Refactor API types and sync logic

Rename and refactor the types passed over the API to be based on an
entity that's either living or a tombstone.  A living entity has a
deleted property that's either undefined or false, while a tombstone
has a deleted property set to true.  All entities have a numeric id
and an updatedAt timestamp.

To sync entities, an array of replacements are passed around. Living
entities are replaced with tombstones when they're deleted. And
tombstones are replaced with living entities when restored.

server/streams.ts

@@ -1,6 +1,6 @@
-import { Schedule } from "~/shared/types/schedule"
 import { readAccounts } from "~/server/database";
 import { canSeeCrew } from "./utils/schedule";
+import type { ApiAccount, ApiEvent } from "~/shared/types/api";
 
 function sendMessage(
 	stream: WritableStream<string>,
@@ -65,22 +65,58 @@ export function cancelSessionStreams(sessionId: number) {
 	}
 }
 
-export async function broadcastUpdate(schedule: Schedule) {
+const encodeEventCache = new WeakMap<ApiEvent, Map<ApiAccount["type"] | undefined, string>>();
+function encodeEvent(event: ApiEvent, accountType: ApiAccount["type"] | undefined) {
+	const cache = encodeEventCache.get(event);
+	const cacheEntry = cache?.get(accountType);
+	if (cacheEntry) {
+		return cacheEntry;
+	}
+
+	let data: string;
+	if (event.type === "schedule-update") {
+		if (!canSeeCrew(accountType)) {
+			event = {
+				type: event.type,
+				updatedFrom: event.updatedFrom,
+				data: filterSchedule(event.data),
+			};
+		}
+		data = JSON.stringify(event);
+	} else {
+		throw Error(`encodeEvent cannot encode ${event.type} event`);
+	}
+
+	if (cache) {
+		cache.set(accountType, data);
+	} else {
+		encodeEventCache.set(event, new Map([[accountType, data]]));
+	}
+	return data;
+}
+
+export async function broadcastEvent(event: ApiEvent) {
 	const id = Date.now();
 	console.log(`broadcasting update to ${streams.size} clients`);
 	if (!streams.size) {
 		return;
 	}
 	const accounts = await readAccounts();
-	const filteredSchedule = filterSchedule(schedule);
 	for (const [stream, streamData] of streams) {
-		let accountType: string | undefined;
-		if (streamData.accountId !== undefined) {
-			accountType = accounts.find(a => a.id === streamData.accountId)?.type
+		// Account events are specially handled and only sent to the account they belong to.
+		if (event.type === "account-update") {
+			if (streamData.accountId === event.data.id) {
+				sendMessage(stream, `id: ${id}\nevent: update\ndata: ${JSON.stringify(event)}\n\n`);
+			}
+
+		} else {
+			let accountType: ApiAccount["type"] | undefined;
+			if (streamData.accountId !== undefined) {
+				accountType = accounts.find(a => a.id === streamData.accountId)?.type
+			}
+			const data = encodeEvent(event, accountType)
+			sendMessage(stream, `id: ${id}\nevent: update\ndata: ${data}\n\n`);
 		}
-		const data = JSON.stringify(canSeeCrew(accountType) ? schedule : filteredSchedule);
-		const message = `id: ${id}\nevent: update\ndata: ${data}\n\n`
-		sendMessage(stream, message);
 	}
 }