import async from 'async';
import merge from 'mixin-deep';
import GitHub from 'github-base';
import DataStore from 'data-store';
import ghUrl from 'parse-github-url';
import ask from 'ask-for-github-auth';
import stringify from 'stringify-author';
import ghContrib from 'github-contributors';

const store = new DataStore('update-contributors');

/**
 * Pulldown github contributors and update the `contributors` property
 * in the provided package.json object.
 *
 * ```js
 * var pkg = require('./package.json');
 * update(pkg, function (err, results) {
 *   if (err) return console.error(err);
 *   console.log(reults);
 *   //=> updated package.json object
 * });
 * ```
 *
 * @param  {Object} `pkg` Object representing the package.json to update.
 * @param  {Object} `options` Options to use for github authentication.
 * @param  {Object} `options.creds` Github credentials. May be a token or a username and password. If execuled [ask-for-github-auth][] will be used.
 * @param  {Boolean} `options.stringify` When set to `false` the contributors will be objects in the `contributors` array. Defaults to `true`.
 * @param {Function} `cb` Callback function that will get an `err` when an error happens or a `results` with the updated package.json object.
 * @api public
 * @name update
 */

export default function(pkg, options, cb) {
  if (typeof options === 'function') {
    cb = options;
    options = {};
  }
  let repo;
  if (typeof pkg.repository === 'object') {
    repo = ghUrl(pkg.repository.url);
  } else {
    repo = ghUrl(pkg.repository);
  }
  if (!repo) return cb(new Error('Invalid repository property.'));

  async.waterfall([
    // ask for creds
    (next) => {
      if (options.creds) {
        let creds = options.creds;
        delete options.creds;
        return next(null, creds);
      }
      ask({store}, next);
    },

    // update creds on options
    (creds, next) => {
      options = merge({}, options, creds);
      next();
    },

    // get contributors
    async.apply(ghContrib, repo.repopath, options),

    // get contributor information
    (contributors, next) => {
      if (!Array.isArray(contributors)) {
        return next(new Error(contributors.message));
      }
      const github = new GitHub(options);
      pkg.contributors = [];
      async.eachSeries(contributors, (contributor, nextContributor) => {
        github.get('/users/:login', contributor, (err, user) => {
          if (err) return nextContributor(err);
          if (user && user.message && user.message === 'Bad credentials') {
            return nextContributor(new Error(user.message));
          }
          let contrib = {
            name: user.name || user.login,
            email: user.email || '',
            url: user.html_url
          };
          if (options.stringify !== false) {
            contrib = stringify(contrib);
          }
          pkg.contributors.push(contrib);
          nextContributor();
        });
      }, next);
    }
  ], (err) => {
    if (err) return cb(err);
    cb(null, pkg);
  });

}