handle selection sort logic

Author: AhmedAbdoElhawary

lib/features/sorting/selection/view_model/selection_sort_notifier.dart

@@ -6,50 +6,88 @@ class SelectionSortNotifier extends SortingNotifier {
   @override
   Future<void> buildSort() async {
     final list = List<SortableItem>.from(state.list);
+    final values = list.map((e) => e.value).toList();
 
-    for (int i = 0; i < list.length - 1; i++) {
+    final steps = selectionSortSteps(values);
+
+    for (final step in steps) {
       if (operation != SortingEnum.played) return;
 
-      int minIndex = i;
+      switch (step.action) {
+        case SortingStatus.compared:
+          list[step.index1] = list[step.index1].copyWith(sortedStatus: SortingStatus.compared);
+          list[step.index2] = list[step.index2].copyWith(sortedStatus: SortingStatus.compared);
+          state = state.copyWith(list: list);
 
-      for (int j = i + 1; j < list.length; j++) {
-        if (operation != SortingEnum.played) return;
+          await Future.delayed(speedDuration);
 
-        list[minIndex] = list[minIndex].copyWith(sortedStatus: SortingStatus.compared);
-        list[j] = list[j].copyWith(sortedStatus: SortingStatus.compared);
-        state = state.copyWith(list: list);
-        await Future.delayed(speedDuration);
+          break;
 
-        if (list[j].value < list[minIndex].value) minIndex = j;
+        case SortingStatus.swapped:
+          list[step.index1] = list[step.index1].copyWith(sortedStatus: SortingStatus.swapped);
+          list[step.index2] = list[step.index2].copyWith(sortedStatus: SortingStatus.swapped);
+          state = state.copyWith(list: list);
 
-        list[j] = list[j].copyWith(sortedStatus: SortingStatus.unSorted);
-        list[minIndex] = list[minIndex].copyWith(sortedStatus: SortingStatus.unSorted);
-        state = state.copyWith(list: list);
-      }
+          await Future.delayed(speedDuration);
 
-      if (minIndex != i) {
-        list[minIndex] = list[minIndex].copyWith(sortedStatus: SortingStatus.swapped);
-        list[i] = list[i].copyWith(sortedStatus: SortingStatus.swapped);
-        state = state.copyWith(list: list);
-        await Future.delayed(speedDuration);
+          list.swap(step.index1, step.index2);
 
-        list.swap(i, minIndex);
+          final positions = Map<int, Offset>.from(state.positions);
+          final tempPosition = positions[list[step.index1].id]!;
+          positions[list[step.index1].id] = positions[list[step.index2].id]!;
+          positions[list[step.index2].id] = tempPosition;
 
-        final positions = Map<int, Offset>.from(state.positions);
-        final temp = positions[list[i].id]!;
-        positions[list[i].id] = positions[list[minIndex].id]!;
-        positions[list[minIndex].id] = temp;
+          state = state.copyWith(list: list, positions: positions);
+          break;
 
-        state = state.copyWith(list: list, positions: positions);
-        await Future.delayed(speedDuration);
+        case SortingStatus.unSorted:
+          list[step.index1] = list[step.index1].copyWith(sortedStatus: SortingStatus.unSorted);
+          list[step.index2] = list[step.index2].copyWith(sortedStatus: SortingStatus.unSorted);
+          state = state.copyWith(list: list);
+          break;
 
-        list[i] = list[i].copyWith(sortedStatus: SortingStatus.unSorted);
-        list[minIndex] = list[minIndex].copyWith(sortedStatus: SortingStatus.unSorted);
-        state = state.copyWith(list: list);
+        // i don't want to make it green while sorting and mark all of them at once as green at the end
+        case SortingStatus.sorted:
+        case SortingStatus.none:
+          list[step.index1] = list[step.index1].copyWith(sortedStatus: SortingStatus.none);
+          state = state.copyWith(list: list);
+          break;
       }
+
+      await Future.delayed(speedDuration);
     }
 
     await greenSortedItemsAsDone();
   }
 
+  List<SortingStep> selectionSortSteps(List<int> values) {
+    final steps = <SortingStep>[];
+    final arr = List<int>.from(values);
+
+    for (int i = 0; i < arr.length - 1; i++) {
+      int minIndex = i;
+
+      for (int j = i + 1; j < arr.length; j++) {
+        steps.add(SortingStep(index1: minIndex, index2: j, action: SortingStatus.compared)); // external
+
+        if (arr[j] < arr[minIndex]) {
+          // steps.add(SortingStep(index1: j, index2: j + 1, action: SortingStatus.swapped)); // external
+          minIndex = j;
+        }
+
+        // steps.add(SortingStep(index1: j, index2: j + 1, action: SortingStatus.unSorted)); // external
+      }
+
+      steps.add(SortingStep(index1: i, index2: minIndex, action: SortingStatus.swapped)); // external
+
+      final temp = arr[i];
+      arr[i] = arr[minIndex];
+      arr[minIndex] = temp;
+
+      // steps.add(SortingStep(
+      //     index1: arr.length - i - 1, index2: arr.length - i - 1, action: SortingStatus.sorted)); // external
+    }
+
+    return steps;
+  }
 }