Migrated from neostr-brainstorm.

Added unit tests.

schema.go

@@ -0,0 +1,154 @@
+// This module provides methods for creating nodes and relationships according
+// to a defined schema.
+
+package heartwood
+
+import (
+	"context"
+	"fmt"
+	"github.com/neo4j/neo4j-go-driver/v6/neo4j"
+)
+
+// ========================================
+// Schema Match Keys
+// ========================================
+
+func NewMatchKeys() *MatchKeys {
+	return &MatchKeys{
+		keys: map[string][]string{
+			"User":  {"pubkey"},
+			"Relay": {"url"},
+			"Event": {"id"},
+			"Tag":   {"name", "value"},
+		},
+	}
+}
+
+// ========================================
+// Node Constructors
+// ========================================
+
+func NewUserNode(pubkey string) *Node {
+	return NewNode("User", Properties{"pubkey": pubkey})
+}
+
+func NewRelayNode(url string) *Node {
+	return NewNode("Relay", Properties{"url": url})
+}
+
+func NewEventNode(id string) *Node {
+	return NewNode("Event", Properties{"id": id})
+}
+
+func NewTagNode(name string, value string, rest []string) *Node {
+	return NewNode("Tag", Properties{
+		"name":  name,
+		"value": value,
+		"rest":  rest})
+}
+
+// ========================================
+// Relationship Constructors
+// ========================================
+
+func NewSignedRel(
+	start *Node, end *Node, props Properties) (*Relationship, error) {
+	return NewRelationshipWithValidation(
+		"SIGNED", "User", "Event", start, end, props)
+
+}
+
+func NewTaggedRel(
+	start *Node, end *Node, props Properties) (*Relationship, error) {
+	return NewRelationshipWithValidation(
+		"TAGGED", "Event", "Tag", start, end, props)
+}
+
+func NewReferencesEventRel(
+	start *Node, end *Node, props Properties) (*Relationship, error) {
+	return NewRelationshipWithValidation(
+		"REFERENCES", "Event", "Event", start, end, props)
+}
+
+func NewReferencesUserRel(
+	start *Node, end *Node, props Properties) (*Relationship, error) {
+	return NewRelationshipWithValidation(
+		"REFERENCES", "Event", "User", start, end, props)
+}
+
+// ========================================
+// Relationship Constructor Helpers
+// ========================================
+
+func validateNodeLabel(node *Node, role string, expectedLabel string) error {
+	if !node.Labels.Contains(expectedLabel) {
+		return fmt.Errorf(
+			"expected %s node to have label '%s'. got %v",
+			role, expectedLabel, node.Labels.ToArray(),
+		)
+	}
+
+	return nil
+}
+
+func NewRelationshipWithValidation(
+	rtype string,
+	startLabel string,
+	endLabel string,
+	start *Node,
+	end *Node,
+	props Properties) (*Relationship, error) {
+	var err error
+
+	err = validateNodeLabel(start, "start", startLabel)
+	if err != nil {
+		return nil, err
+	}
+
+	err = validateNodeLabel(end, "end", endLabel)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewRelationship(rtype, start, end, props), nil
+}
+
+// ========================================
+// Schema Indexes and Constaints
+// ========================================
+
+// SetNeo4jSchema ensures that the necessary indexes and constraints exist in
+// the database
+func SetNeo4jSchema(ctx context.Context, driver neo4j.Driver) error {
+	schemaQueries := []string{
+		`CREATE CONSTRAINT user_pubkey IF NOT EXISTS
+		 FOR (n:User) REQUIRE n.pubkey IS UNIQUE`,
+
+		`CREATE INDEX user_pubkey IF NOT EXISTS
+		 FOR (n:User) ON (n.pubkey)`,
+
+		`CREATE INDEX event_id IF NOT EXISTS
+		 FOR (n:Event) ON (n.id)`,
+
+		`CREATE INDEX event_kind IF NOT EXISTS
+		 FOR (n:Event) ON (n.kind)`,
+
+		`CREATE INDEX tag_name_value IF NOT EXISTS
+		 FOR (n:Tag) ON (n.name, n.value)`,
+	}
+
+	// Create indexes and constraints
+	for _, query := range schemaQueries {
+		_, err := neo4j.ExecuteQuery(ctx, driver,
+			query,
+			nil,
+			neo4j.EagerResultTransformer,
+			neo4j.ExecuteQueryWithDatabase("neo4j"))
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}