feat: show tasks completed today

backend/main.py

@@ -1024,6 +1024,8 @@ async def list_tasks(
     completed: bool | None = None,
     due_from: datetime | None = None,
     due_to: datetime | None = None,
+    completed_from: datetime | None = None,
+    completed_to: datetime | None = None,
     cursor: str | None = None,
     page: int | None = Query(default=None, ge=1),
     page_size: int | None = Query(default=None, ge=1, le=100),
@@ -1048,10 +1050,20 @@ async def list_tasks(
         query = query.where(Task.list_id == list_id)
     if completed is not None:
         query = query.where(Task.completed.is_(completed))
-    if due_from is not None:
-        query = query.where(Task.due_at >= due_from)
-    if due_to is not None:
-        query = query.where(Task.due_at < due_to)
+    if due_from is not None and due_to is not None and completed_from is not None and completed_to is not None:
+        query = query.where(or_(
+            and_(Task.due_at >= due_from, Task.due_at < due_to),
+            and_(Task.completed_at >= completed_from, Task.completed_at < completed_to),
+        ))
+    else:
+        if due_from is not None:
+            query = query.where(Task.due_at >= due_from)
+        if due_to is not None:
+            query = query.where(Task.due_at < due_to)
+        if completed_from is not None:
+            query = query.where(Task.completed_at >= completed_from)
+        if completed_to is not None:
+            query = query.where(Task.completed_at < completed_to)
     if q:
         pattern = f"%{q}%"
         list_match = exists(
@@ -1355,6 +1367,8 @@ async def batch_update_tasks(
     if payload.soft_delete:
         changes["deleted_at"] = utcnow()
     if changes:
+        if changes.get("completed") is False:
+            changes["completed_at"] = None
         changes["version"] = Task.version + 1
         changes["updated_at"] = utcnow()
         target_ids = set(task_ids)