feat: add sort stake pools by saturation

[lgobbi-atix]

Context

The current sort order for results returned from the DbSyncStakePoolProvider.queryStakePools method is ordered by name. We require the interface to also include saturation.

Proposed Solution

• Add saturation sort field with desc order as default
• Adapt withSort function to be able to sort queries other than findPoolData
• Refactor DbSyncStakePoolProvider.queryStakePools so it can identify which query to use to order the response

Important Changes Introduced

• DbSyncStakePoolProvider.queryStakePools refactor
• Added getQueryBySortType private method to DbSyncStakePoolProvider
• Added sort by saturation to pool metrics query
• Fix a bug where sorting by name was case sensitive, leading to results like: ['CLIO1','July 2021','banderini']
• Fix a bug where sorting by name desc would return pools with no name first instead of last
• Fixed tests related to those bugs

[mkazlauskas]

Looks good overall. Query building is getting complicated (and therefore difficult to read), but I don't think there's an easy solution to that.

[ivaylo-andonov]

More of a question, considering the intense increase in complexity and theoretically more sorting fields requested in the future, do we think that maintaining modular DB queries + additional logic populating minimum requested data for a simple operation like sort is still the better option than having one composed DB query (with joined required tables) providing stake pool data at once (sorted, filtered and paginated), if it's feasible at all to happen at DB level? 🤔

[rhyslbw]

@IvayloAndonov Please create a SPIKE for further exploration of this technical debt reducer in a later sprint.

[rhyslbw]

I expect fix: make stake pool order by name case insensitive and move nulls to last to be a separate commit before either a single commit with the refactor + feature, or two extra commits.

[lgobbi-atix]

I expect fix: make stake pool order by name case insensitive and move nulls to last to be a separate commit before either a single commit with the refactor + feature, or two extra commits.

I left the first commit with the refactor + feature as it's kinda hard to separate them and added a new commit after with the fix

[rhyslbw]

Great work @lgobbi-atix.

[mkazlauskas]

Looks good, nice work! 🎉

[ssong-iohk]

Can you add the test case (i.e. happy path - the request with filters/sort query parameters) to stakePoolHttpProvider.test.ts

[lgobbi-atix]

Can you add the test case (i.e. happy path - the request with filters/sort query parameters) to stakePoolHttpProvider.test.ts

The provider interface didn't change. The response for those tests are mocked, it doesn't make sense to add the filters and everything there. Those cases should already be covered with https://github.com/input-output-hk/cardano-js-sdk/pull/270/files#diff-7bf95288ddba72cc435fbe56613884016d332bdba413afd23c5e1e7bcc69ce42R684

[rhyslbw]

it doesn't make sense to add the filters and everything there

Right, the HTTPService implementations are just plumbing, and we could even look at refactoring the base class to be usable without needing to extend.

[ssong-iohk]

LGTM.
I will run regression test against testnet then approve unless any issues are found.
And @lgobbi-atix I think you can resolve conflict.

[ssong-iohk]

Regression test will be conducted after merging ( due to tricky rebase). Any found issue at that time, will handle with a separate ticket(s). (Hopefully not)!