func for droplet migration and change state

Signed-off-by: Jeff Carr <jcarr@wit.com>

change.go

@@ -129,3 +129,65 @@ func (d *Droplet) SetMemory(b int64) *Event {
 func (d *Droplet) SetCpus(b int64) {
 	log.Info("Set the number of cpus for the droplet", b)
 }
+
+// records an event that the droplet changed state (aka turned on, turned off, etc)
+func (c *Cluster) ChangeDropletState(d *Droplet, newState DropletState) error {
+	if c == nil {
+		return errors.New("cluster is nil")
+	}
+	if d == nil {
+		return errors.New("droplet is nil")
+	}
+	if d.CurrentState == newState {
+		// droplet status didn't change
+		return nil
+	}
+	var e *Event
+	e = new(Event)
+
+	e.Droplet = d.Hostname
+	e.OrigVal = convertToString(d.CurrentState)
+	e.NewVal = convertToString(newState)
+	e.FieldName = "status"
+
+	now := time.Now()
+	e.Start = timestamppb.New(now)
+
+	c.Events = append(c.Events, e)
+	return nil
+}
+
+// records an event that the droplet migrated to another hypervisor
+func (c *Cluster) DropletMoved(d *Droplet, newh *Hypervisor) error {
+	if c == nil {
+		return errors.New("cluster is nil")
+	}
+	if d == nil {
+		return errors.New("droplet is nil")
+	}
+	if newh == nil {
+		return errors.New("hypervisor is nil")
+	}
+	if d.CurrentHypervisor == newh.Hostname {
+		// droplet didn't move
+		return nil
+	}
+
+	// make a change event
+	var e *Event
+	e = new(Event)
+
+	e.Droplet = d.Hostname
+	e.OrigVal = d.CurrentHypervisor
+	e.NewVal = newh.Hostname
+	e.FieldName = "droplet migrate"
+
+	now := time.Now()
+	e.Start = timestamppb.New(now)
+
+	c.Events = append(c.Events, e)
+	
+	// update the droplet record
+        d.CurrentHypervisor = newh.Hostname
+	return nil
+}