## Incoming Sarafu ##
When users exchange CIC <> National Currency we have to manually send them Mpesa or CIC.
We would like to automate this.

## Solution ##
Configure - using our own system AfricasTalking API to automatically send Sarafu / Mpesa based on rules:
 
### Incoming Sarafu Rules - MPESA out ###
 - *white list* The chama (group accounts only but eventually anyone) must only be able to cash out - using the exchange option to an Agent account
 - *amount* The max cash out is the minimum of (30,000 Sarafu, half their balance, their total amount of outward trade volume to other users (standard transactions)
 - *time* They can only cash out once per month
  - *rate* The Sarafu (and their community) to Mpesa  rate should be calculated as follows:
    - CIC_supply_b: Get the total CIC supply off **blockchain** - the amount of **CIC_burn** 
    - total_reserve_b: Get the total reserve off **blockchain** - the amount of **cash_out** we've gotten (in USD)
    - CIC_burn_amount = whatever they have sent to exhange


The Reserve (xDAI) pulled out
>    const reserveOut_xDAI = total_reserve_b * (Math.pow(1 + (-1 * CIC_burn) / CIC_supply_b, 1 / trr) - 1);

  -  Mpesa_out = reserveOut_xDAI **USD => KSH** rate
  -  reserve_given = reserve_out - CIC_created*fee (0.02) (this is given to the user)
  -  Simulate as if done on blockchain .... new_cic_supply_b = cic_supply_b - CIC_burn
  -  Simulate as if done on blockchain .... new_total_reserve_b = total_reserve_b - reserveOut_xDAI


### Outgoing Sarafu Rules - MPESA In ###
 - *white list* Only users sending via paybill receive Sarafu. Non users receive a invitation to join Sarafu sms (alert to admins there was a donation).
 - *amount* The max sarafu out is 20,000 Sarafu per user, KYC_limit max, supply_max
 - *time* No limit
 - *rate* The Mpesa to Sarafu (and their community) rate should be calculated as follows:
    - CIC_supply_b: Get the total CIC supply off **blockchain** + the amount of **CIC_given** 
    - total_reserve_b: Get the total reserve off **blockchain** + the amount of **cash_in** we've gotten (in USD)
    - cash_in_amount = Mpesa_in **KSH -> USD** rate (what is the current USD <> KSH rate)

The amount cashed in = cash_in_amount
>    const CIC_Created = cic_supply_b * (Math.pow(1 + cash_in_amount / total_reserve_b, trr) - 1);
   
  - **CIC_given = CIC_Created - CIC_created*fee (0.02)**
  - Simulate as if done on blockchain .... new_cic_supply_b = cic_supply_b + CIC_given
  - Simulate as if done on blockchain .... new_total_reserve_b = total_reserve_b + cash_in_amount




### Security ###
 - Balance alerts: On both Mpesa and CIC balances: The paybill from which Sarafu is sent needs to send a sms and email alert when low 
 - Failure alerts: If the API session fails an sms and email alert should be sent
 - Reject on not enough Mpesa balance: If there is not enough Mpesa (on incoming Sarafu) the transaction should be rejected and an email sent to admin along with a SMS to admin and user (Sarafu should not be taken from user). (message should be visible also on mgmt platform txn view and user view and admin view).
 - Reject on not enough Sarafu balance: If there is not enough Sarafu (on incoming Mpesa) the transaction should be rejected and an email sent to admin along with a SMS to admin and user (Mpesa should not be taken from user). (message should be visible also on mgmt platform txn view and user view and admin view).

### Variables ###
 - The account from which Sarafu is sent should be a Agent account
 - The cash-out rules for a chama (minimum and time limit)
 - Alert balance levels
 - Fees: Mpesa to Sarafu 
 - Fees: Sarafu to Mpesa