// app.server.module.ts
import { NgModule } from '@angular/core';
import { ServerModule } from '@angular/platform-server';
import { ModuleMapLoaderModule } from '@nguniversal/module-map-ngfactory-loader';

import { AppModule } from './app.module';
import { AppComponent } from './app.component';

@NgModule({
    imports: [
        ServerModule,
        ModuleMapLoaderModule,
        AppModule
    ],
    bootstrap: [AppComponent]
})
export class AppServerModule {}

// main.server.ts
export { AppServerModule } from './app/app.server.module';

{
    "extends": "../tsconfig.json",
    "compilerOptions": {
        "module": "commonjs",
    },
    "angularCompilerOptions": {
        "entryModule": "app/app.server.module#AppServerModule",
    }
}

"server": {
    "builder": "@angular-devkit/build-angular:server",
    "options": {
        "outputPath": "dist-server",
        "main": "src/main.server.ts",
        "tsConfig": "src/tsconfig.server.json"
    },
}

// server.ts
import 'zone.js/dist/zone-node';
import 'reflect-metadata';

import { join } from 'path';
import { readFileSync } from 'fs';
import { enableProdMode } from '@angular/core';
import { renderModuleFactory } from '@angular/platform-server';
import { provideModuleMap } from '@nguniversal/module-map-ngfactory-loader';

const PORT = Number(process.env.PORT);
const DIST_FOLDER = join(process.cwd(), 'dist');
const document = readFileSync(join(DIST_FOLDER, 'index.html')).toString();

import { AppServerModuleNgFactory, LAZY_MODULE_MAP } from './dist-server/main';

import * as Koa from 'koa';
import * as Router from 'koa-router';

router.get('/*', async (ctx: Koa.Context) => {
    const { url } = ctx.request;

    ctx.body = await renderModuleFactory(AppServerNgModuleFactory, {
        document,
        url,
        extraProviders: [provideModuleMap(LAZY_MODULE_MAP)]
    });
});

app.use(router.routes());

app.listen(PORT, () => {
    console.log(`Koa server is running and listening at port ${PORT}`);
});