@bigfishtv/cockpit/es/reducers/imageRequestQueue.js

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

/**
 * @module Reducers/imageRequestQueue
 */

import { ENABLE_IMAGE_REQUEST_QUEUE, DISABLE_IMAGE_REQUEST_QUEUE, REQUEST_GENERATED_IMAGE, CANCEL_GENERATED_IMAGE_REQUEST, GENERATED_IMAGE_REQUEST_FULFILLED } from '../constants/ActionTypes';

var MAX_ACTIVE_REQUESTS = 25;
var IMAGE_REQUEST_QUEUE_INTERVAL = 50; // ms
var IMAGE_REQUEST_INITIAL_DELAY = 250; // ms
var IMAGE_REQUEST_TIMEOUT = 5000; // ms

var initialState = { queue: [], enabled: false };

var queue = [];
var pendingAssets = 0;
var processQueue = function processQueue() {
	if (!queue.length) return;
	// filter out unresolved requests older than 5 seconds
	var prePurgeCount = queue.length;
	queue = queue.filter(function (_ref) {
		var created = _ref.created;
		return Date.now() - created < IMAGE_REQUEST_TIMEOUT;
	});
	var purgeCount = prePurgeCount - queue.length;
	pendingAssets -= purgeCount;
	// if (purgeCount) console.log('Purged ' + purgeCount + ' requests from the queue')

	// Recheck queue length after oldie purge
	if (!queue.length) return;

	// Active requests at max, leave it for a tick
	if (pendingAssets > MAX_ACTIVE_REQUESTS) return;

	// Check if request is too young to be considered yet
	var actionAge = Date.now() - queue[0].created;
	if (actionAge < IMAGE_REQUEST_INITIAL_DELAY) return;

	var action = queue.shift();
	if (action.callback) {
		// console.log('🏁 allowing this asset', action.key)
		action.callback(action.url);
		pendingAssets++;
	}
};

setInterval(processQueue, IMAGE_REQUEST_QUEUE_INTERVAL);

export default function () {
	var state = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : initialState;
	var action = arguments[1];

	switch (action.type) {
		case ENABLE_IMAGE_REQUEST_QUEUE:
			return _extends({}, state, { enabled: true });
		case DISABLE_IMAGE_REQUEST_QUEUE:
			return _extends({}, state, { enabled: false });
		case REQUEST_GENERATED_IMAGE:
			if (state.enabled) queue.push(_extends({}, action, { created: Date.now() }));else action.callback(action.url);
			return _extends({}, state, { queue: queue });
		case GENERATED_IMAGE_REQUEST_FULFILLED:
		case CANCEL_GENERATED_IMAGE_REQUEST:
			// if (action.type === GENERATED_IMAGE_REQUEST_FULFILLED) console.log('✅ asset request completed', action.key)
			// if (action.type === CANCEL_GENERATED_IMAGE_REQUEST) console.log('🗑 cancel loading of this asset', action.key)
			pendingAssets--;
			if (state.enabled) queue = queue.filter(function (item) {
				return item.callback !== action.callback;
			});
			return _extends({}, state, { queue: queue });
	}
	return _extends({}, state, { queue: queue });
}