Indexer: User Position APR stats

[dib542]

Required

User stats: Pair position APR

The calculation of a user's position's generated APR requires knowledge of:

• the value that the user deposited into a pool: ie. the equivalent reserve value at that point in time
  (available from /tx_query each deposit and withdrawal has Reserves[0/1][Deposited/Withdrawn])
• the value of those user's shares now: ie. the most recent equivalent reserve value
  (using current pools state: value = userShares/totalShares*(reserve0*price0 + reserve1*price1))

Solution

This would be best calculated via the indexer so that the query for original deposited value can be calculated from all of the matching rows and return only that value (rather than having to send the entire paginated history of the user's deposits and withdrawals to calculate the previous deposit value).

This endpoint could receive a query of /users/deposits/{address}/APY and that could return a single number for each deposit pair. Or if extended a query of /dualitylabs/duality/dex/user/deposits/{address} could have APY appended to the rest of the row data.