Address remaining QA items: indexes, validation, UX improvements

Backend:
- [W1] Add server_default=func.now() on created_at/updated_at
- [W2] Add index on reset_at column (migration 016)
- [W7] Document weekly reset edge case in code comment

Frontend:
- [W4] Extract shared isTodoOverdue() utility in lib/utils.ts,
  used consistently across TodosPage, TodoItem, TodoList
- [W5] Delete requires double-click confirmation (button turns red
  for 2s, second click confirms) with optimistic removal
- [W6] Stat cards now reflect filtered counts, not global
- [S3] Optimistic delete with rollback on error
- [S4] Add "None" to priority segmented filter
- [S7] Sort todos within groups by due date ascending

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/alembic/versions/016_add_todo_indexes_and_defaults.py

@@ -0,0 +1,28 @@
+"""Add index on reset_at and server defaults on timestamps
+
+Revision ID: 016
+Revises: 015
+Create Date: 2026-02-23
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "016"
+down_revision = "015"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_index("ix_todos_reset_at", "todos", ["reset_at"])
+    op.alter_column("todos", "created_at", server_default=sa.func.now())
+    op.alter_column("todos", "updated_at", server_default=sa.func.now())
+
+
+def downgrade() -> None:
+    op.alter_column("todos", "updated_at", server_default=None)
+    op.alter_column("todos", "created_at", server_default=None)
+    op.drop_index("ix_todos_reset_at", table_name="todos")

backend/app/models/todo.py

@@ -18,11 +18,11 @@ class Todo(Base):
     completed_at: Mapped[Optional[datetime]] = mapped_column(nullable=True)
     category: Mapped[Optional[str]] = mapped_column(String(100), nullable=True)
     recurrence_rule: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
-    reset_at: Mapped[Optional[datetime]] = mapped_column(nullable=True)
+    reset_at: Mapped[Optional[datetime]] = mapped_column(nullable=True, index=True)
     next_due_date: Mapped[Optional[date]] = mapped_column(Date, nullable=True)
     project_id: Mapped[Optional[int]] = mapped_column(Integer, ForeignKey("projects.id"), nullable=True)
-    created_at: Mapped[datetime] = mapped_column(default=func.now())
-    updated_at: Mapped[datetime] = mapped_column(default=func.now(), onupdate=func.now())
+    created_at: Mapped[datetime] = mapped_column(default=func.now(), server_default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(default=func.now(), onupdate=func.now(), server_default=func.now())
 
     # Relationships
     project: Mapped[Optional["Project"]] = relationship(back_populates="todos")

backend/app/routers/todos.py

@@ -41,7 +41,7 @@ def _calculate_recurrence(
         target_weekday = 6 if first_day_of_week == 0 else 0  # Python weekday for start
         days_ahead = (target_weekday - today.weekday()) % 7
         if days_ahead == 0:
-            days_ahead = 7  # Always push to *next* week
+            days_ahead = 7  # Always push to *next* week, even if completed on the first day
         reset_date = today + timedelta(days=days_ahead)
 
         if current_due_date:

frontend/src/components/todos/TodoItem.tsx

@@ -1,10 +1,11 @@
+import { useState } from 'react';
 import { useMutation, useQueryClient } from '@tanstack/react-query';
 import { toast } from 'sonner';
 import { Trash2, Pencil, Calendar, Clock, AlertCircle, RefreshCw } from 'lucide-react';
-import { format, isToday, isPast, parseISO, startOfDay } from 'date-fns';
+import { format, isToday, parseISO } from 'date-fns';
 import api from '@/lib/api';
 import type { Todo } from '@/types';
-import { cn } from '@/lib/utils';
+import { cn, isTodoOverdue } from '@/lib/utils';
 import { Checkbox } from '@/components/ui/checkbox';
 import { Button } from '@/components/ui/button';
 
@@ -26,8 +27,11 @@ const recurrenceLabels: Record<string, string> = {
   monthly: 'Monthly',
 };
 
+const QUERY_KEYS = [['todos'], ['dashboard'], ['upcoming']] as const;
+
 export default function TodoItem({ todo, onEdit }: TodoItemProps) {
   const queryClient = useQueryClient();
+  const [confirmingDelete, setConfirmingDelete] = useState(false);
 
   const toggleMutation = useMutation({
     mutationFn: async () => {
@@ -35,9 +39,7 @@ export default function TodoItem({ todo, onEdit }: TodoItemProps) {
       return data;
     },
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['todos'] });
-      queryClient.invalidateQueries({ queryKey: ['dashboard'] });
-      queryClient.invalidateQueries({ queryKey: ['upcoming'] });
+      QUERY_KEYS.forEach((key) => queryClient.invalidateQueries({ queryKey: [...key] }));
       toast.success(todo.completed ? 'Todo marked incomplete' : 'Todo completed!');
     },
     onError: () => {
@@ -49,20 +51,42 @@ export default function TodoItem({ todo, onEdit }: TodoItemProps) {
     mutationFn: async () => {
       await api.delete(`/todos/${todo.id}`);
     },
+    onMutate: async () => {
+      // Optimistic removal
+      await queryClient.cancelQueries({ queryKey: ['todos'] });
+      const previous = queryClient.getQueryData<Todo[]>(['todos']);
+      queryClient.setQueryData<Todo[]>(['todos'], (old) =>
+        old ? old.filter((t) => t.id !== todo.id) : []
+      );
+      return { previous };
+    },
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['todos'] });
-      queryClient.invalidateQueries({ queryKey: ['dashboard'] });
-      queryClient.invalidateQueries({ queryKey: ['upcoming'] });
+      QUERY_KEYS.forEach((key) => queryClient.invalidateQueries({ queryKey: [...key] }));
       toast.success('Todo deleted');
     },
-    onError: () => {
+    onError: (_err, _vars, context) => {
+      // Rollback on failure
+      if (context?.previous) {
+        queryClient.setQueryData(['todos'], context.previous);
+      }
       toast.error('Failed to delete todo');
     },
   });
 
+  const handleDelete = () => {
+    if (!confirmingDelete) {
+      setConfirmingDelete(true);
+      // Auto-reset after 2 seconds if not confirmed
+      setTimeout(() => setConfirmingDelete(false), 2000);
+      return;
+    }
+    deleteMutation.mutate();
+    setConfirmingDelete(false);
+  };
+
   const dueDate = todo.due_date ? parseISO(todo.due_date) : null;
   const isDueToday = dueDate ? isToday(dueDate) : false;
-  const isOverdue = dueDate && !todo.completed ? isPast(startOfDay(dueDate)) && !isDueToday : false;
+  const isOverdue = isTodoOverdue(todo.due_date, todo.completed);
 
   const resetDate = todo.reset_at ? parseISO(todo.reset_at) : null;
   const nextDueDate = todo.next_due_date ? parseISO(todo.next_due_date) : null;
@@ -155,10 +179,15 @@ export default function TodoItem({ todo, onEdit }: TodoItemProps) {
       <Button
         variant="ghost"
         size="icon"
-        aria-label="Delete todo"
-        onClick={() => deleteMutation.mutate()}
+        aria-label={confirmingDelete ? 'Confirm delete' : 'Delete todo'}
+        onClick={handleDelete}
         disabled={deleteMutation.isPending}
-        className="h-7 w-7 shrink-0 hover:bg-destructive/10 hover:text-destructive"
+        className={cn(
+          'h-7 w-7 shrink-0',
+          confirmingDelete
+            ? 'bg-destructive/20 text-destructive'
+            : 'hover:bg-destructive/10 hover:text-destructive'
+        )}
       >
         <Trash2 className="h-3 w-3" />
       </Button>

frontend/src/components/todos/TodoList.tsx

@@ -1,7 +1,8 @@
 import { useMemo } from 'react';
 import { CheckSquare } from 'lucide-react';
-import { parseISO, isToday, isPast, startOfDay } from 'date-fns';
+import { parseISO, isToday, compareAsc } from 'date-fns';
 import type { Todo } from '@/types';
+import { isTodoOverdue } from '@/lib/utils';
 import { EmptyState } from '@/components/ui/empty-state';
 import TodoItem from './TodoItem';
 
@@ -17,6 +18,14 @@ interface TodoGroup {
   todos: Todo[];
 }
 
+/** Sort todos by due_date ascending (earliest first), nulls last. */
+function sortByDueDate(a: Todo, b: Todo): number {
+  if (!a.due_date && !b.due_date) return 0;
+  if (!a.due_date) return 1;
+  if (!b.due_date) return -1;
+  return compareAsc(parseISO(a.due_date), parseISO(b.due_date));
+}
+
 export default function TodoList({ todos, onEdit, onAdd }: TodoListProps) {
   const groups = useMemo(() => {
     const overdue: Todo[] = [];
@@ -36,16 +45,20 @@ export default function TodoList({ todos, onEdit, onAdd }: TodoListProps) {
         continue;
       }
 
-      const dueDate = parseISO(todo.due_date);
-      if (isToday(dueDate)) {
+      if (isToday(parseISO(todo.due_date))) {
         today.push(todo);
-      } else if (isPast(startOfDay(dueDate))) {
+      } else if (isTodoOverdue(todo.due_date, false)) {
         overdue.push(todo);
       } else {
         upcoming.push(todo);
       }
     }
 
+    // Sort date-bearing groups by due date ascending
+    overdue.sort(sortByDueDate);
+    today.sort(sortByDueDate);
+    upcoming.sort(sortByDueDate);
+
     const result: TodoGroup[] = [];
     if (overdue.length > 0) result.push({ key: 'overdue', label: 'Overdue', todos: overdue });
     if (today.length > 0) result.push({ key: 'today', label: 'Today', todos: today });

frontend/src/components/todos/TodosPage.tsx

@@ -3,6 +3,7 @@ import { Plus, CheckSquare, CheckCircle2, AlertCircle, Search, ChevronDown } fro
 import { useQuery } from '@tanstack/react-query';
 import api from '@/lib/api';
 import type { Todo } from '@/types';
+import { isTodoOverdue } from '@/lib/utils';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Card, CardContent } from '@/components/ui/card';
@@ -14,6 +15,7 @@ import TodoForm from './TodoForm';
 
 const priorityFilters = [
   { value: '', label: 'All' },
+  { value: 'none', label: 'None' },
   { value: 'low', label: 'Low' },
   { value: 'medium', label: 'Medium' },
   { value: 'high', label: 'High' },
@@ -59,14 +61,9 @@ export default function TodosPage() {
     [todos, filters]
   );
 
-  const now = new Date();
-  const todayStr = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`;
-
-  const totalCount = todos.filter((t) => !t.completed).length;
-  const completedCount = todos.filter((t) => t.completed).length;
-  const overdueCount = todos.filter(
-    (t) => !t.completed && t.due_date && t.due_date < todayStr
-  ).length;
+  const totalCount = filteredTodos.filter((t) => !t.completed).length;
+  const completedCount = filteredTodos.filter((t) => t.completed).length;
+  const overdueCount = filteredTodos.filter((t) => isTodoOverdue(t.due_date, t.completed)).length;
 
   const handleEdit = (todo: Todo) => {
     setEditingTodo(todo);

frontend/src/lib/utils.ts

@@ -1,6 +1,17 @@
 import { type ClassValue, clsx } from 'clsx';
 import { twMerge } from 'tailwind-merge';
+import { parseISO, isToday, isPast, startOfDay } from 'date-fns';
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs));
 }
+
+/**
+ * Check if a todo's due date is overdue (past and not today).
+ * Returns false if no due_date or if the todo is completed.
+ */
+export function isTodoOverdue(dueDate: string | undefined, completed: boolean): boolean {
+  if (!dueDate || completed) return false;
+  const parsed = parseISO(dueDate);
+  return isPast(startOfDay(parsed)) && !isToday(parsed);
+}