handler/src/core/ioc/container.ts

import { Container } from 'iti';
import { SernEmitter } from '../';
import { isAsyncFunction } from 'node:util/types';

import * as assert from 'node:assert';
import { Subject } from 'rxjs';
import { DefaultServices, ModuleStore } from '../_internal';

/**
 * Provides all the defaults for sern to function properly.
 * The only user provided dependency needs to be @sern/client
 */
export class CoreContainer<T extends Partial<Dependencies>> extends Container<T, {}> {
    private ready$ = new Subject<never>();
    private beenCalled = new Set<PropertyKey>();
    constructor() {
        super();

        this.listenForInsertions();

        (this as Container<{}, {}>)
            .add({
                '@sern/errors': () => new DefaultServices.DefaultErrorHandling(),
                '@sern/emitter': () => new SernEmitter(),
                '@sern/store': () => new ModuleStore(),
            })
            .add(ctx => {
                return {
                    '@sern/modules': () =>
                        new DefaultServices.DefaultModuleManager(ctx['@sern/store']),
                };
            });
    }

    private listenForInsertions() {
        assert.ok(
            !this.isReady(),
            'listening for init functions should only occur prior to sern being ready.',
        );
        const unsubscriber = this.on('containerUpserted', e => this.callInitHooks(e));

        this.ready$.subscribe({
            complete: unsubscriber,
        });
    }

    private async callInitHooks(e: { key: keyof T; newContainer: T[keyof T] | null }) {
        const dep = e.newContainer;

        assert.ok(dep);
        //Ignore any dependencies that are not objects or array
        if (typeof dep !== 'object' || Array.isArray(dep)) {
            return;
        }
        if ('init' in dep && typeof dep.init === 'function' && !this.beenCalled.has(e.key)) {
            isAsyncFunction(dep.init) ? await dep.init() : dep.init();
            this.beenCalled.add(e.key);
        }
    }

    isReady() {
        return this.ready$.closed;
    }
    ready() {
        this.ready$.unsubscribe();
    }
}