feat(theme): VS Code theme JSON/JSONC parser (#39)

lib/core/theme/parser/jsonc_preprocessor.dart

@@ -0,0 +1,90 @@
+/// Strips JSONC (comments, trailing commas) to valid JSON for [dart:convert].
+String stripJsonc(String input) {
+  final out = StringBuffer();
+  var i = 0;
+  final len = input.length;
+
+  while (i < len) {
+    final ch = input[i];
+    final next = i + 1 < len ? input[i + 1] : '';
+
+    if (ch == '"') {
+      out.write(_copyStringLiteral(input, i));
+      i = _skipStringLiteral(input, i);
+      continue;
+    }
+
+    if (ch == '/' && next == '/') {
+      i += 2;
+      while (i < len && input[i] != '\n') {
+        i++;
+      }
+      continue;
+    }
+
+    if (ch == '/' && next == '*') {
+      i += 2;
+      while (i < len) {
+        if (input[i] == '*' && i + 1 < len && input[i + 1] == '/') {
+          i += 2;
+          break;
+        }
+        i++;
+      }
+      continue;
+    }
+
+    if (ch == ',') {
+      var j = i + 1;
+      while (j < len && _isWhitespace(input[j])) {
+        j++;
+      }
+      if (j < len && (input[j] == '}' || input[j] == ']')) {
+        i++;
+        continue;
+      }
+    }
+
+    out.write(ch);
+    i++;
+  }
+
+  return out.toString();
+}
+
+bool _isWhitespace(String c) => c == ' ' || c == '\t' || c == '\n' || c == '\r';
+
+String _copyStringLiteral(String s, int start) {
+  final buf = StringBuffer();
+  var i = start;
+  buf.write(s[i]);
+  i++;
+  while (i < s.length) {
+    final ch = s[i];
+    buf.write(ch);
+    if (ch == '\\' && i + 1 < s.length) {
+      i++;
+      buf.write(s[i]);
+    } else if (ch == '"') {
+      i++;
+      break;
+    }
+    i++;
+  }
+  return buf.toString();
+}
+
+int _skipStringLiteral(String s, int start) {
+  var i = start + 1;
+  while (i < s.length) {
+    if (s[i] == '\\') {
+      i += 2;
+      continue;
+    }
+    if (s[i] == '"') {
+      return i + 1;
+    }
+    i++;
+  }
+  return s.length;
+}

lib/core/theme/parser/vscode_theme_manifest.dart

@@ -0,0 +1,120 @@
+import 'dart:convert';
+
+import 'jsonc_preprocessor.dart';
+
+/// Parsed VS Code theme manifest (subset used by Querya).
+class VsCodeThemeManifest {
+  const VsCodeThemeManifest({
+    this.name,
+    this.type,
+    this.colors = const {},
+    this.tokenColors = const [],
+  });
+
+  final String? name;
+
+  /// `dark` or `light` when present.
+  final String? type;
+
+  final Map<String, String> colors;
+
+  final List<TokenColorRule> tokenColors;
+
+  bool get isDark => type?.toLowerCase() == 'dark';
+  bool get isLight => type?.toLowerCase() == 'light';
+
+  factory VsCodeThemeManifest.fromJsonString(String source) {
+    final cleaned = stripJsonc(source);
+    final dynamic decoded;
+    try {
+      decoded = jsonDecode(cleaned);
+    } on FormatException catch (e) {
+      throw VsCodeThemeParseException('Invalid JSON after JSONC strip: ${e.message}');
+    }
+    if (decoded is! Map<String, dynamic>) {
+      throw VsCodeThemeParseException('Theme root must be a JSON object');
+    }
+    return VsCodeThemeManifest.fromJson(decoded);
+  }
+
+  factory VsCodeThemeManifest.fromJson(Map<String, dynamic> json) {
+    final colorsRaw = json['colors'];
+    final colors = <String, String>{};
+    if (colorsRaw is Map) {
+      for (final e in colorsRaw.entries) {
+        final k = e.key?.toString();
+        final v = e.value?.toString();
+        if (k != null && k.isNotEmpty && v != null && v.isNotEmpty) {
+          colors[k] = v;
+        }
+      }
+    }
+
+    final tokenColorsRaw = json['tokenColors'];
+    final rules = <TokenColorRule>[];
+    if (tokenColorsRaw is List) {
+      for (final item in tokenColorsRaw) {
+        if (item is Map<String, dynamic>) {
+          final rule = TokenColorRule.tryParse(item);
+          if (rule != null) rules.add(rule);
+        }
+      }
+    }
+
+    return VsCodeThemeManifest(
+      name: json['name']?.toString(),
+      type: json['type']?.toString(),
+      colors: colors,
+      tokenColors: rules,
+    );
+  }
+}
+
+/// One `tokenColors` entry from a VS Code theme file.
+class TokenColorRule {
+  const TokenColorRule({
+    required this.scopes,
+    this.foreground,
+    this.background,
+    this.fontStyle,
+  });
+
+  final List<String> scopes;
+  final String? foreground;
+  final String? background;
+  final String? fontStyle;
+
+  static TokenColorRule? tryParse(Map<String, dynamic> json) {
+    final scopeRaw = json['scope'];
+    final scopes = <String>[];
+    if (scopeRaw is String && scopeRaw.isNotEmpty) {
+      scopes.add(scopeRaw);
+    } else if (scopeRaw is List) {
+      for (final s in scopeRaw) {
+        final t = s?.toString();
+        if (t != null && t.isNotEmpty) scopes.add(t);
+      }
+    }
+    if (scopes.isEmpty) return null;
+
+    final settings = json['settings'];
+    if (settings is! Map) {
+      return TokenColorRule(scopes: scopes);
+    }
+
+    return TokenColorRule(
+      scopes: scopes,
+      foreground: settings['foreground']?.toString(),
+      background: settings['background']?.toString(),
+      fontStyle: settings['fontStyle']?.toString(),
+    );
+  }
+}
+
+class VsCodeThemeParseException implements Exception {
+  VsCodeThemeParseException(this.message);
+  final String message;
+
+  @override
+  String toString() => 'VsCodeThemeParseException: $message';
+}

test/core/theme/parser/jsonc_preprocessor_test.dart

@@ -0,0 +1,35 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/theme/parser/jsonc_preprocessor.dart';
+
+void main() {
+  group('stripJsonc', () {
+    test('removes line comments outside strings', () {
+      const input = '''
+{
+  // sidebar
+  "a": 1
+}
+''';
+      final out = stripJsonc(input);
+      expect(out.contains('//'), isFalse);
+      expect(out.contains('"a"'), isTrue);
+    });
+
+    test('preserves // inside string', () {
+      const input = '{"x": "http://example.com"}';
+      expect(stripJsonc(input), contains('http://'));
+    });
+
+    test('removes block comments', () {
+      const input = '{ /* block */ "k": 2 }';
+      final out = stripJsonc(input);
+      expect(out.contains('/*'), isFalse);
+      expect(out.contains('"k"'), isTrue);
+    });
+
+    test('removes trailing comma', () {
+      const input = '{"a": 1,}';
+      expect(stripJsonc(input), '{"a": 1}');
+    });
+  });
+}

test/core/theme/parser/vscode_theme_manifest_test.dart

@@ -0,0 +1,45 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/theme/parser/vscode_theme_manifest.dart';
+
+void main() {
+  group('VsCodeThemeManifest', () {
+    test('parses minimal dark theme with JSONC', () {
+      const src = '''
+{
+  // theme
+  "name": "Test Dark",
+  "type": "dark",
+  "colors": {
+    "editor.background": "#1e1e1e",
+    "sideBar.background": "#252526",
+  },
+  "tokenColors": [
+    {
+      "scope": "comment",
+      "settings": { "foreground": "#6A9955" }
+    },
+    {
+      "scope": ["keyword", "storage.type"],
+      "settings": { "foreground": "#569CD6", "fontStyle": "italic" }
+    },
+  ],
+}
+''';
+      final m = VsCodeThemeManifest.fromJsonString(src);
+      expect(m.name, 'Test Dark');
+      expect(m.isDark, isTrue);
+      expect(m.colors['editor.background'], '#1e1e1e');
+      expect(m.tokenColors.length, 2);
+      expect(m.tokenColors.first.scopes, ['comment']);
+      expect(m.tokenColors.first.foreground, '#6A9955');
+      expect(m.tokenColors[1].scopes, ['keyword', 'storage.type']);
+    });
+
+    test('throws on invalid JSON', () {
+      expect(
+        () => VsCodeThemeManifest.fromJsonString('{ not json }'),
+        throwsA(isA<VsCodeThemeParseException>()),
+      );
+    });
+  });
+}