class="kw">package com.hypixel.hytale.server.worldgen.climate.util;

class="kw">import com.hypixel.hytale.math.util.MathUtil;
class="kw">import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
class="kw">import it.unimi.dsi.fastutil.ints.IntArrayList;
class="kw">import it.unimi.dsi.fastutil.ints.Int2ObjectMap.Entry;
class="kw">import it.unimi.dsi.fastutil.objects.ObjectIterator;
class="kw">import java.util.Arrays;
class="kw">import java.util.PriorityQueue;
class="kw">import javax.annotation.Nonnull;

class="kw">public class DistanceTransform {
   class="kw">private class="kw">static class="kw">final IntArrayList EMPTY_LIST = new IntArrayList();
   class="kw">private class="kw">static class="kw">final int[] DX = new int[]{-1, 1, 0, 0, -1, -1, 1, 1};
   class="kw">private class="kw">static class="kw">final int[] DY = new int[]{0, 0, -1, 1, -1, 1, -1, 1};
   class="kw">private class="kw">static class="kw">final double[] COST = new double[]{1.0, 1.0, 1.0, 1.0, Math.sqrt(2.0), Math.sqrt(2.0), Math.sqrt(2.0), Math.sqrt(2.0)};

   class="kw">public DistanceTransform() {
   }

   class="kw">public class="kw">static void apply(@Nonnull IntMap var0, @Nonnull DoubleMap var1, double var2) {
      if (var2 <= 0.0) {
         throw new IllegalArgumentException("radius must be > 0");
      }

      int var4 = var0.width;
      int var5 = var0.height;
      int var6 = var4 * var5;
      Int2ObjectOpenHashMap var7 = new Int2ObjectOpenHashMap();
      Int2ObjectOpenHashMap var8 = new Int2ObjectOpenHashMap();

      for (int var9 = 0; var9 < var5; var9++) {
         for (int var10 = 0; var10 < var4; var10++) {
            int var11 = var0.index(var10, var9);
            int var12 = var0.at(var11);
            ((IntArrayList)var7.computeIfAbsent(var12, var0x -> new IntArrayList())).add(var11);

            for (int var13 = 0; var13 < 4; var13++) {
               int var14 = var10 + DX[var13];
               int var15 = var9 + DY[var13];
               if (var14 >= 0 && var14 < var4 && var15 >= 0 && var15 < var5) {
                  int var16 = var0.index(var14, var15);
                  if (var0.at(var16) != var12) {
                     ((IntArrayList)var8.computeIfAbsent(var12, var0x -> new IntArrayList())).add(var11);
                     break;
                  }
               }
            }
         }
      }

      double[] var27 = new double[var6];
      PriorityQueue var28 = new PriorityQueue<>(DistanceTransform.Node::sort);
      ObjectIterator var29 = var7.int2ObjectEntrySet().iterator();

      while (var29.hasNext()) {
         Entry var30 = (Entry<IntArrayList>)var29.next();
         int var31 = var30.getIntKey();
         IntArrayList var32 = (IntArrayList)var30.getValue();
         IntArrayList var33 = (IntArrayList)var8.getOrDefault(var31, EMPTY_LIST);
         if (var33.isEmpty()) {
            for (int var37 = 0; var37 < var32.size(); var37++) {
               var1.set(var32.getInt(var37), 1.0);
            }
         } else {
            Arrays.fill(var27, var2);

            for (int var34 = 0; var34 < var33.size(); var34++) {
               int var17 = var33.getInt(var34);
               var27[var17] = 0.0;
               var28.offer(new DistanceTransform.Node(var17, 0.0));
            }

            while (!var28.isEmpty()) {
               DistanceTransform.Node var35 = var28.poll();
               int var38 = var35.index;
               if (!(var35.distance > var27[var38])) {
                  int var18 = var38 % var4;
                  int var19 = var38 / var4;

                  for (int var20 = 0; var20 < DX.length; var20++) {
                     int var21 = var18 + DX[var20];
                     int var22 = var19 + DY[var20];
                     if (var21 >= 0 && var21 < var4 && var22 >= 0 && var22 < var5) {
                        int var23 = var0.index(var21, var22);
                        int var24 = var0.at(var23);
                        if (var24 == var31) {
                           double var25 = var35.distance + COST[var20];
                           if (var25 < var27[var23]) {
                              var27[var23] = var25;
                              var28.offer(new DistanceTransform.Node(var23, var25));
                           }
                        }
                     }
                  }
               }
            }

            for (int var36 = 0; var36 < var32.size(); var36++) {
               int var39 = var32.getInt(var36);
               double var40 = MathUtil.clamp(var27[var39], 0.0, var2);
               var1.set(var39, var40 / var2);
            }
         }
      }
   }

   class="kw">private record Node(int index, double distance) {
      class="kw">private Node {
      }

      class="kw">public class="kw">static int sort(DistanceTransform.Node var0, DistanceTransform.Node var1) {
         class="kw">return Double.compare(var0.distance, var1.distance);
      }
   }
}