# Implementation Plan

## 1. Fix Core Configuration and Environment Management

- [ ] 1.1 Update environment configuration validation
  - Modify `backend/src/config/env.ts` to handle serverless environment variable loading gracefully
  - Add runtime configuration validation with proper fallbacks
  - Implement configuration health check endpoint
  - Add Firebase configuration validation
  - _Requirements: 1.1, 1.2_

- [ ] 1.2 Implement robust error handling middleware
  - Create enhanced error handler in `backend/src/middleware/errorHandler.ts`
  - Add correlation ID generation and tracking
  - Implement structured error logging with Winston
  - Add error categorization and response formatting
  - _Requirements: 4.1, 4.2_

- [ ] 1.3 Fix database query validation issues
  - Update all document-related database queries to validate UUID format before execution
  - Add proper input sanitization in `backend/src/models/DocumentModel.ts`
  - Implement UUID validation utility function
  - Fix the "invalid input syntax for type uuid" errors seen in logs
  - _Requirements: 1.3, 4.1_

## 2. Implement Firebase Storage Integration

- [ ] 2.1 Create Firebase Storage service
  - Implement `backend/src/services/firebaseStorageService.ts` with complete Firebase Storage integration
  - Add file upload, download, delete, and metadata operations
  - Implement secure file path generation and user-based access control
  - Add proper error handling and retry logic for Firebase operations
  - _Requirements: 2.1, 2.5_

- [ ] 2.2 Update file upload endpoints
  - Modify `backend/src/routes/documents.ts` to use Firebase Storage instead of Google Cloud Storage
  - Update upload URL generation to use Firebase Storage signed URLs
  - Implement proper file validation (type, size, security)
  - Add upload progress tracking and monitoring
  - _Requirements: 2.1, 2.4_

- [ ] 2.3 Update document processing pipeline for Firebase Storage
  - Modify `backend/src/services/unifiedDocumentProcessor.ts` to work with Firebase Storage
  - Update file retrieval operations in processing services
  - Ensure PDF generation service can access files from Firebase Storage
  - Update all file path references throughout the codebase
  - _Requirements: 2.1, 3.1_

## 3. Fix Service Dependencies and Orchestration

- [ ] 3.1 Resolve service import and dependency issues
  - Fix circular dependencies in service imports
  - Ensure all required services are properly imported and initialized
  - Add dependency injection pattern for better testability
  - Update service initialization order in `backend/src/index.ts`
  - _Requirements: 6.1, 6.2_

- [ ] 3.2 Fix document processing pipeline orchestration
  - Update `backend/src/services/unifiedDocumentProcessor.ts` to handle all processing steps correctly
  - Ensure proper error handling between processing steps
  - Add processing checkpoints and recovery mechanisms
  - Implement proper status updates throughout the pipeline
  - _Requirements: 3.1, 3.2, 3.6_

- [ ] 3.3 Enhance optimized agentic RAG processor
  - Fix any issues in `backend/src/services/optimizedAgenticRAGProcessor.ts`
  - Ensure proper memory management and garbage collection
  - Add better error handling for LLM API calls
  - Implement proper retry logic with exponential backoff
  - _Requirements: 3.3, 3.4, 4.2_

## 4. Improve LLM Service Integration

- [ ] 4.1 Fix LLM service configuration and initialization
  - Update `backend/src/services/llmService.ts` to handle configuration properly
  - Fix model selection logic and API key validation
  - Add proper timeout handling for LLM API calls
  - Implement cost tracking and usage monitoring
  - _Requirements: 1.4, 3.4_

- [ ] 4.2 Enhance LLM error handling and retry logic
  - Add comprehensive error handling for both Anthropic and OpenAI APIs
  - Implement retry logic with exponential backoff for API failures
  - Add fallback model selection when primary model fails
  - Implement proper JSON parsing and validation for LLM responses
  - _Requirements: 3.4, 4.2_

- [ ] 4.3 Add LLM response validation and self-correction
  - Enhance JSON extraction from LLM responses
  - Add schema validation for CIM review data
  - Implement self-correction mechanism for invalid responses
  - Add quality scoring and validation for generated content
  - _Requirements: 3.4, 4.3_

## 5. Fix PDF Generation and File Operations

- [ ] 5.1 Update PDF generation service for Firebase Storage
  - Modify `backend/src/services/pdfGenerationService.ts` to work with Firebase Storage
  - Ensure generated PDFs are properly stored in Firebase Storage
  - Add proper error handling for PDF generation failures
  - Implement PDF generation progress tracking
  - _Requirements: 3.5, 2.1_

- [ ] 5.2 Implement proper file cleanup and lifecycle management
  - Add automatic cleanup of temporary files during processing
  - Implement file lifecycle management (retention policies)
  - Add proper error handling for file operations
  - Ensure no orphaned files are left in storage
  - _Requirements: 2.1, 4.3_

## 6. Enhance Database Operations and Models

- [ ] 6.1 Fix document model and database operations
  - Update `backend/src/models/DocumentModel.ts` with proper UUID validation
  - Add comprehensive error handling for all database operations
  - Implement proper connection pooling and retry logic
  - Add database operation logging and monitoring
  - _Requirements: 1.3, 6.3_

- [ ] 6.2 Implement processing session tracking
  - Enhance agentic RAG session management in database models
  - Add proper session lifecycle tracking
  - Implement session cleanup and archival
  - Add session analytics and reporting
  - _Requirements: 3.6, 4.4_

- [ ] 6.3 Add vector database integration fixes
  - Ensure vector database service is properly integrated
  - Fix any issues with embedding generation and storage
  - Add proper error handling for vector operations
  - Implement vector database health checks
  - _Requirements: 3.3, 1.3_

## 7. Implement Comprehensive Monitoring and Logging

- [ ] 7.1 Add structured logging throughout the application
  - Implement correlation ID tracking across all services
  - Add comprehensive logging for all processing steps
  - Create structured log format for better analysis
  - Add log aggregation and monitoring setup
  - _Requirements: 4.1, 4.4_

- [ ] 7.2 Implement health check and monitoring endpoints
  - Create comprehensive health check endpoint that tests all services
  - Add monitoring endpoints for processing statistics
  - Implement real-time status monitoring
  - Add alerting for critical failures
  - _Requirements: 4.4, 1.1_

- [ ] 7.3 Add performance monitoring and metrics
  - Implement processing time tracking for all operations
  - Add memory usage monitoring and alerts
  - Create API response time monitoring
  - Add cost tracking for external service usage
  - _Requirements: 4.4, 3.6_

## 8. Update Frontend Integration

- [ ] 8.1 Update frontend Firebase Storage integration
  - Modify frontend upload components to work with Firebase Storage
  - Update authentication flow for Firebase Storage access
  - Add proper error handling and user feedback for upload operations
  - Implement upload progress tracking on frontend
  - _Requirements: 5.1, 5.4_

- [ ] 8.2 Enhance frontend error handling and user experience
  - Add proper error message display for all error scenarios
  - Implement retry mechanisms for failed operations
  - Add loading states and progress indicators
  - Ensure real-time status updates work correctly
  - _Requirements: 5.2, 5.4_

## 9. Testing and Quality Assurance

- [ ] 9.1 Create comprehensive unit tests
  - Write unit tests for all service functions
  - Add tests for error handling scenarios
  - Create tests for configuration validation
  - Add tests for UUID validation and database operations
  - _Requirements: 6.4_

- [ ] 9.2 Implement integration tests
  - Create end-to-end tests for document processing pipeline
  - Add tests for Firebase Storage integration
  - Create tests for external API integrations
  - Add tests for error recovery scenarios
  - _Requirements: 6.4_

- [ ] 9.3 Add performance and load testing
  - Create tests for large file processing
  - Add concurrent processing tests
  - Implement memory leak detection tests
  - Add API rate limiting tests
  - _Requirements: 6.4_

## 10. Documentation and Deployment

- [ ] 10.1 Update configuration documentation
  - Document all required environment variables
  - Create setup guides for Firebase Storage configuration
  - Add troubleshooting guides for common issues
  - Update deployment documentation
  - _Requirements: 1.2_

- [ ] 10.2 Create operational runbooks
  - Document error recovery procedures
  - Create monitoring and alerting setup guides
  - Add performance tuning guidelines
  - Create backup and disaster recovery procedures
  - _Requirements: 4.4_

- [ ] 10.3 Final integration testing and deployment
  - Perform comprehensive end-to-end testing
  - Validate all error scenarios work correctly
  - Test deployment in staging environment
  - Perform production deployment with monitoring
  - _Requirements: 1.1, 2.1, 3.1_