# Nostr Post Scheduler & Private Message API

A Node.js API for scheduling Nostr posts and sending private messages using the Nostr protocol.

## Features

- Schedule public Nostr posts (kind: 1) at a future time
- Reschedule or cancel scheduled posts
- Send encrypted private messages (kind: 4)
- Auto-managing the database, including table creation and indexing
- Efficient background job processing to send scheduled posts just-in-time
- API key authentication for secure access
- Swagger UI documentation available at `/docs` for easy API exploration

## Technology Stack

- **Programming Language**: JavaScript (Node.js)
- **Framework**: Express.js
- **Database**: SQLite (default) or PostgreSQL/MySQL (via .env configuration)
- **Queue System**: Background tasks with node-cron
- **Security**: API key authentication, proper key handling, and rate limiting
- **Documentation**: Swagger UI (`/docs`) and Redoc (`/redoc`)
- **Nostr Libraries**: Nostr-NDK and nostr-tools

## Getting Started

### Prerequisites

- Node.js (v14 or higher)
- npm or yarn

### Installation

1. Clone the repository:

```bash
git clone https://github.com/yourusername/nostr-scheduler-api.git
cd nostr-scheduler-api
```

2. Install dependencies:

```bash
npm install
```

3. Create a `.env` file based on the `.env.example`:

```bash
cp .env.example .env
```

4. Edit the `.env` file with your configuration:

```bash
cp .env.example .env
```

5. Start the server:

```bash
npm start
```

For development with auto-reload:

```bash
npm run dev
```

## API Documentation

Once the server is running, you can access the API documentation at:

- Swagger UI: http://localhost:3000/docs

## API Endpoints

### Schedule a Nostr Post
- **Method**: POST `/schedule/post`
- **Description**: Schedules a new Nostr post at a future time.
- **Request Parameters**:
  - `content`: Content of the Nostr post
  - Either `timestamp` (Unix format) or both `date` (DD/MM/YY or DD/MM/YYYY) and `hour` (HH:MM or HHMM)
  - Optional `relays` (otherwise defaults from .env)

### Reschedule a Nostr Post
- **Method**: PATCH `/schedule/post/{post_id}`
- **Description**: Updates the scheduled time of an existing post.
- **Request Parameters**:
  - `post_id`: ID of the post to reschedule
  - Either new `timestamp` or new `date` + `hour`

### Retrieve a Scheduled Post
- **Method**: GET `/schedule/post/{post_id}`
- **Description**: Returns details of a scheduled post.

### Delete a Scheduled Post
- **Method**: DELETE `/schedule/post/{post_id}`
- **Description**: Cancels a scheduled post before it is sent.

### List All Scheduled Posts
- **Method**: GET `/schedule/posts`
- **Description**: Returns all pending scheduled posts.

### Send a Private Message
- **Method**: POST `/messages/send`
- **Description**: Immediately sends an encrypted private message.
- **Request Parameters**:
  - `recipient_pubkey`: Public key of the recipient
  - `content`: Message content
  - Optional `relays` (otherwise defaults from .env)

### Retrieve Sent Messages
- **Method**: GET `/messages/sent`
- **Description**: Returns a history of sent private messages.

### Webhook for External Triggers
- **Method**: POST `/webhook/trigger`
- **Description**: Allows an external service to trigger a scheduled post immediately.
- **Request Parameters**:
  - `post_id`: ID of the post to send immediately

## Authentication & Security

All API requests require an Admin API Key in the request headers:
- Header: `Authorization: Bearer <ADMIN_API_KEY>`
- If missing or incorrect, the API returns 401 Unauthorized.

Private Key Handling:
- The private key (in nsec or hex format) is stored in .env and never in the database.
- It is only loaded when necessary for signing events.

Rate Limiting:
- Prevents spam and excessive API usage.
- Limited to X requests per minute (configurable).

## Database Schema

### Table: scheduled_posts
| Column    | Type    | Description                           |
|-----------|---------|---------------------------------------|
| id        | INTEGER | Unique ID of the scheduled post (PK)  |
| content   | TEXT    | The content of the scheduled note     |
| timestamp | INTEGER | Auto-saved Unix timestamp             |
| date      | TEXT    | Human-readable date (YYYY-MM-DD)      |
| hour      | TEXT    | Human-readable time (HH:MM)           |
| relays    | TEXT    | Comma-separated list of relays        |
| status    | TEXT    | "pending", "sent", or "failed"        |
| created_at| INTEGER | Creation timestamp                    |
| updated_at| INTEGER | Last update timestamp                 |

### Table: sent_messages
| Column          | Type    | Description                           |
|-----------------|---------|---------------------------------------|
| id              | INTEGER | Unique ID of the message (PK)         |
| recipient_pubkey| TEXT    | The recipient's public key            |
| message         | TEXT    | The message content                   |
| timestamp       | INTEGER | Unix timestamp of when it was sent    |
| relays          | TEXT    | Comma-separated list of relays        |
| event_id        | TEXT    | Event ID of the sent message          |
| created_at      | INTEGER | Creation timestamp                    |

## License

This project is licensed under the MIT License - see the LICENSE file for details.