PICARD-2103: Add UI to manage custom columns

picard/ui/itemviews/__init__.py

@@ -414,14 +414,13 @@ def update_colums_text(self, color=None, bgcolor=None):
             else:
                 if column.align == ColumnAlign.RIGHT:
                     self.setTextAlignment(i, QtCore.Qt.AlignmentFlag.AlignRight | QtCore.Qt.AlignmentFlag.AlignVCenter)
-                # Support custom columns with provider evaluation
-                try:
-                    if isinstance(column, CustomColumn):
+
+                if isinstance(column, CustomColumn):
+                    try:
                         self.setText(i, column.provider.evaluate(self.obj))
-                        continue
-                except Exception:  # noqa: BLE001
-                    # Fallback to default behavior
-                    pass
+                    except (AttributeError, TypeError, ValueError, KeyError, NotImplementedError) as exc:
+                        log.debug("Custom column '%s' evaluate failed: %r", column.key, exc)
+                    continue
                 self.setText(i, self.obj.column(column.key))
 
 

picard/ui/itemviews/basetreeview.py

@@ -91,6 +91,7 @@
 from picard.ui.collectionmenu import CollectionMenu
 from picard.ui.enums import MainAction
 from picard.ui.filter import Filter
+from picard.ui.itemviews.events import header_events
 from picard.ui.itemviews.match_quality_column import MatchQualityColumn, MatchQualityColumnDelegate
 from picard.ui.ratingwidget import RatingWidget
 from picard.ui.scriptsmenu import ScriptsMenu
@@ -176,6 +177,10 @@ def __init__(self, columns, window, parent=None):
         self.setAccessibleDescription(_(self.DESCRIPTION))
         self.tagger = QtCore.QCoreApplication.instance()
         self.window = window
+
+        # Subscribe to header update events
+        header_events.headers_updated.connect(self._on_header_updated)
+
         # Should multiple files dropped be assigned to tracks sequentially?
         self._move_to_multi_tracks = True
 
@@ -387,9 +392,26 @@ def save_state(self):
         config.persist[self.header_state] = state
         config.persist[self.header_locked] = header.is_locked
 
+    def _set_header_labels(self, update_column_count=False):
+        """Set header labels based on current columns.
+
+        Parameters
+        ----------
+        update_column_count : bool, optional
+            Whether to update the column count to match the number of columns,
+            by default False.
+        """
+        from picard.ui.columns import Columns as _Columns
+
+        cols = self.columns
+        if isinstance(cols, _Columns):
+            if update_column_count:
+                self.setColumnCount(len(cols))
+            labels = tuple(_(c.title) for c in cols)
+            self.setHeaderLabels(labels)
+
     def restore_default_columns(self):
-        labels = tuple(_(c.title) for c in self.columns)
-        self.setHeaderLabels(labels)
+        self._set_header_labels(update_column_count=False)
 
         header = self.header()
         header.setStretchLastSection(True)
@@ -407,7 +429,25 @@ def restore_default_columns(self):
 
         self.sortByColumn(-1, QtCore.Qt.SortOrder.AscendingOrder)
 
+    def _refresh_header_labels(self):
+        """Refresh header labels (and count) based on current columns."""
+        self._set_header_labels(update_column_count=True)
+
+    def _on_header_updated(self):
+        """Handle global header update events and refresh if applicable."""
+        from picard.ui.itemviews.custom_columns.shared import get_recognized_view_columns
+
+        recognized = set(get_recognized_view_columns().values())
+        if self.columns not in recognized:
+            return
+        self._refresh_header_labels()
+
     def _init_header(self):
+        # Load any persisted user-defined custom columns before header setup
+        from picard.ui.itemviews.custom_columns.storage import load_persisted_columns_once
+
+        load_persisted_columns_once()
+
         header = ConfigurableColumnsHeader(self.columns, parent=self)
         self.setHeader(header)
 

picard/ui/itemviews/custom_columns/__init__.py

@@ -42,8 +42,10 @@
     CasefoldSortAdapter,
     CompositeSortAdapter,
     DescendingCasefoldSortAdapter,
+    DescendingNaturalSortAdapter,
     DescendingNumericSortAdapter,
     LengthSortAdapter,
+    NaturalSortAdapter,
     NullsFirstAdapter,
     NullsLastAdapter,
     NumericSortAdapter,
@@ -67,6 +69,8 @@
     "DescendingCasefoldSortAdapter",
     "NumericSortAdapter",
     "DescendingNumericSortAdapter",
+    "NaturalSortAdapter",
+    "DescendingNaturalSortAdapter",
     "LengthSortAdapter",
     "ArticleInsensitiveAdapter",
     "CompositeSortAdapter",

picard/ui/itemviews/custom_columns/column_controller.py

@@ -0,0 +1,117 @@
+# -*- coding: utf-8 -*-
+#
+# Picard, the next-generation MusicBrainz tagger
+#
+# Copyright (C) 2025 The MusicBrainz Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+"""Column controller facade for custom column management dialogs.
+
+Thin facade layer that reduces complexity in dialog components by
+encapsulating validation and specification management logic.
+
+Classes
+-------
+ColumnController
+    Facade class that simplifies custom column operations for dialogs.
+"""
+
+from typing import Iterable
+
+from picard.ui.itemviews.custom_columns.column_spec_service import ColumnSpecService
+from picard.ui.itemviews.custom_columns.spec_list_model import SpecListModel
+from picard.ui.itemviews.custom_columns.storage import CustomColumnSpec
+from picard.ui.itemviews.custom_columns.validation import (
+    ColumnSpecValidator,
+    ValidationContext,
+    ValidationReport,
+)
+
+
+class ColumnController:
+    """Facade for custom column operations in dialog components.
+
+    Provides simplified interface for common custom column operations,
+    delegating to specialized services.
+
+    Parameters
+    ----------
+    spec_service : ColumnSpecService
+        Service for managing column specifications.
+    validator : ColumnSpecValidator
+        Validator for checking specification validity.
+    """
+
+    def __init__(self, spec_service: ColumnSpecService, validator: ColumnSpecValidator) -> None:
+        """Initialize the column controller with required services."""
+        self._spec_service = spec_service
+        self._validator = validator
+
+    def validate_specs(self, specs: Iterable[CustomColumnSpec]) -> dict[str, ValidationReport]:
+        """Validate multiple column specifications.
+
+        Returns
+        -------
+        dict[str, ValidationReport]
+            Dictionary mapping specification keys to validation reports.
+        """
+        return self._validator.validate_multiple(specs)
+
+    def first_invalid_spec(self, specs: Iterable[CustomColumnSpec]) -> CustomColumnSpec | None:
+        """Find the first invalid specification in a collection.
+
+        Returns
+        -------
+        CustomColumnSpec | None
+            First invalid specification found, or None if all valid.
+        """
+        reports = self.validate_specs(specs)
+        for spec, report in reports.items():
+            if not report.is_valid:
+                return spec
+        return None
+
+    def first_invalid_spec_report(self, report: dict[str, ValidationReport]) -> tuple[str, ValidationReport] | None:
+        """Get first invalid specification with its validation report.
+
+        Returns
+        -------
+        tuple[str, ValidationReport] | None
+            (key, validation_report) for first invalid spec, or None.
+        """
+        for key, validation_report in report.items():
+            if not validation_report.is_valid:
+                return key, validation_report
+        return None
+
+    def validate_single(self, spec: CustomColumnSpec, existing_keys: set[str]) -> ValidationReport:
+        """Validate a single column specification.
+
+        Returns
+        -------
+        ValidationReport
+            Report detailing the validation result.
+        """
+        context = ValidationContext(existing_keys=existing_keys)
+        return self._validator.validate(spec, context)
+
+    def apply_all(self, model: SpecListModel) -> None:
+        """Apply all specifications from a model.
+
+        Deduplicates and persists specifications.
+        """
+        self._spec_service.deduplicate_model_by_keys(model)
+        self._spec_service.persist_and_register(model.specs())