Add scheduled rebalancing

[sisyphusSmiling]

Description

• Adds scheduled rebalancing support with individualized RebalanceHandlers wired into a central per-Pool Registry
• Support for per-Position recurring configuration as an extensible path
• Adds support in FCM Pool for Position ID visibility to ensure non-existent pids are not registered
• Tests passing, but I wasn't able to add tests specific to this new setup

Lifecycle

Creation

1. Position is created
2. Pool registers the PID in its associated Registry in account storage, optionally passing a PID-specific recurring config
3. Registry stores the PID in its registry
4. Registry initializes a RebalanceHandler in storage with paths derived from the Pool UUID & the Position ID
5. Registry schedules the first scheduled rebalance based on either the custom or default recurring config

Updating Default Recurring Config

1. Run the set_default_rebalance_recurring_config.cdc transaction with the desired values
2. Registry stores the updated config as default
3. Any successive RebalanceHandler scheduled executions are scheduled using the default (unless they have a custom config stored)

Steps to Initialize from Current State

1. Update FCM contract
2. Deploy FCMRegistry contract to FMC account (see contract init for starting default config values) - Registry is initialized in account storage
3. Run backfill_positions.cdc transaction (--compute-limit 9999) which will register all existing PIDs in the Registry. This should spin up RebalanceHandlers for all existing Positions

• If you run into computation limits (possible on Testnet especially)
  1. Get all Position IDs (see get_position_ids.cdc script)
  2. Pass in segments of the returned ID array in to backfill_specific_positions.cdc transaction to backfill in partitions. Again, the transaction will fail if one of the provided IDs does not exist in the Pool as a failsafe.

---

For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the standards mentioned here.
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels
• Go WTF 💚

[turbolent]

Type can be inferred

Suggested change

	let health: UFix128 = self.positionHealth(pid: pid)
	let health = self.positionHealth(pid: pid)

[turbolent]

Does this act like a set, where only the keys matter? Or can there be entries with true and false value?

If the former, maybe switch the value type to Void and use self.registeredPositions[pid] = ()

[turbolent]

Use switch-case instead for repeated test of viewType:

Suggested change

	if viewType == Type<StoragePath>() {
	return FlowCreditMarketRegistry.deriveRebalanceHandlerStoragePath(poolUUID: self.poolUUID, positionID: self.positionID)
	} else if viewType == Type<PublicPath>() {
	return FlowCreditMarketRegistry.deriveRebalanceHandlerPublicPath(poolUUID: self.poolUUID, positionID: self.positionID)
	} else if viewType == Type<MetadataViews.Display>() {
	return MetadataViews.Display(
	name: "Flow Credit Market Pool Position Rebalance Scheduled Transaction Handler",
	description: "Scheduled Transaction Handler that can execute rebalance transactions on behalf of a Flow Credit Market Pool with UUID \(self.poolUUID) and Position ID \(self.positionID)",
	thumbnail: MetadataViews.HTTPFile(url: "")
	)
	}
	switch viewType {
	case Type<StoragePath>():
	return FlowCreditMarketRegistry.deriveRebalanceHandlerStoragePath(
	poolUUID: self.poolUUID,
	positionID: self.positionID
	)
	case Type<PublicPath>():
	return FlowCreditMarketRegistry.deriveRebalanceHandlerPublicPath(
	poolUUID: self.poolUUID,
	positionID: self.positionID
	)
	case Type<MetadataViews.Display>():
	return MetadataViews.Display(
	name: "Flow Credit Market Pool Position Rebalance Scheduled Transaction Handler",
	description: "Scheduled Transaction Handler that can execute rebalance transactions on behalf of a Flow Credit Market Pool with UUID \(self.poolUUID) and Position ID \(self.positionID)",
	thumbnail: MetadataViews.HTTPFile(url: "")
	)
	}

[turbolent]

Suggested change

	let ref = self.borrowScheduledTransaction(id: id)
	if ref != nil && ref!.status() != FlowTransactionScheduler.Status.Scheduled {
	destroy <- self.scheduledTxns.remove(key: id)
	}
	if let ref = self.borrowScheduledTransaction(id: id) {
	if ref.status() != FlowTransactionScheduler.Status.Scheduled {
	destroy <- self.scheduledTxns.remove(key: id)
	}
	}