# AIVA: Dead-Letter Queue for Email Handling

This PRD outlines the implementation of a dead-letter queue (DLQ) for handling permanently failed emails within the AIVA system. This will improve error handling, prevent message loss, and enable analysis of persistent email delivery issues.

### GPM-066: Implement Dead-Letter Queue Storage
**Goal:** Create the storage mechanism for failed emails.
**Acceptance Criteria:**
- A new database table or collection named `dead_letter_emails` exists.
- The table/collection contains fields for: `original_message_id`, `timestamp`, `error_message`, `recipient`, `sender`, and `email_content`.
**Files:** `database/migrations/create_dead_letter_emails_table.py`, `models/dead_letter_email.py`
**Spawns:** Implement the function to route failed emails to the DLQ.

### GPM-067: Route Failed Emails to DLQ
**Goal:** Implement the logic to automatically move emails that have exceeded retry attempts to the dead-letter queue.
**Acceptance Criteria:**
-  After the maximum number of retry attempts (defined in GPM-065), an email that still fails to send is moved to the `dead_letter_emails` table/collection.
-  A log entry is created indicating that the email was moved to the DLQ, including the `original_message_id`.
**Files:** `services/email_service.py`, `utils/retry_handler.py`
**Spawns:** Create an API endpoint to view and manage the dead-letter queue.

### GPM-068: Create API Endpoint for DLQ Management
**Goal:** Provide an API endpoint for viewing and potentially re-processing emails in the DLQ.
**Acceptance Criteria:**
- A `GET /dead_letter_emails` endpoint exists that returns a paginated list of emails in the DLQ.
- The response includes all fields from the `dead_letter_emails` table/collection.
-  A `GET /dead_letter_emails/{id}` endpoint exists that returns a single email from the DLQ based on its ID.
**Files:** `api/routes/dead_letter_emails.py`, `api/schemas/dead_letter_email.py`
**Spawns:** Implement functionality to resend emails from the DLQ.

### GPM-069: Implement Email Resend Functionality
**Goal:** Allow administrators to resend emails from the dead-letter queue.
**Acceptance Criteria:**
- A `POST /dead_letter_emails/{id}/resend` endpoint exists.
- When called, the email with the specified ID is removed from the DLQ and re-queued for sending through the regular email sending process.
- A log entry is created indicating that the email was re-queued, including the `original_message_id`.
-  Error handling is implemented to prevent infinite loops if resending the email also fails repeatedly. Limit the number of resend attempts.
**Files:** `api/routes/dead_letter_emails.py`, `services/email_service.py`
**Spawns:** Implement alerting when emails are added to the dead-letter queue.

### GPM-070: Implement DLQ Alerting
**Goal:** Notify administrators when emails are added to the dead-letter queue.
**Acceptance Criteria:**
- A notification (e.g., email, Slack message) is sent to administrators when a new email is added to the `dead_letter_emails` table/collection.
- The notification includes information about the email, such as the recipient, subject, and error message.
-  The notification mechanism is configurable (e.g., enable/disable, change notification channel).
**Files:** `services/alerting_service.py`, `config/alerting.py`
**Spawns:** Implement a dashboard to visualize DLQ statistics.

### GPM-071: Add Metrics and Monitoring for DLQ
**Goal:** Add metrics to track the number of emails in the DLQ and create monitoring dashboards.
**Acceptance Criteria:**
- Metrics are collected for the number of emails added to the DLQ per day.
- Metrics are collected for the most common error messages in the DLQ.
- A dashboard is created to visualize these metrics.
**Files:** `monitoring/metrics.py`, `monitoring/dashboard.json`
**Spawns:** Investigate the root causes of emails ending up in the dead-letter queue.
