require('babel-register');

const { getChallenges } = require('@freecodecamp/curriculum');
const fs = require('fs');
const path = require('path');
const { Observable } = require('rx');
const { dasherize } = require('../api-server/server/utils');

let pathMap = {};

function createPathMigrationMap() {
  return new Promise(resolve => {
    Observable.of(getChallenges())
      .map(blocks => {
        blocks.forEach(block => {
          const { name: blockName, superBlock, challenges } = block;
          if (!(dasherize(superBlock) in pathMap)) {
            pathMap[dasherize(superBlock)] = {};
          }
          if (!(dasherize(blockName) in pathMap[superBlock])) {
            pathMap[dasherize(superBlock)][
              dasherize(blockName)
            ] = challenges.map(({ title, challengeType }) => ({
              dashedName: dasherize(title),
              challengeType
            }));
          }
        });
      })
      .subscribe(() => {}, console.error, () => {
        const migMap = Object.keys(pathMap)
          .filter(key => !key.includes('certificate'))
          .map(superBlock => {
            return Object.keys(pathMap[superBlock])
              .map(block => {
                return pathMap[superBlock][block].reduce(
                  (map, { dashedName, challengeType }) => ({
                    ...map,
                    [dashedName]:
                      challengeType === 7
                        ? `/${superBlock}/${block}`
                        : `/${superBlock}/${block}/${dashedName}`
                  }),
                  {}
                );
              })
              .reduce(
                (acc, current) => ({
                  ...acc,
                  ...current
                }),
                {}
              );
          })
          .reduce(
            (acc, current) => ({
              ...acc,
              ...current
            }),
            {}
          );
        fs.writeFileSync(
          path.resolve(
            __dirname,
            '../api-server/server/resources/pathMigration.json'
          ),
          JSON.stringify(migMap, null, 2)
        );
        resolve();
      });
  });
}

exports.createPathMigrationMap = createPathMigrationMap;