From c0c4da1bc3b2d41e2d95300a7ee03ae8bd71a152 Mon Sep 17 00:00:00 2001
From: Uwe Klotz <uklotz@mixxx.org>
Date: Wed, 9 Sep 2020 17:04:43 +0200
Subject: [PATCH] Fallback: Parse "artist-title" with a single dash from file
 name

As requested and suggested on Discourse:
https://mixxx.discourse.group/t/metadata-from-filename-not-creating-artist-title/19901
---
 src/test/trackmetadata_test.cpp | 48 +++++++++++++++++++++++------
 src/track/trackinfo.cpp         | 53 +++++++++++++++++++--------------
 src/track/trackinfo.h           |  2 +-
 3 files changed, 70 insertions(+), 33 deletions(-)

diff --git a/src/test/trackmetadata_test.cpp b/src/test/trackmetadata_test.cpp
index aec136ab0c2..51f2e2286c3 100644
--- a/src/test/trackmetadata_test.cpp
+++ b/src/test/trackmetadata_test.cpp
@@ -14,19 +14,19 @@ TEST_F(TrackMetadataTest, parseArtistTitleFromFileName) {
     }
     {
         mixxx::TrackInfo trackInfo;
-        trackInfo.parseArtistTitleFromFileName(" only-title ", true);
-        EXPECT_EQ(QString(), trackInfo.getArtist());
-        EXPECT_EQ("only-title", trackInfo.getTitle());
+        trackInfo.parseArtistTitleFromFileName(" artist-title ", true);
+        EXPECT_EQ("artist", trackInfo.getArtist());
+        EXPECT_EQ("title", trackInfo.getTitle());
     }
     {
         mixxx::TrackInfo trackInfo;
-        trackInfo.parseArtistTitleFromFileName(" only -_title ", true);
-        EXPECT_EQ(QString(), trackInfo.getArtist());
-        EXPECT_EQ("only -_title", trackInfo.getTitle());
+        trackInfo.parseArtistTitleFromFileName(" artist -_title ", true);
+        EXPECT_EQ("artist", trackInfo.getArtist());
+        EXPECT_EQ("_title", trackInfo.getTitle());
     }
     {
         mixxx::TrackInfo trackInfo;
-        trackInfo.parseArtistTitleFromFileName(" only  -  title ", false);
+        trackInfo.parseArtistTitleFromFileName(" only  -  title.mp3", false);
         EXPECT_EQ(QString(), trackInfo.getArtist());
         EXPECT_EQ("only  -  title", trackInfo.getTitle());
     }
@@ -38,9 +38,39 @@ TEST_F(TrackMetadataTest, parseArtistTitleFromFileName) {
     }
     {
         mixxx::TrackInfo trackInfo;
-        trackInfo.parseArtistTitleFromFileName(" only -\ttitle\t", true);
+        trackInfo.parseArtistTitleFromFileName(" ar.tist -\tti.tle\t.mp3", true);
+        EXPECT_EQ("ar.tist", trackInfo.getArtist());
+        EXPECT_EQ("ti.tle", trackInfo.getTitle());
+    }
+    {
+        mixxx::TrackInfo trackInfo;
+        trackInfo.parseArtistTitleFromFileName(" -artist - -title-.mp3", true);
+        EXPECT_EQ("-artist", trackInfo.getArtist());
+        EXPECT_EQ("-title-", trackInfo.getTitle());
+    }
+    {
+        mixxx::TrackInfo trackInfo;
+        trackInfo.parseArtistTitleFromFileName(" -artist ti-tle- ", true);
         EXPECT_EQ(QString(), trackInfo.getArtist());
-        EXPECT_EQ("only -\ttitle", trackInfo.getTitle());
+        EXPECT_EQ("-artist ti-tle-", trackInfo.getTitle());
+    }
+    {
+        mixxx::TrackInfo trackInfo;
+        trackInfo.parseArtistTitleFromFileName(" artist- title ", true);
+        EXPECT_EQ("artist", trackInfo.getArtist());
+        EXPECT_EQ("title", trackInfo.getTitle());
+    }
+    {
+        mixxx::TrackInfo trackInfo;
+        trackInfo.parseArtistTitleFromFileName(" artist- ", true);
+        EXPECT_EQ("artist", trackInfo.getArtist());
+        EXPECT_EQ(QString(), trackInfo.getTitle());
+    }
+    {
+        mixxx::TrackInfo trackInfo;
+        trackInfo.parseArtistTitleFromFileName(" -title ", true);
+        EXPECT_EQ(QString(), trackInfo.getArtist());
+        EXPECT_EQ("title", trackInfo.getTitle());
     }
     {
         mixxx::TrackInfo trackInfo;
diff --git a/src/track/trackinfo.cpp b/src/track/trackinfo.cpp
index 14f33f2e4d9..3d843634bd0 100644
--- a/src/track/trackinfo.cpp
+++ b/src/track/trackinfo.cpp
@@ -1,41 +1,48 @@
 #include "track/trackinfo.h"
 
-
-namespace mixxx {
+#include <QFileInfo>
 
 namespace {
 
+const QString kDefaultArtistTitleSeparator = QStringLiteral("_-_");
 const QString kArtistTitleSeparatorWithSpaces = QStringLiteral(" - ");
-const QString kArtistTitleSeparator = QStringLiteral("_-_");
-
-const QChar kFileExtensionSeparator = '.';
+const QChar kFallbackArtistTitleSeparator = QChar('-');
 
 } // anonymous namespace
 
+namespace mixxx {
+
 bool TrackInfo::parseArtistTitleFromFileName(
-        QString fileName,
+        const QString& fileName,
         bool splitArtistTitle) {
     bool modified = false;
-    fileName = fileName.trimmed();
-    auto titleWithFileType = fileName;
+    auto title = QFileInfo(fileName).completeBaseName().trimmed();
     if (splitArtistTitle) {
-        fileName.replace(kArtistTitleSeparatorWithSpaces, kArtistTitleSeparator);
-        if (fileName.count(kArtistTitleSeparator) == 1) {
-            auto artist = fileName.section(kArtistTitleSeparator, 0, 0).trimmed();
-            if (!artist.isEmpty()) {
-                setArtist(artist);
-                modified = true;
-            }
-            titleWithFileType = fileName.section(kArtistTitleSeparator, 1).trimmed();
+        QString artist;
+        // Preprocessing for disambiguation
+        auto splitArtist = title;
+        splitArtist.replace(kArtistTitleSeparatorWithSpaces, kDefaultArtistTitleSeparator);
+        // Splitting
+        QString artistTitleSeparator;
+        if (splitArtist.count(kDefaultArtistTitleSeparator) == 1) {
+            artistTitleSeparator = kDefaultArtistTitleSeparator;
+        } else if (splitArtist.count(kFallbackArtistTitleSeparator) == 1) {
+            artistTitleSeparator = kFallbackArtistTitleSeparator;
+        }
+        if (!artistTitleSeparator.isEmpty()) {
+            const int splitPos = splitArtist.indexOf(artistTitleSeparator);
+            DEBUG_ASSERT(splitPos >= 0);
+            DEBUG_ASSERT(splitPos == splitArtist.lastIndexOf(artistTitleSeparator));
+            artist = splitArtist.left(splitPos).trimmed();
+            const auto rightLen = splitArtist.size() - (splitPos + artistTitleSeparator.size());
+            title = splitArtist.right(rightLen).trimmed();
+        }
+        if (!artist.isEmpty() && artist != getArtist()) {
+            setArtist(artist);
+            modified = true;
         }
     }
-    auto title = titleWithFileType;
-    if (titleWithFileType.contains(kFileExtensionSeparator)) {
-        // Strip file extension starting at the right-most '.'
-        title = titleWithFileType.section(kFileExtensionSeparator, 0, -2);
-    }
-    title = title.trimmed();
-    if (!title.isEmpty()) {
+    if (!title.isEmpty() && title != getTitle()) {
         setTitle(title);
         modified = true;
     }
diff --git a/src/track/trackinfo.h b/src/track/trackinfo.h
index 3315244ad49..9ab4269390a 100644
--- a/src/track/trackinfo.h
+++ b/src/track/trackinfo.h
@@ -66,7 +66,7 @@ class TrackInfo final {
 
     // Returns true if modified
     bool parseArtistTitleFromFileName(
-            QString fileName,
+            const QString& fileName,
             bool splitArtistTitle);
 
     // Adjusts floating-point properties to match their string representation