Refactored into namespaced packages.

events/id.go

@@ -0,0 +1,37 @@
+package events
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+)
+
+// Serialize returns the canonical JSON array representation of the event.
+// used for ID computation: [0, pubkey, created_at, kind, tags, content].
+func (e *Event) Serialize() ([]byte, error) {
+	serialized := []interface{}{
+		0,
+		e.PubKey,
+		e.CreatedAt,
+		e.Kind,
+		e.Tags,
+		e.Content,
+	}
+
+	bytes, err := json.Marshal(serialized)
+	if err != nil {
+		return []byte{}, err
+	}
+	return bytes, nil
+}
+
+// GetID computes and returns the event ID as a lowercase, hex-encoded SHA-256 hash
+// of the serialized event.
+func (e *Event) GetID() (string, error) {
+	bytes, err := e.Serialize()
+	if err != nil {
+		return "", err
+	}
+	hash := sha256.Sum256(bytes)
+	return hex.EncodeToString(hash[:]), nil
+}