refactor: unify backend and frontend servers (#3)

* refactor: unify backend and frontend servers

* refactor: correct paths for openapi & drizzle

* refactor: move api-client to client

* fix: drizzle paths

* chore: fix linting issues

* fix: form reset issue

app/client/api-client/core/serverSentEvents.gen.ts

@@ -0,0 +1,237 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import type { Config } from "./types.gen";
+
+export type ServerSentEventsOptions<TData = unknown> = Omit<RequestInit, "method"> &
+	Pick<Config, "method" | "responseTransformer" | "responseValidator"> & {
+		/**
+		 * Fetch API implementation. You can use this option to provide a custom
+		 * fetch instance.
+		 *
+		 * @default globalThis.fetch
+		 */
+		fetch?: typeof fetch;
+		/**
+		 * Implementing clients can call request interceptors inside this hook.
+		 */
+		onRequest?: (url: string, init: RequestInit) => Promise<Request>;
+		/**
+		 * Callback invoked when a network or parsing error occurs during streaming.
+		 *
+		 * This option applies only if the endpoint returns a stream of events.
+		 *
+		 * @param error The error that occurred.
+		 */
+		onSseError?: (error: unknown) => void;
+		/**
+		 * Callback invoked when an event is streamed from the server.
+		 *
+		 * This option applies only if the endpoint returns a stream of events.
+		 *
+		 * @param event Event streamed from the server.
+		 * @returns Nothing (void).
+		 */
+		onSseEvent?: (event: StreamEvent<TData>) => void;
+		serializedBody?: RequestInit["body"];
+		/**
+		 * Default retry delay in milliseconds.
+		 *
+		 * This option applies only if the endpoint returns a stream of events.
+		 *
+		 * @default 3000
+		 */
+		sseDefaultRetryDelay?: number;
+		/**
+		 * Maximum number of retry attempts before giving up.
+		 */
+		sseMaxRetryAttempts?: number;
+		/**
+		 * Maximum retry delay in milliseconds.
+		 *
+		 * Applies only when exponential backoff is used.
+		 *
+		 * This option applies only if the endpoint returns a stream of events.
+		 *
+		 * @default 30000
+		 */
+		sseMaxRetryDelay?: number;
+		/**
+		 * Optional sleep function for retry backoff.
+		 *
+		 * Defaults to using `setTimeout`.
+		 */
+		sseSleepFn?: (ms: number) => Promise<void>;
+		url: string;
+	};
+
+export interface StreamEvent<TData = unknown> {
+	data: TData;
+	event?: string;
+	id?: string;
+	retry?: number;
+}
+
+export type ServerSentEventsResult<TData = unknown, TReturn = void, TNext = unknown> = {
+	stream: AsyncGenerator<TData extends Record<string, unknown> ? TData[keyof TData] : TData, TReturn, TNext>;
+};
+
+export const createSseClient = <TData = unknown>({
+	onRequest,
+	onSseError,
+	onSseEvent,
+	responseTransformer,
+	responseValidator,
+	sseDefaultRetryDelay,
+	sseMaxRetryAttempts,
+	sseMaxRetryDelay,
+	sseSleepFn,
+	url,
+	...options
+}: ServerSentEventsOptions): ServerSentEventsResult<TData> => {
+	let lastEventId: string | undefined;
+
+	const sleep = sseSleepFn ?? ((ms: number) => new Promise((resolve) => setTimeout(resolve, ms)));
+
+	const createStream = async function* () {
+		let retryDelay: number = sseDefaultRetryDelay ?? 3000;
+		let attempt = 0;
+		const signal = options.signal ?? new AbortController().signal;
+
+		while (true) {
+			if (signal.aborted) break;
+
+			attempt++;
+
+			const headers =
+				options.headers instanceof Headers
+					? options.headers
+					: new Headers(options.headers as Record<string, string> | undefined);
+
+			if (lastEventId !== undefined) {
+				headers.set("Last-Event-ID", lastEventId);
+			}
+
+			try {
+				const requestInit: RequestInit = {
+					redirect: "follow",
+					...options,
+					body: options.serializedBody,
+					headers,
+					signal,
+				};
+				let request = new Request(url, requestInit);
+				if (onRequest) {
+					request = await onRequest(url, requestInit);
+				}
+				// fetch must be assigned here, otherwise it would throw the error:
+				// TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+				const _fetch = options.fetch ?? globalThis.fetch;
+				const response = await _fetch(request);
+
+				if (!response.ok) throw new Error(`SSE failed: ${response.status} ${response.statusText}`);
+
+				if (!response.body) throw new Error("No body in SSE response");
+
+				const reader = response.body.pipeThrough(new TextDecoderStream()).getReader();
+
+				let buffer = "";
+
+				const abortHandler = () => {
+					try {
+						reader.cancel();
+					} catch {
+						// noop
+					}
+				};
+
+				signal.addEventListener("abort", abortHandler);
+
+				try {
+					while (true) {
+						const { done, value } = await reader.read();
+						if (done) break;
+						buffer += value;
+
+						const chunks = buffer.split("\n\n");
+						buffer = chunks.pop() ?? "";
+
+						for (const chunk of chunks) {
+							const lines = chunk.split("\n");
+							const dataLines: Array<string> = [];
+							let eventName: string | undefined;
+
+							for (const line of lines) {
+								if (line.startsWith("data:")) {
+									dataLines.push(line.replace(/^data:\s*/, ""));
+								} else if (line.startsWith("event:")) {
+									eventName = line.replace(/^event:\s*/, "");
+								} else if (line.startsWith("id:")) {
+									lastEventId = line.replace(/^id:\s*/, "");
+								} else if (line.startsWith("retry:")) {
+									const parsed = Number.parseInt(line.replace(/^retry:\s*/, ""), 10);
+									if (!Number.isNaN(parsed)) {
+										retryDelay = parsed;
+									}
+								}
+							}
+
+							let data: unknown;
+							let parsedJson = false;
+
+							if (dataLines.length) {
+								const rawData = dataLines.join("\n");
+								try {
+									data = JSON.parse(rawData);
+									parsedJson = true;
+								} catch {
+									data = rawData;
+								}
+							}
+
+							if (parsedJson) {
+								if (responseValidator) {
+									await responseValidator(data);
+								}
+
+								if (responseTransformer) {
+									data = await responseTransformer(data);
+								}
+							}
+
+							onSseEvent?.({
+								data,
+								event: eventName,
+								id: lastEventId,
+								retry: retryDelay,
+							});
+
+							if (dataLines.length) {
+								yield data as any;
+							}
+						}
+					}
+				} finally {
+					signal.removeEventListener("abort", abortHandler);
+					reader.releaseLock();
+				}
+
+				break; // exit loop on normal completion
+			} catch (error) {
+				// connection failed or aborted; retry after delay
+				onSseError?.(error);
+
+				if (sseMaxRetryAttempts !== undefined && attempt >= sseMaxRetryAttempts) {
+					break; // stop after firing error
+				}
+
+				// exponential backoff: double retry each attempt, cap at 30s
+				const backoff = Math.min(retryDelay * 2 ** (attempt - 1), sseMaxRetryDelay ?? 30000);
+				await sleep(backoff);
+			}
+		}
+	};
+
+	const stream = createStream();
+
+	return { stream };
+};