From 916a6a6abb1ee60c3313c80da41c56fedee5b070 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Mon, 27 Feb 2023 16:15:04 -0300
Subject: [PATCH] support for naddr on nip19.

---
 nip19/nip19.go      | 61 ++++++++++++++++++++++++++++++++++++++++++--
 nip19/nip19_test.go | 62 +++++++++++++++++++++++++++++++++++++++++++++
 nip19/utils.go      |  2 ++
 pointers.go         |  7 +++++
 4 files changed, 130 insertions(+), 2 deletions(-)

diff --git a/nip19/nip19.go b/nip19/nip19.go
index afce90b..7e64d58 100644
--- a/nip19/nip19.go
+++ b/nip19/nip19.go
@@ -2,6 +2,7 @@ package nip19
 
 import (
 	"bytes"
+	"encoding/binary"
 	"encoding/hex"
 	"fmt"
 
@@ -74,6 +75,35 @@ func Decode(bech32string string) (prefix string, value any, err error) {
 				// ignore
 			}
 
+			curr = curr + 2 + len(v)
+		}
+	case "naddr":
+		var result nostr.EntityPointer
+		curr := 0
+		for {
+			t, v := readTLVEntry(data[curr:])
+			if v == nil {
+				// end here
+				if result.Kind == 0 || result.Identifier == "" || result.PublicKey == "" {
+					return prefix, result, fmt.Errorf("incomplete naddr")
+				}
+
+				return prefix, result, nil
+			}
+
+			switch t {
+			case TLVDefault:
+				result.Identifier = string(v)
+			case TLVRelay:
+				result.Relays = append(result.Relays, string(v))
+			case TLVAuthor:
+				result.PublicKey = hex.EncodeToString(v)
+			case TLVKind:
+				result.Kind = int(binary.BigEndian.Uint32(v))
+			default:
+				// ignore
+			}
+
 			curr = curr + 2 + len(v)
 		}
 	}
@@ -145,11 +175,11 @@ func EncodeProfile(publicKeyHex string, relays []string) (string, error) {
 
 func EncodeEvent(eventIdHex string, relays []string) (string, error) {
 	buf := &bytes.Buffer{}
-	pubkey, err := hex.DecodeString(eventIdHex)
+	id, err := hex.DecodeString(eventIdHex)
 	if err != nil {
 		return "", fmt.Errorf("invalid id '%s': %w", eventIdHex, err)
 	}
-	writeTLVEntry(buf, TLVDefault, pubkey)
+	writeTLVEntry(buf, TLVDefault, id)
 
 	for _, url := range relays {
 		writeTLVEntry(buf, TLVRelay, []byte(url))
@@ -162,3 +192,30 @@ func EncodeEvent(eventIdHex string, relays []string) (string, error) {
 
 	return encode("nevent", bits5)
 }
+
+func EncodeEntity(publicKey string, kind int, identifier string, relays []string) (string, error) {
+	buf := &bytes.Buffer{}
+
+	writeTLVEntry(buf, TLVDefault, []byte(identifier))
+
+	for _, url := range relays {
+		writeTLVEntry(buf, TLVRelay, []byte(url))
+	}
+
+	pubkey, err := hex.DecodeString(publicKey)
+	if err != nil {
+		return "", fmt.Errorf("invalid pubkey '%s': %w", pubkey, err)
+	}
+	writeTLVEntry(buf, TLVAuthor, pubkey)
+
+	kindBytes := make([]byte, 4)
+	binary.BigEndian.PutUint32(kindBytes, uint32(kind))
+	writeTLVEntry(buf, TLVKind, kindBytes)
+
+	bits5, err := convertBits(buf.Bytes(), 8, 5, true)
+	if err != nil {
+		return "", fmt.Errorf("failed to convert bits: %w", err)
+	}
+
+	return encode("naddr", bits5)
+}
diff --git a/nip19/nip19_test.go b/nip19/nip19_test.go
index 5bd7396..5b976de 100644
--- a/nip19/nip19_test.go
+++ b/nip19/nip19_test.go
@@ -2,6 +2,7 @@ package nip19
 
 import (
 	"testing"
+
 	"github.com/nbd-wtf/go-nostr"
 )
 
@@ -107,3 +108,64 @@ func TestEncodeNprofile(t *testing.T) {
 		t.Error("produced an unexpected nprofile string")
 	}
 }
+
+func TestEncodeDecodeNaddr(t *testing.T) {
+	naddr, err := EncodeEntity(
+		"3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d",
+		30023,
+		"banana",
+		[]string{
+			"wss://relay.nostr.example.mydomain.example.com",
+			"wss://nostr.banana.com",
+		})
+	if err != nil {
+		t.Errorf("shouldn't error: %s", err)
+	}
+	if naddr != "naddr1qqrxyctwv9hxzqfwwaehxw309aex2mrp0yhxummnw3ezuetcv9khqmr99ekhjer0d4skjm3wv4uxzmtsd3jjucm0d5q3vamnwvaz7tmwdaehgu3wvfskuctwvyhxxmmdqgsrhuxx8l9ex335q7he0f09aej04zpazpl0ne2cgukyawd24mayt8grqsqqqa28a3lkds" {
+		t.Errorf("produced an unexpected naddr string: %s", naddr)
+	}
+
+	prefix, data, err := Decode(naddr)
+	if err != nil {
+		t.Errorf("shouldn't error: %s", err)
+	}
+	if prefix != "naddr" {
+		t.Error("returned invalid prefix")
+	}
+	ep := data.(nostr.EntityPointer)
+	if ep.PublicKey != "3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d" {
+		t.Error("returned wrong pubkey")
+	}
+	if ep.Kind != 30023 {
+		t.Error("returned wrong kind")
+	}
+	if ep.Identifier != "banana" {
+		t.Error("returned wrong identifier")
+	}
+	if ep.Relays[0] != "wss://relay.nostr.example.mydomain.example.com" || ep.Relays[1] != "wss://nostr.banana.com" {
+		t.Error("returned wrong relays")
+	}
+}
+
+func TestDecodeNaddrWithoutRelays(t *testing.T) {
+	prefix, data, err := Decode("naddr1qq98yetxv4ex2mnrv4esygrl54h466tz4v0re4pyuavvxqptsejl0vxcmnhfl60z3rth2xkpjspsgqqqw4rsf34vl5")
+	if err != nil {
+		t.Errorf("shouldn't error: %s", err)
+	}
+	if prefix != "naddr" {
+		t.Error("returned invalid prefix")
+	}
+	ep := data.(nostr.EntityPointer)
+	if ep.PublicKey != "7fa56f5d6962ab1e3cd424e758c3002b8665f7b0d8dcee9fe9e288d7751ac194" {
+		t.Error("returned wrong pubkey")
+	}
+	if ep.Kind != 30023 {
+		t.Error("returned wrong kind")
+	}
+	if ep.Identifier != "references" {
+		t.Error("returned wrong identifier")
+	}
+	if len(ep.Relays) != 0 {
+		t.Error("relays should have been an empty array")
+	}
+}
diff --git a/nip19/utils.go b/nip19/utils.go
index 517e334..08aebe1 100644
--- a/nip19/utils.go
+++ b/nip19/utils.go
@@ -7,6 +7,8 @@ import (
 const (
 	TLVDefault uint8 = 0
 	TLVRelay   uint8 = 1
+	TLVAuthor  uint8 = 2
+	TLVKind    uint8 = 3
 )
 
 func readTLVEntry(data []byte) (typ uint8, value []byte) {
diff --git a/pointers.go b/pointers.go
index 4e62fd0..8efa8cd 100644
--- a/pointers.go
+++ b/pointers.go
@@ -9,3 +9,10 @@ type EventPointer struct {
 	ID     string
 	Relays []string
 }
+
+type EntityPointer struct {
+	PublicKey  string
+	Kind       int
+	Identifier string
+	Relays     []string
+}