@rivetkit/core/src/common/eventsource.ts

import type { EventSource } from "eventsource";
import { logger } from "@/client/log";

// Global singleton promise that will be reused for subsequent calls
let eventSourcePromise: Promise<typeof EventSource> | null = null;

/**
 * Import `eventsource` from the custom `eventsource` library. We need a custom implemnetation since we need to attach our own custom headers to the request.
 **/
export async function importEventSource(): Promise<typeof EventSource> {
	// Return existing promise if we already started loading
	if (eventSourcePromise !== null) {
		return eventSourcePromise;
	}

	// Create and store the promise
	eventSourcePromise = (async () => {
		let _EventSource: typeof EventSource;

		// Node.js environment
		try {
			const es = await import("eventsource");
			_EventSource = es.EventSource;
			logger().debug("using eventsource from npm");
		} catch (err) {
			// EventSource not available
			_EventSource = class MockEventSource {
				constructor() {
					throw new Error(
						'EventSource support requires installing the "eventsource" peer dependency.',
					);
				}
			} as unknown as typeof EventSource;
			logger().debug("using mock eventsource");
		}

		return _EventSource;
	})();

	return eventSourcePromise;
}

//export async function importEventSource(): Promise<typeof EventSource> {
//	// Return existing promise if we already started loading
//	if (eventSourcePromise !== null) {
//		return eventSourcePromise;
//	}
//
//	// Create and store the promise
//	eventSourcePromise = (async () => {
//		let _EventSource: typeof EventSource;
//
//		if (typeof EventSource !== "undefined") {
//			// Browser environment
//			_EventSource = EventSource;
//			logger().debug("using native eventsource");
//		} else {
//			// Node.js environment
//			try {
//				const es = await import("eventsource");
//				_EventSource = es.EventSource;
//				logger().debug("using eventsource from npm");
//			} catch (err) {
//				// EventSource not available
//				_EventSource = class MockEventSource {
//					constructor() {
//						throw new Error(
//							'EventSource support requires installing the "eventsource" peer dependency.',
//						);
//					}
//				} as unknown as typeof EventSource;
//				logger().debug("using mock eventsource");
//			}
//		}
//
//		return _EventSource;
//	})();
//
//	return eventSourcePromise;
//}