docs: Add comprehensive callback and dual scheduling analysis

- Create detailed analysis of callback system requirements - Document dual scheduling method architecture (content fetch vs user notification) - Include implementation approach with realistic time estimates - Add complexity assessment and risk analysis - Provide technical considerations and security guidelines - Include testing strategy and performance impact analysis - Document design patterns and platform-specific resources Resolves: User feedback on callback system and dual scheduling needs
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+# Callback & Dual Scheduling Analysis
+
+**Document Created**: 2025-08-26 11:17:26 UTC  
+**Author**: Matthew Raymer  
+**Status**: 🔄 **RESEARCH & ANALYSIS**  
+**Priority**: 🔴 **HIGH** - Core functionality enhancement required
+
+## 🎯 **REQUIREMENTS ANALYSIS**
+
+### **User Feedback Summary**
+> "BTW, I still think it's worth starting a branch where we use the notification plugin, but a note on the plugin itself: seems like it'll need a couple things. One is to accept some callbacks (eg. for API calls out to a reporting service and then saving in the DB). The other is that I believe we need two 'schedule' methods, one that does the call-API-store-in-DB function and the other that does the retrieve-from-DB-and-notify-user function."
+
+### **Core Requirements Identified**
+1. **Callback System**: Accept callbacks for external service integration
+2. **Dual Scheduling**: Separate content fetch from user notification
+3. **API Integration**: Support for external reporting services
+4. **Database Operations**: Callback-based storage and retrieval
+
+---
+
+## 🔍 **CURRENT IMPLEMENTATION ANALYSIS**
+
+### **Existing Scheduling Method**
+```typescript
+// Current single method approach
+async scheduleDailyNotification(options: NotificationOptions): Promise<void>
+```
+
+**Current Behavior**:
+- Single method handles both content fetching and notification scheduling
+- Limited to basic URL fetching without callback support
+- No separation of concerns between data operations and user notification
+- Basic error handling without external service integration
+
+### **Current API Call Handling**
+```typescript
+// Basic URL fetching in Android implementation
+String url = call.getString("url", "");
+// No callback support for API responses
+// No database storage integration
+// No external service reporting
+```
+
+### **Gap Analysis**
+- ❌ **No callback mechanism** for external service integration
+- ❌ **No dual scheduling** - single method handles everything
+- ❌ **Limited API integration** - basic HTTP requests only
+- ❌ **No database callback support** for storage operations
+- ❌ **No reporting service integration** for analytics
+
+---
+
+## 🏗️ **PROPOSED ARCHITECTURE**
+
+### **Dual Scheduling Methods**
+
+#### **Method 1: Content Fetch & Storage**
+```typescript
+async scheduleContentFetch(options: ContentFetchOptions): Promise<void>
+```
+
+**Purpose**: Handle API calls and database storage
+**Responsibilities**:
+- Make API calls to external services
+- Execute database storage callbacks
+- Handle retry logic and fallbacks
+- Report to analytics/reporting services
+- Cache content for later use
+
+#### **Method 2: User Notification**
+```typescript
+async scheduleUserNotification(options: UserNotificationOptions): Promise<void>
+```
+
+**Purpose**: Retrieve stored content and notify users
+**Responsibilities**:
+- Retrieve content from database/cache
+- Execute user notification callbacks
+- Handle notification display logic
+- Manage user interaction callbacks
+- Track notification engagement
+
+### **Callback System Architecture**
+
+#### **Callback Types**
+```typescript
+interface CallbackSystem {
+  // API callbacks
+  apiCallbacks: {
+    onSuccess: (response: any) => Promise<void>;
+    onError: (error: Error) => Promise<void>;
+    onRetry: (attempt: number) => Promise<boolean>;
+  };
+  
+  // Database callbacks
+  databaseCallbacks: {
+    onStore: (data: any) => Promise<void>;
+    onRetrieve: (id: string) => Promise<any>;
+    onError: (error: Error) => Promise<void>;
+  };
+  
+  // Reporting callbacks
+  reportingCallbacks: {
+    onMetrics: (metrics: NotificationMetrics) => Promise<void>;
+    onAnalytics: (event: string, data: any) => Promise<void>;
+  };
+}
+```
+
+#### **Callback Registration**
+```typescript
+interface CallbackRegistry {
+  registerCallback(type: CallbackType, callback: Function): void;
+  unregisterCallback(type: CallbackType, id: string): void;
+  executeCallback(type: CallbackType, data: any): Promise<void>;
+  validateCallback(callback: Function): boolean;
+}
+```
+
+---
+
+## 🔧 **IMPLEMENTATION APPROACH**
+
+### **Phase 1: Interface Updates**
+**Estimated Effort**: 4-6 hours
+
+1. **Extend existing interfaces**
+   ```typescript
+   interface NotificationOptions {
+     // Existing properties...
+     
+     // New callback properties
+     apiCallbacks?: APICallbacks;
+     databaseCallbacks?: DatabaseCallbacks;
+     reportingCallbacks?: ReportingCallbacks;
+   }
+   ```
+
+2. **Create new scheduling interfaces**
+   ```typescript
+   interface ContentFetchOptions {
+     url: string;
+     apiCallbacks: APICallbacks;
+     databaseCallbacks: DatabaseCallbacks;
+     retryConfig: RetryConfig;
+   }
+   
+   interface UserNotificationOptions {
+     contentId: string;
+     notificationCallbacks: NotificationCallbacks;
+     userInteractionCallbacks: UserInteractionCallbacks;
+   }
+   ```
+
+### **Phase 2: Core Implementation**
+**Estimated Effort**: 12-16 hours
+
+1. **Implement callback registry system**
+   - Callback registration and validation
+   - Execution engine with error handling
+   - Lifecycle management
+
+2. **Create dual scheduling methods**
+   - `scheduleContentFetch()` implementation
+   - `scheduleUserNotification()` implementation
+   - Backward compatibility layer
+
+3. **Add callback execution logic**
+   - API call handling with callbacks
+   - Database operation callbacks
+   - Reporting service integration
+
+### **Phase 3: Platform Integration**
+**Estimated Effort**: 8-12 hours
+
+1. **Android implementation**
+   - WorkManager integration for background tasks
+   - Callback execution in native code
+   - Database callback support
+
+2. **iOS implementation**
+   - BGTaskScheduler integration
+   - Callback handling in Swift
+   - Core Data callback support
+
+3. **Web implementation**
+   - Service Worker integration
+   - Browser notification callbacks
+   - IndexedDB callback support
+
+---
+
+## 📊 **COMPLEXITY ASSESSMENT**
+
+### **Technical Complexity**: 🔴 **HIGH**
+- **Architecture Changes**: Significant interface redesign required
+- **Platform Integration**: Need to implement across Android/iOS/Web
+- **Callback Management**: Complex lifecycle and error handling
+- **Backward Compatibility**: Must maintain existing API functionality
+
+### **Business Complexity**: 🟡 **MEDIUM**
+- **User Impact**: Existing users need migration path
+- **Testing Requirements**: Comprehensive callback testing needed
+- **Documentation**: Significant API documentation updates required
+- **Training**: Team needs to understand new callback patterns
+
+### **Risk Factors**: 🔴 **HIGH**
+- **Interface Changes**: Breaking changes to existing API
+- **Performance Impact**: Callback overhead on notification delivery
+- **Platform Differences**: Ensuring consistent behavior across platforms
+- **Error Handling**: Complex callback failure scenarios
+
+---
+
+## 🚀 **RECOMMENDED IMPLEMENTATION STRATEGY**
+
+### **1. Research & Design Phase (Days 1-2)**
+- [ ] **Complete callback system design**
+- [ ] **Create interface mockups**
+- [ ] **Design migration strategy**
+- [ ] **Plan testing approach**
+
+### **2. Core Implementation Phase (Days 2-4)**
+- [ ] **Implement callback registry system**
+- [ ] **Create dual scheduling methods**
+- [ ] **Add callback execution logic**
+- [ ] **Implement error handling**
+
+### **3. Platform Integration Phase (Days 4-5)**
+- [ ] **Android callback integration**
+- [ ] **iOS callback integration**
+- [ ] **Web callback integration**
+- [ ] **Cross-platform testing**
+
+### **4. Testing & Documentation Phase (Day 5)**
+- [ ] **Comprehensive callback testing**
+- [ ] **Performance validation**
+- [ ] **API documentation updates**
+- [ ] **Migration guide creation**
+
+---
+
+## 🔒 **SECURITY CONSIDERATIONS**
+
+### **Callback Security**
+- **Input Validation**: Validate all callback parameters
+- **Sandboxing**: Execute callbacks in controlled environment
+- **Rate Limiting**: Prevent callback abuse
+- **Authentication**: Validate callback sources
+
+### **Data Security**
+- **Encryption**: Encrypt sensitive data in callbacks
+- **Access Control**: Limit callback access to necessary data
+- **Audit Logging**: Log all callback executions
+- **Error Handling**: Prevent information leakage in errors
+
+---
+
+## 📈 **PERFORMANCE IMPACT**
+
+### **Callback Overhead**
+- **Execution Time**: Additional 10-50ms per callback
+- **Memory Usage**: Callback registry storage
+- **Battery Impact**: Minimal on modern devices
+- **Network Impact**: Depends on callback implementation
+
+### **Optimization Strategies**
+- **Callback Batching**: Execute multiple callbacks together
+- **Async Execution**: Non-blocking callback execution
+- **Caching**: Cache callback results where appropriate
+- **Lazy Loading**: Load callbacks only when needed
+
+---
+
+## 🧪 **TESTING STRATEGY**
+
+### **Unit Testing**
+- **Callback Registration**: Test callback 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 callback execution time
+- **Memory Usage**: Monitor memory impact of callbacks
+- **Battery Impact**: Test battery usage with callbacks
+- **Scalability**: Test with multiple concurrent callbacks
+
+---
+
+## 📚 **REFERENCES & RESOURCES**
+
+### **Design Patterns**
+- **Observer Pattern**: For callback registration and execution
+- **Strategy Pattern**: For different callback execution strategies
+- **Factory Pattern**: For creating different callback types
+- **Chain of Responsibility**: For callback execution flow
+
+### **Platform-Specific Resources**
+- **Android**: WorkManager, AlarmManager, Room database
+- **iOS**: BGTaskScheduler, UNCalendarNotificationTrigger, Core Data
+- **Web**: Service Workers, IndexedDB, Browser Notifications API
+
+### **Best Practices**
+- **Error Handling**: Comprehensive error handling for callbacks
+- **Performance**: Optimize callback execution for mobile devices
+- **Security**: Secure callback execution and data handling
+- **Testing**: Thorough testing of callback scenarios
+
+---
+
+**Next Steps**: Complete callback system design and create implementation plan  
+**Estimated Timeline**: 3-5 days for full implementation  
+**Success Criteria**: Dual scheduling methods working with full callback support  
+**Risk Level**: 🔴 **HIGH** - Requires careful planning and implementation