Todo Management - Chronos Calendar

Overview

Chronos Calendar includes a powerful todo management system that helps you organize tasks alongside your calendar events. Todos can be categorized into custom lists, scheduled for specific dates, and reordered via drag-and-drop.

Todo Lists (Categories)

System Lists

Each user starts with default system lists:

Inbox: Default list for uncategorized tasks
Today: Tasks scheduled for today
Upcoming: Tasks scheduled for future dates

System lists cannot be deleted or renamed, but you can create unlimited custom lists.

Custom Lists

Create your own lists to organize todos by project, context, or priority:

Create List

Add a new list with custom name and color

Customize

Choose from multiple color options

Reorder

Drag lists to change their order

Delete

Remove custom lists (todos are reassigned)

Creating a List

# From todos.py:205-222
@router.post("/todo-lists")
@limiter.limit(settings.RATE_LIMIT_API)
async def create_todo_list(request: Request, todo_list: TodoListCreate, current_user: CurrentUser):
    supabase = get_supabase_client()
    user_id = current_user["id"]

    list_data = {
        "user_id": user_id,
        "name": Encryption.encrypt(todo_list.name, user_id),
        "color": todo_list.color,
        "is_system": False,
        "order": get_next_order(supabase, "todo_lists", user_id),
    }

    result = supabase.table("todo_lists").insert(list_data).execute()
    if not result.data:
        raise HTTPException(status_code=500, detail="Failed to create list")
    return to_camel_case(decrypt_field(result.data[0], "name", user_id, skip_if_system=True))

List names are encrypted at rest for privacy, just like event data.

Managing Todos

Creating Todos

Add a new todo with:

Title: Task description (required)
List: Target category (required)
Scheduled Date: Optional due date
Completion Status: Automatically set to incomplete

# From todos.py:98-125
@router.post("")
@limiter.limit(settings.RATE_LIMIT_API)
async def create_todo(request: Request, todo: TodoCreate, current_user: CurrentUser):
    supabase = get_supabase_client()
    user_id = current_user["id"]

    # Validate list exists
    list_check = (
        supabase.table("todo_lists")
        .select("id")
        .eq("id", todo.listId)
        .eq("user_id", user_id)
        .execute()
    )
    if not list_check.data:
        raise HTTPException(status_code=400, detail="Invalid list_id")

    todo_data = {
        "user_id": user_id,
        "title": Encryption.encrypt(todo.title, user_id),
        "list_id": todo.listId,
        "scheduled_date": str(todo.scheduledDate) if todo.scheduledDate else None,
        "order": get_next_order(supabase, "todos", user_id),
        "completed": False,
    }

Updating Todos

Title
Completion
List
Scheduled Date

Edit the todo text:

await api.updateTodo(todoId, {
  title: "Updated task description"
})

Mark as complete/incomplete:

await api.updateTodo(todoId, {
  completed: true
})

Completed todos are typically shown with strikethrough or moved to a “Completed” section.

Move to a different category:

await api.updateTodo(todoId, {
  listId: newListId
})

# From todos.py:138-147
if "list_id" in update_data and update_data["list_id"]:
    list_check = (
        supabase.table("todo_lists")
        .select("id")
        .eq("id", update_data["list_id"])
        .eq("user_id", user_id)
        .execute()
    )
    if not list_check.data:
        raise HTTPException(status_code=400, detail="Invalid list_id")

Set or change the due date:

await api.updateTodo(todoId, {
  scheduledDate: "2024-03-15"
})

Todos with scheduled dates appear in date-based views and the “Today” list.

Deleting Todos

Remove a todo permanently:

# From todos.py:169-185
@router.delete("/{todo_id}")
@limiter.limit(settings.RATE_LIMIT_API)
async def delete_todo(request: Request, todo_id: UUID, current_user: CurrentUser):
    supabase = get_supabase_client()

    result = (
        supabase.table("todos")
        .delete()
        .eq("id", str(todo_id))
        .eq("user_id", current_user["id"])
        .execute()
    )

    if not result.data:
        raise HTTPException(status_code=404, detail="Todo not found")

    return {"message": "Todo deleted"}

Deleting a todo is permanent and cannot be undone. Consider marking as complete instead.

Ordering and Reordering

Automatic Ordering

New todos are automatically placed at the top of the list:

# From todos.py:51-61
def get_next_order(supabase, table: str, user_id: str) -> int:
    result = (
        supabase.table(table)
        .select("order")
        .eq("user_id", user_id)
        .order("order")
        .limit(1)
        .execute()
    )
    min_order = result.data[0]["order"] if result.data else 0
    return min_order - 1  # New items get negative order for top placement

This ensures new todos appear at the top without having to renumber existing items.

Drag-and-Drop Reordering

Reorder todos by dragging them:

# From todos.py:287-292
@router.post("/reorder")
@limiter.limit(settings.RATE_LIMIT_API)
async def reorder_todos(request: Request, reorder_request: ReorderRequest, current_user: CurrentUser):
    supabase = get_supabase_client()
    reorder_items(supabase, "todos", current_user["id"], reorder_request.todoIds)
    return {"message": "Reordered"}

How reordering works

When you drag a todo to a new position:

Frontend captures the new order of todo IDs
Array of IDs sent to /reorder endpoint
Backend assigns sequential order numbers (0, 1, 2, …)
Database updated with new order values

# From todos.py:64-72
def reorder_items(supabase, table: str, user_id: str, item_ids: list[UUID]):
    for index, item_id in enumerate(item_ids):
        (
            supabase.table(table)
            .update({"order": index})
            .eq("id", str(item_id))
            .eq("user_id", user_id)
            .execute()
        )

List Reordering

You can also reorder the lists themselves:

# From todos.py:279-284
@router.post("/todo-lists/reorder")
@limiter.limit(settings.RATE_LIMIT_API)
async def reorder_todo_lists(request: Request, reorder_request: CategoryReorderRequest, current_user: CurrentUser):
    supabase = get_supabase_client()
    reorder_items(supabase, "todo_lists", current_user["id"], reorder_request.categoryIds)
    return {"message": "Reordered"}

Data Privacy and Encryption

Encrypted Fields

Sensitive todo data is encrypted:

Todo titles: Task descriptions
List names: Category names (except system lists)

# From todos.py:37-48
def decrypt_field(data: dict, field: str, user_id: str, skip_if_system: bool = False) -> dict:
    result = dict(data)
    if skip_if_system and result.get("is_system"):
        return result  # System lists not encrypted
    if result.get(field):
        try:
            result[field] = Encryption.decrypt(result[field], user_id)
        except ValueError:
            logger.warning("Failed to decrypt %s for %s", field, result.get("id"))
            result[field] = "[Decryption Error]"
    return result

System list names (Inbox, Today, Upcoming) are not encrypted since they’re standard across all users.

API Endpoints

Todo Endpoints

GET /todos

List all todos, optionally filtered by list ID

POST /todos

Create a new todo

PUT /todos/:id

Update an existing todo

DELETE /todos/:id

Delete a todo

POST /todos/reorder

Reorder todos via drag-and-drop

List Management Endpoints

GET /todo-lists

List all todo lists/categories

POST /todo-lists

Create a new list

PUT /todo-lists/:id

Update list name or color

DELETE /todo-lists/:id

Delete a custom list

POST /todo-lists/reorder

Reorder lists in sidebar

Rate Limiting

All todo endpoints are rate-limited:

# From todos.py:75-76
@router.get("")
@limiter.limit(settings.RATE_LIMIT_API)
async def list_todos(...):

Rate limits prevent abuse and ensure fair usage. The default limit is configured in settings.RATE_LIMIT_API.

Field Mapping

Camel Case Conversion

API uses camelCase while database uses snake_case:

# From todos.py:19-27
CAMEL_TO_SNAKE = {"listId": "list_id", "scheduledDate": "scheduled_date"}
SNAKE_TO_CAMEL = {
    "user_id": "userId",
    "list_id": "listId",
    "scheduled_date": "scheduledDate",
    "created_at": "createdAt",
    "updated_at": "updatedAt",
    "is_system": "isSystem",
}

Conversion happens automatically in request/response handlers.

Local Storage

Todos are also stored locally in IndexedDB for offline access:

// From db.ts:63-73, 75-83
export interface DexieTodo {
  id: string;
  userId: string;
  title: string;
  completed: boolean;
  scheduledDate?: string;
  listId: string;
  order: number;
  createdAt: string;
  updatedAt: string;
}

export interface DexieTodoList {
  id: string;
  userId: string;
  name: string;
  color: string;
  icon?: string;
  isSystem: boolean;
  order: number;
}

Database schema:

// From db.ts:112-113
todos: "id, listId, userId, order",
todoLists: "id, userId, order",

Integration with Calendar

Todos with scheduled dates appear in calendar views:

Day View: Shows todos scheduled for that day
Week View: Displays todos across the week
Today View: Special filter for today’s todos

Scheduled date filtering

When rendering calendar views, todos are filtered by scheduledDate:

const todosForDate = todos.filter(todo => 
  todo.scheduledDate === formatDate(currentDate)
)

This allows you to see both events and tasks in a unified timeline.

Best Practices

Use Categories

Organize todos into meaningful lists (Work, Personal, Shopping, etc.)

Schedule Tasks

Set scheduled dates to see todos alongside calendar events

Regular Cleanup

Delete or archive completed todos to keep lists manageable

Priority Ordering

Drag important tasks to the top of each list

Getting Started

Features

User Guide

Architecture

​Overview

​Todo Lists (Categories)

​System Lists

​Custom Lists

Create List

Customize

Reorder

Delete

​Creating a List

​Managing Todos

​Creating Todos

​Updating Todos

​Deleting Todos

​Ordering and Reordering

​Automatic Ordering

​Drag-and-Drop Reordering

​List Reordering

​Data Privacy and Encryption

​Encrypted Fields

​API Endpoints

​Todo Endpoints

GET /todos

POST /todos

PUT /todos/:id

DELETE /todos/:id

POST /todos/reorder

​List Management Endpoints

GET /todo-lists

POST /todo-lists

PUT /todo-lists/:id

DELETE /todo-lists/:id

POST /todo-lists/reorder

​Rate Limiting

​Field Mapping

​Camel Case Conversion

​Local Storage

​Integration with Calendar

​Best Practices

Use Categories

Schedule Tasks

Regular Cleanup

Priority Ordering

Build docs developers (and LLMs) love

Overview

Todo Lists (Categories)

System Lists

Custom Lists

Creating a List

Managing Todos

Creating Todos

Updating Todos

Deleting Todos

Ordering and Reordering

Automatic Ordering

Drag-and-Drop Reordering

List Reordering

Data Privacy and Encryption

Encrypted Fields

API Endpoints

Todo Endpoints

List Management Endpoints

Rate Limiting

Field Mapping

Camel Case Conversion

Local Storage

Integration with Calendar

Best Practices