node-fftcg/backend/session.coffee

# node libraries
redis = (require 'redis')
crypto = (require 'crypto')
logger = (require 'logging').default 'session'

# expiry times in seconds
EXPIRY =
  # games expire 1 week after creation
  game:    1 * 60 * 60 * 24 * 7
  # logins expire 1 month after last action
  login:   1 * 60 * 60 * 24 * 7 * 4


FFTCGSESSION = () ->
  @db = redis.createClient
    host: 'redis'
    port: 6379

  @db.on 'error', (err) ->
    logger.error err.message

  return

FFTCGSESSION::start = (data) ->
  that = @

  new Promise (resolve) ->
    # hash data
    hmac = crypto.createHmac 'sha256', Math.random().toString()
    hmac.update (JSON.stringify data)
    digest = hmac.digest 'base64'
    logger.debug 'digest', digest

    # push (hash, data) into DB for the configured timespan
    that.db.setex digest, EXPIRY.login, (JSON.stringify data), (err) ->
      resolve digest

FFTCGSESSION::check = (digest) ->
  that = @

  new Promise (resolve, reject) ->
    # refresh expiry timer on digest
    that.db.expire digest, EXPIRY.login, (err, res) ->
      if res == 0
        reject null

      else
        that.db.get digest, (err, res) ->
          resolve JSON.parse res

module.exports = FFTCGSESSION