implement referral logic (partly done, to implement TIMEFRAME)

[jellegerbrandy]

https://trello.com/c/XvBbXnjS/1-specify-referral-logic

x% out of reputation and tokens awarded to referral in time frame y from registration on top of ...
x = 10%, y = 1 month.
In a further version x can depend inversely on some measure of engagement such as the amount of reputation/tokens created via contributions.

Todo for this:

• extend User model with a "referrer" - which is the id of the user that has given the referral
• create_user should get an optional referrer argument
• need to check that the referrer is an existing user in the DB, upon creation of the new user and in every action involving the referrer.
• (the API should be correspondingly extended)
• add contract parameters:

1. referral_reward_fraction - this is the fraction of the referred user's gained reputation or tokens that should be rewarded to the referrer.
2. referral_timeframe - this is the time frame in which after a new user has been created following a referral the referrer will be rewarded for the referred user's consensused contributions.

• caclulate payout to referrer when user is awarded tokens and reputation following a consensused contribution.
  if time_since_referred_user_created <= referral_timeframe
  referrer_reputation_reward = referral_reward_fraction * earned_reputation
  referrer_token_reward = referral_reward_fraction * earned_tokens
• it should be noted that what the referrer gets is not at the expense of the referred, i.e. the referred does not need to pay the referrer.

neet to update pseudocode:

In pseudocode:

def create_evaluation(...):
      ...
     reward_previous_evaluations
     reward_contributor

     for user in previous_evaluators + [contributor]:
          user_rep_reward_delta  = soething # the rewards the user has gotten as a contributor or prev evaluator
          if datetime.now() - user.creation_time <= self.REFERAL_TIMEFRAME:
             if user.referrer:
                   user.referrer += self.REFERAL_REWARD * user_rep_reward_delta
     # and hte same for evaluation

[elad-shtilerman]

• question: when does the payout happen? proposal: on any call to create_evaluation, also these payouts are calculated an assigned (up to Y days after the referred user was created)
• answer in the first version, we want the inviters to get x% only out of rewards for consensused contirbutions and not from earned reputation during evaluations.
• question: how are the payout calculated? Is it: referrer gets 10% of all payouts of the referral? And which payouts count?
• answer so only payouts for consensused contributions count.
• question: we have one value for X, or we want to have an "x" for tokens and one for rep?
• answer: for the first working version we can leave it at a uniform 10% for both token and rep and afterwards refine it.

[jellegerbrandy]

this is implemented now, but without taking into account the TIMEFRAME