v1/services/auth.js

// @flow
import Service from './Service'
import nanoid from 'nanoid'
import moniker from 'moniker'
import type { AppContext } from '../Roleypoly'
// import type { Models } from '../models'

export type DMChallenge = {
  userId: string, // snowflake of the user
  human: string, // humanized string for input elsewhere, adjective adjective noun
  magic: string, // magic URL, a nanoid
  issuedAt: Date
}

export default class AuthService extends Service {
  M: { AuthChallenge: any }
  monikerGen = moniker.generator([ moniker.adjective, moniker.adjective, moniker.noun ], { glue: ' ' })
  constructor (ctx: AppContext) {
    super(ctx)
    this.M = ctx.M
  }

  async createDMChallenge (userId: string): Promise<DMChallenge> {
    const out: DMChallenge = {
      userId,
      human: this.monikerGen.choose(),
      magic: nanoid(10),
      issuedAt: new Date()
    }

    await this.M.AuthChallenge.build({ ...out, type: 'dm' }).save()
    this.log.debug('created DM auth challenge', out)
    return out
  }

  async fetchDMChallenge (input: { human: string } | { magic: string }): Promise<?DMChallenge> {
    const challenge: ?DMChallenge = this.M.AuthChallenge.findOne({ where: input })
    if (challenge == null) {
      this.log.debug('challenge not found', challenge)
      return null
    }

    // if issued more than 1 hour ago, it doesn't matter.
    if (+challenge.issuedAt + 3.6e5 < new Date()) {
      this.log.debug('challenge expired', challenge)
      return null
    }

    return challenge
  }
}