Remove src/ folder

pkgs/messages_shrinker/lib/messages_shrinker.dart

@@ -1,8 +1,74 @@
-/// Support for doing something awesome.
-///
-/// More dartdocs go here.
-library message_shrinker;
+import 'dart:convert';
+import 'dart:io';
 
-export 'src/messages_shrinker.dart';
+import 'package:messages/package_intl_object.dart';
+import 'package:messages_deserializer/messages_deserializer_json.dart';
+import 'package:messages_serializer/messages_serializer.dart';
 
-// TODO: Export any libraries intended for clients of this package.
+class MessageShrinker {
+  void shrink(
+    String dataFile,
+    String constInstancesFile,
+    String outputFile,
+  ) {
+    final constInstances =
+        _parseConstInstances(File(constInstancesFile).readAsStringSync());
+
+    final file = File(dataFile);
+    if (dataFile.endsWith('.json')) {
+      final buffer = file.readAsStringSync();
+      final newBuffer = shrinkJson(buffer, constInstances);
+      final newFile = File(outputFile)..createSync(recursive: true);
+      newFile.writeAsStringSync(newBuffer);
+    } else {
+      throw ArgumentError('Not a valid Message file');
+    }
+  }
+
+  /// Shrink a json message file by de- and reserializing, keeping only the
+  /// message indices in [messagesToKeep].
+  String shrinkJson(String buffer, List<int> messagesToKeep) {
+    final sizeBefore = buffer.length;
+    final json = JsonDeserializer(buffer).deserialize(OldIntlObject());
+    final data = JsonSerializer(json.preamble.hasIds)
+        .serialize(
+          json.preamble.hash,
+          json.preamble.locale,
+          json.messages,
+          messagesToKeep,
+        )
+        .data;
+    final sizeAfter = data.length;
+    final change = (sizeBefore - sizeAfter) / sizeBefore;
+    final changeInPercent = (change * 100).toStringAsFixed(2);
+    print('Reduced size from $sizeBefore to $sizeAfter by $changeInPercent %');
+    return data;
+  }
+
+  /// Receive a file emitted by const_finder from the SDK, which has the
+  /// structure:
+  /// ```json
+  /// {
+  ///   "constantInstances": [
+  ///     {
+  ///       "index": 1,
+  ///       "_name": "constantNameOne"
+  ///     },
+  ///     {
+  ///       "index": 2,
+  ///       "_name": "constantNameTwo"
+  ///     },
+  ///     ...
+  ///   ],
+  ///   "nonConstantLocations": []
+  /// }
+  /// ```
+  List<int> _parseConstInstances(String fileContents) {
+    final decoded = jsonDecode(fileContents) as Map<String, dynamic>;
+    final instances = decoded['constantInstances'] as List;
+    return instances
+        .map((e) => e as Map<String, dynamic>)
+        .map((e) => e['index'] as int)
+        .toList();
+  }
+}