import React from 'react';
import { renderToString } from 'react-dom/server';
import { StaticRouter } from 'react-router-dom';
import { has } from 'lodash';
import debug from 'debug';

import NewsApp from '../../news/NewsApp';

const routerLog = debug('fcc:boot:news:router');
const apiLog = debug('fcc:boot:news:api');

export default function newsBoot(app) {
  const router = app.loopback.Router();
  const api = app.loopback.Router();

  router.get('/n', (req, res) => res.redirect('/news'));
  router.get('/n/:shortId', createReferralHandler(app));

  router.get('/news', serveNewsApp);
  router.get('/news/*', serveNewsApp);

  api.post('/p', createPopularityHandler(app));

  app.use(api);
  app.use(router);
}

function serveNewsApp(req, res) {
  const context = {};
  const markup = renderToString(
    <StaticRouter basename='/news' context={context} location={req.url}>
      <NewsApp />
    </StaticRouter>
  );
  if (context.url) {
    routerLog('redirect found in `renderToString`');
    // 'client-side' routing hit on a redirect
    return res.redirect(context.url);
  }
  routerLog('news markup sending');
  return res.render('layout-news', { title: 'News | freeCodeCamp', markup });
}

function createReferralHandler(app) {
  const { Article } = app.models;

  return function referralHandler(req, res, next) {
    const { shortId } = req.params;
    if (!shortId) {
      return res.redirect('/news');
    }
    routerLog('shortId', shortId);
    return Article.findOne(
      {
        where: {
          or: [{ shortId }, { slugPart: shortId }]
        }
      },
      (err, article) => {
        if (err) {
          next(err);
        }
        if (!article) {
          return res.redirect('/news');
        }
        const {
          slugPart,
          shortId,
          author: { username }
        } = article;
        const slug = `/news/${username}/${slugPart}--${shortId}`;
        return res.redirect(slug);
      }
    );
  };
}

function createPopularityHandler(app) {
  const { Article, Popularity } = app.models;

  return function handlePopularityStats(req, res, next) {
    const { body, user } = req;
    if (
      !has(body, 'event') ||
      !has(body, 'timestamp') ||
      !has(body, 'shortId')
    ) {
      console.warn('Popularity event recieved from client is malformed');
      console.log(JSON.stringify(body, null, 2));
      // sending 200 because the client shouldn't care for this
      return res.sendStatus(200);
    }
    res.sendStatus(200);
    const { shortId } = body;
    apiLog('shortId', shortId);
    const populartiyUpdate = {
      ...body,
      byAuthenticatedUser: !!user
    };
    Popularity.findOne({ where: { articleId: shortId } }, (err, popularity) => {
      if (err) {
        apiLog(err);
        return next(err);
      }
      if (popularity) {
        return popularity.updateAttribute(
          'events',
          [populartiyUpdate, ...popularity.events],
          err => {
            if (err) {
              apiLog(err);
              return next(err);
            }
            return apiLog('poplarity updated');
          }
        );
      }
      return Popularity.create(
        {
          events: [populartiyUpdate],
          articleId: shortId
        },
        err => {
          if (err) {
            apiLog(err);
            return next(err);
          }
          return apiLog('poulartiy created');
        }
      );
    });
    return body.event === 'view'
      ? Article.findOne({ where: { shortId } }, (err, article) => {
          if (err) {
            apiLog(err);
            next(err);
          }
          return article.updateAttributes(
            { viewCount: article.viewCount + 1 },
            err => {
              if (err) {
                apiLog(err);
                return next(err);
              }
              return apiLog('article views updated');
            }
          );
        })
      : null;
  };
}