games/packages/server/src/table.ts

import { t } from "elysia";
import { combine, Property } from "kefir";
import Bus, { type Bus as TBus } from "kefir-bus";
import {
	newSimpleGameState,
	resolveSimpleAction,
	SimpleAction,
	SimpleConfiguration,
	SimpleGameState,
} from "./games/simple";
import { transform } from "./kefir-extension";

export const WsOut = t.Object({
	players: t.Optional(t.Array(t.String())),
	playersReady: t.Optional(t.Record(t.String(), t.Boolean())),
	view: t.Optional(t.Any()),
});
export type TWsOut = typeof WsOut.static;
export const WsIn = t.Union([
	t.Object({ ready: t.Boolean() }),
	t.Object({ action: t.Any() }),
	t.Object({ quit: t.Literal(true) }),
]);
export type TWsIn = typeof WsIn.static;

type Attributed = { humanKey: string };
type TablePayload<GameConfig, GameState, GameAction> = {
	inputs: {
		connectionChanges: TBus<
			Attributed & { presence: "joined" | "left" },
			never
		>;

		readys: TBus<Attributed & { ready: boolean }, never>;
		actions: TBus<Attributed & GameAction, never>;
		quits: TBus<Attributed, never>;
	};
	outputs: {
		playersPresent: Property<string[], never>;
		playersReady: Property<{ [key: string]: boolean }, unknown>;
		gameConfig: Property<GameConfig | null, never>;
		gameState: Property<GameState | null, never>;
	};
};

const tables: {
	[key: string]: TablePayload<unknown, unknown, unknown>;
} = {};

export const liveTable = <GameConfig, GameState, GameAction>(key: string) => {
	if (!(key in tables)) {
		const inputs: TablePayload<
			GameConfig,
			GameState,
			GameAction
		>["inputs"] = {
			connectionChanges: Bus(),
			readys: Bus(),
			actions: Bus(),
			quits: Bus(),
		};
		const { connectionChanges, readys, actions, quits } = inputs;
		// =======

		const playersPresent = connectionChanges
			.scan((prev, evt) => {
				if (evt.presence == "left" && prev[evt.humanKey] == 1) {
					const { [evt.humanKey]: _, ...rest } = prev;
					return rest;
				}
				return {
					...prev,
					[evt.humanKey]:
						(prev[evt.humanKey] ?? 0) +
						(evt.presence == "joined" ? 1 : -1),
				};
			}, {} as { [key: string]: number })
			.map((counts) => Object.keys(counts));

		const playersReady = transform(
			{} as { [key: string]: boolean },
			[
				playersPresent,
				(prev, players: string[]) =>
					Object.fromEntries(
						players.map((p) => [p, prev[p] ?? false])
					),
			],
			[
				readys,
				(prev, evt: { humanKey: string; ready: boolean }) =>
					prev[evt.humanKey] != null
						? { ...prev, [evt.humanKey]: evt.ready }
						: prev,
			]
		);

		const gameStarts = playersReady
			.filter(
				(pr) =>
					Object.values(pr).length > 0 &&
					Object.values(pr).every((ready) => ready)
			)
			.map((_) => null);

		const gameConfig = playersPresent.map((players) => ({
			game: "simple",
			players,
		}));

		const gameState = transform(
			null as SimpleGameState | null,
			[
				combine([gameStarts], [gameConfig], (_, config) => config),
				(prev, startConfig: SimpleConfiguration) =>
					prev == null ? newSimpleGameState(startConfig) : prev,
			],
			[
				combine([actions], [gameConfig], (action, config) => ({
					action,
					config,
				})),
				(
					prev,
					evt: {
						action: Attributed & SimpleAction;
						config: SimpleConfiguration;
					}
				) =>
					prev != null
						? resolveSimpleAction({
								config: evt.config,
								state: prev,
								action: evt.action,
								humanKey: evt.action.humanKey,
						  })
						: prev,
			]
		).toProperty();

		tables[key] = {
			inputs,
			outputs: {
				playersPresent,
				playersReady,
				gameConfig: gameConfig as Property<unknown, never>,
				gameState: gameState as Property<unknown, never>,
			},
		};

		// cleanup
		tables[key].outputs.playersPresent
			.debounce(30000, { immediate: false })
			.filter((players) => players.length === 0)
			.skip(1)
			.onValue((_) => {
				console.log("DELETING LIVE TABLE");
				delete tables[key];
			});
	}
	return tables[key] as TablePayload<GameConfig, GameState, GameAction>;
};