fix(event handling): use internal pubsub for view update (#1118)

* start sub

* start implement subsciptions

* start subscription

* implementation for member done

* admin done

* fix: tests

* extend handlers

* prepary notification

* no errors in adminapi

* changed current sequence in all packages

* ignore mocks

* works

* subscriptions as singleton

* tests

* refactor: rename function scope var

internal/eventstore/subscription.go

@@ -0,0 +1,73 @@
+package eventstore
+
+import (
+	"sync"
+
+	"github.com/caos/zitadel/internal/eventstore/models"
+)
+
+var (
+	subscriptions map[models.AggregateType][]*Subscription = map[models.AggregateType][]*Subscription{}
+	subsMutext    sync.Mutex
+)
+
+type Subscription struct {
+	Events     chan *models.Event
+	aggregates []models.AggregateType
+}
+
+func (es *eventstore) Subscribe(aggregates ...models.AggregateType) *Subscription {
+	events := make(chan *models.Event, 100)
+	sub := &Subscription{
+		Events:     events,
+		aggregates: aggregates,
+	}
+
+	subsMutext.Lock()
+	defer subsMutext.Unlock()
+
+	for _, aggregate := range aggregates {
+		_, ok := subscriptions[aggregate]
+		if !ok {
+			subscriptions[aggregate] = make([]*Subscription, 0, 1)
+		}
+		subscriptions[aggregate] = append(subscriptions[aggregate], sub)
+	}
+
+	return sub
+}
+
+func notify(aggregates []*models.Aggregate) {
+	subsMutext.Lock()
+	defer subsMutext.Unlock()
+	for _, aggregate := range aggregates {
+		subs, ok := subscriptions[aggregate.Type()]
+		if !ok {
+			continue
+		}
+		for _, sub := range subs {
+			for _, event := range aggregate.Events {
+				sub.Events <- event
+			}
+		}
+	}
+}
+
+func (s *Subscription) Unsubscribe() {
+	subsMutext.Lock()
+	defer subsMutext.Unlock()
+	for _, aggregate := range s.aggregates {
+		subs, ok := subscriptions[aggregate]
+		if !ok {
+			continue
+		}
+		for i := len(subs) - 1; i >= 0; i-- {
+			if subs[i] == s {
+				subs[i] = subs[len(subs)-1]
+				subs[len(subs)-1] = nil
+				subs = subs[:len(subs)-1]
+			}
+		}
+	}
+	close(s.Events)
+}