# Station Master

A railroad operations game set in the era of timetable-and-train-order railroading (1840–1950),
being built as a multiplayer browser game with an authoritative server.

You are the Station Master of a lineside Office on a shared east–west Division. Trains run to a
timetable with no radios — just pocket watches and written orders. You switch cars, work freight and
passengers, and take your turn as Superintendent deciding whether it is safe to clear a following
train into an occupied Subdivision. Get that wrong and two trains meet at speed.

## Status

Design complete, implementation just begun.

- **Rules** — fully specified. Ten gaps in the original prototype rules found and resolved.
- **Card faces** — every card's printed values specified.
- **Architecture** — six documents, including a 20-component build plan.
- **Code** — build step 1 of 12 complete: card catalogue, state model, seeded RNG.

The MVP target is **solitaire, one Office, a fixed number of Days**, with a server talking to a
single browser.

## Layout

```
station-master/
├── CHANGELOG.md        ← what changed and why, in detail, commit to commit
├── TODO.md             ← open questions, provisional numbers, things to come back to
├── docs/
│   ├── rules/          ← the ruleset, card reference, glossary, decision record
│   ├── architecture/   ← how it is built, and what the pieces are
│   └── design/         ← board layout studies and rendering samples
├── public/replays/     ← saved games published to the site's replay directory
├── scripts/            ← build and deploy the static site
├── src/
│   ├── engine/         ← pure rules engine: no I/O, no clock, deterministic from a seed
│   ├── sim/            ← bot, harness, replay, board rendering
│   └── web/            ← the playable site: splash, game, replay viewer
└── test/
```

Start with [`docs/design.md`](docs/design.md) — it indexes everything. Commit messages stay high
level; [`CHANGELOG.md`](CHANGELOG.md) carries the reasoning and the measurements, and
[`TODO.md`](TODO.md) is what we have decided not to forget.

## Development

Requires **Node 22.18+**, which runs TypeScript directly by type stripping. There is no build step.

```sh
npm install
npm test          # node --test
npm run typecheck # tsc --noEmit
```

Because Node strips types rather than compiling them, the codebase is restricted to **erasable
syntax**: no `enum`, no parameter properties, no namespaces. `tsconfig.json` enforces this.

## Design notes worth knowing

- **The rules engine is pure.** No I/O, no clock, no sockets, and all randomness derives from one
  stored seed — so any game is exactly replayable, and a full game can be driven in a unit test with
  no server at all.
- **It has two entry points, not one.** `apply(state, intent)` for player actions, and
  `advance(state)` for everything the game does on its own — Mainline movement, collisions, the Stage
  clock, Superintendent rotation.
- **State is `fold(events)`.** The event log is the source of truth, which is what gives reconnection,
  restart recovery and post-game replay from a single decision.
- **Never call `Math.random()`.** One ambient random call silently breaks replay.