const fs = require('fs');
const path = require('path');
const LRU = require('lru-cache');
const express = require('express');
const favicon = require('serve-favicon');
const compression = require('compression');
const microcache = require('route-cache');
const resolve = file => path.resolve(__dirname, file);
const {createBundleRenderer} = require('vue-server-renderer');
const cookieParser = require('cookie-parser');

const config = require('./config/env.js');

const isProd = process.env.NODE_ENV === 'production';
const useMicroCache = process.env.MICRO_CACHE !== 'false';
const serverInfo =
    `express/${require('express/package.json').version} ` +
    `vue-server-renderer/${require('vue-server-renderer/package.json').version}`;

const app = express()

function createRenderer(bundle, options) {
    return createBundleRenderer(bundle, Object.assign(options, {
        cache: LRU({
            max: 1000,
            maxAge: 1000 * 60 * 15
        }),
        basedir: resolve('./dist'),
        runInNewContext: false
    }))
}

let renderer;
let readyPromise;
const templatePath = resolve('./src/index.template.html');
if (isProd) {

    const template = fs.readFileSync(templatePath, 'utf-8');
    const bundle = require('./dist/vue-ssr-server-bundle.json');
    const clientManifest = require('./dist/vue-ssr-client-manifest.json');
    renderer = createRenderer(bundle, {
        template,
        clientManifest
    })
} else {
    readyPromise = require('./build/setup-dev-server')(
        app,
        templatePath,
        (bundle, options) => {
            renderer = createRenderer(bundle, options)
        }
    )
}

const serve = (path, cache) => express.static(resolve(path), {
    maxAge: cache && isProd ? 1000 * 60 * 60 * 24 * 30 : 0
});

app.use(cookieParser());
app.use(compression({threshold: 0}));
app.use(favicon('./public/favicon.svg'));
app.use('/dist', serve('./dist', true));
app.use('/public', serve('./public', true));
app.use('/manifest.json', serve('./manifest.json', true));
app.use('/service-worker.js', serve('./dist/service-worker.js'));


app.use(microcache.cacheSeconds(1, req => useMicroCache && req.originalUrl));

function render(req, res) {
    const s = Date.now();

    res.setHeader("Content-Type", "text/html");
    res.setHeader("Server", serverInfo);

    const handleError = err => {
        if (err.url) {
            res.redirect(err.url)
        } else if (err.code === 404) {
            res.status(404).send('404 | Page Not Found')
        } else {
            res.status(500).send('500 | Internal Server Error');
            console.error(`error during render : ${req.url}`);
            console.error(err.stack)
        }
    };

    const context = {
        title: 'SkipTyler Dev', // default title
        meta: `<meta id="qq" name="description" content="" />`,
        url: req.url,
        cookies: req.cookies
    };
    renderer.renderToString(context, (err, html) => {
        if (err) {
            return handleError(err)
        }
        res.send(html);
        if (!isProd) {
            console.log(`whole request: ${Date.now() - s}ms`)
        }
    })
}

app.get('*', isProd ? render : (req, res) => {
    readyPromise.then(() => render(req, res))
});

const port = process.env.PORT || config.VUE_PORT;
app.listen(port, () => {
    console.log(`server started at localhost:${port}`)
});