const util = require('util');
const fetch = require('node-fetch');
const groupArray = require('group-array');

module.exports = async function(robot, kredits) {

  robot.logger.debug('[hubot-kredits] Loading MediaWiki integration...')

  const Contributor = kredits.Contributor;
  const Operator = kredits.Operator;

  const apiURL =  process.env.KREDITS_MEDIAWIKI_URL + 'api.php';

  const robot = {
    data: {},
    brain: {
      set(key, value) {
        this.data[key] = value;
      },
      get(key) {
        return this.data[key];
      }
    }
  };

  function fetchChanges () {
    const params = [
      'action=query',
      'format=json',
      'list=recentchanges',
      'rctype=edit|new',
      'rcshow=!minor|!bot|!anon|!redirect',
      'rclimit=max',
      'rcprop=ids|title|timestamp|user|sizes|comment|flags'
    ];

    const url = `${apiURL}?${params.join('&')}`;

    return fetch(url).then(res => {
      if (res.status === 200) {
        return res.json();
      } else {
        robot.logger.warn(`Fetching ${url} returned HTTP status ${res.status}:`);
        robot.logger.warn(res.body);
        throw Error('Unexpected response from '+url);
      }
    }).then(res => {
      return res.query.recentchanges;
    });
  }

  function groupChangesByUser (changes) {
    return groupArray(changes, 'user');
  }

  function analyzeUserChanges (user, changes) {
    robot.logger.info(`Analyzing ${changes.length} edits from ${user} ...`);
    const results = {};

    results.pagesCreated = changes.filter(c => c.type === 'new');
    results.pagesChanged = changes.filter(c => c.type === 'edit');
    results.linesAdded = changes
      .map(c => { return (c.oldlen < c.newlen) ? (c.newlen - c.oldlen) : 0; })
      .reduce((a, b) => a + b);

    robot.logger.info(`Created ${results.pagesCreated.length} pages`);
    robot.logger.info(`Edited ${results.pagesChanged.length} pages`);
    robot.logger.info(`Added ${results.linesAdded} lines of text\n`);

    return results;
  }

  function createProposalForUserChanges (user, changes) {
    const details = analyzeUserChanges(user, changes);

    // robot.logger.info(util.inspect(details));
  }

  fetchChanges()
    .then(res => groupChangesByUser(res))
    .then(res => {
      Object.keys(res).forEach(user => createProposalForUserChanges(user, res[user]));
    });

};