Figure out when to sync contracts

[taoeffect]

Problem

In setupChelonia.js this code was commented out:

  /*
  await sbp('gi.db/settings/load', SETTING_CURRENT_USER).then(async (identityContractID) => {
    // This loads CHELONIA_STATE when _not_ running as a service worker
    const cheloniaState = await sbp('chelonia/rootState')
    if (!cheloniaState || !identityContractID) return
    if (cheloniaState.loggedIn?.identityContractID !== identityContractID) return
    // it is important we first login before syncing any contracts here since that will load the
    // state and the contract sideEffects will sometimes need that state, e.g. loggedIn.identityContractID
    await sbp('chelonia/contract/sync', identityContractID).then(async () => {
      const contractIDs = groupContractsByType(cheloniaState.contracts)
      await syncContractsInOrder(contractIDs)
    }).catch(e => {
      console.error('[setupChelonia] Error syncing identity contract and groups', e)
    })
  })
  */

It's since been uncommented and @corrideat says he doesn't like it there because:

The problem is that:
(1) as it stands, anytime the SW is awoken it'll re-sync all contracts. This is bad because it results in unnecessary network activity (imagine you get a notification and you sync entire chatrooms). It's also bad for snapshots and for building an offline PWA.
(2) however, if we remove it, notifications break (as they are now), because not subscribing to a contract (over WS) means that we'll stop getting push events for them later
(3) fixing (2) is complicated by the fact that if we don't sync a contract, getting notifications or other events for them isn't very useful, as a sync is needed.
I'm leaning towards a 'lazy sync' approach, using different strategies based on the situation:
For regular SW wake up calls, the contract will merely be marked as a 'contract of interest', but we won't get any events for it, unless we manually sync it.
For app loads (using the browser), a full sync is done, much like now, except that in a way that's compatible both with local snapshots and the offline PWA
More specific details are still a WIP

I asked in a followup why in (1) @corrideat said "and for building an offline PWA." His reply:

Because the SW will be awoken but it's offline, so a sync isn't possible?

So we should look into detecting whether or not we're online before doing that sync, and then if we aren't, doing it once we come back online.

Solution

It needs to be uncommented but also rewritten to take into account the changes coming in with user state snapshots and the offline cache stuff.