perf(grid): compile LIKE/ILIKE RegExp once per filter, not per row (#877)

lib/features/workspace/grid_filter_engine.dart

@@ -125,6 +125,7 @@ class _PredicateNode extends _FilterAstNode {
     this.inValues = const [],
     this.betweenMin,
     this.betweenMax,
+    this.likeRegex,
   });
 
   final int colIndex;
@@ -134,6 +135,10 @@ class _PredicateNode extends _FilterAstNode {
   final String? betweenMin;
   final String? betweenMax;
 
+  /// Compiled once at parse time for LIKE / ILIKE (and NOT variants), so the
+  /// per-row scan does not rebuild the same RegExp for every row.
+  final RegExp? likeRegex;
+
   @override
   bool evaluate(List<String> row, List<String> lowerColumns) {
     if (colIndex < 0 || colIndex >= row.length) return false;
@@ -172,21 +177,25 @@ class _PredicateNode extends _FilterAstNode {
 
     // LIKE / NOT LIKE
     if (upperOp == 'LIKE') {
-      final regex = _likeToRegExp(targetValue, caseSensitive: true);
+      final regex =
+          likeRegex ?? _likeToRegExp(targetValue, caseSensitive: true);
       return regex.hasMatch(cellValue);
     }
     if (upperOp == 'NOT LIKE') {
-      final regex = _likeToRegExp(targetValue, caseSensitive: true);
+      final regex =
+          likeRegex ?? _likeToRegExp(targetValue, caseSensitive: true);
       return !regex.hasMatch(cellValue);
     }
 
     // ILIKE / NOT ILIKE
     if (upperOp == 'ILIKE') {
-      final regex = _likeToRegExp(targetValue, caseSensitive: false);
+      final regex =
+          likeRegex ?? _likeToRegExp(targetValue, caseSensitive: false);
       return regex.hasMatch(cellValue);
     }
     if (upperOp == 'NOT ILIKE') {
-      final regex = _likeToRegExp(targetValue, caseSensitive: false);
+      final regex =
+          likeRegex ?? _likeToRegExp(targetValue, caseSensitive: false);
       return !regex.hasMatch(cellValue);
     }
 
@@ -497,6 +506,10 @@ abstract final class _FilterLexer {
               colIndex: colIdx,
               op: op,
               targetValue: patVal.value,
+              likeRegex: _PredicateNode._likeToRegExp(
+                patVal.value,
+                caseSensitive: likeType == 'LIKE',
+              ),
             ),
             consumedChars: (lPos - start) + patVal.consumedChars,
           );

test/features/workspace/data_grid_engines_test.dart

@@ -101,6 +101,66 @@ void main() {
       expect(resIlike, equals([1]));
     });
 
+    test('LIKE is case-sensitive while ILIKE ignores case', () {
+      List<int> run(String f) => GridFilterEngine.filterRowIndices(
+            filterText: f,
+            columns: columns,
+            rows: rows,
+          );
+      expect(run("status LIKE 'act%'"), isEmpty);
+      expect(run("status ILIKE 'act%'"), equals([0, 2]));
+    });
+
+    test('NOT LIKE / NOT ILIKE invert the match', () {
+      List<int> run(String f) => GridFilterEngine.filterRowIndices(
+            filterText: f,
+            columns: columns,
+            rows: rows,
+          );
+      expect(run("status NOT LIKE 'ACT%'"), equals([1, 3]));
+      expect(run("status NOT ILIKE '%pend%'"), equals([0, 2, 3]));
+      expect(run("status NOT LIKE 'act%'"), equals([0, 1, 2, 3]));
+    });
+
+    test('LIKE supports _ wildcard and treats regex metacharacters literally',
+        () {
+      final specialRows = [
+        ['a.c'],
+        ['abc'],
+        ['a+c'],
+        ['(x)'],
+      ];
+      List<int> run(String f) => GridFilterEngine.filterRowIndices(
+            filterText: f,
+            columns: ['v'],
+            rows: specialRows,
+          );
+      expect(run("v LIKE 'a_c'"), equals([0, 1, 2]));
+      expect(run("v LIKE 'a.c'"), equals([0]));
+      expect(run("v LIKE 'a+c'"), equals([2]));
+      expect(run("v LIKE '(x)'"), equals([3]));
+    });
+
+    test('LIKE inside AND / OR gives the same result on every row', () {
+      final many = [
+        for (var i = 0; i < 2000; i++) ['$i', i.isEven ? 'ACTIVE' : 'PENDING'],
+      ];
+      final res = GridFilterEngine.filterRowIndices(
+        filterText: "status LIKE 'ACT%' AND id LIKE '%9' OR status ILIKE 'pen%' AND id LIKE '1%'",
+        columns: ['id', 'status'],
+        rows: many,
+      );
+      final expected = [
+        for (var i = 0; i < many.length; i++)
+          if ((many[i][1].startsWith('ACT') && many[i][0].endsWith('9')) ||
+              (many[i][1].toLowerCase().startsWith('pen') &&
+                  many[i][0].startsWith('1')))
+            i,
+      ];
+      expect(res, equals(expected));
+      expect(res, isNotEmpty);
+    });
+
     test('filters with IN and NOT IN list of literals', () {
       final resIn = GridFilterEngine.filterRowIndices(
         filterText: "status IN ('PENDING', 'CANCELLED')",