From 4dcb575caa29aff5b33d3c2e294fdb32e3bafb4c Mon Sep 17 00:00:00 2001
From: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>
Date: Tue, 12 Dec 2023 20:22:33 +0300
Subject: [PATCH] [#56] Add multi-level domain name support

Signed-off-by: Ekaterina Lebedeva <ekaterina.lebedeva@yadro.com>
---
 nns/nns_contract.go | 26 +++++++++++++-------------
 tests/nns_test.go   |  9 +++++++++
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/nns/nns_contract.go b/nns/nns_contract.go
index d187584..202a03d 100644
--- a/nns/nns_contract.go
+++ b/nns/nns_contract.go
@@ -219,7 +219,7 @@ func GetPrice() int {
 
 // IsAvailable checks whether the provided domain name is available.
 func IsAvailable(name string) bool {
-	fragments := splitAndCheck(name, false)
+	fragments := splitAndCheck(name)
 	if fragments == nil {
 		panic("invalid domain name format")
 	}
@@ -231,16 +231,19 @@ func IsAvailable(name string) bool {
 		}
 		return true
 	}
-	return parentExpired(ctx, 0, fragments)
+	if parentExpired(ctx, fragments) {
+		panic("parent does not exist or is expired")
+	}
+	return storage.Get(ctx, append([]byte{prefixName}, getTokenKey([]byte(name))...)) == nil
 }
 
 // parentExpired returns true if any domain from fragments doesn't exist or is expired.
 // first denotes the deepest subdomain to check.
-func parentExpired(ctx storage.Context, first int, fragments []string) bool {
+func parentExpired(ctx storage.Context, fragments []string) bool {
 	now := int64(runtime.GetTime())
 	last := len(fragments) - 1
 	name := fragments[last]
-	for i := last; i >= first; i-- {
+	for i := last; i > 0; i-- {
 		if i != last {
 			name = fragments[i] + "." + name
 		}
@@ -258,7 +261,7 @@ func parentExpired(ctx storage.Context, first int, fragments []string) bool {
 
 // Register registers a new domain with the specified owner and name if it's available.
 func Register(name string, owner interop.Hash160, email string, refresh, retry, expire, ttl int) bool {
-	fragments := splitAndCheck(name, true)
+	fragments := splitAndCheck(name)
 	if fragments == nil {
 		panic("invalid domain name format")
 	}
@@ -277,7 +280,7 @@ func Register(name string, owner interop.Hash160, email string, refresh, retry,
 		if tldBytes == nil {
 			panic("TLD not found")
 		}
-		if parentExpired(ctx, 1, fragments) {
+		if parentExpired(ctx, fragments) {
 			panic("one of the parent domains is not registered")
 		}
 		parentKey := getTokenKey([]byte(name[len(fragments[0])+1:]))
@@ -388,7 +391,7 @@ func checkBaseRecords(typ RecordType, data string) bool {
 	case A:
 		return checkIPv4(data)
 	case CNAME:
-		return splitAndCheck(data, true) != nil
+		return splitAndCheck(data) != nil
 	case TXT:
 		return len(data) <= maxTXTRecordLength
 	case AAAA:
@@ -508,7 +511,7 @@ func getNameState(ctx storage.Context, tokenID []byte) NameState {
 	tokenKey := getTokenKey(tokenID)
 	ns := getNameStateWithKey(ctx, tokenKey)
 	fragments := std.StringSplit(string(tokenID), ".")
-	if parentExpired(ctx, 1, fragments) {
+	if parentExpired(ctx, fragments) {
 		panic("parent domain has expired")
 	}
 	return ns
@@ -716,16 +719,13 @@ func isAlNum(c uint8) bool {
 }
 
 // splitAndCheck splits domain name into parts and validates it.
-func splitAndCheck(name string, allowMultipleFragments bool) []string {
+func splitAndCheck(name string) []string {
 	l := len(name)
 	if l < minDomainNameLength || maxDomainNameLength < l {
 		return nil
 	}
 	fragments := std.StringSplit(name, ".")
 	l = len(fragments)
-	if l > 2 && !allowMultipleFragments {
-		return nil
-	}
 	for i := 0; i < l; i++ {
 		if !checkFragment(fragments[i], i == l-1) {
 			return nil
@@ -846,7 +846,7 @@ func checkIPv6(data string) bool {
 
 // tokenIDFromName returns token ID (domain.root) from the provided name.
 func tokenIDFromName(name string) string {
-	fragments := splitAndCheck(name, true)
+	fragments := splitAndCheck(name)
 	if fragments == nil {
 		panic("invalid domain name format")
 	}
diff --git a/tests/nns_test.go b/tests/nns_test.go
index 77a610c..7ee43ae 100644
--- a/tests/nns_test.go
+++ b/tests/nns_test.go
@@ -334,6 +334,15 @@ func TestNNSIsAvailable(t *testing.T) {
 		"myemail@frostfs.info", refresh, retry, expire, ttl)
 
 	c.Invoke(t, false, "isAvailable", "domain.com")
+
+	c.Invoke(t, true, "isAvailable", "dom.domain.com")
+	c.InvokeFail(t, "parent does not exist or is expired", "isAvailable", "dom.dom.domain.com")
+
+	c1.Invoke(t, true, "register",
+		"dom.domain.com", acc.ScriptHash(),
+		"myemail@frostfs.info", refresh, retry, expire, ttl)
+	c.Invoke(t, false, "isAvailable", "dom.domain.com")
+	c.Invoke(t, true, "isAvailable", "dom.dom.domain.com")
 }
 
 func TestNNSRenew(t *testing.T) {