@ -87,7 +104,7 @@ func (b *JSPFBackend) ImportListens(export models.ListensResult, importResult mo
 func (b *JSPFBackend) ImportLoves(export models.LovesResult, importResult models.ImportResult, progress chan models.Progress) (models.ImportResult, error) {
 	for _, love := range export.Items {
 		track := loveAsTrack(love)
-		b.tracks = append(b.tracks, track)
+		b.playlist.Tracks = append(b.playlist.Tracks, track)
 		importResult.ImportCount += 1
 		importResult.UpdateTimestamp(love.Created)
 	}
@@ -162,21 +179,38 @@ func makeMusicBrainzExtension(t models.Track) jspf.MusicBrainzTrackExtension {
 	return extension
 }
 
-func (b JSPFBackend) writeJSPF(tracks []jspf.Track) error {
+func (b *JSPFBackend) readJSPF() error {
+	if b.append {
+		file, err := os.Open(b.filePath)
+		if err != nil {
+			return err
+		}
+
+		defer file.Close()
+		stat, err := file.Stat()
+		if err != nil {
+			return err
+		}
+
+		if stat.Size() == 0 {
+			// Zero length file, treat as a new file
+			return nil
+		} else {
+			playlist := jspf.JSPF{}
+			err := playlist.Read(file)
+			if err != nil {
+				return err
+			}
+			b.playlist = playlist.Playlist
+		}
+	}
+
+	return nil
+}
+
+func (b *JSPFBackend) writeJSPF() error {
 	playlist := jspf.JSPF{
-		Playlist: jspf.Playlist{
-			Title:      b.title,
-			Creator:    b.creator,
-			Identifier: b.identifier,
-			Date:       time.Now(),
-			Tracks:     tracks,
-			Extension: map[string]any{
-				jspf.MusicBrainzPlaylistExtensionId: jspf.MusicBrainzPlaylistExtension{
-					LastModifiedAt: time.Now(),
-					Public:         true,
-				},
-			},
-		},
+		Playlist: b.playlist,
 	}
 
 	file, err := os.Create(b.filePath)