heos/README.md

# HEOS panel

A phone-sized web remote for a Denon HEOS system, meant to be added to the
iOS home screen and used instead of the HEOS app. One Flask process serves
both the interface and the HTTP bridge behind it.

Everything it does fits on one screen:

- **Volume** up/down for the Home 400 and the Living Room pair. A tap lands
  on the next multiple of `VOLUME_STEP` — from 23 it goes to 25, not 28 —
  so the levels stay round. Hold to keep moving.
- **Group** either room with the AVR — the AVR is always the host, so its
  sound takes over whatever joins it
- **Ungroup** either room again, or all of them at once
- **Change the AVR's input**, listed under the names you gave them, minus
  the sources you deleted in the AVR's setup menu

## The kit it assumes

| Room | Device | How HEOS addresses it |
| --- | --- | --- |
| Living Room | 2× Denon Home 200 as an In-Room Group | a **group** (`gid`) |
| Lego Room | Denon Home 400 | a **player** (`pid`) |
| Home Cinema | Denon AVR-X3800H | a **player**, plus Telnet on port 23 |

Any other mix works — it is all in `config.py`.

## Install

```bash
cd /var/www/html/heos
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
python3 app.py
```

Then open `http://<pi-ip>:5005/`.

The virtual environment is not optional on a current Raspberry Pi OS:
`pip install` straight into the system Python is refused there with
`externally-managed-environment`. It also keeps Flask out of the way of
anything else running on the Pi.

Every later `python3 ...` command here assumes the environment is active
(`source .venv/bin/activate`); `deactivate` when you are done. The service
below calls the environment's Python directly, so it does not care.

## Configure

Open `http://<pi-ip>:5005/api/targets` and copy the exact `name` HEOS reports
for each device into `TARGETS` in `config.py`. The names come from whatever
you typed in the HEOS app, so they rarely match the model names.

```python
TARGETS = {
    "avr":               {"label": "Home Cinema", "heos_name": "Home Cinema"},
    "home400":           {"label": "Lego Room",   "heos_name": "Lego Room"},
    "living_room_group": {"label": "Living Room", "heos_name": "Denon Home 200 L"},
}
HOST_KEY  = "avr"                                  # always the group host
ROOM_KEYS = ["home400", "living_room_group"]       # the cards, in order
```

`HEOS_HOST` only needs to point at **one** device: HEOS is distributed, so any
unit can see and control the whole network. `AVR_HOST` must be the AVR itself.

`VOLUME_STEP` is the grid the volume buttons snap to, not simply how much
they add: at 5, a tap moves 23 to 25 and 25 to 30.

The input picker already leaves out sources switched off in the AVR's own
setup menu (it asks the AVR with `SSSOD ?`). `AVR_INPUT_CODES` narrows it
further to the sources you actually use, and sets their order; leave it empty
to list everything the AVR still has switched on.

## Add it to the iOS home screen

Open the page in Safari → Share → **Add to Home Screen**. It then launches
full-screen with no browser chrome, which is the point of the exercise.

Safari will only offer that over plain HTTP on the LAN, which is fine here;
if you ever put it behind a domain name, give it HTTPS.

## Run it as a service

```ini
# /etc/systemd/system/heos-panel.service
[Unit]
Description=HEOS panel
After=network-online.target

[Service]
ExecStart=/home/pi/heos/.venv/bin/python /home/pi/heos/app.py
WorkingDirectory=/home/pi/heos
Restart=always
User=pi

[Install]
WantedBy=multi-user.target
```

```bash
sudo systemctl enable --now heos-panel
```

## How the grouping actually works

Worth knowing, because HEOS makes two things easy to get wrong.

**`set_group` replaces a group wholesale.** There is no "add this player".
Joining a second room therefore re-sends every member of the group, and the
host's `pid` has to come first — that is what makes the AVR the leader whose
content everyone plays.

**Your Home 200 pair is a group, not a speaker.** Merging it into the AVR
means sending *both* speakers' pids; sending only the leader would leave the
second Home 200 playing on its own. And once merged, the pair's own `gid`
stops existing, so:

- unmerging re-issues `set_group` with the pair's two pids, rebuilding it
- volume falls back to setting both players directly, since there is no
  group volume to set any more

The panel learns the pair's members the first time it sees them un-merged and
remembers them in `members.json`, which is what lets it rebuild the pair after
a restart. If you would rather pin them down, list them in `config.py`:

```python
"living_room_group": {
    "label": "Living Room",
    "heos_name": "Denon Home 200 L",
    "players": ["Denon Home 200 L", "Denon Home 200 R"],   # leader first
},
```

Leaving a room deliberately does *not* rewrite the AVR's group, so the other
room's music does not restart.

## Two protocols, not one

| | HEOS CLI (port 1255) | Denon Telnet (port 23) |
| --- | --- | --- |
| Speaks | JSON, `heos://player/...` | plain text, `SIGAME`, `SSFUN ?` |
| Used for | players, groups, volume | the AVR's **renamed** input list |

HEOS only knows generic input ids like `inputs/hdmi_in_1`; the names you gave
your sources live in the AVR's own protocol, which is why both are here.

The Telnet connection is held open, so input changes made with the physical
remote show up in the panel too. Some Denon models only accept **one** Telnet
connection at a time — if another integration (Home Assistant, say) already
holds it, the AVR card will read `offline` while the HEOS half keeps working.

## HTTP API

Used by the interface:

| | |
| --- | --- |
| `GET /api/state` | everything the UI draws, in one call |
| `GET /api/targets` | every player and group HEOS can see |
| `POST /api/volume` | `{"target": "home400", "steps": 1}` — taps, snapped to `VOLUME_STEP`. Also takes `delta` (raw points) or `level` (absolute) |
| `POST /api/mute` | `{"target": "home400"}` |
| `POST /api/group` | `{"target": "home400", "joined": true}` |
| `POST /api/group/none` | every room back on its own |
| `GET /api/avr/inputs` | your renamed sources |
| `POST /api/avr/input` | `{"code": "GAME"}` |

`POST /volume/up` and `/volume/down` take one snapped tap by default; pass
`?step=3` and they move that many raw points instead, as they always did.

The original bridge's endpoints still answer, so existing Shortcuts and
scripts keep working: `/targets`, `/volume`, `/volume/{set,up,down,mute}`,
`/playback/{play,pause,stop,next,previous}`, `/group/{create,remove}`,
`/inputs`, `/input/{set,relay}`, `/avr/{raw,input,inputs}`, `/raw/<command>`.

Two of them are worth keeping for troubleshooting:

```
GET /raw/browse/browse?sid=1027     # any heos:// command, raw reply
GET /avr/raw?cmd=SSFUN ?            # any Telnet command, every line back
```

## Working on it

```bash
python3 app.py --demo                       # fake speakers, real interface
python3 -m unittest discover -s tests -t .  # runs against a fake HEOS network
python3 tools/make_icons.py                 # re-render the icons from static/logo.svg
```

## Layout

```
app.py          Flask: the UI, the API, and the old bridge's routes
controller.py   what a room is, what grouping means, volume
heos.py         HEOS CLI client (persistent socket, reconnects itself)
avr.py          Denon Telnet client + the renamed input list
config.py       your devices and preferences
demo.py         fake speakers for --demo
templates/ static/   the interface
tests/          fake HEOS + AVR servers, and tests against them
```