Signage/README.md

# Signage

Ekklesia's visual programming, timeline, synchronization, and display-delivery module.

Signage decides **what is on a screen, when, and on which screens together**. It natively supports
static images; every other kind of content reaches a screen because another Ekklesia module
registered a content provider and contributed a live React renderer for it. Signage never learns what
an announcement, a Bible passage, or a trivia question is.

This repository is a standalone, independently versioned Ekklesia module package. It is not a fork of
Ekklesia and vendors none of its SDKs.

- Module id: `signage`
- Package: `@ekklesia/signage`
- Manifest version: 8, with the Module Database ABI v1 (`database: { abi: 1 }`)

## Status

Version 0.1.4 is feature-complete for its declared scope, and Signage has run in production since
0.1.1. What exists today:

- The module package, manifest (v8), four capabilities, six permissions, ten operator settings, and
  one logical storage bucket.
- Eleven tables and a single initial migration, declared non-destructive.
- Native image ingest: one image per streamed request, 25 MiB, content-addressed, with display and
  thumbnail renditions and temporary object keys removed after any unsuccessful upload.
- The content provider contract and registry, a bounded and sanitized call path, and Signage's own
  built-in image provider registered through that same capability.
- Timelines, provider source slots, pinned slots, channel groups, synchronized audience channels,
  authoritative playback with absolute instants, activation and scheduling, and viewer
  registration, assignment, heartbeat, and health.
- A management-UI artifact and a full-viewport display artifact, both built through the canonical
  Ekklesia module UI pipeline and mounted through the platform's browser ABI.
- Two permanent scene layers with a crossfade that never fades the outgoing slide, provider
  renderers mounted as browser contributions, the built-in "Content unavailable" slate, deliberate
  blackout, and offline continuation from this display's own persisted state.

No cutover from the legacy Announcements container has happened or is planned by this repository.
Video, audio, MQTT, Home Assistant, Companion, and a notification outbox are out of scope; so is
any content module — Signage ships with no announcements, scripture, or trivia, and cannot render
any until one is installed.

### Offline cold start is not yet possible

A display that is **already mounted** keeps playing with no network: its schedule, playback state,
provider payloads, and media are Signage's own, persisted by this module in IndexedDB and Cache
Storage. Core's service worker caches module *code*, not Signage domain data.

A display that is **restarted while Ekklesia is completely unreachable** cannot mount Signage at all.
Mounting requires an authenticated module descriptor, and Core does not yet cache one. True offline
cold start depends on a Core-provided authorized offline display descriptor or lease; until that
exists, this module does not claim it. See ADR 0006.

## Developing Signage

Signage builds and tests on its own. You need no Ekklesia checkout and no Ekklesia account:

- **Node.js** in the range `engines.node` declares (`>=24.11.0 <25`); `.node-version` names the
  version CI uses.
- **pnpm** at the version `packageManager` pins, through Corepack (`corepack enable`).

```bash
git clone <this repository> signage
cd signage
corepack enable
pnpm install --frozen-lockfile
```

Ekklesia's module-development packages (`@ekklesia/module-sdk`, `@ekklesia/module-database`,
`@ekklesia/module-ui-sdk`, `@ekklesia/ui`, `@ekklesia/design-tokens`, `@ekklesia/module-ui-build`,
`@ekklesia/module-pack`, `@ekklesia/typescript-config`) come from Ekklesia's public package registry.
The committed `.npmrc` points the `@ekklesia` scope at it, and reading it needs **no token** and no
login (platform ADRs 0053 and 0054); never add a credential to that file. Everything else comes from
the public npm registry. `package.json` takes the Ekklesia packages as `^0.2.0` ranges, except
`@ekklesia/module-pack`, which is pinned exactly; `pnpm-lock.yaml` pins every package's exact version
and integrity, so always install with `--frozen-lockfile` unless you mean to change a dependency.

`pnpm-workspace.yaml` holds this repository's own pnpm settings: it allows esbuild's install script,
exempts exactly the Ekklesia package train in the lockfile from pnpm's minimum release age, and keeps
one narrowly scoped advisory override. It does not make Signage part of any other workspace.

Signage requires Ekklesia 0.2: manifest version 8 and the Module Database ABI v1 (platform ADR 0050).
It reaches PostgreSQL only through the ABI v1 executor the platform hands it, with its own Drizzle
tables and the module-side adapter from `@ekklesia/module-database/drizzle`. Core receives SQL text,
bound values, and plain schema metadata, never a Drizzle object.

### Commands

```bash
pnpm lint        # Biome, with this repository's biome.json
pnpm typecheck   # node, browser, and browser-test projects
pnpm test        # unit, browser-artifact, and display contract tests (vitest.config.ts)
pnpm build       # tsc, then the canonical module UI build of the primary and display artifacts
pnpm validate    # after build: the built package and its migrations, as the platform reads them
```

CI runs exactly these, from a clean checkout.

`pnpm validate` uses only the published SDK parsers. It cannot check what only an Ekklesia
installation knows: compatibility with that installation, other installed modules' capabilities and
dependencies, or a migration's checksum against a database's applied history. Ekklesia checks those
when Signage is installed.

Never run a migration against a persistent database while developing this module. Signage reads no
environment variable, constructs no database client, configures no object storage, hardcodes no
Ekklesia URL, opens no socket of its own, and applies no migration: every one of those reaches it
through the host.

### Changing the schema

```bash
pnpm migration:generate   # drizzle-kit, into drizzle/
```

`tests/schema.test.ts` pins the checksum of the generated SQL, so a regenerated migration fails the
suite until the pin is updated deliberately. `drizzle/meta/_ekklesia.json` declares the migration
non-destructive: `tests/schema.test.ts` asserts it, and Ekklesia's own migration validation enforces
it when Signage is packaged and installed.

### Verifying what only a browser can show

Automated DOM assertions cannot prove a crossfade, a letterboxed image, or a slate. Those are
verified by driving the **built** artifacts in a real Chromium against a stub host and reading the
frames: native fill, both letterboxed fits, a contributed renderer, a frozen mid-crossfade composite,
the slate, a blackout, the offline indicator, every management tab, and the narrow-screen gate. The
harness is deliberately not committed — it stubs a host and would rot into a second, wrong
description of the platform ABI.

## What Signage owns, and what providers own

| Signage owns | A content provider owns |
| --- | --- |
| Native image assets and their renditions | Its own domain content and tables |
| Saved timelines, repeating patterns, and slots | Which of its content is available now |
| Channel groups and synchronized audience channels | Selecting the next item from one of its sources |
| Slot timing and authoritative playback | Repeat and no-repeat policy |
| Timeline activation and scheduling | Audience-specific variants and fallback |
| Viewer registration, assignment, heartbeat, health | Its own live React presentation |
| Transitions, offline continuation, playback controls | Dynamic change within one slide |
| The management and display UI | Its own internal multi-stage behaviour |

## Licence and scope

Deployment, the module store, a theme editor, a mobile management UI, video and audio, MQTT, Home
Assistant, Companion, and any migration of legacy Announcements data are explicitly out of scope for
this repository.