fix: move v2 pkgs (#1331)

* fix: move eventstore pkgs

* fix: move eventstore pkgs

* fix: remove v2 view

* fix: remove v2 view

internal/eventstore/read_model.go

@@ -0,0 +1,47 @@
+package eventstore
+
+import "time"
+
+//ReadModel is the minimum representation of a View model.
+// It implements a basic reducer
+// it might be saved in a database or in memory
+type ReadModel struct {
+	AggregateID       string        `json:"-"`
+	ProcessedSequence uint64        `json:"-"`
+	CreationDate      time.Time     `json:"-"`
+	ChangeDate        time.Time     `json:"-"`
+	Events            []EventReader `json:"-"`
+	ResourceOwner     string        `json:"-"`
+}
+
+//AppendEvents adds all the events to the read model.
+// The function doesn't compute the new state of the read model
+func (rm *ReadModel) AppendEvents(events ...EventReader) *ReadModel {
+	rm.Events = append(rm.Events, events...)
+	return rm
+}
+
+//Reduce is the basic implementaion of reducer
+// If this function is extended the extending function should be the last step
+func (rm *ReadModel) Reduce() error {
+	if len(rm.Events) == 0 {
+		return nil
+	}
+
+	if rm.AggregateID == "" {
+		rm.AggregateID = rm.Events[0].Aggregate().ID
+	}
+	if rm.ResourceOwner == "" {
+		rm.ResourceOwner = rm.Events[0].Aggregate().ResourceOwner
+	}
+
+	if rm.CreationDate.IsZero() {
+		rm.CreationDate = rm.Events[0].CreationDate()
+	}
+	rm.ChangeDate = rm.Events[len(rm.Events)-1].CreationDate()
+	rm.ProcessedSequence = rm.Events[len(rm.Events)-1].Sequence()
+	// all events processed and not needed anymore
+	rm.Events = nil
+	rm.Events = []EventReader{}
+	return nil
+}