daily-notification-plugin/docs/IMPLEMENTATION_PLAN.md

Implementation Plan: Callback System & Dual Scheduling

Document Created: 2025-08-26 11:17:26 UTC
Author: Matthew Raymer
Status: 📋 PLANNING PHASE
Priority: 🔴 HIGH - Core functionality enhancement required

🎯 IMPLEMENTATION OVERVIEW

Goal

Transform the Daily Notification Plugin from a single-method scheduler to a dual-method system with comprehensive callback support for external service integration.

Key Changes

1. Add callback system for API, database, and reporting services
2. Implement dual scheduling methods:
   • scheduleContentFetch() - API calls and database storage
   • scheduleUserNotification() - Database retrieval and user notification
3. Maintain backward compatibility with existing API

---

🚀 IMMEDIATE NEXT STEPS

Step 1: Create Feature Branch (Next 30 minutes)

git checkout -b feature/callback-api-integration
git push -u origin feature/callback-api-integration

Step 2: Interface Design (Next 2-4 hours)

• Design callback interfaces
• Create dual scheduling method signatures
• Plan backward compatibility strategy
• Document interface changes

Step 3: Implementation Planning (Next 2-3 hours)

• Break down implementation into tasks
• Estimate effort for each component
• Identify dependencies and risks
• Create testing strategy

---

📋 DETAILED IMPLEMENTATION TASKS

Phase 1: Interface Updates (Day 1)

Task 1.1: Extend Existing Interfaces

Estimated Effort: 2-3 hours
Priority: 🔴 HIGH

// Update NotificationOptions interface
interface NotificationOptions {
  // Existing properties...
  
  // New callback properties
  apiCallbacks?: APICallbacks;
  databaseCallbacks?: DatabaseCallbacks;
  reportingCallbacks?: ReportingCallbacks;
}

Subtasks:

• Define APICallbacks interface
• Define DatabaseCallbacks interface
• Define ReportingCallbacks interface
• Update existing interface tests

Task 1.2: Create New Scheduling Interfaces

Estimated Effort: 2-3 hours
Priority: 🔴 HIGH

interface ContentFetchOptions {
  url: string;
  apiCallbacks: APICallbacks;
  databaseCallbacks: DatabaseCallbacks;
  retryConfig: RetryConfig;
}

interface UserNotificationOptions {
  contentId: string;
  notificationCallbacks: NotificationCallbacks;
  userInteractionCallbacks: UserInteractionCallbacks;
}

Subtasks:

• Design ContentFetchOptions interface
• Design UserNotificationOptions interface
• Create supporting interfaces (RetryConfig, etc.)
• Write interface documentation

Phase 2: Core Implementation (Days 2-3)

Task 2.1: Callback Registry System

Estimated Effort: 6-8 hours
Priority: 🔴 HIGH

class CallbackRegistry {
  registerCallback(type: CallbackType, callback: Function): string;
  unregisterCallback(type: CallbackType, id: string): boolean;
  executeCallback(type: CallbackType, data: any): Promise<void>;
  validateCallback(callback: Function): boolean;
}

Subtasks:

• Implement callback registration system
• Add callback validation and security
• Create callback execution engine
• Add error handling and logging
• Write comprehensive tests

Task 2.2: Dual Scheduling Methods

Estimated Effort: 8-10 hours
Priority: 🔴 HIGH

// New method 1: Content fetch and storage
async scheduleContentFetch(options: ContentFetchOptions): Promise<void>

// New method 2: User notification
async scheduleUserNotification(options: UserNotificationOptions): Promise<void>

Subtasks:

• Implement scheduleContentFetch() method
• Implement scheduleUserNotification() method
• Add API call handling with callbacks
• Add database operation callbacks
• Implement retry and fallback logic
• Write method tests

Task 2.3: Backward Compatibility Layer

Estimated Effort: 4-6 hours
Priority: 🟡 MEDIUM

// Maintain existing method for backward compatibility
async scheduleDailyNotification(options: NotificationOptions): Promise<void> {
  // Route to appropriate new method based on options
  if (options.apiCallbacks || options.databaseCallbacks) {
    return this.scheduleContentFetch(this.convertToContentFetchOptions(options));
  } else {
    return this.scheduleUserNotification(this.convertToUserNotificationOptions(options));
  }
}

Subtasks:

• Refactor existing method to use new system
• Add deprecation warnings
• Create migration path for existing users
• Ensure existing functionality continues to work

Phase 3: Platform Integration (Days 3-4)

Task 3.1: Android Implementation

Estimated Effort: 6-8 hours
Priority: 🔴 HIGH

Subtasks:

• Update Android plugin to support callbacks
• Integrate with WorkManager for background tasks
• Add database callback support
• Implement API callback handling
• Add error handling and logging

Task 3.2: iOS Implementation

Estimated Effort: 6-8 hours
Priority: 🔴 HIGH

Subtasks:

• Update iOS plugin to support callbacks
• Integrate with BGTaskScheduler
• Add Core Data callback support
• Implement API callback handling
• Add error handling and logging

Task 3.3: Web Implementation

Estimated Effort: 4-6 hours
Priority: 🟡 MEDIUM

Subtasks:

• Update web plugin to support callbacks
• Integrate with Service Workers
• Add IndexedDB callback support
• Implement API callback handling
• Add error handling and logging

Phase 4: Testing & Documentation (Day 5)

Task 4.1: Comprehensive Testing

Estimated Effort: 8-10 hours
Priority: 🔴 HIGH

Subtasks:

• Write unit tests for callback system
• Test dual scheduling methods
• Test API integration scenarios
• Test database callback scenarios
• Test cross-platform compatibility
• Performance testing

Task 4.2: Documentation Updates

Estimated Effort: 4-6 hours
Priority: 🟡 MEDIUM

Subtasks:

• Update API documentation
• Create callback usage examples
• Add dual scheduling examples
• Create migration guide
• Update README and examples

---

🔧 TECHNICAL IMPLEMENTATION DETAILS

Callback Execution Model

// Asynchronous callback execution with error handling
async executeCallback(type: CallbackType, data: any): Promise<void> {
  try {
    const callbacks = this.getCallbacks(type);
    const promises = callbacks.map(callback => 
      this.executeSingleCallback(callback, data)
    );
    
    await Promise.allSettled(promises);
  } catch (error) {
    this.handleCallbackError(type, error);
  }
}

Error Handling Strategy

// Comprehensive error handling for callbacks
private handleCallbackError(type: CallbackType, error: Error): void {
  // Log error for debugging
  this.logger.error(`Callback execution failed for type: ${type}`, error);
  
  // Execute error callbacks if available
  this.executeErrorCallbacks(type, error);
  
  // Fallback to default error handling
  this.executeDefaultErrorHandling(type, error);
}

Retry and Fallback Logic

// Retry logic with exponential backoff
async executeWithRetry<T>(
  operation: () => Promise<T>,
  maxRetries: number = 3,
  baseDelay: number = 1000
): Promise<T> {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      return await operation();
    } catch (error) {
      if (attempt === maxRetries) throw error;
      
      const delay = baseDelay * Math.pow(2, attempt - 1);
      await this.sleep(delay);
    }
  }
  throw new Error('Max retries exceeded');
}

---

🧪 TESTING STRATEGY

Unit Testing

• Callback Registration: Test registration/unregistration
• Callback Execution: Test successful and failed executions
• Error Handling: Test various error scenarios
• Performance: Test callback execution performance

Integration Testing

• API Integration: Test with real external services
• Database Integration: Test database callback scenarios
• Cross-Platform: Test consistency across platforms
• End-to-End: Test complete notification flow

Performance Testing

• Callback Latency: Measure execution time
• Memory Usage: Monitor memory impact
• Battery Impact: Test battery usage
• Scalability: Test with multiple callbacks

---

📊 SUCCESS CRITERIA

Functional Requirements

• Callback System: 100% callback execution success rate
• Dual Scheduling: Both methods working independently
• API Integration: Successful external service integration
• Database Support: Reliable callback-based storage operations
• Backward Compatibility: Existing code continues to work

Quality Requirements

• Test Coverage: 95%+ coverage for new functionality
• Performance: No degradation in existing functionality
• Security: Secure callback execution and validation
• Documentation: Complete API documentation updates

Platform Requirements

• Android: Full callback support with WorkManager
• iOS: Full callback support with BGTaskScheduler
• Web: Full callback support with Service Workers
• Cross-Platform: Consistent behavior across platforms

---

🚨 RISKS & MITIGATION

High-Risk Areas

1. Interface Changes: Breaking changes to existing API

   • Mitigation: Maintain backward compatibility with deprecation warnings

2. Performance Impact: Callback overhead on notification delivery

   • Mitigation: Implement callback batching and optimization

3. Platform Differences: Ensuring consistent behavior across platforms

   • Mitigation: Create platform-agnostic callback interfaces

4. Error Handling: Complex callback failure scenarios

   • Mitigation: Comprehensive error handling with fallbacks

Risk Mitigation Strategies

• Phased Implementation: Implement in small, testable units
• Comprehensive Testing: Test all scenarios thoroughly
• Performance Monitoring: Monitor impact throughout implementation
• Rollback Plan: Maintain ability to revert changes if needed

---

📅 TIMELINE & MILESTONES

Week 1: Foundation & Design

• Day 1: Interface design and planning
• Day 2: Core implementation planning
• Day 3: Begin core implementation

Week 2: Implementation & Integration

• Day 4: Complete core implementation
• Day 5: Begin platform integration
• Day 6: Complete platform integration
• Day 7: Begin testing

Week 3: Testing & Documentation

• Day 8: Complete testing
• Day 9: Documentation updates
• Day 10: Final review and deployment

---

🎯 NEXT IMMEDIATE ACTIONS

Today (Next 4-6 hours)

1. Create feature branch for implementation
2. Complete interface design for callback system
3. Create implementation plan with task breakdown
4. Set up testing framework for new functionality

Tomorrow (Next 8-10 hours)

1. Begin core implementation of callback registry
2. Implement dual scheduling methods
3. Add backward compatibility layer
4. Begin platform integration planning

---

Status: 📋 PLANNING PHASE - Ready to begin implementation
Next Milestone: Complete interface design and create feature branch
Estimated Completion: 2-3 weeks for full implementation
Priority: 🔴 HIGH - Core functionality enhancement required