Gracefully handle users being offline

[Makeshift]

Stuff won't load properly if they're offline.

Unhandled rejection esi:Error: Error from ESI service for https://esi.tech.ccp.is/v1/fleets/1025011408543/members/: {"error":"{'error_label': 'FleetCandidateOffline', 'error_dict': {'invitee': (2, 95334207)}}"}: cannot POST /v1/fleets/1025011408543/members/?datasource=tranquility&language=en-us (420)
    at getExceptionFromAgentError (/home/user/eve-goons-newwaitlist/eve-goons-waitlist/node_modules/eve-swagger/lib/internal/esi-agent.js:82:17)
    at /home/user/eve-goons-newwaitlist/eve-goons-waitlist/node_modules/eve-swagger/lib/internal/esi-agent.js:243:22
    at Request.callback (/home/user/eve-goons-newwaitlist/eve-goons-waitlist/node_modules/superagent/lib/node/index.js:703:3)
    at IncomingMessage.<anonymous> (/home/user/eve-goons-newwaitlist/eve-goons-waitlist/node_modules/superagent/lib/node/index.js:922:12)
    at emitNone (events.js:91:20)
    at IncomingMessage.emit (events.js:185:7)
    at endReadableNT (_stream_readable.js:974:12)
    at _combinedTickCallback (internal/process/next_tick.js:74:11)
    at process._tickCallback (internal/process/next_tick.js:98:9)

[samuelgrant]

We should check to see if users are online before we let them join the waitlist. Furthermore, let's remove people (or at least hide them using a bool) if ESI has reported they are offline for more than two minutes.

[Makeshift]

They can go offline while waiting though, we should still check either prior to invite or we should just stop it from being spammed if they're offline

[samuelgrant]

I would still check /location/online once a minute or so, even if you don't hide them displaying an indicator to the FC may be useful. With the removal of the communication fields (#58) we now have room for status indicators.

[samuelgrant]

Current plan:

• Users cannot join the waitlist while they are offline. If they try to join while they are offline they will be rejected and get a notification prompting them to login first.
• Add a check to see if the user is online in the globalWaitlist.js file.
  • If the user is online then do the other checks.
  • If the user is offline set an offline error or increase by one. If they reach a value that indicates they have been offline for five minutes remove them from the waitlist. - Perhaps flag them on the FC page after two minutes.
  • If the user is flagged offline for some reason don't check their location or any other functions that might be put in this timer function.
  • I don't plan on blocking invites for offline users. The FCs get feedback now to say they were rejected for being offline. Adding a function to block that seems pointless, it adds to code complexity and it would be delayed.

I want to update the polling timer so it is once every 30 seconds.

@Makeshift what do you think?

[Makeshift]

Eh I'd rather not straight up remove people for being offline, they might have swapped characters for a minute and the FC can shout out on comms to tell them to get their asses online. The rest sounds fine though.

[samuelgrant]

the idea was that they would be removed after being offline but I will set a flag instead

[samuelgrant]

Now that the FCs get feedback for failed invites I am going to close this issue. Once #47 has been implemented I will add an online check before letting people join the waitlist and I may still remove someone who has been offline for a while (~15 minutes), either way they will be flagged for the FCs.