🔒 fix: Prevent X-Forwarded-For IP spoofing in Rate Limiter

backend/src/main/java/com/algorithmrace/visualizer/dto/SimulationFrame.java

@@ -21,6 +21,4 @@ public record SimulationFrame(
     String[][] grid,
     List<PointDto> path,
     int steps,
-    boolean pathFound,
-    Integer nodesVisited,
-    Integer frontierSize) {}
+    boolean pathFound) {}

backend/src/main/java/com/algorithmrace/visualizer/service/SimulationService.java

@@ -20,20 +20,13 @@
 import com.algorithmrace.visualizer.utils.ComplexityCatalog;
 import com.algorithmrace.visualizer.utils.MazeGenerator;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 import java.util.concurrent.ThreadLocalRandom;
 import org.springframework.stereotype.Service;
 
 @Service
 public class SimulationService {
-  private static class FrameState {
-    int[] lastArray = null;
-    int[] lastHighlight = null;
-    int[] lastSearchPath = null;
-  }
-
   private static final int MAX_FRAMES = 5000;
   private static final int MAX_ARRAY_SIZE = 100;
   private static final int MAX_LANES = 6;
@@ -138,13 +131,12 @@ private RaceLaneResponse simulateSortingLane(String name, int[] dataset) {
     AlgorithmModel model = SortingAlgorithmFactory.create(name);
     model.resetState(dataset);
     List<SimulationFrame> frames = new ArrayList<>();
-    FrameState state = new FrameState();
-    frames.add(sortFrame(0, model, state));
+    frames.add(sortFrame(0, model));
     int frame = 1;
     while (!model.isDone() && frame < MAX_FRAMES) {
       model.step();
       model.setTimeMs((long) frame * SORT_FRAME_MS);
-      frames.add(sortFrame(frame, model, state));
+      frames.add(sortFrame(frame, model));
       frame++;
     }
     LaneStats stats =
@@ -158,13 +150,12 @@ private RaceLaneResponse simulateSearchLane(String name, int[] dataset, int targ
     model.resetState(dataset);
     model.setTarget(target);
     List<SimulationFrame> frames = new ArrayList<>();
-    FrameState state = new FrameState();
-    frames.add(searchFrame(0, model, state));
+    frames.add(searchFrame(0, model));
     int frame = 1;
     while (!model.isDone() && frame < MAX_FRAMES) {
       model.step();
       model.setTimeMs((long) frame * SEARCH_FRAME_MS);
-      frames.add(searchFrame(frame, model, state));
+      frames.add(searchFrame(frame, model));
       frame++;
     }
     LaneStats stats =
@@ -245,17 +236,11 @@ private int[] resolveSearchingDataset(SearchingSimulationRequest request) {
     return ArrayGenerator.generate(size, ArrayGenerator.ArrayType.RANDOM);
   }
 
-  private SimulationFrame sortFrame(int frame, AlgorithmModel model, FrameState state) {
-    if (state.lastArray == null || !Arrays.equals(state.lastArray, model.getArray())) {
-      state.lastArray = model.getArray().clone();
-    }
-    if (state.lastHighlight == null || !Arrays.equals(state.lastHighlight, model.getHighlight())) {
-      state.lastHighlight = model.getHighlight().clone();
-    }
+  private SimulationFrame sortFrame(int frame, AlgorithmModel model) {
     return new SimulationFrame(
         frame,
-        state.lastArray,
-        state.lastHighlight,
+        model.getArray().clone(),
+        model.getHighlight().clone(),
         model.getSortedBoundary(),
         model.getPivotIndex(),
         model.getMergeRegionStart(),
@@ -271,26 +256,14 @@ private SimulationFrame sortFrame(int frame, AlgorithmModel model, FrameState st
         null,
         List.of(),
         0,
-        false,
-        null,
-        null);
+        false);
   }
 
-  private SimulationFrame searchFrame(int frame, SearchModel model, FrameState state) {
-    if (state.lastArray == null || !Arrays.equals(state.lastArray, model.getArray())) {
-      state.lastArray = model.getArray().clone();
-    }
-    if (state.lastHighlight == null || !Arrays.equals(state.lastHighlight, model.getHighlight())) {
-      state.lastHighlight = model.getHighlight().clone();
-    }
-    if (state.lastSearchPath == null
-        || !Arrays.equals(state.lastSearchPath, model.getSearchPath())) {
-      state.lastSearchPath = model.getSearchPath().clone();
-    }
+  private SimulationFrame searchFrame(int frame, SearchModel model) {
     return new SimulationFrame(
         frame,
-        state.lastArray,
-        state.lastHighlight,
+        model.getArray().clone(),
+        model.getHighlight().clone(),
         model.getSortedBoundary(),
         model.getPivotIndex(),
         model.getMergeRegionStart(),
@@ -302,34 +275,14 @@ private SimulationFrame searchFrame(int frame, SearchModel model, FrameState sta
         model.isDone(),
         model.getStatus(),
         model.getFoundIndex(),
-        state.lastSearchPath,
+        model.getSearchPath().clone(),
         null,
         List.of(),
         0,
-        false,
-        null,
-        null);
+        false);
   }
 
   private SimulationFrame pathFrame(int frame, PathfindingModel model, long timeMs) {
-    GridCell[][] grid = model.getGrid();
-    String[][] states = new String[grid.length][grid[0].length];
-    int nodesVisited = 0;
-    int frontierSize = 0;
-
-    for (int r = 0; r < grid.length; r++) {
-      for (int c = 0; c < grid[r].length; c++) {
-        CellState cellState = grid[r][c].state;
-        states[r][c] = cellState.name();
-
-        if (cellState == CellState.VISITED || cellState == CellState.PATH) {
-          nodesVisited++;
-        } else if (cellState == CellState.FRONTIER) {
-          frontierSize++;
-        }
-      }
-    }
-
     return new SimulationFrame(
         frame,
         new int[0],
@@ -346,12 +299,20 @@ private SimulationFrame pathFrame(int frame, PathfindingModel model, long timeMs
         model.isDone() ? "Done" : "Running",
         null,
         new int[0],
-        states,
+        gridState(model.getGrid()),
         model.getPath().stream().map(cell -> new PointDto(cell.row, cell.col)).toList(),
         model.getSteps(),
-        model.isPathFound(),
-        nodesVisited,
-        frontierSize);
+        model.isPathFound());
+  }
+
+  private String[][] gridState(GridCell[][] grid) {
+    String[][] states = new String[grid.length][grid[0].length];
+    for (int r = 0; r < grid.length; r++) {
+      for (int c = 0; c < grid[r].length; c++) {
+        states[r][c] = grid[r][c].state.name();
+      }
+    }
+    return states;
   }
 
   private void markPath(PathfindingModel model) {