// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import { EventBufferConfig } from '../types/buffer';
import { AuthSession } from '../../../singleton/Auth/types';

import { PinpointEventBuffer } from './PinpointEventBuffer';

// Map of buffers by region -> appId
const eventBufferMap: Record<string, Record<string, PinpointEventBuffer>> = {};

export type GetEventBufferInput = EventBufferConfig & {
	appId: string;
	region: string;
	credentials: Required<AuthSession>['credentials'];
	identityId?: AuthSession['identityId'];
	userAgentValue?: string;
};

/**
 * Returns a PinpointEventBuffer instance for the specified region & app ID, creating one if it does not yet exist.
 *
 * @internal
 */
export const getEventBuffer = ({
	appId,
	region,
	credentials,
	bufferSize,
	flushInterval,
	flushSize,
	resendLimit,
	identityId,
	userAgentValue,
}: GetEventBufferInput): PinpointEventBuffer => {
	if (eventBufferMap[region]?.[appId]) {
		const buffer = eventBufferMap[region][appId];

		/*
		If the identity or credentials has changed flush out the buffer and create a new instance. The old instance will be garbage
		collected.
		*/
		const shouldFlushBuffer =
			buffer.identityHasChanged(identityId) ||
			buffer.haveCredentialsChanged(credentials);

		if (shouldFlushBuffer) {
			buffer.flush();
		} else {
			return buffer;
		}
	}

	const buffer = new PinpointEventBuffer({
		appId,
		bufferSize,
		credentials,
		flushInterval,
		flushSize,
		identityId,
		region,
		resendLimit,
		userAgentValue,
	});

	if (!eventBufferMap[region]) {
		eventBufferMap[region] = {};
	}

	eventBufferMap[region][appId] = buffer;

	return buffer;
};