Allow modules to report scheduled rewards

[bajtos]

Per the discussion in CheckerNetwork/core#259, we want each Station Module to own the implementation of querying rewards scheduled for the Station operator.

A possible solution: add a new API similar to Zinnia.jobCompleted() and a new event type that can be printed to stdout, similar to the existing type jobs-completed.

[juliangruber]

Question: Not every module might use scheduled rewards, it's entirely possible for a module to pay directly and not have an understanding of scheduled rewards. How can we unify this?

I assume we need to know more about the 2nd module before it makes sense to continue with this issue.

[bajtos]

Question: Not every module might use scheduled rewards, it's entirely possible for a module to pay directly and not have an understanding of scheduled rewards.

Agreed 💯

How can we unify this?
I assume we need to know more about the 2nd module before it makes sense to continue with this issue.

+1, it's hard to design a generic solution when we have only one module.

OTOH, with the current Station Desktop UI, it's very clear what options modules have:

• They can pay operators directly, in which case the Station UI will see the paid rewards in the wallet balance (& transaction list) and no additional support is required from the module.
• The module implements some variant of scheduled rewards, in which case the module needs to tell the Station what amount of rewards is allocated to the user but not paid yet.

If a module needs something else, then we will need to change the Station Desktop UI & design to support that. Potentially also the Station Core vs Station Desktop integration, since it's currently the responsibility of Station Core to discover scheduled rewards. See

• https://github.com/filecoin-station/core/blob/1061ebc321d34b3330b6cd3cdd11ce49279e4c77/commands/station.js#L84-L88
• https://github.com/filecoin-station/core/blob/1061ebc321d34b3330b6cd3cdd11ce49279e4c77/lib/rewards.js#L14-L18

My goal for this task was to move the logic querying the smart contract from Station Core to the Zinnia module. Supporting modules that don't use scheduled rewards or use a different mechanism is IMO out of the scope of this task.