word_search: fix pagination

lib/search.dart

@@ -31,14 +31,14 @@ extension JaDBConnection on DatabaseExecutor {
     String word, {
     SearchMode searchMode = SearchMode.Auto,
     int page = 0,
-    int pageSize = 10,
+    int? pageSize,
   }) =>
       searchWordWithDbConnection(
         this,
         word,
-        searchMode,
-        page,
-        pageSize,
+        searchMode: searchMode,
+        page: page,
+        pageSize: pageSize,
       );
 
   ///
@@ -50,7 +50,11 @@ extension JaDBConnection on DatabaseExecutor {
     String word, {
     SearchMode searchMode = SearchMode.Auto,
   }) =>
-      searchWordCountWithDbConnection(this, word, searchMode);
+      searchWordCountWithDbConnection(
+        this,
+        word,
+        searchMode: searchMode,
+      );
 
   /// Given a list of radicals, search which kanji contains all
   /// of the radicals, find their other radicals, and return those.

lib/search/word_search/entry_id_query.dart

@@ -43,11 +43,23 @@ String _filterFTSSensitiveCharacters(String word) {
 (String, List<Object?>) _kanjiReadingTemplate(
   String tableName,
   String word, {
-  int pageSize = 10,
+  int? pageSize,
+  int? offset,
   bool countOnly = false,
-}) =>
-    (
-      '''
+}) {
+  assert(tableName == JMdictTableNames.kanjiElement ||
+      tableName == JMdictTableNames.readingElement);
+  assert(!countOnly || pageSize == null);
+  assert(!countOnly || offset == null);
+  assert(pageSize == null || pageSize > 0);
+  assert(offset == null || offset >= 0);
+  assert(
+    offset == null || pageSize != null,
+    'Offset should only be used with pageSize set',
+  );
+
+  return (
+    '''
         WITH
           fts_results AS (
             SELECT DISTINCT
@@ -87,27 +99,33 @@ String _filterFTSSensitiveCharacters(String word) {
         ORDER BY
           "score" DESC,
           "entryId" ASC
+        ${pageSize != null ? 'LIMIT ?' : ''}
+        ${offset != null ? 'OFFSET ?' : ''}
       '''
-          .trim(),
-      [
-        _filterFTSSensitiveCharacters(word),
-        _filterFTSSensitiveCharacters(word),
-        if (!countOnly) pageSize,
-        _filterFTSSensitiveCharacters(word),
-        if (!countOnly) pageSize,
-      ]
-    );
+        .trim(),
+    [
+      _filterFTSSensitiveCharacters(word),
+      _filterFTSSensitiveCharacters(word),
+      if (!countOnly) pageSize,
+      _filterFTSSensitiveCharacters(word),
+      if (!countOnly) pageSize,
+      if (pageSize != null) pageSize,
+      if (offset != null) offset,
+    ]
+  );
+}
 
 Future<List<ScoredEntryId>> _queryKanji(
   DatabaseExecutor connection,
   String word,
-  int pageSize,
+  int? pageSize,
   int? offset,
 ) {
   final (query, args) = _kanjiReadingTemplate(
     JMdictTableNames.kanjiElement,
     word,
     pageSize: pageSize,
+    offset: offset,
   );
   return connection.rawQuery(query, args).then((result) => result
       .map((row) => ScoredEntryId(
@@ -134,13 +152,14 @@ Future<int> _queryKanjiCount(
 Future<List<ScoredEntryId>> _queryKana(
   DatabaseExecutor connection,
   String word,
-  int pageSize,
+  int? pageSize,
   int? offset,
 ) {
   final (query, args) = _kanjiReadingTemplate(
     JMdictTableNames.readingElement,
     word,
     pageSize: pageSize,
+    offset: offset,
   );
   return connection.rawQuery(query, args).then((result) => result
       .map((row) => ScoredEntryId(
@@ -167,9 +186,16 @@ Future<int> _queryKanaCount(
 Future<List<ScoredEntryId>> _queryEnglish(
   DatabaseExecutor connection,
   String word,
-  int pageSize,
+  int? pageSize,
   int? offset,
 ) async {
+  assert(pageSize == null || pageSize > 0);
+  assert(offset == null || offset >= 0);
+  assert(
+    offset == null || pageSize != null,
+    'Offset should only be used with pageSize set',
+  );
+
   final result = await connection.rawQuery(
     '''
     SELECT
@@ -235,7 +261,7 @@ Future<List<ScoredEntryId>> fetchEntryIds(
   DatabaseExecutor connection,
   String word,
   SearchMode searchMode,
-  int pageSize,
+  int? pageSize,
   int? offset,
 ) async {
   if (searchMode == SearchMode.Auto) {

lib/search/word_search/word_search.dart

@@ -24,16 +24,16 @@ enum SearchMode {
 
 Future<List<WordSearchResult>?> searchWordWithDbConnection(
   DatabaseExecutor connection,
-  String word,
-  SearchMode searchMode,
-  int page,
-  int pageSize,
-) async {
+  String word, {
+  SearchMode searchMode = SearchMode.Auto,
+  int page = 0,
+  int? pageSize,
+}) async {
   if (word.isEmpty) {
     return null;
   }
 
-  final offset = page * pageSize;
+  final int? offset = pageSize != null ? page * pageSize : null;
   final List<ScoredEntryId> entryIds = await fetchEntryIds(
     connection,
     word,
@@ -82,9 +82,9 @@ Future<List<WordSearchResult>?> searchWordWithDbConnection(
 
 Future<int?> searchWordCountWithDbConnection(
   DatabaseExecutor connection,
-  String word,
-  SearchMode searchMode,
-) async {
+  String word, {
+  SearchMode searchMode = SearchMode.Auto,
+}) async {
   if (word.isEmpty) {
     return null;
   }