Add event stream module

events/multi_observer.go

@@ -0,0 +1,59 @@
+package events
+
+import (
+	"sync"
+
+	"github.com/9seconds/mtg/v2/mtglib"
+)
+
+type multiObserver struct {
+	observers []Observer
+}
+
+func (m multiObserver) EventStart(evt mtglib.EventStart) {
+	wg := &sync.WaitGroup{}
+	wg.Add(len(m.observers))
+
+	for _, v := range m.observers {
+		go func(obs Observer) {
+			defer wg.Done()
+
+			obs.EventStart(evt)
+		}(v)
+	}
+
+	wg.Wait()
+}
+
+func (m multiObserver) EventFinish(evt mtglib.EventFinish) {
+	wg := &sync.WaitGroup{}
+	wg.Add(len(m.observers))
+
+	for _, v := range m.observers {
+		go func(obs Observer) {
+			defer wg.Done()
+
+			obs.EventFinish(evt)
+		}(v)
+	}
+
+	wg.Wait()
+}
+
+func (m multiObserver) Shutdown() {
+	for _, v := range m.observers {
+		v.Shutdown()
+	}
+}
+
+func newMultiObserver(factories []ObserverFactory) Observer {
+	observers := make([]Observer, len(factories))
+
+	for i, v := range factories {
+		observers[i] = v()
+	}
+
+	return multiObserver{
+		observers: observers,
+	}
+}