/**
 * Copyright (c) 2017-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

function execute() {
  const extractTranslations = require('../write-translations.js');

  const CWD = process.cwd();
  const fs = require('fs-extra');
  const readMetadata = require('./readMetadata.js');
  const renderToStaticMarkup = require('react-dom/server').renderToStaticMarkup;
  const path = require('path');
  const toSlug = require('../core/toSlug.js');
  const React = require('react');
  const mkdirp = require('mkdirp');
  const glob = require('glob');
  const chalk = require('chalk');
  const Site = require('../core/Site.js');
  const siteConfig = require(CWD + '/siteConfig.js');
  const translate = require('./translate.js');
  const versionFallback = require('./versionFallback.js');

  const feed = require('./feed.js');
  const sitemap = require('./sitemap.js');

  const join = path.join;

  const ENABLE_TRANSLATION = fs.existsSync(join(CWD, 'languages.js'));
  const ENABLE_VERSIONING = fs.existsSync(join(CWD, 'versions.json'));

  let languages;
  if (ENABLE_TRANSLATION) {
    languages = require(CWD + '/languages.js');
  } else {
    languages = [
      {
        enabled: true,
        name: 'English',
        tag: 'en',
      },
    ];
  }
  // create the folder path for a file if it does not exist, then write the file
  function writeFileAndCreateFolder(file, content) {
    mkdirp.sync(file.replace(new RegExp('/[^/]*$'), ''));

    fs.writeFileSync(file, content);
  }

  const TABLE_OF_CONTENTS_TOKEN = '<AUTOGENERATED_TABLE_OF_CONTENTS>';

  // takes the content of a doc article and returns the content with a table of
  // contents inserted
  const insertTableOfContents = rawContent => {
    const regexp = /\n###\s+(`.*`.*)\n/g;
    let match;
    const headers = [];
    while ((match = regexp.exec(rawContent))) {
      headers.push(match[1]);
    }

    const tableOfContents = headers
      .map(header => `  - [${header}](#${toSlug(header)})`)
      .join('\n');

    return rawContent.replace(TABLE_OF_CONTENTS_TOKEN, tableOfContents);
  };

  // returns true if a file should be excluded from concatentation to
  // default Docusaurus styles
  function isSeparateCss(file) {
    if (!siteConfig.separateCss) {
      return false;
    }
    for (let i = 0; i < siteConfig.separateCss.length; i++) {
      if (file.includes(siteConfig.separateCss[i])) {
        return true;
      }
    }
    return false;
  }

  console.log('generate.js triggered...');

  // array of tags of enabled languages
  const enabledLanguages = [];
  languages.filter(lang => lang.enabled).map(lang => {
    enabledLanguages.push(lang.tag);
  });

  readMetadata.generateMetadataDocs();
  const Metadata = require('../core/metadata.js');

  // TODO: what if the project is a github org page? We should not use
  // siteConfig.projectName in this case. Otherwise a GitHub org doc URL would
  // look weird: https://myorg.github.io/myorg/docs

  // TODO: siteConfig.projectName is a misnomer. The actual project name is
  // `title`. `projectName` is only used to generate a folder, which isn't
  // needed when the project's a GitHub org page

  const buildDir = join(CWD, 'build', siteConfig.projectName);

  // mdToHtml is a map from a markdown file name to its html link, used to
  // change relative markdown links that work on GitHub into actual site links
  const mdToHtml = {};
  Object.keys(Metadata).forEach(id => {
    const metadata = Metadata[id];
    if (metadata.language !== 'en' || metadata.original_id) {
      return;
    }
    let htmlLink =
      siteConfig.baseUrl + metadata.permalink.replace('/next/', '/');
    if (htmlLink.includes('/docs/en/')) {
      htmlLink = htmlLink.replace('/docs/en/', '/docs/en/VERSION/');
    } else {
      htmlLink = htmlLink.replace('/docs/', '/docs/VERSION/');
    }
    mdToHtml[metadata.source] = htmlLink;
  });

  const DocsLayout = require('../core/DocsLayout.js');
  const Redirect = require('../core/Redirect.js');

  fs.removeSync(join(CWD, 'build'));

  // create html files for all docs by going through all doc ids
  Object.keys(Metadata).forEach(id => {
    const metadata = Metadata[id];
    // determine what file to use according to its id
    let file;
    if (metadata.original_id) {
      if (ENABLE_TRANSLATION && metadata.language !== 'en') {
        file = join(CWD, 'translated_docs', metadata.language, metadata.source);
      } else {
        file = join(CWD, 'versioned_docs', metadata.source);
      }
    } else {
      if (metadata.language === 'en') {
        file = join(CWD, '..', readMetadata.getDocsPath(), metadata.source);
      } else {
        file = join(CWD, 'translated_docs', metadata.language, metadata.source);
      }
    }

    if (!fs.existsSync(file)) {
      return;
    }

    let rawContent = readMetadata.extractMetadata(fs.readFileSync(file, 'utf8'))
      .rawContent;

    const language = metadata.language;

    // generate table of contents if appropriate
    if (rawContent && rawContent.indexOf(TABLE_OF_CONTENTS_TOKEN) != -1) {
      rawContent = insertTableOfContents(rawContent);
    }

    let latestVersion;
    if (ENABLE_VERSIONING) {
      latestVersion = JSON.parse(
        fs.readFileSync(join(CWD, 'versions.json'), 'utf8')
      )[0];
    }

    // replace any links to markdown files to their website html links
    Object.keys(mdToHtml).forEach(function(key, index) {
      let link = mdToHtml[key];
      link = link.replace('/en/', '/' + language + '/');
      link = link.replace(
        '/VERSION/',
        metadata.version && metadata.version !== latestVersion
          ? '/' + metadata.version + '/'
          : '/'
      );
      // replace relative links without "./"
      rawContent = rawContent.replace(
        new RegExp('\\]\\(' + key, 'g'),
        '](' + link
      );
      // replace relative links with "./"
      rawContent = rawContent.replace(
        new RegExp('\\]\\(\\./' + key, 'g'),
        '](' + link
      );
    });

    // replace any relative links to static assets to absolute links
    rawContent = rawContent.replace(
      /\]\(assets\//g,
      '](' + siteConfig.baseUrl + 'docs/assets/'
    );

    const docComp = (
      <DocsLayout metadata={metadata} language={language} config={siteConfig}>
        {rawContent}
      </DocsLayout>
    );
    const str = renderToStaticMarkup(docComp);

    const targetFile = join(buildDir, metadata.permalink);
    writeFileAndCreateFolder(targetFile, str);

    // generate english page redirects when languages are enabled
    if (ENABLE_TRANSLATION && metadata.permalink.indexOf('docs/en') !== -1) {
      const redirectComp = (
        <Redirect
          metadata={metadata}
          language={language}
          config={siteConfig}
          redirect={siteConfig.baseUrl + metadata.permalink}
        />
      );
      const redirectStr = renderToStaticMarkup(redirectComp);

      // create a redirects page for doc files
      const redirectFile = join(
        buildDir,
        metadata.permalink.replace('docs/en', 'docs')
      );
      writeFileAndCreateFolder(redirectFile, redirectStr);
    }
  });

  // copy docs assets if they exist
  if (fs.existsSync(join(CWD, '..', readMetadata.getDocsPath(), 'assets'))) {
    fs.copySync(
      join(CWD, '..', readMetadata.getDocsPath(), 'assets'),
      join(buildDir, 'docs', 'assets')
    );
  }

  // create html files for all blog posts (each article)
  if (fs.existsSync(join(__dirname, '..', 'core', 'MetadataBlog.js'))) {
    fs.removeSync(join(__dirname, '..', 'core', 'MetadataBlog.js'));
  }
  readMetadata.generateMetadataBlog();
  const MetadataBlog = require('../core/MetadataBlog.js');
  const BlogPostLayout = require('../core/BlogPostLayout.js');

  let files = glob.sync(join(CWD, 'blog', '**', '*.*'));
  files
    .sort()
    .reverse()
    .forEach(file => {
      const extension = path.extname(file);
      if (extension !== '.md' && extension !== '.markdown') {
        return;
      }

      // convert filename to use slashes
      const filePath = path
        .basename(file)
        .replace('-', '/')
        .replace('-', '/')
        .replace('-', '/')
        .replace(/\.md$/, '.html');
      const result = readMetadata.extractMetadata(
        fs.readFileSync(file, {encoding: 'utf8'})
      );
      const rawContent = result.rawContent;
      const metadata = Object.assign(
        {path: filePath, content: rawContent},
        result.metadata
      );
      metadata.id = metadata.title;

      let language = 'en';
      const blogPostComp = (
        <BlogPostLayout
          metadata={metadata}
          language={language}
          config={siteConfig}>
          {rawContent}
        </BlogPostLayout>
      );
      const str = renderToStaticMarkup(blogPostComp);

      let targetFile = join(buildDir, 'blog', filePath);
      writeFileAndCreateFolder(targetFile, str);
    });
  // create html files for all blog pages (collections of article previews)
  const BlogPageLayout = require('../core/BlogPageLayout.js');
  const perPage = 10;
  for (let page = 0; page < Math.ceil(MetadataBlog.length / perPage); page++) {
    let language = 'en';
    const metadata = {page: page, perPage: perPage};
    const blogPageComp = (
      <BlogPageLayout
        metadata={metadata}
        language={language}
        config={siteConfig}
      />
    );
    const str = renderToStaticMarkup(blogPageComp);

    let targetFile = join(
      buildDir,
      'blog',
      page > 0 ? 'page' + (page + 1) : '',
      'index.html'
    );
    writeFileAndCreateFolder(targetFile, str);
  }
  // create rss files for all blog pages, if there are any blog files
  if (MetadataBlog.length > 0) {
    let targetFile = join(buildDir, 'blog', 'feed.xml');
    writeFileAndCreateFolder(targetFile, feed());
    targetFile = join(buildDir, 'blog', 'atom.xml');
    writeFileAndCreateFolder(targetFile, feed('atom'));
  }

  // create sitemap
  if (MetadataBlog.length > 0 && Object.keys(Metadata).length > 0) {
    let targetFile = join(buildDir, 'sitemap.xml');
    sitemap(xml => {
      writeFileAndCreateFolder(targetFile, xml);
    });
  }

  // copy blog assets if they exist
  if (fs.existsSync(join(CWD, 'blog', 'assets'))) {
    fs.copySync(join(CWD, 'blog', 'assets'), join(buildDir, 'blog', 'assets'));
  }

  // copy all static files from docusaurus
  files = glob.sync(join(__dirname, '..', 'static', '**'));
  files.forEach(file => {
    let targetFile = join(
      buildDir,
      // TODO: use x-platform path functions
      file.split('/static/')[1] || ''
    );
    // parse css files to replace colors according to siteConfig
    if (file.match(/\.css$/)) {
      let cssContent = fs.readFileSync(file, 'utf8');

      if (
        !siteConfig.colors ||
        !siteConfig.colors.primaryColor ||
        !siteConfig.colors.secondaryColor
      ) {
        console.error(
          `${chalk.yellow(
            'Missing color configuration.'
          )} Make sure siteConfig.colors includes primaryColor and secondaryColor fields.`
        );
      }

      Object.keys(siteConfig.colors).forEach(key => {
        const color = siteConfig.colors[key];
        cssContent = cssContent.replace(new RegExp('\\$' + key, 'g'), color);
      });

      mkdirp.sync(targetFile.replace(new RegExp('/[^/]*$'), ''));
      fs.writeFileSync(targetFile, cssContent);
    } else if (!fs.lstatSync(file).isDirectory()) {
      mkdirp.sync(targetFile.replace(new RegExp('/[^/]*$'), ''));
      fs.copySync(file, targetFile);
    }
  });

  // copy all static files from user
  files = glob.sync(join(CWD, 'static', '**'), {dot: true});
  files.forEach(file => {
    // parse css files to replace colors according to siteConfig
    if (file.match(/\.css$/) && !isSeparateCss(file)) {
      const mainCss = join(buildDir, 'css', 'main.css');
      let cssContent = fs.readFileSync(file, 'utf8');
      cssContent = fs.readFileSync(mainCss, 'utf8') + '\n' + cssContent;

      Object.keys(siteConfig.colors).forEach(key => {
        const color = siteConfig.colors[key];
        cssContent = cssContent.replace(new RegExp('\\$' + key, 'g'), color);
      });

      fs.writeFileSync(mainCss, cssContent);
    } else if (!fs.lstatSync(file).isDirectory()) {
      let parts = file.split('/static/');
      let targetFile = join(buildDir, parts[1]);
      mkdirp.sync(targetFile.replace(new RegExp('/[^/]*$'), ''));
      fs.copySync(file, targetFile);
    }
  });

  // compile/copy pages from user
  let pagesArr = [];
  files = glob.sync(join(CWD, 'pages', '**'));
  files.forEach(file => {
    // render .js files to strings
    if (file.match(/\.js$/)) {
      // make temp file for sake of require paths
      const parts = file.split('pages');
      let tempFile = join(__dirname, '..', 'pages', parts[1]);
      tempFile = tempFile.replace(
        path.basename(file),
        'temp' + path.basename(file)
      );
      mkdirp.sync(tempFile.replace(new RegExp('/[^/]*$'), ''));
      fs.copySync(file, tempFile);

      const ReactComp = require(tempFile);

      let targetFile = join(buildDir, parts[1]);
      targetFile = targetFile.replace(/\.js$/, '.html');

      const regexLang = /\/pages\/(.*)\//;
      const match = regexLang.exec(file);
      const langParts = match[1].split('/');
      if (langParts.indexOf('en') !== -1) {
        // copy and compile a page for each enabled language from the English file
        for (let i = 0; i < enabledLanguages.length; i++) {
          let language = enabledLanguages[i];
          // skip conversion from english file if a file exists for this language
          if (
            language !== 'en' &&
            // TODO: use path functions
            fs.existsSync(file.replace('/en/', '/' + language + '/'))
          ) {
            continue;
          }
          translate.setLanguage(language);
          const str = renderToStaticMarkup(
            <Site language={language} config={siteConfig}>
              <ReactComp language={language} />
            </Site>
          );
          writeFileAndCreateFolder(
            // TODO: use path functions
            targetFile.replace('/en/', '/' + language + '/'),
            str
          );
        }
      } else {
        // allow for rendering of other files not in pages/en folder
        let language = 'en';
        for (let i = 0; i < langParts.length; i++) {
          if (enabledLanguages.indexOf(langParts[i]) !== -1) {
            language = langParts[i];
          }
        }
        translate.setLanguage(language);
        const str = renderToStaticMarkup(
          <Site language={language} config={siteConfig}>
            <ReactComp language={language} />
          </Site>
        );
        writeFileAndCreateFolder(targetFile, str);
      }
      fs.removeSync(tempFile);
    } else if (siteConfig.wrapPagesHTML && file.match(/\.html$/)) {
      const parts = file.split('pages');
      const targetFile = join(buildDir, parts[1]);
      const str = renderToStaticMarkup(
        <Site language="en" config={siteConfig}>
          <div dangerouslySetInnerHTML={{__html: fs.readFileSync(file, { encoding: "utf8" })}} />
        </Site>
      );

      writeFileAndCreateFolder(targetFile, str);
    } else if (!fs.lstatSync(file).isDirectory()) {
      // copy other non .js files
      let parts = file.split('pages');
      let targetFile = join(buildDir, parts[1]);
      mkdirp.sync(targetFile.replace(new RegExp('/[^/]*$'), ''));
      fs.copySync(file, targetFile);
    }
  });

  // copy html files in 'en' to base level as well
  files = glob.sync(join(buildDir, 'en', '**'));
  files.forEach(file => {
    let targetFile = file.replace(join(buildDir, 'en'), join(buildDir));
    if (file.match(/\.html$/)) {
      fs.copySync(file, targetFile);
    }
  });

  // Generate CNAME file if a custom domain is specified in siteConfig
  if (siteConfig.cname) {
    let targetFile = join(buildDir, 'CNAME');
    fs.writeFileSync(targetFile, siteConfig.cname);
  }
}

module.exports = execute;