From fddd527975caab54c3c58e0d59d0e1ddc8b3e9b9 Mon Sep 17 00:00:00 2001
From: Alexander Capehart <alex@oxycblt.org>
Date: Sat, 4 Jan 2025 13:40:52 -0700
Subject: [PATCH] musikr.tag: handle compilation flag

---
 .../org/oxycblt/musikr/tag/parse/TagFields.kt | 20 +++++++++----------
 .../org/oxycblt/musikr/tag/parse/TagParser.kt | 13 ++++++++++--
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagFields.kt b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagFields.kt
index a4c48d76a..08620d399 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagFields.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagFields.kt
@@ -205,18 +205,16 @@ internal fun Metadata.genreNames() = xiph["GENRE"] ?: mp4["©gen"] ?: mp4["gnre"
 // Compilation Flag
 internal fun Metadata.isCompilation() =
     // TCMP is a non-standard itunes extension
+    // We also only look for tags that are actually valid
+    // (i.e. 1 for true, 0 for false)
     (xiph["COMPILATION"]
-            ?: xiph["ITUNESCOMPILATION"]
-            ?: mp4["cpil"]
-            ?: mp4["----:COM.APPLE.ITUNES:COMPILATION"]
-            ?: mp4["----:COM.APPLE.ITUNES:ITUNESCOMPILATION"]
-            ?: id3v2["TCMP"]
-            ?: id3v2["TXXX:COMPILATION"]
-            ?: id3v2["TXXX:ITUNESCOMPILATION"])
-        ?.let {
-            // Ignore invalid instances of this tag
-            it == listOf("1")
-        }
+        ?: xiph["ITUNESCOMPILATION"]
+        ?: mp4["cpil"]
+        ?: mp4["----:COM.APPLE.ITUNES:COMPILATION"]
+        ?: mp4["----:COM.APPLE.ITUNES:ITUNESCOMPILATION"]
+        ?: id3v2["TCMP"]
+        ?: id3v2["TXXX:COMPILATION"]
+        ?: id3v2["TXXX:ITUNESCOMPILATION"]) == listOf("1")
 
 // ReplayGain information
 internal fun Metadata.replayGainTrackAdjustment() =
diff --git a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagParser.kt b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagParser.kt
index fcf3e48b8..42d76af43 100644
--- a/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagParser.kt
+++ b/musikr/src/main/java/org/oxycblt/musikr/tag/parse/TagParser.kt
@@ -32,6 +32,7 @@ internal interface TagParser {
 
 private data object TagParserImpl : TagParser {
     override fun parse(file: DeviceFile, metadata: Metadata): ParsedTags {
+        val compilation = metadata.isCompilation()
         return ParsedTags(
             durationMs = metadata.properties.durationMs,
             replayGainTrackAdjustment = metadata.replayGainTrackAdjustment(),
@@ -46,12 +47,20 @@ private data object TagParserImpl : TagParser {
             albumMusicBrainzId = metadata.albumMusicBrainzId(),
             albumName = metadata.albumName(),
             albumSortName = metadata.albumSortName(),
-            releaseTypes = metadata.releaseTypes() ?: listOf(),
+            // Compilation flag implies a compilation release type in the case that
+            // we don't have any other release types
+            releaseTypes =
+                metadata.releaseTypes() ?: listOf("compilation").takeIf { compilation } ?: listOf(),
             artistMusicBrainzIds = metadata.artistMusicBrainzIds() ?: listOf(),
             artistNames = metadata.artistNames() ?: listOf(),
             artistSortNames = metadata.artistSortNames() ?: listOf(),
             albumArtistMusicBrainzIds = metadata.albumArtistMusicBrainzIds() ?: listOf(),
-            albumArtistNames = metadata.albumArtistNames() ?: listOf(),
+            // Compilation pretty heavily implies various artists in the case that we don't
+            // have any other album artists
+            albumArtistNames =
+                metadata.albumArtistNames()
+                    ?: listOf("Various Artists").takeIf { compilation }
+                    ?: listOf(),
             albumArtistSortNames = metadata.albumArtistSortNames() ?: listOf(),
             genreNames = metadata.genreNames() ?: listOf())
     }