Finished event to subgraph conversion.

Wrote expander pattern for custom rules.

expanders.go

@@ -0,0 +1,88 @@
+package heartwood
+
+import (
+	roots "git.wisehodl.dev/jay/go-roots/events"
+)
+
+type Expander func(e roots.Event, s *Subgraph)
+type ExpanderRegistry []Expander
+
+func NewExpanderRegistry() ExpanderRegistry {
+	return []Expander{}
+}
+
+func GetDefaultExpanderRegistry() ExpanderRegistry {
+	registry := NewExpanderRegistry()
+
+	registry.Add(ExpandTaggedEvents)
+	registry.Add(ExpandTaggedUsers)
+
+	return registry
+}
+
+func (r *ExpanderRegistry) Add(m Expander) {
+	*r = append(*r, m)
+}
+
+// Default Expander Functions
+
+func ExpandTaggedEvents(e roots.Event, s *Subgraph) {
+	tagNodes := s.NodesByLabel("Tag")
+	for _, tag := range e.Tags {
+		if !isValidTag(tag) {
+			continue
+		}
+		name := tag[0]
+		value := tag[1]
+
+		if name != "e" || !roots.Hex64Pattern.MatchString(value) {
+			continue
+		}
+
+		tagNode := findTagNode(tagNodes, name, value)
+		if tagNode == nil {
+			continue
+		}
+
+		referencedEvent := NewEventNode(value)
+
+		s.AddNode(referencedEvent)
+		s.AddRel(NewReferencesEventRel(tagNode, referencedEvent, nil))
+	}
+}
+
+func ExpandTaggedUsers(e roots.Event, s *Subgraph) {
+	tagNodes := s.NodesByLabel("Tag")
+	for _, tag := range e.Tags {
+		if !isValidTag(tag) {
+			continue
+		}
+		name := tag[0]
+		value := tag[1]
+
+		if name != "p" || !roots.Hex64Pattern.MatchString(value) {
+			continue
+		}
+
+		tagNode := findTagNode(tagNodes, name, value)
+		if tagNode == nil {
+			continue
+		}
+
+		referencedEvent := NewUserNode(value)
+
+		s.AddNode(referencedEvent)
+		s.AddRel(NewReferencesUserRel(tagNode, referencedEvent, nil))
+	}
+}
+
+// Helpers
+
+func findTagNode(nodes []*Node, name, value string) *Node {
+	for _, node := range nodes {
+		if node.Props["name"] == name && node.Props["value"] == value {
+			return node
+		}
+	}
+	return nil
+}