Drag and drop cards between Kanban columns (#204)

src/ui/pyqt/board_view.py

@@ -1,6 +1,7 @@
 """Kanban board view for planning tasks."""
 
-from PyQt6.QtCore import Qt, pyqtSignal
+from PyQt6.QtCore import QMimeData, Qt, pyqtSignal
+from PyQt6.QtGui import QDrag
 from PyQt6.QtWidgets import (
     QFrame,
     QHBoxLayout,
@@ -13,13 +14,13 @@
 
 from logic.board import BOARD_STAGES, group_by_stage
 
-STAGE_LABELS = {
+BOARD_STAGE_LABELS = {
     "backlog": "Backlog",
     "in_progress": "In progress",
     "done": "Done",
 }
 
-CARD_ACTIONS = "Complete", "Edit", "Delete"
+BOARD_MIME_TYPE = "application/x-schedplus-task"
 
 
 class BoardCard(QWidget):
@@ -33,7 +34,7 @@ def __init__(self, task, parent=None):
         super().__init__(parent)
         self.task = task
         self.setObjectName("BoardCard")
-        self.setToolTip("Double-click to edit")
+        self.setToolTip("Drag to a column to move it; double-click to edit")
         self.setCursor(Qt.CursorShape.PointingHandCursor)
 
         layout = QVBoxLayout(self)
@@ -103,18 +104,43 @@ def __init__(self, task, parent=None):
         self.edit_button.clicked.connect(lambda: self.edit_requested.emit(task))
         self.delete_button.clicked.connect(lambda: self.delete_requested.emit(task))
 
+    @staticmethod
+    def drag_mime(task) -> QMimeData:
+        mime = QMimeData()
+        mime.setData(BOARD_MIME_TYPE, task.id.encode("utf-8"))
+        return mime
+
+    def mousePressEvent(self, event):
+        if event.button() == Qt.MouseButton.LeftButton:
+            drag = QDrag(self)
+            drag.setMimeData(self.drag_mime(self.task))
+            drag.setPixmap(self.grab())
+            drag.setHotSpot(drag.pixmap().rect().center())
+            drag.exec(Qt.DropAction.MoveAction)
+        super().mousePressEvent(event)
+
+    def mouseDoubleClickEvent(self, event):
+        if event.button() == Qt.MouseButton.LeftButton:
+            self.edit_requested.emit(self.task)
+        super().mouseDoubleClickEvent(event)
+
 
 class BoardColumn(QWidget):
     """A single stage column holding task cards."""
 
     edit_requested = pyqtSignal(object)
     delete_requested = pyqtSignal(object)
     complete_requested = pyqtSignal(object)
+    move_requested = pyqtSignal(str, str)
 
-    def __init__(self, title: str, parent=None):
+    def __init__(self, stage: str, parent=None):
         super().__init__(parent)
+        self.stage = stage
         self.setObjectName("BoardColumn")
+        self.setAcceptDrops(True)
+        self.setToolTip("Drop a card here to move it")
 
+        title = BOARD_STAGE_LABELS[stage]
         layout = QVBoxLayout(self)
         layout.setContentsMargins(10, 12, 10, 12)
         layout.setSpacing(8)
@@ -155,6 +181,27 @@ def set_tasks(self, tasks):
             self.card_layout.insertWidget(self.card_layout.count() - 1, card)
         self.empty_label.setVisible(len(tasks) == 0)
 
+    def dragEnterEvent(self, event):
+        if event.mimeData().hasFormat(BOARD_MIME_TYPE):
+            event.acceptProposedAction()
+        else:
+            event.ignore()
+
+    def dragMoveEvent(self, event):
+        if event.mimeData().hasFormat(BOARD_MIME_TYPE):
+            event.acceptProposedAction()
+        else:
+            event.ignore()
+
+    def dropEvent(self, event):
+        mime = event.mimeData()
+        if not mime.hasFormat(BOARD_MIME_TYPE):
+            event.ignore()
+            return
+        task_id = bytes(mime.data(BOARD_MIME_TYPE)).decode("utf-8")
+        self.move_requested.emit(task_id, self.stage)
+        event.acceptProposedAction()
+
 
 class BoardView(QWidget):
     """Kanban planning board: one column per stage."""
@@ -163,6 +210,7 @@ class BoardView(QWidget):
     edit_requested = pyqtSignal(object)
     delete_requested = pyqtSignal(object)
     complete_requested = pyqtSignal(object)
+    move_requested = pyqtSignal(object, str)
 
     def __init__(self, scheduler, parent=None):
         super().__init__(parent)
@@ -192,10 +240,11 @@ def __init__(self, scheduler, parent=None):
         self.columns_row.setSpacing(14)
         self.columns: dict[str, BoardColumn] = {}
         for stage in BOARD_STAGES:
-            column = BoardColumn(STAGE_LABELS[stage])
+            column = BoardColumn(stage)
             column.edit_requested.connect(self.edit_requested)
             column.delete_requested.connect(self.delete_requested)
             column.complete_requested.connect(self.complete_requested)
+            column.move_requested.connect(self._resolve_move)
             self.columns[stage] = column
             self.columns_row.addWidget(column, 1)
         layout.addWidget(self.columns_widget, 1)
@@ -224,5 +273,11 @@ def refresh(self):
             f"{total_on_board} of {len(self.scheduler.get_tasks())} tasks on the board"
         )
 
+    def _resolve_move(self, task_id: str, stage: str):
+        for task in self.scheduler.get_tasks():
+            if task.id == task_id:
+                self.move_requested.emit(task, stage)
+                return
+
     def focus_add(self):
         self.add_button.setFocus()

src/ui/pyqt/window.py

@@ -34,7 +34,7 @@
 from logic.validation import ValidationError
 from schedplus.identity import get_application_identity
 from ui.pyqt.add_dialog import AddTaskDialog, EditTaskDialog
-from ui.pyqt.board_view import BoardView
+from ui.pyqt.board_view import BOARD_STAGE_LABELS, BoardView
 from ui.pyqt.calendar_view import CalendarWorkspace
 from ui.pyqt.ics_import_dialog import IcsImportDialog
 from ui.pyqt.settings_dialog import SettingsDialog, SettingsStore, UiPreferences
@@ -123,6 +123,7 @@ def __init__(self, scheduler):
         self.board_page.edit_requested.connect(self.open_edit_dialog)
         self.board_page.delete_requested.connect(self.delete_task)
         self.board_page.complete_requested.connect(self.complete_task)
+        self.board_page.move_requested.connect(self.move_board_task)
 
         self._create_shortcuts()
         self.show_page(self.preferences.startup_view)
@@ -307,6 +308,22 @@ def delete_task(self, task):
         except StorageError as exc:
             self._show_storage_error("Unable to delete task", exc)
 
+    def move_board_task(self, task, stage):
+        if task.board_stage == stage:
+            return
+        self.scheduler.undo_manager.record_edit(task)
+        draft = replace(task, board_stage=stage)
+        try:
+            self.scheduler.update_task(draft)
+            self.refresh_views()
+            self.show_status_message(f"Task moved to {BOARD_STAGE_LABELS[stage]}")
+        except ValidationError as exc:
+            self.refresh_views()
+            self._show_validation_error(exc)
+        except StorageError as exc:
+            self.refresh_views()
+            self._show_storage_error("Unable to move task", exc)
+
     def complete_task(self, task):
         try:
             if task.completed == "true":

tests/test_pyqt_task_workspace.py

@@ -5,13 +5,15 @@
 
 os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
 
+from PyQt6.QtCore import QMimeData, Qt
 from PyQt6.QtWidgets import QApplication
 
 from logic import local_time
 from logic.ical_import import ICSImportPlan, SkippedEvent
-from logic.scheduler import Task
+from logic.scheduler import Scheduler, Task
+from logic.storage import sqlite_storage as storage
 from ui.pyqt.add_dialog import AddTaskDialog, EditTaskDialog
-from ui.pyqt.board_view import BoardColumn, BoardView
+from ui.pyqt.board_view import BOARD_MIME_TYPE, BoardCard, BoardColumn, BoardView
 from ui.pyqt.calendar_view import CalendarWorkspace
 from ui.pyqt.ics_import_dialog import IcsImportDialog
 from ui.pyqt.settings_dialog import SettingsDialog, UiPreferences
@@ -38,6 +40,15 @@ def app():
     yield application
 
 
+@pytest.fixture
+def task_database(monkeypatch, tmp_path):
+    path = tmp_path / "data" / "tasks.db"
+    path.parent.mkdir()
+    monkeypatch.setattr(storage, "prepare_database", lambda: path)
+    monkeypatch.setattr(storage, "_configure_logging", lambda _directory: None)
+    return path
+
+
 def test_theme_installs_brand_palette_and_covers_core_widgets(app):
     from PyQt6.QtGui import QPalette
 
@@ -272,7 +283,7 @@ def test_board_empty_state(app):
 
 def test_board_column_cards_forward_signals(app):
     task = Task(date="2026-09-11", time="09:00", text="Card", board_stage="backlog")
-    column = BoardColumn("Backlog")
+    column = BoardColumn("backlog")
     column.set_tasks([task])
     emitted = []
     column.complete_requested.connect(emitted.append)
@@ -299,6 +310,103 @@ def test_board_reflects_refreshed_scheduler(app):
     assert "1 of 1 tasks" in board.count_label.text()
 
 
+def test_board_card_mime_carries_task_id(app):
+    task = Task(date="2026-09-11", time="09:00", text="Card")
+    card = BoardCard(task)
+
+    assert card.drag_mime(task).hasFormat(BOARD_MIME_TYPE)
+    assert bytes(card.drag_mime(task).data(BOARD_MIME_TYPE)).decode("utf-8") == task.id
+
+
+def test_board_column_accepts_task_drops(app):
+    from PyQt6.QtCore import QPoint, QPointF
+    from PyQt6.QtGui import QDragEnterEvent, QDropEvent
+
+    column = BoardColumn("backlog")
+    moved = []
+    column.move_requested.connect(lambda task_id, stage: moved.append((task_id, stage)))
+
+    mime = QMimeData()
+    mime.setData(BOARD_MIME_TYPE, b"task-1")
+    enter = QDragEnterEvent(
+        QPoint(4, 4),
+        Qt.DropAction.MoveAction,
+        mime,
+        Qt.MouseButton.LeftButton,
+        Qt.KeyboardModifier.NoModifier,
+    )
+    column.dragEnterEvent(enter)
+    assert enter.isAccepted()
+
+    drop = QDropEvent(
+        QPointF(4, 4),
+        Qt.DropAction.MoveAction,
+        mime,
+        Qt.MouseButton.LeftButton,
+        Qt.KeyboardModifier.NoModifier,
+    )
+    column.dropEvent(drop)
+
+    assert drop.isAccepted()
+    assert moved == [("task-1", "backlog")]
+
+
+def test_board_view_resolves_column_move_to_task(app):
+    task = Task(date="2026-09-11", time="09:00", text="Card", board_stage="backlog")
+    board = BoardView(MemoryScheduler([task]))
+    emitted = []
+    board.move_requested.connect(lambda moved, stage: emitted.append((moved, stage)))
+
+    board.columns["backlog"].move_requested.emit(task.id, "done")
+
+    assert emitted == [(task, "done")]
+
+
+def test_window_board_move_persists_without_touching_completion(app, task_database):
+    storage.initialize_database()
+    scheduler = Scheduler()
+    task = scheduler.add_task(
+        "2026-09-11", "09:00", "Plan release", board_stage="backlog"
+    )
+    window = SchedPlusWindow(scheduler)
+
+    window.move_board_task(task, "done")
+
+    persisted = scheduler.load_tasks()[0]
+    assert persisted.board_stage == "done"
+    assert persisted.completed == task.completed
+    assert window.board_page.columns["done"].card_layout.count() == 2
+
+
+def test_window_board_move_to_same_column_is_noop(app, task_database):
+    storage.initialize_database()
+    scheduler = Scheduler()
+    task = scheduler.add_task(
+        "2026-09-11", "09:00", "Plan release", board_stage="backlog"
+    )
+    window = SchedPlusWindow(scheduler)
+
+    window.move_board_task(task, "backlog")
+
+    assert scheduler.load_tasks()[0].board_stage == "backlog"
+
+
+def test_window_undo_reverts_board_move(app, task_database):
+    storage.initialize_database()
+    scheduler = Scheduler()
+    task = scheduler.add_task(
+        "2026-09-11", "09:00", "Plan release", board_stage="backlog"
+    )
+    window = SchedPlusWindow(scheduler)
+
+    window.move_board_task(task, "done")
+    assert scheduler.load_tasks()[0].board_stage == "done"
+
+    scheduler.undo_manager.undo()
+
+    assert scheduler.load_tasks()[0].board_stage == "backlog"
+
+
 def test_add_dialog_boards_task_when_checked(app):
     dialog = AddTaskDialog()