feat: Add getLayerByName to SpriteFusionTilemapData (#3755)

Introduced a `getLayerByName` method to retrieve a layer by its name in
`SpriteFusionTilemapData`.

Author: ufrshubham

packages/flame_sprite_fusion/lib/src/sprite_fusion_tilemap_data.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:flame_sprite_fusion/flame_sprite_fusion.dart';
 
 /// A class that holds the data of the tilemap from a sprite fusion.
@@ -36,4 +37,12 @@ class SpriteFusionTilemapData {
           .toList(growable: false),
     );
   }
+
+  /// Gets a layer by its [name].
+  ///
+  /// Returns the first layer found with the given name.
+  /// For multiple layers with the same name, use [layers] property directly.
+  SpriteFusionLayerData? getLayerByName(String name) {
+    return layers.firstWhereOrNull((layer) => layer.name == name);
+  }
 }

packages/flame_sprite_fusion/pubspec.yaml

@@ -16,6 +16,7 @@ environment:
   flutter: ">=3.32.0"
 
 dependencies:
+  collection: ^1.19.1
   flame: ^1.33.0
   flutter:
     sdk: flutter

packages/flame_sprite_fusion/test/sprite_fusion_data_test.dart

@@ -234,5 +234,90 @@ void main() {
       expect(tileData.tileSize, map['tileSize']);
       expect(tileData.layers.length, 2);
     });
+
+    test('getLayerByName returns the correct layer', () {
+      final tilemapData = SpriteFusionTilemapData(
+        mapWidth: 10,
+        mapHeight: 10,
+        tileSize: 32,
+        layers: [
+          SpriteFusionLayerData(
+            name: 'background',
+            tiles: [],
+            collider: false,
+          ),
+          SpriteFusionLayerData(
+            name: 'foreground',
+            tiles: [],
+            collider: true,
+          ),
+        ],
+      );
+
+      final layer = tilemapData.getLayerByName('foreground');
+
+      expect(layer, isNotNull);
+      expect(layer?.name, 'foreground');
+      expect(layer?.collider, true);
+    });
+
+    test('getLayerByName returns null for non-existent layer', () {
+      final tilemapData = SpriteFusionTilemapData(
+        mapWidth: 10,
+        mapHeight: 10,
+        tileSize: 32,
+        layers: [
+          SpriteFusionLayerData(
+            name: 'background',
+            tiles: [],
+            collider: false,
+          ),
+        ],
+      );
+
+      final layer = tilemapData.getLayerByName('nonExistent');
+
+      expect(layer, isNull);
+    });
+
+    test('getLayerByName returns first layer when multiple have same name', () {
+      final tilemapData = SpriteFusionTilemapData(
+        mapWidth: 10,
+        mapHeight: 10,
+        tileSize: 32,
+        layers: [
+          SpriteFusionLayerData(
+            name: 'duplicate',
+            tiles: [SpriteFusionTileData(id: 1, x: 0, y: 0)],
+            collider: false,
+          ),
+          SpriteFusionLayerData(
+            name: 'duplicate',
+            tiles: [SpriteFusionTileData(id: 2, x: 1, y: 1)],
+            collider: true,
+          ),
+        ],
+      );
+
+      final layer = tilemapData.getLayerByName('duplicate');
+
+      expect(layer, isNotNull);
+      expect(layer?.name, 'duplicate');
+      expect(layer?.collider, false);
+      expect(layer?.tiles.first.id, 1);
+    });
+
+    test('getLayerByName returns null for empty layers list', () {
+      final tilemapData = SpriteFusionTilemapData(
+        mapWidth: 10,
+        mapHeight: 10,
+        tileSize: 32,
+        layers: [],
+      );
+
+      final layer = tilemapData.getLayerByName('anyLayer');
+
+      expect(layer, isNull);
+    });
   });
 }