# ESPresso Frame Server

Pulls photos from an [Immich](https://immich.app) album, resizes/dithers/quantizes
them to the E Ink Spectra 6 panel's exact 6-color format, and serves the
frame a ready-to-display image once an hour. All the image processing
happens here so the ESP32 never has to decode a JPEG or run a dithering
algorithm itself -- it just streams the response straight to the panel.

## Setup

1. **Get an Immich API key**: in Immich, go to Account Settings -> API Keys
   -> New API Key. Read-only access to albums/assets is enough.
2. **Run the server**:
   ```
   docker compose up -d
   ```
3. Open `http://<this-machine>:8420/` in a browser, enter your Immich URL
   and API key, click **Load Albums**, pick one, and **Save**.
4. On the ESP32's captive portal setup form, set the **Tools Server** field
   to `<this-machine>:8420`.

## Endpoints

- `GET /` -- config UI
- `GET /api/albums` -- lists Immich albums (used by the config UI)
- `POST /api/config` -- saves Immich URL/API key/album/order
- `GET /frame/image` -- returns the current photo pre-processed into the
  panel's raw 800x480, 4-bit-per-pixel, 2-pixels-per-byte format
  (`application/octet-stream`, exactly 192,000 bytes)
- `GET /health` -- liveness check

## Notes

- Config (including the Immich API key) is stored in `./data/config.json`
  on the host via the compose volume mount.
- `/frame/image` isn't authenticated yet. That's fine on a trusted home
  LAN for now, but worth revisiting once the ESP32 side is wired up to
  send a shared device token.
- The 6-color palette RGB values in `app/image_pipeline.py` are
  approximations, not measured values (Waveshare doesn't publish exact
  color primaries for this panel) -- tune them once you can compare a
  rendered test image against the real panel.

## Deploying a pre-built image

Every push to `main` that touches `server/` triggers a Gitea Actions
workflow (`.gitea/workflows/server-docker-build.yml`) that builds this
image and pushes it to this repo's Gitea Container Registry at
`git.thumeit.com/tfaour/espresso-frame-server`. `docker-compose.yml`
already points at that image, so a deploy host doesn't need this repo's
build context at all -- just the compose file:

```
docker compose pull
docker compose up -d
```

`docker compose build` (or `up --build`) still works too, for local
iteration against your own Dockerfile changes.

## Local development (without Docker)

```
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
CONFIG_PATH=./data/config.json uvicorn app.main:app --reload --port 8420
```