initial draft of neo4j database driver

pkg/neo4j/schema.go

@@ -0,0 +1,108 @@
+package neo4j
+
+import (
+	"context"
+	"fmt"
+)
+
+// applySchema creates Neo4j constraints and indexes for Nostr events
+// Neo4j uses Cypher queries to define schema constraints and indexes
+func (n *N) applySchema(ctx context.Context) error {
+	n.Logger.Infof("applying Nostr schema to neo4j")
+
+	// Create constraints and indexes using Cypher queries
+	// Constraints ensure uniqueness and are automatically indexed
+	constraints := []string{
+		// Unique constraint on Event.id (event ID must be unique)
+		"CREATE CONSTRAINT event_id_unique IF NOT EXISTS FOR (e:Event) REQUIRE e.id IS UNIQUE",
+
+		// Unique constraint on Author.pubkey (author public key must be unique)
+		"CREATE CONSTRAINT author_pubkey_unique IF NOT EXISTS FOR (a:Author) REQUIRE a.pubkey IS UNIQUE",
+
+		// Unique constraint on Marker.key (marker key must be unique)
+		"CREATE CONSTRAINT marker_key_unique IF NOT EXISTS FOR (m:Marker) REQUIRE m.key IS UNIQUE",
+	}
+
+	// Additional indexes for query optimization
+	indexes := []string{
+		// Index on Event.kind for kind-based queries
+		"CREATE INDEX event_kind IF NOT EXISTS FOR (e:Event) ON (e.kind)",
+
+		// Index on Event.created_at for time-range queries
+		"CREATE INDEX event_created_at IF NOT EXISTS FOR (e:Event) ON (e.created_at)",
+
+		// Index on Event.serial for serial-based lookups
+		"CREATE INDEX event_serial IF NOT EXISTS FOR (e:Event) ON (e.serial)",
+
+		// Composite index for common query patterns (kind + created_at)
+		"CREATE INDEX event_kind_created_at IF NOT EXISTS FOR (e:Event) ON (e.kind, e.created_at)",
+
+		// Index on Tag.type for tag-type queries
+		"CREATE INDEX tag_type IF NOT EXISTS FOR (t:Tag) ON (t.type)",
+
+		// Index on Tag.value for tag-value queries
+		"CREATE INDEX tag_value IF NOT EXISTS FOR (t:Tag) ON (t.value)",
+
+		// Composite index for tag queries (type + value)
+		"CREATE INDEX tag_type_value IF NOT EXISTS FOR (t:Tag) ON (t.type, t.value)",
+	}
+
+	// Execute all constraint creation queries
+	for _, constraint := range constraints {
+		if _, err := n.ExecuteWrite(ctx, constraint, nil); err != nil {
+			return fmt.Errorf("failed to create constraint: %w", err)
+		}
+	}
+
+	// Execute all index creation queries
+	for _, index := range indexes {
+		if _, err := n.ExecuteWrite(ctx, index, nil); err != nil {
+			return fmt.Errorf("failed to create index: %w", err)
+		}
+	}
+
+	n.Logger.Infof("schema applied successfully")
+	return nil
+}
+
+// dropAll drops all data from neo4j (useful for testing)
+func (n *N) dropAll(ctx context.Context) error {
+	n.Logger.Warningf("dropping all data from neo4j")
+
+	// Delete all nodes and relationships
+	_, err := n.ExecuteWrite(ctx, "MATCH (n) DETACH DELETE n", nil)
+	if err != nil {
+		return fmt.Errorf("failed to drop all data: %w", err)
+	}
+
+	// Drop all constraints
+	constraints := []string{
+		"DROP CONSTRAINT event_id_unique IF EXISTS",
+		"DROP CONSTRAINT author_pubkey_unique IF EXISTS",
+		"DROP CONSTRAINT marker_key_unique IF EXISTS",
+	}
+
+	for _, constraint := range constraints {
+		_, _ = n.ExecuteWrite(ctx, constraint, nil)
+		// Ignore errors as constraints may not exist
+	}
+
+	// Drop all indexes
+	indexes := []string{
+		"DROP INDEX event_kind IF EXISTS",
+		"DROP INDEX event_created_at IF EXISTS",
+		"DROP INDEX event_serial IF EXISTS",
+		"DROP INDEX event_kind_created_at IF EXISTS",
+		"DROP INDEX tag_type IF EXISTS",
+		"DROP INDEX tag_value IF EXISTS",
+		"DROP INDEX tag_type_value IF EXISTS",
+	}
+
+	for _, index := range indexes {
+		_, _ = n.ExecuteWrite(ctx, index, nil)
+		// Ignore errors as indexes may not exist
+	}
+
+	// Reapply schema after dropping
+	return n.applySchema(ctx)
+}