# IMAP Connectivity Feature Design

## Overview

This document outlines the design for implementing IMAP connectivity in the Email Organizer application. The feature allows users to configure their IMAP server connection details, test the connection, and synchronize their email folders from the IMAP server to the application.

## Current State Analysis

### Existing Infrastructure
- **User Model**: Already has `imap_config` field (JSON type) for storing IMAP configuration
- **Authentication**: User authentication system is already implemented
- **Folder Management**: Basic folder CRUD operations exist
- **UI Framework**: Uses htmx, AlpineJS, and DaisyUI for dynamic interfaces
- **Database**: PostgreSQL with SQLAlchemy ORM
- **IMAP Service**: Implemented in [`app/imap_service.py`](app/imap_service.py:11)
- **Processed Emails Service**: Implemented in [`app/processed_emails_service.py`](app/processed_emails_service.py:7)
- **Blueprint Structure**: Modular blueprints for folders, IMAP, and emails

### Current Implementation Status
- IMAP connection handling logic fully implemented
- IMAP configuration UI operational via modal dialogs
- Folder synchronization from IMAP server functional
- IMAP testing functionality complete
- Email processing status tracking operational
- Two-step sync process (connection test + folder selection) implemented

### IMAP Service Architecture
The IMAP service provides:
- Connection management and authentication
- Folder listing and synchronization
- Email retrieval and metadata extraction
- Connection testing and validation
- Email UID tracking for processed emails

## System Architecture

### High-Level Flow

```mermaid
graph TD
    A[User Clicks IMAP Config] --> B[Show IMAP Configuration Modal]
    B --> C[User Enters Connection Details]
    C --> D{User Tests Connection}
    D -->|Success| E[Show Success Message]
    D -->|Failure| F[Show Error Message]
    E --> G[User Syncs Folders]
    F --> C
    G --> H[Fetch IMAP Folders]
    H --> I[Create Local Folders]
    I --> J[Update UI]
```

### Data Flow

```mermaid
sequenceDiagram
    participant U as User
    participant M as Main UI
    participant S as Server
    participant IMAP as IMAP Server
    participant DB as Database
    
    U->>M: Click "Configure IMAP"
    M->>S: GET /api/imap/config
    S->>M: Return IMAP config modal
    M->>U: Show configuration form
    U->>M: Enter connection details
    M->>S: POST /api/imap/test
    S->>IMAP: Test connection
    IMAP-->>S: Connection result
    S->>M: Return test result
    M->>U: Show test result
    U->>M: Click "Sync Folders"
    M->>S: POST /api/imap/sync
    S->>IMAP: List folders
    IMAP-->>S: Folder list
    S->>DB: Create/update folders
    DB-->>S: Success/failure
    S->>M: Return sync result
    M->>U: Show sync result
```





## Security Considerations

1. **Password Storage**: Passwords are stored as plain text in the JSON configuration. This is acceptable for the initial implementation but should be enhanced with encryption in the future.

2. **Connection Security**: SSL/TLS is enforced by default using IMAP4_SSL.

3. **Input Validation**: All user inputs are validated on both client and server sides.

4. **Error Handling**: Detailed error messages are provided to users, but sensitive information is not exposed.

## Performance Considerations

1. **Connection Management**: Each operation creates a new connection to avoid state issues.
   - Connection timeout handling prevents hanging operations
   - Proper cleanup of failed connections to avoid resource leaks

2. **Email Processing**: Batch operations for processing multiple emails efficiently
   - Bulk operations for marking emails as processed
   - Efficient database queries with proper indexing

3. **Folder Synchronization**: Optimized folder listing and email count updates
   - Deduplication of folder names to prevent duplicate entries
   - Efficient updates to folder metadata and email counts

## Error Handling Strategy

1. **Connection Errors**: Clear error messages for authentication failures, network issues, and server problems.

2. **Validation Errors**: Field-specific validation errors for form inputs.

3. **Sync Errors**: Detailed error messages for folder synchronization failures.

4. **Logging**: All errors are logged to the console for debugging.

## Current Implementation Status

### Fully Implemented Features
- IMAP configuration modal with form validation
- Connection testing with detailed error messages
- Two-step sync process (connection test + folder selection)
- Folder type assignment during sync
- Email processing status tracking
- Pending email counts and management
- HTMX-based UI updates
- Error handling and user feedback

### UI Components
- IMAP configuration modal ([`app/templates/partials/imap_config_modal.html`](app/templates/partials/imap_config_modal.html:1))
- Folder selection modal ([`app/templates/partials/folder_selection_modal.html`](app/templates/partials/folder_selection_modal.html:1))
- Pending emails dialog ([`app/templates/partials/pending_emails_dialog.html`](app/templates/partials/pending_emails_dialog.html:1))
- Loading states and error messages

### API Endpoints
- `/api/imap/config`: GET/POST - IMAP configuration modal
- `/api/imap/test`: POST - Test IMAP connection
- `/api/imap/sync`: POST - Legacy sync endpoint
- `/api/imap/sync-selected`: POST - New sync endpoint with folder selection
- `/api/folders/<id>/pending-emails`: GET - Get pending emails for a folder
- `/api/folders/<id>/emails/<uid>/process`: POST - Mark email as processed

## Success Metrics

1. **Functional**: Users can configure IMAP connections, test them, and sync folders successfully.
2. **Usability**: The UI is intuitive and provides clear feedback for all operations.
3. **Reliability**: IMAP connections are stable and handle various server configurations.
4. **Performance**: Folder synchronization completes in reasonable time.
5. **Security**: User credentials are handled securely.
6. **Email Tracking**: Accurate pending email counts and processing status.