Transmission Manager

<h1 align="center">
  <img src="web/transmission-manager.png" height="64" style="vertical-align: middle;" />
  Transmission Manager
</h1>

A lightweight, modern, single-binary web application for viewing and managing torrents from a [Transmission](https://transmissionbt.com/) RPC daemon.

Transmission Manager serves a fast, clean, dark-mode Single Page Application (SPA) and proxies Transmission RPC calls through a minimal Go backend—all contained within a single executable.

---

## Features

- **Single Static Binary**: All frontend assets (`index.html`, `app.js`, `styles.css`) are embedded directly into the Go binary using `embed`. Zero runtime asset dependencies.
- **Modern Dark-Mode UI**: Built with vanilla HTML5, CSS3 (using CSS variables), and JavaScript. Responsive, compact layout designed for both desktop and mobile screens.
- **Live Polling & In-Place Updates**: Keyed DOM reconciliation updates existing torrent cards in place without screen flickering or scroll jumping. Selectable refresh interval (1s, 3s, 5s, 10s).
- **Rich Sorting & Filtering**:
  - Filter torrents instantly by name.
  - Sort by **Status**, **Name**, **Progress**, **Ratio**, **Size**, **Speed**, or **Availability**.
- **Interactive Controls**: Pause or resume individual torrents directly from the web interface.
- **Smart Seed Scheduler**: Opt completed torrents in from the Scheduler tab, choose 1–100 managed seed slots, and rotate an idle slot to the least recently seeded waiting torrent after one hour without upload. A persistent cycle history shows activations and rotations.
- **Robust Transmission RPC Support**:
  - Automatically handles Transmission `409 Conflict` session ID (`X-Transmission-Session-Id`) handshakes.
  - Supports optional HTTP Basic Authentication.

---

## Configuration

Transmission Manager is configured entirely via environment variables:

| Variable | Required | Description |
| :--- | :---: | :--- |
| `TRANSMISSION_URL` | **Yes** | Absolute HTTP or HTTPS RPC endpoint URL of your Transmission instance. |
| `TRANSMISSION_RPC_USERNAME` | No | Basic Authentication username for Transmission RPC. |
| `TRANSMISSION_RPC_PASSWORD` | No | Basic Authentication password for Transmission RPC. |
| `SCHEDULER_DB_PATH` | No | SQLite database path (default `./data/scheduler.db`). |

The scheduler runs in the server even when no browser is open. It manages only opted-in torrents. A scheduled torrent that continues uploading can keep its slot indefinitely, so rotation does not guarantee a fixed maximum waiting time. Manual pause or resume of an opted-in torrent is temporary; the scheduler restores its chosen state on its next check.

---

## Quick Start

### Using Docker

Run the container directly:

```bash
docker run -d \
  --name transmission-manager \
  -p 8080:8080 \
  -v transmission-manager-data:/app/data \
  -e TRANSMISSION_URL=http://192.168.1.100:9091/transmission/rpc \
  -e TRANSMISSION_RPC_USERNAME=admin \
  -e TRANSMISSION_RPC_PASSWORD=secret \
  transmission-manager:latest
```

### Using Docker Compose

Create a `docker-compose.yml`:

```yaml
services:
  transmission-manager:
    build: .
    container_name: transmission-manager
    ports:
      - "8080:8080"
    volumes:
      - transmission-manager-data:/app/data
    environment:
      TRANSMISSION_URL: http://192.168.1.100:9091/transmission/rpc
      TRANSMISSION_RPC_USERNAME: admin
      TRANSMISSION_RPC_PASSWORD: secret
    restart: unless-stopped

volumes:
  transmission-manager-data:
```

Then start the application:

```bash
docker compose up -d
```

Open your browser and navigate to `http://localhost:8080`.

---

## Building from Source

### Prerequisites

- [Go](https://go.dev/) 1.24 or later

### Build

Compile the single binary with embedded frontend assets:

```bash
git clone https://github.com/your-repo/transmission-manager.git
cd transmission-manager
go build -ldflags="-s -w" -o transmission-manager .
```

### Run

```bash
export TRANSMISSION_URL="http://localhost:9091/transmission/rpc"
./transmission-manager
```

By default, the server listens on port `8080`.

Keep the `data` directory (or the path set by `SCHEDULER_DB_PATH`) across restarts to preserve scheduler settings, opt-ins, and cycle history. The app creates the database directory on startup and exits with a clear error if it cannot open the database.