Fix profile search prefix matching

src/nostrdb.c

@@ -3625,12 +3625,18 @@ int ndb_search_profile(struct ndb_txn *txn, struct ndb_search *search, const cha
 	int rc;
 	struct ndb_search_key s;
 	MDB_val k, v;
+	size_t query_len;
 	search->cursor = NULL;
 
 	MDB_cursor **cursor = (MDB_cursor **)&search->cursor;
 
 	ndb_make_search_key_low(&s, query);
 
+	// Store the lowercased query for prefix matching in subsequent calls
+	lowercase_strncpy(search->query, query, sizeof(search->query) - 1);
+	search->query[sizeof(search->query) - 1] = '\0';
+	query_len = strlen(search->query);
+
 	k.mv_data = &s;
 	k.mv_size = sizeof(s);
 
@@ -3650,6 +3656,11 @@ int ndb_search_profile(struct ndb_txn *txn, struct ndb_search *search, const cha
 		search->key = k.mv_data;
 		assert(v.mv_size == 8);
 		search->profile_key = *((uint64_t*)v.mv_data);
+
+		// Verify the first result matches the query prefix
+		if (strncmp(search->key->search, search->query, query_len) != 0) {
+			goto cleanup;
+		}
 		return 1;
 	}
 
@@ -3670,10 +3681,12 @@ int ndb_search_profile_next(struct ndb_search *search)
 	int rc;
 	MDB_val k, v;
 	unsigned char *init_id;
+	size_t query_len;
 
 	init_id = search->key->id;
 	k.mv_data = search->key;
 	k.mv_size = sizeof(*search->key);
+	query_len = strlen(search->query);
 
 retry:
 	if ((rc = mdb_cursor_get(search->cursor, &k, &v, MDB_NEXT))) {
@@ -3685,6 +3698,11 @@ int ndb_search_profile_next(struct ndb_search *search)
 		assert(v.mv_size == 8);
 		search->profile_key = *((uint64_t*)v.mv_data);
 
+		// Check if this result still matches the query prefix
+		if (strncmp(search->key->search, search->query, query_len) != 0) {
+			return 0;
+		}
+
 		// skip duplicate pubkeys
 		if (!memcmp(init_id, search->key->id, 32))
 			goto retry;

src/nostrdb.h

@@ -180,6 +180,7 @@ struct ndb_search {
 	struct ndb_search_key *key;
 	uint64_t profile_key;
 	void *cursor; // MDB_cursor *
+	char query[24]; // Original query for prefix matching
 };
 
 // From-client event

test.c

@@ -18,6 +18,7 @@
 #include <assert.h>
 #include <unistd.h>
 #include <sys/stat.h>
+#include <ctype.h>
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
 
@@ -910,6 +911,58 @@ static void test_profile_search(struct ndb *ndb)
 	ndb_end_query(&txn);
 }
 
+static void test_profile_search_prefix(struct ndb *ndb)
+{
+	struct ndb_txn txn;
+	struct ndb_search search;
+	int count = 0;
+	const char *name;
+	NdbProfile_table_t profile;
+	const char *prefix = "jean";
+	size_t prefix_len = strlen(prefix);
+
+	assert(ndb_begin_query(ndb, &txn));
+
+	// Search for prefix "jean"
+	if (!ndb_search_profile(&txn, &search, prefix)) {
+		// No results is valid if no profiles match
+		ndb_end_query(&txn);
+		printf("ok test_profile_search_prefix (no matches)\n");
+		return;
+	}
+
+	// First result should match the prefix
+	profile = lookup_profile(&txn, search.profile_key);
+	name = NdbProfile_name_get(profile);
+	assert(name != NULL);
+	// Convert to lowercase for comparison since search is case-insensitive
+	for (size_t i = 0; i < prefix_len && name[i]; i++) {
+		assert(tolower((unsigned char)name[i]) == tolower((unsigned char)prefix[i]));
+	}
+	count++;
+
+	// All subsequent results should also match the prefix
+	while (ndb_search_profile_next(&search)) {
+		profile = lookup_profile(&txn, search.profile_key);
+		name = NdbProfile_name_get(profile);
+		assert(name != NULL);
+		// Verify prefix match (case-insensitive)
+		for (size_t i = 0; i < prefix_len && name[i]; i++) {
+			assert(tolower((unsigned char)name[i]) == tolower((unsigned char)prefix[i]));
+		}
+		count++;
+		// Safety limit to avoid infinite loops in tests
+		if (count > 1000) break;
+	}
+
+	// The search should have stopped because prefix no longer matches,
+	// not because we ran out of entries in the entire database
+	ndb_search_profile_end(&search);
+	ndb_end_query(&txn);
+
+	printf("ok test_profile_search_prefix (found %d matches)\n", count);
+}
+
 static void test_profile_updates()
 {
 	static const int alloc_size = 1024 * 1024;
@@ -994,6 +1047,7 @@ static void test_load_profiles()
 	ndb_end_query(&txn);
 
 	test_profile_search(ndb);
+	test_profile_search_prefix(ndb);
 
 	ndb_destroy(ndb);
 
@@ -1038,6 +1092,7 @@ static void test_migrate() {
 	assert(ndb_end_query(&txn));
 
 	test_profile_search(ndb);
+	test_profile_search_prefix(ndb);
 	ndb_destroy(ndb);
 }