Fix syncing when network latency is present (#4)

* WIP

* Add debug

* Dedupe inserts

* Add deterministic ordering

* Fix whitespaces

* Update insta

* Add integration test script

* Rename

* Add test

* Working for non-deletes

* omg it mostly works for deletes

* Isdeleted fix

* remove created dates

* update api

* Take document id

* No max attempt

* works

* Use string uuids

* .

* working!!!! (hopefully)

* Improve bundling

* Add module

* lint

* .

* lint

* Fix CI

* use toolchain

* clean up

* Add useSlowFileEvents

* Delete fuzz

* Fix CI

* use docker

* fix script

* clean up

* Clean up

* change node version

* Build docker image on every commit

* fix ci

* 1 db per vault

* Add scritps folder

* Bump versions

* Lint

* .

* Fix tests for real

* Style

* .

* try

* Consistent ordering

* Fix tests

* hmm

* .

* Clean up diff

* Fixes

* .

* Fix version bump

* .

* .

* .

frontend/sync-client/src/services/connected-state.ts

@@ -0,0 +1,51 @@
+import type { Settings } from "../persistence/settings";
+import type { Logger } from "../tracing/logger";
+import { createPromise } from "../utils/create-promise";
+import { retriedFetchFactory } from "../utils/retried-fetch";
+
+export class ConnectedState {
+	private resolveIsSyncEnabled: (() => void) | undefined;
+	private syncIsEnabled: Promise<void> | undefined;
+
+	public constructor(
+		settings: Settings,
+		private readonly logger: Logger
+	) {
+		settings.addOnSettingsChangeHandlers((newSettings, oldSettings) => {
+			if (!oldSettings.isSyncEnabled && newSettings.isSyncEnabled) {
+				this.handleComingOnline();
+			} else if (
+				oldSettings.isSyncEnabled &&
+				!newSettings.isSyncEnabled
+			) {
+				this.handleGoingOffline();
+			}
+		});
+	}
+
+	public getFetchImplementation(
+		fetch: typeof globalThis.fetch,
+		{ doRetries = true }: { doRetries: boolean } = { doRetries: true }
+	): typeof globalThis.fetch {
+		const retriedFetch = doRetries
+			? retriedFetchFactory(this.logger, fetch)
+			: fetch;
+
+		return async (input: RequestInfo | URL): Promise<Response> => {
+			if (this.syncIsEnabled !== undefined) {
+				await this.syncIsEnabled;
+			}
+			return retriedFetch(input);
+		};
+	}
+
+	private handleComingOnline(): void {
+		this.logger.debug("Sync is enabled");
+		this.resolveIsSyncEnabled?.();
+	}
+
+	private handleGoingOffline(): void {
+		this.logger.debug("Sync is disabled");
+		[this.syncIsEnabled, this.resolveIsSyncEnabled] = createPromise();
+	}
+}