fix: encode now-timestamps to avoid overwrites

What was happening was that when a timestamp, which are
monotonic-timestamps, included an e.g. ".001" suffix, it would be
considered as "in the future" if the indexer was quick enough to pick it
up, and then be converted to "new Date().getTime()". So if two messages
were written to a channel fast enough, BOTH would get set to "new
Date().getTime()" and the second would overwrite the first in leveldb.

This change ensures that proper monotonic-timestamps are used
throughout.

views/messages.js

@@ -1,4 +1,5 @@
 var View = require('kappa-view-level')
+var timestamp = require('monotonic-timestamp')
 var through = require('through2')
 var readonly = require('read-only-stream')
 var charwise = require('charwise')
@@ -15,12 +16,11 @@ module.exports = function (lvl) {
       if (!msg.value.timestamp) return []
 
       // If the message is from <<THE FUTURE>>, index it at _now_.
-      var timestamp = msg.value.timestamp
-      var now = new Date().getTime()
-      if (timestamp > now) timestamp = now
+      var ts = msg.value.timestamp
+      if (isFutureMonotonicTimestamp(ts)) ts = timestamp()
 
       if (msg.value.type.startsWith('chat/') && msg.value.content.channel) {
-        var key = 'msg!' + msg.value.content.channel + '!' + charwise.encode(timestamp)
+        var key = 'msg!' + msg.value.content.channel + '!' + charwise.encode(ts)
         return [
           [key, msg]
         ]
@@ -89,3 +89,17 @@ function sanitize (msg) {
   if (typeof msg.value.content.text !== 'string') return null
   return msg
 }
+
+function monotonicTimestampToTimestamp (timestamp) {
+  if (/^[0-9]+\.[0-9]+$/.test(String(timestamp))) {
+    return Number(String(timestamp).split('.')[0])
+  } else {
+    return timestamp
+  }
+}
+
+function isFutureMonotonicTimestamp () {
+  var timestamp = monotonicTimestampToTimestamp(timestamp)
+  var now = new Date().getTime()
+  return timestamp > now
+}