support deleting "a" references.

deleting.go

@@ -3,6 +3,8 @@ package khatru
 import (
 	"context"
 	"fmt"
+	"strconv"
+	"strings"
 
 	"github.com/nbd-wtf/go-nostr"
 )
@@ -10,10 +12,35 @@ import (
 func (rl *Relay) handleDeleteRequest(ctx context.Context, evt *nostr.Event) error {
 	// event deletion -- nip09
 	for _, tag := range evt.Tags {
-		if len(tag) >= 2 && tag[0] == "e" {
-			// first we fetch the event
+		if len(tag) >= 2 {
+			var f nostr.Filter
+
+			switch tag[0] {
+			case "e":
+				f = nostr.Filter{IDs: []string{tag[1]}}
+			case "a":
+				spl := strings.Split(tag[1], ":")
+				if len(spl) != 3 {
+					continue
+				}
+				kind, err := strconv.Atoi(spl[0])
+				if err != nil {
+					continue
+				}
+				author := spl[1]
+				identifier := spl[2]
+				f = nostr.Filter{
+					Kinds:   []int{kind},
+					Authors: []string{author},
+					Tags:    nostr.TagMap{"d": []string{identifier}},
+					Until:   &evt.CreatedAt,
+				}
+			default:
+				continue
+			}
+
 			for _, query := range rl.QueryEvents {
-				ch, err := query(ctx, nostr.Filter{IDs: []string{tag[1]}})
+				ch, err := query(ctx, f)
 				if err != nil {
 					continue
 				}