/* CONFIGURATION STARTS HERE */

  /* Step 1: enter your domain name like notion.afuture.me */
  const MY_DOMAIN = '你的域名';
  
  /*
   * Step 2: enter your URL slug to page ID mapping
   * The key on the left is the slug (without the slash)
   * The value on the right is the Notion page ID
   */
  const SLUG_TO_PAGE = {
    '': 'pageid',
  };
  
  /* Step 3: enter your page title and description for SEO purposes */
  const PAGE_TITLE = '';
  const PAGE_DESCRIPTION = '';
  
  /* Step 4: enter a Google Font name, you can choose from https://fonts.font.im */
  const GOOGLE_FONT = '';
  
  /* Step 5: enter any custom scripts you'd like */
  const CUSTOM_SCRIPT = ``;
  
  /* CONFIGURATION ENDS HERE */
  
  const PAGE_TO_SLUG = {};
  const slugs = [];
  const pages = [];
  Object.keys(SLUG_TO_PAGE).forEach(slug => {
    const page = SLUG_TO_PAGE[slug];
    slugs.push(slug);
    pages.push(page);
    PAGE_TO_SLUG[page] = slug;
  });
  
  addEventListener('fetch', event => {
    event.respondWith(fetchAndApply(event.request));
  });

  function generateSitemap() {
    let sitemap = '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
    slugs.forEach(
      (slug) =>
        (sitemap +=
          '<url><loc>https://' + MY_DOMAIN + '/' + slug + '</loc></url>')
    );
    sitemap += '</urlset>';
    return sitemap;
  }
  
  const corsHeaders = {
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET, HEAD, POST, PUT, OPTIONS',
    'Access-Control-Allow-Headers': 'Content-Type',
  };
  
  function handleOptions(request) {
    if (request.headers.get('Origin') !== null &&
      request.headers.get('Access-Control-Request-Method') !== null &&
      request.headers.get('Access-Control-Request-Headers') !== null) {
      // Handle CORS pre-flight request.
      return new Response(null, {
        headers: corsHeaders
      });
    } else {
      // Handle standard OPTIONS request.
      return new Response(null, {
        headers: {
          'Allow': 'GET, HEAD, POST, PUT, OPTIONS',
        }
      });
    }
  }
  
  async function fetchAndApply(request) {
    if (request.method === 'OPTIONS') {
      return handleOptions(request);
    }
    let url = new URL(request.url);
    if (url.pathname === '/robots.txt') {
      return new Response('Sitemap: https://' + MY_DOMAIN + '/sitemap.xml');
    }
    if (url.pathname === '/sitemap.xml') {
      let response = new Response(generateSitemap());
      response.headers.set('content-type', 'application/xml');
      return response;
    }
    const notionUrl = 'https://www.notion.so' + url.pathname;
    let response;
    if (url.pathname.startsWith('/app') && url.pathname.endsWith('js')) {
      response = await fetch(notionUrl);
      let body = await response.text();
      response = new Response(body.replace(/www.notion.so/g, MY_DOMAIN).replace(/notion.so/g, MY_DOMAIN), response);
      response.headers.set('Content-Type', 'application/x-javascript');
    } else if ((url.pathname.startsWith('/api'))) {
      // Forward API
      response = await fetch(notionUrl, {
        body: request.body,
        headers: {
          'content-type': 'application/json;charset=UTF-8',
          'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36'
        },
        method: 'POST',
      });
      response = new Response(response.body, response);
      response.headers.set('Access-Control-Allow-Origin', '*');
    } else if (slugs.indexOf(url.pathname.slice(1)) > -1) {
      const pageId = SLUG_TO_PAGE[url.pathname.slice(1)];
      return Response.redirect('https://' + MY_DOMAIN + '/' + pageId, 301);
    } else {
      response = await fetch(notionUrl, {
        body: request.body,
        headers: request.headers,
        method: request.method,
      });
      response = new Response(response.body, response);
      response.headers.delete('Content-Security-Policy');
      response.headers.delete('X-Content-Security-Policy');
    }
  
    return appendJavascript(response, SLUG_TO_PAGE);
  }
  
  class MetaRewriter {
    element(element) {
      if (PAGE_TITLE !== '') {
        if (element.getAttribute('property') === 'og:title'
          || element.getAttribute('name') === 'twitter:title') {
          element.setAttribute('content', PAGE_TITLE);
        }
        if (element.tagName === 'title') {
          element.setInnerContent(PAGE_TITLE);
        }
      }
      if (PAGE_DESCRIPTION !== '') {
        if (element.getAttribute('name') === 'description'
          || element.getAttribute('property') === 'og:description'
          || element.getAttribute('name') === 'twitter:description') {
          element.setAttribute('content', PAGE_DESCRIPTION);
        }
      }
      if (element.getAttribute('property') === 'og:url'
        || element.getAttribute('name') === 'twitter:url') {
        element.setAttribute('content', MY_DOMAIN);
      }
      if (element.getAttribute('name') === 'apple-itunes-app') {
        element.remove();
      }
    }
  }
  
  class HeadRewriter {
    element(element) {
      if (GOOGLE_FONT !== '') {
        element.append(`<link href="https://fonts.font.im/css?family=${GOOGLE_FONT.replace(' ', '+')}:Regular,Bold,Italic&display=swap" rel="stylesheet">
        <style>* { font-family: "${GOOGLE_FONT}" !important; }</style>`, {
         html: true
        });
      }
      element.append(`<style>
      div.notion-topbar > div > div:nth-child(3) { display: none !important; }
      div.notion-topbar > div > div:nth-child(4) { display: none !important; }
      div.notion-topbar > div > div:nth-child(5) { display: none !important; }
      div.notion-topbar > div > div:nth-child(6) { display: none !important; }
      div.notion-topbar-mobile > div:nth-child(3) { display: none !important; }
      div.notion-topbar-mobile > div:nth-child(4) { display: none !important; }
      </style>`, {
        html: true
      })
    }
  }
  
  class BodyRewriter {
    constructor(SLUG_TO_PAGE) {
      this.SLUG_TO_PAGE = SLUG_TO_PAGE;
    }
    element(element) {
      element.append(`<div style="display:none">Powered by <a href="http://notion.afuture.me">afuture</a></div>
      <script>
      const SLUG_TO_PAGE = ${JSON.stringify(this.SLUG_TO_PAGE)};
      const PAGE_TO_SLUG = {};
      const slugs = [];
      const pages = [];
      let redirected = false;
      Object.keys(SLUG_TO_PAGE).forEach(slug => {
        const page = SLUG_TO_PAGE[slug];
        slugs.push(slug);
        pages.push(page);
        PAGE_TO_SLUG[page] = slug;
      });
      function getPage() {
        return location.pathname.slice(-32);
      }
      function getSlug() {
        return location.pathname.slice(1);
      }
      function updateSlug() {
        const slug = PAGE_TO_SLUG[getPage()];
        if (slug != null) {
          history.replaceState(history.state, '', '/' + slug);
        }
      }
      const observer = new MutationObserver(function() {
        if (redirected) return;
        const nav = document.querySelector('.notion-topbar');
        const mobileNav = document.querySelector('.notion-topbar-mobile');
        if (nav && nav.firstChild && nav.firstChild.firstChild
          || mobileNav && mobileNav.firstChild) {
          redirected = true;
          updateSlug();
          const onpopstate = window.onpopstate;
          window.onpopstate = function() {
            if (slugs.includes(getSlug())) {
              const page = SLUG_TO_PAGE[getSlug()];
              if (page) {
                history.replaceState(history.state, 'bypass', '/' + page);
              }
            }
            onpopstate.apply(this, [].slice.call(arguments));
            updateSlug();
          };
        }
      });
      observer.observe(document.querySelector('#notion-app'), {
        childList: true,
        subtree: true,
      });
      const replaceState = window.history.replaceState;
      window.history.replaceState = function(state) {
        if (arguments[1] !== 'bypass' && slugs.includes(getSlug())) return;
        return replaceState.apply(window.history, arguments);
      };
      const pushState = window.history.pushState;
      window.history.pushState = function(state) {
        const dest = new URL(location.protocol + location.host + arguments[2]);
        const id = dest.pathname.slice(-32);
        if (pages.includes(id)) {
          arguments[2] = '/' + PAGE_TO_SLUG[id];
        }
        return pushState.apply(window.history, arguments);
      };
      const open = window.XMLHttpRequest.prototype.open;
      window.XMLHttpRequest.prototype.open = function() {
        arguments[1] = arguments[1].replace('${MY_DOMAIN}', 'www.notion.so');
        return open.apply(this, [].slice.call(arguments));
      };
    </script>${CUSTOM_SCRIPT}`, {
        html: true
      });
    }
  }
  
  async function appendJavascript(res, SLUG_TO_PAGE) {
    return new HTMLRewriter()
      .on('title', new MetaRewriter())
      .on('meta', new MetaRewriter())
      .on('head', new HeadRewriter())
      .on('body', new BodyRewriter(SLUG_TO_PAGE))
      .transform(res);
  }