How to order struct in descending and ascending order?

Question

I have the following struct used for adding few details. Objective is to sort in descending order. Initially highest totalpoints record will be displayed. I would like to create two buttons

1) Forward - which will fetch highest totalpoints record and again if we click on the same button it should fetch the next highest totalpoints record from the struct.

2) Backward - vice-versa of above.

struct struUser{
    address userAddress;
    uint256 id;
    bytes32 originalKshoplink;
    bytes32 orginalDocumentConvention;
    bool validated;
    uint32 Points;
    uint32 totalPoints;
}

If i add the first record then it will be something like:

UserAddress: 0x000123

Id:1

originalKshoplink :http://kshoplink

originalDocumentConvention :doc1

validated:true

Points:10

totalPoints:10

If i add the second record then it will be something like:

UserAddress: 0x000123

Id:1

originalKshoplink :http://kshoplink

originalDocumentConvention :doc1

validated:true

Points:10

totalPoints:20(earlier 10points + 10points for this record)

This is for one user and i have some similar records for other user. Now i have to write a function which will return the UserAddress and his totalPoints(e.g. 100 totalPoints consider this as base).

Consider the current viewed totalPoints are 100. When i click on forward button it should fetch the next highest UserAddress and his totalPoints(e.g. 90 totalPoints), when i click again on forward button it should fetch the next highest UserAddress and his totalPoints(e.g. 80 totalPoints).

Consider the current viewed totalPoints are 80. When i click on backward button it should fetch second highest UserAddress and his totalPoints(e.g.90 totalPoints) , when i click again on backward it should fetch the third highest userAddress and his totalPoints(e.g. 100 totalPoints).

How should i achieve this in solidity? kindly let me know in case of any queries.

Answer 1

Sorting in a smart contract is going to cost you a lot of gas, especially with large arrays.

You could set up a centralized database that replicates the data in the smart contract. Then, you could have the database system do the sorting off-chain.

Users can then still verify that the data you provide is correct, because they could pull each record out of the smart contract.