update docs.

docs/design/system-architecture.md

@@ -18,27 +18,37 @@ graph TB
     subgraph "Application Layer"
         F[Flask App] --> G[Main Blueprint]
         F --> H[Auth Blueprint]
-        G --> I[IMAP Service]
-        G --> J[Folder Management]
-        H --> K[User Authentication]
+        G --> I[Folders Blueprint]
+        G --> J[IMAP Blueprint]
+        G --> K[Emails Blueprint]
+        I --> L[Folder CRUD Operations]
+        J --> M[IMAP Configuration & Sync]
+        K --> N[Email Processing]
+        H --> O[User Authentication]
+    end
+    
+    subgraph "Service Layer"
+        P[IMAP Service] --> Q[Email Operations]
+        R[Processed Emails Service] --> S[Email Tracking]
     end
     
     subgraph "Data Layer"
-        L[PostgreSQL] --> M[User Model]
-        L --> N[Folder Model]
-        M --> O[IMAP Configuration]
-        N --> P[Folder Rules]
-        N --> Q[Email Metadata]
+        T[PostgreSQL] --> U[User Model]
+        T --> V[Folder Model]
+        T --> W[ProcessedEmail Model]
+        U --> X[IMAP Configuration]
+        V --> Y[Folder Rules & Metadata]
+        W --> Z[Email Processing Status]
     end
     
     subgraph "External Services"
-        R[IMAP Server] --> I
-        S[Future AI Service] --> I
+        AA[IMAP Server] --> P
     end
     
     D --> F
-    F --> L
-    I --> R
+    F --> T
+    P --> AA
+    Q --> R
 ```
 
 ## System Components
@@ -62,11 +72,10 @@ The Flask application follows a modular blueprint architecture:
 Implements the factory pattern for creating Flask application instances with configuration support.
 
 #### Main Blueprint
-Handles core application functionality:
-- Folder CRUD operations
-- IMAP configuration and testing
-- Folder synchronization
-- User interface endpoints
+The main application blueprint coordinates all core functionality through sub-blueprints:
+- **Folders Blueprint**: Handles folder CRUD operations, type management, and user interface
+- **IMAP Blueprint**: Manages IMAP configuration, connection testing, and folder synchronization
+- **Emails Blueprint**: Processes email operations and pending email management
 
 #### Auth Blueprint
 Manages user authentication:
@@ -74,7 +83,26 @@ Manages user authentication:
 - Password validation and hashing
 - Session management
 
-### 3. Data Layer
+### 3. Service Layer
+
+The application implements a service layer pattern for business logic:
+
+#### IMAP Service
+Handles communication with IMAP servers:
+- Connection management and authentication
+- Folder listing and synchronization
+- Email retrieval and metadata extraction
+- Connection testing and validation
+- Email UID tracking for processed emails
+
+#### Processed Emails Service
+Manages email processing status tracking:
+- Records which emails have been processed
+- Provides pending email counts
+- Handles bulk email processing operations
+- Maintains email processing history
+
+### 4. Data Layer
 
 The system uses PostgreSQL with SQLAlchemy ORM for data persistence:
 
@@ -92,8 +120,17 @@ Stores email organization rules and metadata:
 - Relationship: Foreign key to user
 - Rule definition: Natural language rule text
 - Organization settings: Priority, enable/disable flag
-- Email metrics: Total count, pending count
+- Email metrics: Total count, pending count, emails count
 - Email metadata: Recent emails information in JSON format
+- Folder types: Tidy, Destination, or Ignore
+
+#### ProcessedEmail Model
+Tracks email processing status:
+- Primary key: Integer auto-increment ID
+- Relationships: Foreign keys to User and Folder
+- Email UID tracking: Unique identifiers from IMAP server
+- Processing status: Pending or processed flags
+- Timestamps: First seen, processed, and update times
 
 ### 4. External Services
 
@@ -178,19 +215,19 @@ sequenceDiagram
 - **Benefits**: Supports multiple environments (development, testing, production)
 
 ### 2. Blueprint Pattern
-- **Implementation**: Separated functionality in [`app/routes.py`](app/routes.py:9) and [`app/auth.py`](app/auth.py:9)
-- **Purpose**: Modularize application features
-- **Benefits**: Code organization, easier testing, scalability
+- **Implementation**: Modular blueprint structure in [`app/routes.py`](app/routes.py:12)
+- **Purpose**: Modularize application features into logical groups
+- **Benefits**: Code organization, easier testing, scalability, clear separation of concerns
 
 ### 3. Service Layer Pattern
-- **Implementation**: IMAP service in [`app/imap_service.py`](app/imap_service.py:10)
+- **Implementation**: IMAP service in [`app/imap_service.py`](app/imap_service.py:11) and Processed Emails service in [`app/processed_emails_service.py`](app/processed_emails_service.py:7)
 - **Purpose**: Encapsulate business logic and external communication
-- **Benefits**: Separation of concerns, reusability, testability
+- **Benefits**: Separation of concerns, reusability, testability, centralized business rules
 
 ### 4. Repository Pattern
 - **Implementation**: SQLAlchemy models in [`app/models.py`](app/models.py:13)
 - **Purpose**: Abstract data access layer
-- **Benefits**: Database independence, centralized query logic
+- **Benefits**: Database independence, centralized query logic, type safety
 
 ## Security Considerations
 
@@ -229,14 +266,22 @@ sequenceDiagram
 ## Scalability
 
 ### 1. Architecture
-- Modular design supports feature expansion
-- Service layer allows for additional email providers
-- Database schema designed for growth
+- Modular blueprint structure supports feature expansion
+- Service layer allows for additional email providers and processing logic
+- Database schema designed for growth with processed email tracking
+- Current folder type system (Tidy, Destination, Ignore) provides flexible organization
 
-### 2. Future Enhancements
+### 2. Current Implementation Status
+- IMAP connectivity and folder synchronization fully implemented
+- Email processing status tracking operational
+- Folder type management with UI components complete
+- Authentication system with session management functional
+
+### 3. Future Enhancements
 - AI-powered rule recommendations
 - Additional email provider support
 - Multi-tenant architecture support
+- Enhanced email analytics and reporting
 
 ## Error Handling