# Project Research Summary

## Executive Summary

This project involves building a weekly scheduler with calendar integration, designed as a modern, responsive web application for individual task management. Based on expert recommendations, the solution leverages React with Next.js as the core frontend framework, paired with TypeScript for type safety and Jotai for efficient state management. The architecture follows component-based patterns with clear separation of concerns, emphasizing local-first storage while supporting optional backend integration. Key pitfalls in this domain include inconsistent date/time handling, poor conflict resolution, inadequate offline support, and fragile calendar integrations, all of which require careful attention during implementation.

## Key Findings

### Stack Recommendations
- **Frontend**: React 18.3+ with Next.js 16+ for SSR and modern features; TypeScript 5.4+ for safety
- **Styling**: Tailwind CSS 3.4+ for rapid UI development
- **State Management**: Jotai 2.0+ for fine-grained state handling
- **Data Handling**: TanStack Query 5.0+ for server state, date-fns 3.6+ for date manipulation
- **Database**: localStorage/IndexedDB for client-side persistence with optional PostgreSQL 15+ for backend

### Feature Landscape
- **Table Stakes**: Weekly view display, task creation/editing/deletion, day navigation, responsive design, local storage persistence, drag-and-drop reordering, date/time selection
- **Differentiators**: Calendar integration, theme customization, recurring tasks, task categories/tags, reminders, export/import
- **Anti-Features**: Complex permissions, email notifications, multi-user collaboration, advanced reporting (defer to later phases)

### Architectural Patterns
- **Component Structure**: Weekly view, task list, creation form, navigation controls, data store, persistence layer, calendar sync service, week calculation service, validation layer
- **Data Flow**: User interaction → Component updates → Data processing → Storage operations → External sync → UI refresh
- **Patterns**: Component-based architecture, centralized state management, observer pattern for calendar sync
- **Anti-patterns**: Monolithic components, direct DOM manipulation, inconsistent data flow

### Critical Pitfalls
1. **Inconsistent Date/Time Handling**: Time zones and DST transitions causing scheduling errors
2. **Poor Event Conflict Resolution**: Incorrect handling of overlapping tasks
3. **Inadequate Offline Support**: Failure to function during connectivity issues
4. **Calendar Integration Fragility**: API instability causing sync failures

## Implications for Roadmap

Suggested phases based on dependencies and architectural patterns:

1. **Foundation & Core Features** — Establish essential functionality and data flow before introducing complexity
   - Delivers: Basic weekly view, task CRUD, navigation, persistence, drag-and-drop
   - Features from FEATURES.md: Weekly view, task creation/edit/delete, navigation, persistence, drag-and-drop
   - Avoids pitfalls: Offline support, basic date handling

2. **Advanced Features & UI Polish** — Add differentiators and enhance user experience
   - Delivers: Recurring tasks, categories, reminders, theme customization
   - Features from FEATURES.md: Recurring tasks, categories, reminders, themes
   - Avoids pitfalls: Complex UI, inefficient data storage

3. **Calendar Integration** — Enable syncing with external calendar systems
   - Delivers: Google/Apple calendar integration
   - Features from FEATURES.md: Calendar integration
   - Avoids pitfalls: Integration fragility, improper error handling

4. **Export & Advanced Functionality** — Provide data portability and advanced scheduling
   - Delivers: Import/export, advanced filtering
   - Features from FEATURES.md: Export/import, advanced categorization
   - Avoids pitfalls: Inadequate recurrence logic, inefficient data flow

Research Flags:
- Needs research: Phase 3 (Calendar Integration)
- Standard patterns: Phase 1 (Foundation), Phase 2 (Advanced Features), Phase 4 (Export/Advanced)

## Confidence Assessment

| Area | Confidence | Notes |
|------|------------|-------|
| Stack | HIGH | Well-documented with clear rationale and versioning |
| Features | HIGH | Comprehensive feature mapping with clear prioritization |
| Architecture | HIGH | Detailed component breakdown with clear communication patterns |
| Pitfalls | MEDIUM | Good coverage of critical and moderate risks but limited depth on minor issues |

Gaps to Address:
- Specific testing strategies for date/time handling
- Detailed calendar API integration patterns
- Performance benchmarks for large datasets
- Accessibility requirements for keyboard navigation

## Sources

- Modern React development patterns (2025)
- Next.js 16+ best practices
- Community adoption statistics for frontend tools
- Competitor analysis: TeuxDeux, Tweek.so, Google Tasks
- User experience research (2025)
- React-based calendar application architecture patterns
- Modern web application design principles
- Calendar integration best practices (Google Calendar API, Apple Calendar API)
- Community insights from calendar app design forums and UX communities
- Industry analysis of popular calendar applications (Google Calendar, Apple Calendar, Outlook)
- Common issues reported in developer forums and Stack Overflow
- Academic research on temporal data handling in distributed systems
- Post-mortems from calendar application failures