My-Weekly-ToDo-List/Version 01/.planning/research/ARCHITECTURE.md

Architecture Patterns

Domain: Weekly Scheduler with Calendar Integration Researched: Sat Jan 24 2026

Recommended Architecture

A weekly scheduler with calendar integration typically follows a component-based architecture with clear separation between UI presentation, data management, and external integrations.

The core architecture consists of:

1. Presentation Layer - Responsible for rendering the weekly schedule grid
2. Data Management Layer - Handles task storage, retrieval, and organization
3. Calendar Integration Layer - Manages connections to external calendar services
4. Business Logic Layer - Manages scheduling rules and workflows

Component Boundaries

Component	Responsibility	Communicates With
Weekly View Component	Renders the weekly schedule grid with days and time slots	Task Data Store, Navigation Controls
Task List Component	Displays tasks for a specific week/day	Data Store, Task Creation Form
Task Creation Form	Handles creating/editing tasks with validation	Data Store, Validation Layer
Navigation Controls	Manage week navigation (previous/next week)	Data Store, Week Calculator
Data Store	Centralized storage and management of tasks and schedule data	Persistence Layer, UI Components
Persistence Layer	Handles local storage or database operations	Data Store, External Sync
Calendar Sync Service	Manages integration with external calendars (Google, Apple)	Calendar APIs, Data Store
Week Calculation Service	Handles date calculations and week boundary logic	Navigation Components, Data Store
Validation Layer	Validates task data before saving	Form Components, Data Store

Data Flow

1. User Interaction: User interacts with UI (clicking days, creating tasks)
2. Component Updates: UI components update state or dispatch actions
3. Data Processing: Business logic processes task creation/update/deletion
4. Storage Operation: Data Store coordinates with persistence layer
5. External Sync: Calendar sync service handles external calendar integration
6. UI Refresh: Changes propagate back to UI through state updates

Patterns to Follow

Pattern 1: Component-Based Architecture

What: Break the application into reusable, self-contained components When: For maintainability and scalability of UI elements Example:

// WeeklyView Component
function WeeklyView({ tasks, onTaskSelect, onTaskCreate }) {
  return (
    <div className="weekly-view">
      <WeekNavigation />
      <DayColumns tasks={tasks} />
    </div>
  );
}

Pattern 2: State Management with Context API or Similar

What: Centralized state management for task data and UI state When: When multiple components need access to the same data Example:

const TaskContext = createContext();

function TaskProvider({ children }) {
  const [tasks, setTasks] = useState([]);
  
  return (
    <TaskContext.Provider value={{ tasks, setTasks }}>
      {children}
    </TaskContext.Provider>
  );
}

Pattern 3: Observer Pattern for Calendar Sync

What: Event-driven architecture for keeping data synchronized When: For external calendar integration and real-time updates Example:

class CalendarSyncService {
  constructor() {
    this.observers = [];
  }
  
  subscribe(observer) {
    this.observers.push(observer);
  }
  
  notifyObservers(change) {
    this.observers.forEach(obs => obs.update(change));
  }
}

Anti-Patterns to Avoid

Anti-Pattern 1: Monolithic Component Structure

What: Having one massive component that handles everything Why bad: Makes code hard to maintain, debug, and test Instead: Break into smaller, focused components

Anti-Pattern 2: Direct DOM Manipulation

What: Interacting directly with DOM elements instead of using state management Why bad: Breaks React's declarative model, leads to unpredictable UI states Instead: Use React state and props for all UI changes

Anti-Pattern 3: Inconsistent Data Flow

What: Mixing different state management patterns throughout the app Why bad: Makes code hard to reason about and maintain Instead: Choose one consistent pattern (Context API, Redux, or Jotai)

Scalability Considerations

Concern	At 100 users	At 10K users	At 1M users
UI Rendering	Standard rendering	Virtualized lists for performance	Server-side rendering + caching
Data Storage	Client-side storage (localStorage)	Backend database with indexing	Distributed database with sharding
Calendar Sync	Client-side polling	Background sync jobs	Asynchronous processing queues
Concurrent Access	Single user context	Multi-user isolation	Database transactions with locking

Sources

• React-based calendar application architecture patterns
• Modern web application design principles
• Calendar integration best practices (Google Calendar API, Apple Calendar API)