import fs from 'node:fs';
import path from 'node:path';

import csvToJson from 'convert-csv-to-json';

const langs = ['da', 'de', 'en', 'fi', 'no', 'sv'];
const csvHeaders = {
  current: 'Current URL',
  redirect: 'Redirect URL',
};

function csvFilePath(lang) {
  return `${import.meta.dirname}/csv/${lang}.csv`;
}

function jsonFilePath(lang) {
  return `${import.meta.dirname}/json/${lang}.json`;
}

function outputFilepath(lang) {
  return path.resolve(
    import.meta.dirname,
    `../netlify/functions/data/${lang}.json`
  );
}

function removeDomain(str) {
  return str.replace(
    /^https?:\/\/((www|test|stage|prod)\.)?scandichotels.(com|de|dk|fi|no|se)/,
    ''
  );
}

function akamaiRedirect(str) {
  return str.replace(
    /^https?:\/\/((www|test|stage|prod)\.)?scandichotels.(com|de|dk|fi|no|se)/,
    (...match) => {
      if (match[3]) {
        switch (match[3]) {
          case 'com':
            return '/en';
          case 'de':
            return '/de';
          case 'dk':
            return '/da';
          case 'fi':
            return '/fi';
          case 'no':
            return '/no';
          case 'se':
            return '/sv';
        }
      }
      return '';
    }
  );
}

function checkPrerequisites() {
  const missingLangs = langs.reduce((acc, lang) => {
    const filepath = csvFilePath(lang);
    if (!fs.existsSync(filepath)) {
      acc.push(filepath);
    }
    return acc;
  }, []);

  if (missingLangs.length > 0) {
    console.error(`Missing CSV file:\n${missingLangs.join('\n')}`);
    process.exit(1);
  }
}

// convert-csv-to-json writes async without callback support
// so we workaround it be overriding console.log which it uses when it is done
async function convertCsvToJson() {
  return new Promise((resolve, reject) => {
    const _consoleLog = console.log;
    let resolved = 0;
    console.log = function (str) {
      if (str.indexOf('File saved:') >= 0) {
        resolved++;
      }

      if (resolved === langs.length) {
        console.log = _consoleLog;
        resolve();
      }
    };

    for (const lang of langs) {
      csvToJson
        .utf8Encoding()
        .fieldDelimiter(',')
        .generateJsonFileFromCsv(csvFilePath(lang), jsonFilePath(lang));
    }

    setTimeout(() => {
      reject('timeout');
    }, 5000);
  });
}

async function makeOutput() {
  for (const lang of langs) {
    try {
      const json = JSON.parse(
        fs.readFileSync(jsonFilePath(lang), {
          encoding: 'utf-8',
        })
      );

      if (Array.isArray(json)) {
        const finalUrls = json.reduce((acc, url) => {
          const from = removeDomain(akamaiRedirect(url[csvHeaders.current]));
          const to = removeDomain(url[csvHeaders.redirect]);

          return {
            ...acc,
            [from]: to,
          };
        }, {});

        fs.writeFileSync(outputFilepath(lang), JSON.stringify(finalUrls), {
          encoding: 'utf-8',
        });
      } else {
        throw new Error(`JSON was not an array: ${jsonFilePath(lang)}`);
      }
    } catch (e) {
      console.error(e);
    }
  }
}

checkPrerequisites();
await convertCsvToJson();
await makeOutput();