# Pi Dashboard Servers

WebSocket servers that feed system stats, alarm audio, and status images to the ESP32-S3 RLCD dashboard.

## File Structure

```
pi/
  run_all.py            # Launches both servers as child processes
  stats_server.py       # Real system stats over WebSocket (port 8765)
  contents_server.py    # Alarm audio + status images over WebSocket (port 8766)
  mock_server.py        # Drop-in replacement for stats_server with random data
  audio_handler.py      # WAV loading, PCM chunking, alarm streaming
  image_handler.py      # PNG to 1-bit monochrome conversion, alpha compositing
  requirements.txt
  assets/
    alarm/              # WAV files for alarm audio
    img/                # Status images (idle.png, on_alarm.png)
```

## Requirements

Python 3.10+

```
pip install -r requirements.txt
```

Dependencies: `websockets`, `psutil`, `Pillow`

## Running

Start both servers:

```
python run_all.py
```

Or run individually:

```
python stats_server.py      # port 8765 only
python contents_server.py   # port 8766 only
python mock_server.py       # port 8765, random data (no psutil needed)
```

## Servers

### stats_server.py -- port 8765

Pushes a JSON object every 2 seconds with real system metrics from `psutil`:

- `cpu_pct`, `mem_pct`, `mem_used_mb`, `disk_pct`
- `cpu_temp` (reads `/sys/class/thermal/` as fallback)
- `uptime_hrs`, `net_rx_kbps`, `net_tx_kbps`
- `services` (mocked until systemd integration)
- `local_time` fields for RTC sync (`y`, `mo`, `d`, `h`, `m`, `s`)

### contents_server.py -- port 8766

Serves alarm audio and status images. Protocol:

**Status image:**
1. Text frame: `{"type":"status_image","width":120,"height":120}`
2. Binary frame: 1-bit monochrome bitmap (1800 bytes)

**Alarm audio:**
1. Text frame: `{"type":"alarm_start","sample_rate":N,"channels":N,"bits":N}`
2. Binary frames: raw PCM chunks (4096 bytes each, paced at ~90% real-time)
3. Text frame: `{"type":"alarm_stop"}`

On connect, sends `idle.png` as the status image. Alarm cycles switch to `on_alarm.png` during playback, then back to `idle.png`.

### mock_server.py -- port 8765

Same JSON schema and 2-second push interval as `stats_server.py`, but all values are randomized. No `psutil` dependency -- useful for development on non-Pi machines.

Does not include `local_time` fields.

## Modules

### audio_handler.py

- `find_wav()` -- finds the first `.wav` in `assets/alarm/`
- `read_wav(path)` -- reads WAV, returns `(pcm_bytes, sample_rate, channels, bits)`
- `stream_alarm(ws, pcm, sr, ch, bits)` -- streams one alarm cycle over WebSocket

### image_handler.py

- `load_status_image(path)` -- loads PNG, composites transparency onto white, converts to 1-bit 120x120 monochrome bitmap (black=1, MSB-first)
- `send_status_image(ws, img_bytes)` -- sends status image header + binary over WebSocket
