make checkInvite check only one invite, invite daemon

checkInvite no longer loops over all invites and checks for expiry, that
functionality has moved to checkInvites. Couple more rogue print
statements removed aswell.

daemon.go

@@ -0,0 +1,50 @@
+package main
+
+import "time"
+
+// https://bbengfort.github.io/snippets/2016/06/26/background-work-goroutines-timer.html THANKS
+
+type Repeater struct {
+	Stopped         bool
+	ShutdownChannel chan string
+	Interval        time.Duration
+	period          time.Duration
+	ctx             *appContext
+}
+
+func NewRepeater(interval time.Duration, ctx *appContext) *Repeater {
+	return &Repeater{
+		Stopped:         false,
+		ShutdownChannel: make(chan string),
+		Interval:        interval,
+		period:          interval,
+		ctx:             ctx,
+	}
+}
+
+func (rt *Repeater) Run() {
+	rt.ctx.info.Println("Invite daemon started")
+	for {
+		select {
+		case <-rt.ShutdownChannel:
+			rt.ShutdownChannel <- "Down"
+			return
+		case <-time.After(rt.period):
+			break
+		}
+		started := time.Now()
+		rt.ctx.storage.loadInvites()
+		rt.ctx.debug.Println("Daemon: Checking invites")
+		rt.ctx.checkInvites()
+		finished := time.Now()
+		duration := finished.Sub(started)
+		rt.period = rt.Interval - duration
+	}
+}
+
+func (rt *Repeater) Shutdown() {
+	rt.Stopped = true
+	rt.ShutdownChannel <- "Down"
+	<-rt.ShutdownChannel
+	close(rt.ShutdownChannel)
+}