import { app, errorHandler } from 'mu';
import bodyParser from 'body-parser';
import fetch from 'node-fetch';
import { CronJob } from 'cron';
import { Delta } from "./lib/delta";
import {
  isKbo,
  getIdentifiers,
  constructOvoStructure,
  updateOvoNumberAndUri,
  getAllOvoAndKboCouples
} from "./lib/queries";
import { CRON_PATTERN } from './config';

app.use(bodyParser.json({
  type: function (req) {
    return /^application\/json/.test(req.get('content-type'));
  }
}));

// TODO update readme with env variables etc at the end

// TODO current issue: when the KBO get updated, it doesn't refresh in the frontend.
// Alternative: endpoint to call in the frontend directly, that way we can trigger a refresh on the OVO ?
app.post('/delta', async function (req, res, next) {
  try {
    const entries = new Delta(req.body).getInsertsFor('https://data.vlaanderen.be/ns/generiek#lokaleIdentificator');

    if (!entries.length) {
      console.log('Delta dit not contain potential KBOs, awaiting the next batch!');
      return res.status(204).send();
    }

    for (let entry of entries) {
      const isEntryKbo = await isKbo(entry)

      if (isEntryKbo) {
        const identifiers = await getIdentifiers(entry);

        const response = await fetch(`https://api.wegwijs.vlaanderen.be/v1/search/organisations?q=kboNumber:${identifiers.kbo}&fields=ovoNumber,kboNumber)`);
        const data = await response.json();

        let wegwijsOvo = null;
        if (data.length) {
          // We got a match on the KBO, getting the associated OVO back
          const wegwijsInfo = data[0]; // Wegwijs should only have only one entry per KBO
          if (wegwijsInfo.ovoNumber)
            wegwijsOvo = wegwijsInfo.ovoNumber;
        }

        if (wegwijsOvo && (wegwijsOvo != identifiers.ovo)) {
          let ovoStructuredIdUri = identifiers.ovoStructuredId;

          if (!ovoStructuredIdUri) {
            ovoStructuredIdUri = await constructOvoStructure(entry);
          }

          await updateOvoNumberAndUri(ovoStructuredIdUri, wegwijsOvo);
        }
      }
    }

    return res.status(200).send().end();
  } catch (e) {
    console.log(`Something unexpected went wrong while handling delta task!`);
    console.error(e);
    return next(e);
  }
});

new CronJob(CRON_PATTERN, async function() {
  const now = new Date().toISOString();
  console.log(`OVO numbers healing triggered by cron job at ${now}`);
  try {
    await healOvoNumbers();
  } catch (err) {
    console.log(`An error occurred during OVO numbers healing at ${now}: ${err}`)
  }
}, null, true);

async function healOvoNumbers() {
  try {
    console.log('Healing starting...');
    const identifiersCouplesOP = await getAllOvoAndKboCouples();
    const identifiersCouplesWegwijs = await getAllOvoAndKboCouplesWegwijs();
  
    for (const identifiersCoupleOP of identifiersCouplesOP) {
      const wegwijsOvo = identifiersCouplesWegwijs[identifiersCoupleOP.kbo];
      // If a KBO can't be found in wegwijs but we already have an OVO for it in OP, we keep that OVO.
      // It happens especially a lot for worship services that sometimes lack data in Wegwijs
      if (wegwijsOvo && (identifiersCoupleOP.ovo != wegwijsOvo)) {
        // We have a mismatch, let's update the OVO number
        let ovoStructuredIdUri = identifiersCoupleOP.ovoStructuredId;
        if (!ovoStructuredIdUri) {
          ovoStructuredIdUri = await constructOvoStructure(identifiersCoupleOP.kboStructuredId);
        }

        await updateOvoNumberAndUri(ovoStructuredIdUri, wegwijsOvo);
      }
    }
    console.log('Healing complete!');
  } catch (err) {
    console.log(`An error occurred during OVO numbers healing: ${err}`)
  }
}

async function getAllOvoAndKboCouplesWegwijs() {
  let couples = {};

  const response = await fetch(`https://api.wegwijs.vlaanderen.be/v1/search/organisations?q=kboNumber:/.*[0-9].*/&fields=ovoNumber,kboNumber&scroll=true`);
  const scrollId = JSON.parse(response.headers.get('x-search-metadata')).scrollId;
  let data = await response.json();

  do {
    data.forEach(unit => {
      couples[unit.kboNumber] = unit.ovoNumber;
    });

    const response = await fetch(`https://api.wegwijs.vlaanderen.be/v1/search/organisations/scroll?id=${scrollId}`);
    data = await response.json();
  } while (data.length)

  return couples;
}

app.use(errorHandler);