const fs = require('fs');
const path = require('path');
const LRU = require('lru-cache');
const pkg = require('../../package.json');
const {createBundleRenderer} = require('vue-server-renderer');

const isDev = process.env.NODE_ENV === 'development' || !process.env.NODE_ENV;
let renderer;
let template = fs.readFileSync(path.join(__dirname, '../../src/index.html'), 'utf-8');

const microCache = LRU({
    max: 10000,
    maxAge: 2000
});

const isCacheable = req => {
    return false;
};

const getContext = (req) => {
    return {
        url: req.url,
        title: 'BLK！',
        user: req.user,
        env: {
            isApp: req.yoho.isApp,
            isiOS: req.yoho.isiOS,
            isAndroid: req.yoho.isAndroid,
            isYohoBuy: req.yoho.isYohoBuy,
            channel: req.yoho.channel
        }
    };
};

const render = (req, res, next) => {
    const cacheable = isCacheable(req);

    if (cacheable) {
        const html = microCache.get(req.url);

        if (html) {
            return res.send(html);
        }
    }
    let context = getContext(req);

    renderer.renderToString(context, (err, html) => {
        if (err) {
            return next(err);
        }
        if (cacheable) {
            microCache.set(req.url, html);
        }
        return res.send(html);
    });
};

if (!isDev) {
    // Promise.all([
    //     rp(`https://cdn.yoho.cn/yohoblk-wap/bundle/yoho-ssr-server-${pkg.version}.json`, {json: true}),
    //     rp(`https://cdn.yoho.cn/yohoblk-wap/bundle/yoho-ssr-client-${pkg.version}.json`, {json: true}),
    // ]).then(results => {
    //     renderer = createBundleRenderer(results[0], {
    //         runInNewContext: false,
    //         template,
    //         clientManifest: results[1]
    //     });
    // });

    const serverBundle = require(`../../public/dist/yohoblk-wap/bundle/yoho-ssr-server-${pkg.version}.json`);
    const clientManifest = require(`../../public/dist/yohoblk-wap/bundle/yoho-ssr-client-${pkg.version}.json`);

    renderer = createBundleRenderer(serverBundle, {
        runInNewContext: false,
        template,
        clientManifest
    });
}

const ssrRender = isDev ? (req, res, next) => {
    let context = getContext(req);

    process.send({action: 'ssr_request', context});
    let event = msg => {
        process.removeListener('message', event);
        if (msg.action === 'ssr_request') {
            if (msg.err) {
                return next(JSON.parse(msg.err));
            }
            return res.end(msg.html);
        }
    };

    process.on('message', event);
} : render;


module.exports = app => {
    app.get(/product\/\d+/, ssrRender);
    app.get('/channel', ssrRender);
    app.get('/channel/man', ssrRender);
    app.get('/channel/woman', ssrRender);
};