feat(library): Add custom date format with live preview

- Replaced DateFormat enum with QString to support custom formats.
- Leveraged QLocale for 'Native' (System Default) date formatting.
- Updated Library Preferences with an editable combobox and live Preview label.
- Added presets for ISO 8601 and Regional formats.
- Added unit tests for date formatting logic.

Author: xARSENICx

src/library/basetracktablemodel.cpp

@@ -115,10 +115,10 @@ void BaseTrackTableModel::setApplyPlayedTrackColor(bool apply) {
     s_bApplyPlayedTrackColor = apply;
 }
 
-mixxx::DateFormat BaseTrackTableModel::s_dateFormat =
-        BaseTrackTableModel::kDateFormatDefault;
+const QString BaseTrackTableModel::kDateFormatDefault = QString();
+QString BaseTrackTableModel::s_dateFormat = BaseTrackTableModel::kDateFormatDefault;
 
-void BaseTrackTableModel::setDateFormat(mixxx::DateFormat format) {
+void BaseTrackTableModel::setDateFormat(const QString& format) {
     s_dateFormat = format;
 }
 

src/library/basetracktablemodel.h

@@ -133,8 +133,8 @@ class BaseTrackTableModel : public QAbstractTableModel, public TrackModel {
     static constexpr bool kApplyPlayedTrackColorDefault = true;
     static void setApplyPlayedTrackColor(bool apply);
 
-    static constexpr mixxx::DateFormat kDateFormatDefault = mixxx::DateFormat::Native;
-    static void setDateFormat(mixxx::DateFormat format);
+    static const QString kDateFormatDefault;
+    static void setDateFormat(const QString& format);
 
   protected:
     // Build a map from the column names to their indices
@@ -311,5 +311,5 @@ class BaseTrackTableModel : public QAbstractTableModel, public TrackModel {
     static std::optional<ColorPalette> s_keyColorPalette;
 
     static bool s_bApplyPlayedTrackColor;
-    static mixxx::DateFormat s_dateFormat;
+    static QString s_dateFormat;
 };

src/preferences/dialog/dlgpreflibrary.cpp

@@ -111,18 +111,19 @@ DlgPrefLibrary::DlgPrefLibrary(
 
     updateSearchLineEditHistoryOptions();
 
-    comboBox_dateFormat->addItem(tr("Native (System Default)"),
-            static_cast<int>(mixxx::DateFormat::Native));
-    comboBox_dateFormat->addItem(tr("YYYY-MM-DD"),
-            static_cast<int>(mixxx::DateFormat::ISO8601));
-    comboBox_dateFormat->addItem(tr("DD/MM/YYYY"),
-            static_cast<int>(mixxx::DateFormat::DayMonthYear));
-    comboBox_dateFormat->addItem(tr("MM/DD/YYYY"),
-            static_cast<int>(mixxx::DateFormat::MonthDayYear));
-    comboBox_dateFormat->addItem(tr("YYYY/MM/DD"),
-            static_cast<int>(mixxx::DateFormat::YearMonthDay));
+    comboBox_dateFormat->setEditable(true);
+    // Use empty string data for Native to invoke QLocale default
+    comboBox_dateFormat->addItem(tr("Native (System Default)"), QString());
+    comboBox_dateFormat->addItem(tr("ISO 8601 (yyyy-MM-dd)"), QStringLiteral("yyyy-MM-dd"));
+    comboBox_dateFormat->addItem(tr("Regional Short (d/M/yy)"), QStringLiteral("d/M/yy"));
+    comboBox_dateFormat->addItem(tr("Regional Long (dd.MM.yyyy)"), QStringLiteral("dd.MM.yyyy"));
+    // Custom option is handled by the edit behavior
+
+    // Update preview initially
+    slotDateFormatChanged(comboBox_dateFormat->currentText());
+
     connect(comboBox_dateFormat,
-            QOverload<int>::of(&QComboBox::currentIndexChanged),
+            &QComboBox::currentTextChanged,
             this,
             &DlgPrefLibrary::slotDateFormatChanged);
 
@@ -283,10 +284,13 @@ void DlgPrefLibrary::slotResetToDefaults() {
     comboBox_search_bpm_fuzzy_range->setCurrentIndex(
             comboBox_search_bpm_fuzzy_range->findData(kDefaultFuzzyRateRangePercent));
 
-    int defaultDateFormat = static_cast<int>(BaseTrackTableModel::kDateFormatDefault);
-    int dateIndex = comboBox_dateFormat->findData(defaultDateFormat);
+    int dateIndex = comboBox_dateFormat->findData(BaseTrackTableModel::kDateFormatDefault);
     if (dateIndex != -1) {
         comboBox_dateFormat->setCurrentIndex(dateIndex);
+    } else {
+        // Fallback or custom default? Default is usually Native (empty string)
+        // which should be found.
+        comboBox_dateFormat->setCurrentIndex(0);
     }
 
     checkBox_show_rhythmbox->setChecked(true);
@@ -331,15 +335,18 @@ void DlgPrefLibrary::slotUpdate() {
     checkBox_show_serato->setChecked(m_pConfig->getValue(
             ConfigKey("[Library]", "ShowSeratoLibrary"), true));
 
-    int dateFormat = m_pConfig->getValue(
+    QString dateFormat = m_pConfig->getValue(
             kDateFormatConfigKey,
-            static_cast<int>(BaseTrackTableModel::kDateFormatDefault));
+            BaseTrackTableModel::kDateFormatDefault);
     int dateIndex = comboBox_dateFormat->findData(dateFormat);
     if (dateIndex != -1) {
         comboBox_dateFormat->setCurrentIndex(dateIndex);
+    } else {
+        // Custom format string
+        comboBox_dateFormat->setCurrentText(dateFormat);
     }
     // Ensure the static member is updated on startup/load
-    BaseTrackTableModel::setDateFormat(static_cast<mixxx::DateFormat>(dateFormat));
+    BaseTrackTableModel::setDateFormat(dateFormat);
 
     switch (m_pConfig->getValue<int>(
             kTrackDoubleClickActionConfigKey,
@@ -747,9 +754,25 @@ void DlgPrefLibrary::setSeratoMetadataEnabled(bool shouldSyncTrackMetadata) {
     }
 }
 
-void DlgPrefLibrary::slotDateFormatChanged(int index) {
-    int formatInt = comboBox_dateFormat->itemData(index).toInt();
-    mixxx::DateFormat format = static_cast<mixxx::DateFormat>(formatInt);
-    m_pConfig->setValue(kDateFormatConfigKey, formatInt);
+void DlgPrefLibrary::slotDateFormatChanged(const QString& text) {
+    QString format = text;
+    // Check if the text matches a predefined item (like "Native (...)")
+    int index = comboBox_dateFormat->findText(text);
+    if (index != -1) {
+        // Use the underlying data (e.g. empty string for Native, or "yyyy-MM-dd" for ISO)
+        format = comboBox_dateFormat->itemData(index).toString();
+    }
+
+    // Update Preview
+    QDate exampleDate = QDate::currentDate();
+    QString previewStr;
+    if (format.isEmpty()) {
+        previewStr = QLocale().toString(exampleDate, QLocale::ShortFormat);
+    } else {
+        previewStr = exampleDate.toString(format);
+    }
+    label_dateFormatPreview->setText(previewStr);
+
+    m_pConfig->setValue(kDateFormatConfigKey, format);
     BaseTrackTableModel::setDateFormat(format);
 }

src/preferences/dialog/dlgpreflibrary.h

@@ -67,7 +67,7 @@ class DlgPrefLibrary : public DlgPreferencePage, public Ui::DlgPrefLibraryDlg {
     void slotBpmRangeSelected(int index);
     void slotBpmColumnPrecisionChanged(int bpmPrecision);
     void slotSeratoMetadataExportClicked(bool);
-    void slotDateFormatChanged(int index);
+    void slotDateFormatChanged(const QString& text);
 
   private:
     void populateDirList();

src/preferences/dialog/dlgpreflibrarydlg.ui

@@ -308,9 +308,16 @@
         </property>
        </widget>
       </item>
-      <item row="11" column="1" colspan="2">
+      <item row="11" column="1">
        <widget class="QComboBox" name="comboBox_dateFormat"/>
       </item>
+      <item row="11" column="2">
+       <widget class="QLabel" name="label_dateFormatPreview">
+        <property name="text">
+         <string>Preview</string>
+        </property>
+       </widget>
+      </item>
 
      </layout>
     </widget>

src/test/datetime_test.cpp

@@ -0,0 +1,36 @@
+#include "util/datetime.h"
+
+#include <gtest/gtest.h>
+
+#include <QDate>
+#include <QLocale>
+
+namespace mixxx {
+
+TEST(DateTimeTest, FormatDate) {
+    QDate date(2023, 10, 25);
+
+    // Test ISO
+    EXPECT_EQ(formatDate(date, "yyyy-MM-dd"), "2023-10-25");
+
+    // Test Custom
+    EXPECT_EQ(formatDate(date, "dd.MM.yy"), "25.10.23");
+
+    // Test Native (empty string)
+    // Should fallback to QLocale::ShortFormat
+    QString native = QLocale().toString(date, QLocale::ShortFormat);
+    EXPECT_EQ(formatDate(date, ""), native);
+}
+
+TEST(DateTimeTest, FormatDateTime) {
+    QDateTime dt(QDate(2023, 10, 25), QTime(14, 30, 0));
+
+    // Test Custom
+    EXPECT_EQ(formatDateTime(dt, "yyyy-MM-dd HH:mm"), "2023-10-25 14:30");
+
+    // Test Native (empty string)
+    QString native = QLocale().toString(dt, QLocale::ShortFormat);
+    EXPECT_EQ(formatDateTime(dt, ""), native);
+}
+
+} // namespace mixxx

src/util/datetime.h

@@ -8,15 +8,6 @@
 
 namespace mixxx {
 
-/// Date format options for library display
-enum class DateFormat {
-    Native = 0,       ///< System locale default (e.g. 5/20/1998)
-    ISO8601 = 1,      ///< YYYY-MM-DD
-    DayMonthYear = 2, ///< DD/MM/YYYY
-    MonthDayYear = 3, ///< MM/DD/YYYY
-    YearMonthDay = 4, ///< YYYY/MM/DD
-};
-
 /// Common utility functions for safely converting and consistently
 /// displaying date time values.
 
@@ -37,59 +28,38 @@ inline QDateTime convertVariantToDateTime(
     return data.toDateTime();
 }
 
-/// Helper to format a QDate according to DateFormat
+/// Helper to format a QDate according to a format string.
+/// If format is empty, uses the system's default locale short format.
 inline QString formatDate(
         const QDate& date,
-        DateFormat format) {
+        const QString& format = QString()) {
     if (!date.isValid()) {
         return QString();
     }
-    switch (format) {
-    case DateFormat::ISO8601:
-        return date.toString(Qt::ISODate);
-    case DateFormat::DayMonthYear:
-        return date.toString(QStringLiteral("dd/MM/yyyy"));
-    case DateFormat::MonthDayYear:
-        // Use standard US format MM/DD/YYYY
-        return date.toString(QStringLiteral("MM/dd/yyyy"));
-    case DateFormat::YearMonthDay:
-        return date.toString(QStringLiteral("yyyy/MM/dd"));
-    case DateFormat::Native:
-    default:
+    if (format.isEmpty()) {
         return QLocale().toString(date, QLocale::ShortFormat);
     }
+    return date.toString(format);
 }
 
-/// Helper to format a QDateTime according to DateFormat
+/// Helper to format a QDateTime according to a format string.
+/// If format is empty, uses the system's default locale short format.
 inline QString formatDateTime(
         const QDateTime& dt,
-        DateFormat format) {
+        const QString& format = QString()) {
     if (!dt.isValid()) {
         return QString();
     }
-    switch (format) {
-    case DateFormat::ISO8601:
-        // Qt::ISODate includes 'T' and can include time zone, but usually we
-        // just want YYYY-MM-DD HH:mm:ss for display. Let's start with a
-        // comprehensive custom format closest to ISO 8601 style preference.
-        return dt.toString(QStringLiteral("yyyy-MM-dd hh:mm"));
-    case DateFormat::DayMonthYear:
-        return dt.toString(QStringLiteral("dd/MM/yyyy hh:mm"));
-    case DateFormat::MonthDayYear:
-        return dt.toString(QStringLiteral("MM/dd/yyyy hh:mm"));
-    case DateFormat::YearMonthDay:
-        return dt.toString(QStringLiteral("yyyy/MM/dd hh:mm"));
-    case DateFormat::Native:
-    default:
-        // Uses QLocale::ShortFormat for both Date and Time
+    if (format.isEmpty()) {
         return QLocale().toString(dt, QLocale::ShortFormat);
     }
+    return dt.toString(format);
 }
 
 /// Format a QDateTime for display to the user using the
 /// application's locale settings or specified preference.
 inline QString displayLocalDateTime(
-        const QDateTime& dt, DateFormat format = DateFormat::Native) {
+        const QDateTime& dt, const QString& format = QString()) {
     return formatDateTime(dt, format);
 }