# Component: Notification Service

## Purpose

The Notification Service provides email notification capabilities to scripts running at site clusters. It manages notification lists, handles email delivery, and integrates with the Store-and-Forward Engine for reliable delivery when the email server is unavailable.

## Location

Central cluster (definition management). Site clusters (email delivery).

## Responsibilities

### Definitions (Central)
- Store notification lists in the configuration database: list name, recipients (name + email address).
- Store email server configuration (SMTP settings).
- Deploy notification lists and SMTP configuration uniformly to all sites. Deployment requires **explicit action** by a user with the Deployment role.
- Managed by users with the Design role.

### Delivery (Site)
- Resolve notification list names to recipient lists.
- Compose and send emails via SMTP.
- On delivery failure, submit the notification to the Store-and-Forward Engine for buffered retry.

## Notification List Definition

Each notification list includes:
- **Name**: Unique identifier (e.g., "Maintenance-Team", "Shift-Supervisors").
- **Recipients**: One or more entries, each with:
  - Recipient name.
  - Email address.

## Email Server Configuration

- SMTP server address, port, authentication credentials, TLS settings.
- Retry settings: Max retry count, fixed time between retries (used by Store-and-Forward Engine).
- Defined centrally, deployed to all sites.

## Script API

```csharp
Notify.To("listName").Send("subject", "message")
```

- Available to instance scripts (via Script Execution Actors), alarm on-trigger scripts (via Alarm Execution Actors), and shared scripts (executing inline).
- Resolves the list name to recipients, composes the email, and attempts delivery.
- On failure, the notification is handed to the Store-and-Forward Engine.

## Dependencies

- **Configuration Database (MS SQL)**: Stores notification list definitions and SMTP config.
- **Store-and-Forward Engine**: Handles buffering for failed email deliveries.
- **Security & Auth**: Design role manages notification lists.
- **Configuration Database (via IAuditService)**: Notification list changes are audit logged.

## Interactions

- **Site Runtime (Script/Alarm Execution Actors)**: Scripts invoke `Notify.To().Send()` through this component.
- **Store-and-Forward Engine**: Failed notifications are buffered here.
- **Deployment Manager**: Receives updated notification lists and SMTP config as part of system-wide artifact deployment (triggered explicitly by Deployment role).