#!/usr/bin/env node

const fs = require("fs");
const path = require("path");
const util = require("util");

const cheerio = require("cheerio");
const lunr = require("lunr");
const marked = require("marked");

/**
 * Constants
 */

const headingsRequired = ["Company blurb"];
const headingsOptional = [
  "Company size",
  "Remote status",
  "Region",
  "Company technologies",
  "Office locations",
  "How to apply",
];
const headingsAll = headingsRequired.concat(headingsOptional);

/**
 * Utility functions
 */

function companyNameToProfileFilename(companyName) {
  return companyName
    .toLowerCase()
    .replace(/&/g, " and ")
    .replace(/'/g, "")
    .replace(/[^a-z0-9]+/gi, "-")
    .replace(/^-|-$/g, "");
}
exports.companyNameToProfileFilename = companyNameToProfileFilename;

// adapted from https://gist.github.com/RandomEtc/2657669
function jsonStringifyUnicodeEscaped(obj) {
  return JSON.stringify(obj).replace(/[\u007f-\uffff]/g, (c) => {
    return "\\u" + ("0000" + c.charCodeAt(0).toString(16)).slice(-4);
  });
}
exports.jsonStringifyUnicodeEscaped = jsonStringifyUnicodeEscaped;

function toIdentifierCase(text) {
  return text
    .replace(/'/g, "")
    .replace(/[^a-z0-9]+/gi, " ")
    .trim()
    .split(/\s+/)
    .map((word, i) => {
      if (i === 0) {
        return word.toLowerCase();
      }
      return word.substr(0, 1).toUpperCase() + word.substr(1).toLowerCase();
    })
    .join("");
}
exports.toIdentifierCase = toIdentifierCase;

function stripExtraChars(text) {
  return text.replace(/\ufe0f/g, "");
}
exports.stripExtraChars = stripExtraChars;

/**
 * Other exports
 */
function getHeadingPropertyNames() {
  return headingsAll.reduce((acc, val) => {
    acc[toIdentifierCase(val)] = val;
    return acc;
  }, {});
}
exports.headingPropertyNames = getHeadingPropertyNames();

/**
 * The main exported function
 *
 * Start with a directory including a README.md and company-profiles/*.md
 * files, and validate and parse the content of the Markdown files.
 */
exports.parseFromDirectory = (contentPath) => {
  const companyNamesSeen = {};
  let errors = [];

  function error(filename, msg, ...params) {
    errors.push({
      filename,
      message: util.format(msg, ...params),
    });
  }

  // Build list of Markdown files containing company profiles.
  const profilesPath = path.join(contentPath, "company-profiles");
  const profileFilenames = fs.readdirSync(profilesPath);

  // Scan the company table in the readme.

  const readmeCompanies = [];

  const readmeMarkdown = stripExtraChars(
    fs.readFileSync(path.join(contentPath, "README.md"), "utf8")
  );

  let inTable = false;
  readmeMarkdown.split("\n").forEach((line) => {
    if (/^\s*-+\s*\|\s*-+\s*\|\s*-+\s*$/.test(line)) {
      inTable = true;
    } else if (/^\s*$/.test(line)) {
      inTable = false;
    } else if (inTable) {
      const fields = line.split("|");
      if (fields.length !== 3) {
        readmeError(
          "Expected 3 table cells but found %d: %s",
          fields.length,
          line
        );
      }
    }
  });

  const $ = cheerio.load(marked.parse(readmeMarkdown));

  function readmeError(msg, ...params) {
    error("README.md", msg, ...params);
  }

  const mainUrl = "remoteintech.company";

  function addTargetBlankAndExternalLinkIcons(el) {
    if (el.type === "tag") {
      const anchorTagElements = el.children.filter(
        (element) => element.name === "a"
      );
      if (anchorTagElements.length > 0) {
        anchorTagElements.forEach((element) => {
          const url = element.attribs.href;
          const urlInfo = getUrlInfo(url);

          if (urlInfo.is_email || urlInfo.is_internal) {
            return;
          }

          element.attribs.target = "_blank";

          $element = $(element);
          $element.append(
            '<span style="vertical-align: text-top;"> <img src="/assets/external-link.svg" /> </span>'
          );
        });
      }

      if (el.children && el.children.length) {
        el.children.forEach((element) => {
          addTargetBlankAndExternalLinkIcons(element);
        });
      }
    }
  }

  /**
   * Getting info about the url. It includes checking isEmail of isInternal
   * @param {*} url
   */
  function getUrlInfo(url) {
    const data = {};

    if (url.match(/^mailto:/)) {
      // checking url email or not
      data.is_email = true;
      return data;
    }

    const mainDomainFromGivenUrl = extractMainDomainFromUrl(url);

    // checking url is email or not
    if (mainDomainFromGivenUrl !== mainUrl) {
      data.is_internal = false;
      return data;
    } else {
      data.is_internal = true;
    }

    return data;
  }

  /**
   * Extracting main domain from the url
   * @param {*} url
   */
  function extractMainDomainFromUrl(url) {
    const domainRe = /(https?:\/\/){0,1}((?:[\w\d-]+\.)+[\w\d]{2,})/i; // taken example from https://stackoverflow.com/questions/6238351/fastest-way-to-detect-external-urls

    const data = domainRe.exec(url);

    const splittedDomain = data[2].split(".");

    if (splittedDomain.length === 2) {
      // check extra subdomain is present or not
      return data[2];
    }

    return (
      splittedDomain[splittedDomain.length - 2] +
      "." +
      splittedDomain[splittedDomain.length - 1]
    ); // return only main domain address
  }

  let lastCompanyName = null;

  $("tr").each((i, tr) => {
    const $tr = $(tr);
    if (i === 0) {
      // Assign an ID to the table.
      $tr.closest("table").attr("id", "companies-table");
      // Skip the table header row.
      return;
    }
    const $td = $tr.children("td");

    const websiteUrl = $td.eq(1).text();
    const websiteText = websiteUrl
      .replace(/^https?:\/\//, "")
      .replace(/^www\./, "")
      .replace(/\/$/, "");

    const readmeEntry = {
      // Strip out warning emoji indicating that this profile is incomplete
      name: $td
        .eq(0)
        .text()
        .replace(/\u26a0/, "")
        .trim(),
      // Detect warning emoji next to company name
      isIncomplete: /\u26a0/.test($td.eq(0).text()),
      websiteUrl,
      websiteText,
      shortRegion: $td.eq(2).text().trim(),
    };

    if (!websiteText) {
      readmeError("Missing website for company: %s", readmeEntry.name);
    }

    if (readmeEntry.name) {
      if (companyNamesSeen[readmeEntry.name.toLowerCase()]) {
        readmeError("Duplicate company: %s", readmeEntry.name);
      }
      companyNamesSeen[readmeEntry.name.toLowerCase()] = true;
    } else {
      readmeError("Missing company name: %s", $tr.html().replace(/\n/g, ""));
    }

    if (
      $td.eq(1).children().length !== 1 ||
      !$td.eq(1).children().eq(0).is("a")
    ) {
      readmeError(
        "Invalid content in Website column: %s",
        $tr.html().replace(/\n/g, "")
      );
    }

    if ($td.eq(2).children().length > 0) {
      readmeError(
        "Extra content in Region column: %s",
        $tr.html().replace(/\n/g, "")
      );
    }

    if (
      lastCompanyName &&
      readmeEntry.name.toLowerCase() < lastCompanyName.toLowerCase()
    ) {
      readmeError(
        'Company is listed out of order: "%s" (should be before "%s")',
        readmeEntry.name,
        lastCompanyName
      );
    }
    lastCompanyName = readmeEntry.name;

    const $profileLink = $td.eq(0).find("a");

    if ($profileLink.length === 1) {
      const match = $profileLink
        .attr("href")
        .match(/^\/company-profiles\/(.*\.md)$/);

      if (match) {
        readmeEntry.linkedFilename = match[1];
        if (profileFilenames.indexOf(readmeEntry.linkedFilename) === -1) {
          readmeError(
            'Missing company profile for "%s", or broken link: "%s"',
            readmeEntry.name,
            $profileLink.attr("href")
          );
        }

        const nameCheck = $profileLink.text().trim();
        if (nameCheck !== readmeEntry.name) {
          readmeError(
            "Extra text in company name: %s, %s",
            jsonStringifyUnicodeEscaped(nameCheck),
            jsonStringifyUnicodeEscaped(readmeEntry.name)
          );
        }
      } else {
        readmeError(
          'Invalid link to company profile for "%s": "%s"',
          readmeEntry.name,
          $profileLink.attr("href")
        );
      }
    } else {
      readmeError(
        'Company "%s" has no linked Markdown profile ("/company-profiles/%s.md")',
        readmeEntry.name,
        companyNameToProfileFilename(readmeEntry.name)
      );
    }

    // Set identifying attributes on table elements
    $tr.attr("class", "company-row").attr("id", "company-row-" + (i - 1));
    $td.eq(0).attr("class", "company-name");
    $td.eq(1).attr("class", "company-website");
    $td.eq(2).attr("class", "company-region");

    // Rewrite company profile link to the correct URL for the static site
    if ($profileLink.length) {
      $profileLink.attr(
        "href",
        $profileLink
          .attr("href")
          .replace(/^\/company-profiles\//, "/")
          .replace(/\.md$/, "/")
      );
    }

    // Rewrite external website link (target="_blank" etc, shorter text)
    const $websiteLink = $td.eq(1).children().eq(0);
    $websiteLink
      .attr("target", "_blank")
      .attr("rel", "noopener noreferrer")
      .text(websiteText);

    readmeCompanies.push(readmeEntry);
  });

  const readmeContent = $("body").html();

  // Scan the individual Markdown files containing the company profiles.

  const allProfileHeadings = {};

  profileFilenames.forEach((filename) => {
    function profileError(msg, ...params) {
      error(filename, msg, ...params);
    }

    const profileMarkdown = stripExtraChars(
      fs.readFileSync(path.join(profilesPath, filename), "utf8")
    );
    const $ = cheerio.load(marked.parse(profileMarkdown));

    let hasTitleError = false;

    if ($("h1").length !== 1) {
      profileError(
        "Expected 1 first-level heading but found %d",
        $("h1").length
      );
      hasTitleError = true;
    }

    if (!$("h1").parent().is("body")) {
      profileError("The main title is wrapped inside of another element.");
    }

    const companyName = $("h1").text();

    if (!/[a-z]/i.test(companyName)) {
      profileError('Company name looks wrong: "%s"', companyName);
      hasTitleError = true;
    }

    const filenameBase = filename.replace(/\.md$/, "");
    const filenameExpected = companyNameToProfileFilename(companyName);
    if (
      !hasTitleError &&
      filenameBase !== filenameExpected &&
      // Some profile files just have shorter names than the company name,
      // which is fine.
      filenameExpected.substring(0, filenameBase.length + 1) !==
        filenameBase + "-"
    ) {
      profileError(
        'Company title "%s" doesn\'t match filename (expected ~ "%s.md")',
        companyName,
        filenameExpected
      );
    }

    const readmeEntry = readmeCompanies.find(
      (readmeEntry) => readmeEntry.linkedFilename === filename
    );

    if (filename !== "example.md" && !readmeEntry) {
      profileError("No link to company profile from readme");
    }

    // Build and validate list of headings contained in this Markdown profile.

    const profileHeadings = [];

    $("h2").each((i, el) => {
      const headingName = $(el).html();

      if (!$(el).parent().is("body")) {
        profileError(
          'The section heading for "%s" is wrapped inside of another element.',
          headingName
        );
      }

      if (profileHeadings.indexOf(headingName) >= 0) {
        profileError('Duplicate section: "%s".', headingName);
      } else {
        // Track headings for this profile
        profileHeadings.push(headingName);

        // Track heading counts across all profiles
        if (!allProfileHeadings[headingName]) {
          allProfileHeadings[headingName] = [];
        }
        allProfileHeadings[headingName].push(filename);
      }

      if (headingsAll.indexOf(headingName) === -1) {
        profileError(
          'Invalid section: "%s".  Expected one of: %s',
          headingName,
          JSON.stringify(headingsAll)
        );
      }
    });

    headingsRequired.forEach((headingName) => {
      if (profileHeadings.indexOf(headingName) === -1) {
        profileError('Required section "%s" not found.', headingName);
      }
    });

    // Build and validate the content of each section in this profile.

    const profileContent = {};
    if (readmeEntry) {
      readmeEntry.profileContent = profileContent;
    }
    let currentHeading = null;

    $("body")
      .children()
      .each((i, el) => {
        const $el = $(el);

        if ($el.is("h1")) {
          return;
        }

        if ($el.is("h2")) {
          currentHeading = $el.html();
          profileContent[currentHeading] = "";
        } else if (currentHeading) {
          // Note: This assumes that the only possible children of the
          // 'body' are block-level elements.  I think this is correct,
          // because from what I've seen, any inline content is wrapped
          // in a <p>.
          addTargetBlankAndExternalLinkIcons(el);
          profileContent[currentHeading] = (
            profileContent[currentHeading] +
            "\n\n" +
            $.html(el)
          ).trim();
        } else {
          profileError(
            "Content is not part of any section: %s",
            $.html(el).replace(/\n/g, "")
          );
        }
      });

    Object.keys(profileContent).forEach((heading) => {
      const sectionText = profileContent[heading]
        .replace(/<[^>]+>/g, "")
        .trim();
      if (!sectionText) {
        profileError(
          'Empty section: "%s". Fill it in or leave it out instead.',
          heading
        );
      }
    });

    // Rewrite profile content to use more code-friendly heading names.
    Object.keys(profileContent).forEach((headingName) => {
      const headingIdentifier = toIdentifierCase(headingName);
      profileContent[headingIdentifier] = profileContent[headingName];
      delete profileContent[headingName];
    });

    if (readmeEntry && profileContent.companyBlurb) {
      // Check for company profiles that were filled in, but the "incomplete"
      // mark was left in the readme, or vice versa.
      const isIncomplete = {
        readme: readmeEntry.isIncomplete,
        sections:
          profileHeadings.length === 1 &&
          profileHeadings[0] === "Company blurb",
        content: /&#x26A0;/.test(profileContent.companyBlurb),
      };
      const incompleteCount = Object.values(isIncomplete).reduce(
        (sum, v) => sum + (v ? 1 : 0),
        0
      );

      // incompleteCount === 0: Profile is incomplete; all 3 indicators are consistent
      // incompleteCount === 3: Profile is "complete"; all 3 indicators are consistent
      if (incompleteCount === 1) {
        if (isIncomplete.readme) {
          profileError(
            "Profile looks complete, but the main readme contains a warning emoji."
          );
        } else if (isIncomplete.sections) {
          profileError(
            'Profile is marked as complete, but it only contains a "Company blurb" heading.'
          );
        } else {
          // isIncomplete.content
          profileError(
            'Profile looks complete, but the "Company blurb" contains a warning emoji.'
          );
        }
      } else if (incompleteCount === 2) {
        if (!isIncomplete.readme) {
          profileError(
            "Profile looks incomplete, but the main readme does not contain a warning emoji."
          );
        } else if (!isIncomplete.sections) {
          profileError(
            "Profile is marked as incomplete, but it contains multiple sections." +
              '\nPlease remove the warning emoji from the "Company blurb" section and the main readme.'
          );
        } else {
          // ! isIncomplete.content
          profileError(
            'Profile looks incomplete, but the "Company blurb" does not contain a warning emoji.'
          );
        }
      }
    }
  });

  const profileHeadingCounts = {};
  Object.keys(allProfileHeadings).forEach((heading) => {
    profileHeadingCounts[heading] = allProfileHeadings[heading].length;
  });

  if (errors.length > 0) {
    return {
      ok: false,
      errors,
      profileFilenames,
      profileHeadingCounts,
    };
  }

  return {
    ok: true,
    profileFilenames,
    profileHeadingCounts,
    companies: readmeCompanies,
    readmeContent,
  };
};

/**
 * Build search index data from the result of parseFromDirectory().
 */
exports.buildSearchData = (data) => {
  const textData = [];

  data.companies.forEach((company, i) => {
    const thisTextData = {
      id: String(i),
      nameText: company.name,
      websiteText: company.websiteText,
    };

    if (company.shortRegion) {
      thisTextData.shortRegion = company.shortRegion;
    }

    Object.keys(exports.headingPropertyNames).forEach((h) => {
      if (company.profileContent[h]) {
        const text = cheerio
          .load(company.profileContent[h])
          .text()
          // Replace warning emoji with a searchable token
          .replace(/\u26a0/, "(_incomplete)");
        thisTextData[h] = text;
      }
    });

    textData.push(thisTextData);
  });

  const index = lunr(function () {
    this.field("nameText");
    this.field("websiteText");
    this.field("shortRegion");

    Object.keys(exports.headingPropertyNames).forEach((h) => {
      this.field(h);
    });

    // https://github.com/olivernn/lunr.js/issues/25#issuecomment-623267494
    this.metadataWhitelist = ["position"];

    // https://github.com/olivernn/lunr.js/issues/192#issuecomment-172915226
    // https://gist.github.com/olivernn/7cd496f8654a0246c53c
    function contractionTrimmer(token) {
      return token.update((str) => {
        return str.replace(/('m|'ve|n't|'d|'ll|'ve|'s|'re)$/, "");
      });
    }
    lunr.Pipeline.registerFunction(contractionTrimmer, "contractionTrimmer");
    this.pipeline.after(lunr.trimmer, contractionTrimmer);

    Object.keys(textData).forEach((c) => this.add(textData[c]));
  });

  const headings = getHeadingPropertyNames();
  headings.nameText = "Company name";
  headings.websiteText = "Website";
  headings.shortRegion = "Region";

  return { index, textData, headings };
};