Start adding merge strategy, closes #57

Author: CodeDoctorDE

api/lib/src/models/cell.dart

@@ -30,3 +30,41 @@ class BoardTile with BoardTileMappable {
 
   BoardTile(this.asset, this.tile);
 }
+
+@MappableClass()
+sealed class CellMergeStrategy {
+  const CellMergeStrategy();
+}
+
+@MappableClass()
+final class StackedCellMergeStrategy extends CellMergeStrategy {
+  final int visiblePercentage;
+  final bool reverse;
+
+  const StackedCellMergeStrategy({
+    this.visiblePercentage = 10,
+    this.reverse = false,
+  });
+}
+
+@MappableClass()
+final class DistributeCellMergeStrategy extends CellMergeStrategy {
+  final int maxCards;
+  final bool reverse;
+  final bool fillVariableSpace;
+
+  const DistributeCellMergeStrategy({
+    this.maxCards = 5,
+    this.reverse = false,
+    this.fillVariableSpace = true,
+  });
+}
+
+@MappableClass()
+enum CellMergeDirection { horizontal, vertical }
+
+@MappableClass()
+final class DirectionalCellMerge extends CellMergeStrategy {
+  final CellMergeDirection direction;
+  const DirectionalCellMerge(this.direction);
+}