Merge pull request #462 from Arthur-Milchior/filter_empty_card

Add a hook to change empty cards to delete

qt/aqt/gui_hooks.py

@@ -862,6 +862,51 @@ class _EditorWillUseFontForFieldFilter:
 editor_will_use_font_for_field = _EditorWillUseFontForFieldFilter()
 
 
+class _EmptyCardsWillBeDeletedFilter:
+    """Allow to change the list of cards to delete.
+
+        For example, an add-on creating a method to delete only empty
+        new cards would be done as follow:
+```
+from anki.consts import CARD_TYPE_NEW
+from anki.utils import ids2str
+from aqt import mw
+from aqt import gui_hooks
+
+def filter(cids, col):
+    return col.db.list(
+            f"select id from cards where (type={CARD_TYPE_NEW} and (id in {ids2str(cids)))")
+
+def emptyNewCard():
+    gui_hooks.append(filter)
+    mw.onEmptyCards()
+    gui_hooks.remove(filter)
+```"""
+
+    _hooks: List[Callable[[List[int]], List[int]]] = []
+
+    def append(self, cb: Callable[[List[int]], List[int]]) -> None:
+        """(cids: List[int])"""
+        self._hooks.append(cb)
+
+    def remove(self, cb: Callable[[List[int]], List[int]]) -> None:
+        if cb in self._hooks:
+            self._hooks.remove(cb)
+
+    def __call__(self, cids: List[int]) -> List[int]:
+        for filter in self._hooks:
+            try:
+                cids = filter(cids)
+            except:
+                # if the hook fails, remove it
+                self._hooks.remove(filter)
+                raise
+        return cids
+
+
+empty_cards_will_be_deleted = _EmptyCardsWillBeDeletedFilter()
+
+
 class _MediaSyncDidProgressHook:
     _hooks: List[Callable[["aqt.mediasync.LogEntryWithTime"], None]] = []
 

qt/aqt/main.py

@@ -1303,6 +1303,7 @@ will be lost. Continue?"""
     def onEmptyCards(self):
         self.progress.start(immediate=True)
         cids = self.col.emptyCids()
+        cids = gui_hooks.empty_cards_will_be_deleted(cids)
         if not cids:
             self.progress.finish()
             tooltip(_("No empty cards."))

qt/tools/genhooks_gui.py

@@ -346,6 +346,30 @@ hooks = [
         name="media_sync_did_progress", args=["entry: aqt.mediasync.LogEntryWithTime"],
     ),
     Hook(name="media_sync_did_start_or_stop", args=["running: bool"]),
+    Hook(
+        name="empty_cards_will_be_deleted",
+        args=["cids: List[int]"],
+        return_type="List[int]",
+        doc="""Allow to change the list of cards to delete.
+
+        For example, an add-on creating a method to delete only empty
+        new cards would be done as follow:
+```
+from anki.consts import CARD_TYPE_NEW
+from anki.utils import ids2str
+from aqt import mw
+from aqt import gui_hooks
+
+def filter(cids, col):
+    return col.db.list(
+            f"select id from cards where (type={CARD_TYPE_NEW} and (id in {ids2str(cids)))")
+
+def emptyNewCard():
+    gui_hooks.append(filter)
+    mw.onEmptyCards()
+    gui_hooks.remove(filter)
+```""",
+    ),
     # Adding cards
     ###################
     Hook(