namestate: improve "stats" object for transfers, expiry and revoke

[pinheadmz]

Adds an expired state to the "stats" object, refactors the toStats() method in namestate.js.

    "stats": {
      "blocksSinceExpired": 21
    }

[coveralls]

coverage: 68.637% (+0.01%) from 68.623% when pulling 7da5443 on pinheadmz:expired1 into 4e87fb1 on handshake-org:master.

[nodech]

Is it okay to have negative numbers in blocksUntilExpire ? (Maybe have better alias if we want to keep this for backwards compatibility reasons)

[pinheadmz]

@nodech you're right on about negative blocksUntilExpire, I had a bug given that claimed names don't expire until the 4-year claim period is over. That is fixed in f82f783

[pinheadmz]

I just realized hsd has never reported expiration date correctly for reserved names. A reserved name does not expire until AFTER the reserved name period if over (four years). The logic can be seen in namestate.isExpired():

hsd/lib/covenants/namestate.js

Lines 208 to 218 in 107ed2b

	// Can only renew once we reach the closed state.
	if (!this.isClosed(height, network))
	return false;
	// Claimed names can only expire once the claim period is over.
	if (this.isClaimable(height, network))
	return false;
	// If we haven't been renewed in a year, start over.
	if (height >= this.renewal + network.names.renewalWindow)
	return true;

(note the typo in the comment, line 212 should say "two years")

However, this API tells me that the reserved name torrentfreak will expire in less than two months:

# hsd-rpc getnameinfo torrentfreak
{
  "start": {
    "reserved": true,
    "week": 17,
    "start": 19152
  },
  "info": {
    "name": "torrentfreak",
    "nameHash": "ea821088b72047a89e1defa25f91194760493a6c2070a289fa8c9a73c6428861",
    "state": "CLOSED",
    "height": 5670,
    "renewal": 15104,
    "owner": {
      "hash": "b2e9a0a48438ca58050a8b77cb1ebb6d8c1767c2de24135b33431501f46f3863",
      "index": 0
    },
    "value": 0,
    "highest": 0,
    "data": "0001036e733103646e73046c6976650001036e7332c00601036e7333c00606011a723d68747470733a2f2f746f7272656e74667265616b2e636f6d0601316e61636c3d527774776f3750472b736b6233356d6c6d6f7a32756356457677355063304b495855434a594d5a6833766b3d",
    "transfer": 0,
    "revoked": 0,
    "claimed": 1,
    "renewals": 0,
    "registered": true,
    "expired": false,
    "weak": true,
    "stats": {
      "renewalPeriodStart": 15104,
      "renewalPeriodEnd": 120224,
      "blocksUntilExpire": 8057,
      "daysUntilExpire": 55.95
    }
  }
}

[nodech]

Fixed expire date as it needs to be: Max(claimPeriodEnd, normal end). If claimed name has been transferred or renewed, it wont expire on claim period end, instead when it should normally expire. But if it has not been transfer/renewed then it will expire on claimPeriod end.