package com.hypixel.hytale.builtin.hytalegenerator.newsystem.bufferbundle;

import com.hypixel.hytale.builtin.hytalegenerator.bounds.Bounds3i;
import com.hypixel.hytale.builtin.hytalegenerator.newsystem.GridUtils;
import com.hypixel.hytale.builtin.hytalegenerator.newsystem.bufferbundle.buffers.NBuffer;
import com.hypixel.hytale.builtin.hytalegenerator.newsystem.bufferbundle.buffers.type.NBufferType;
import com.hypixel.hytale.builtin.hytalegenerator.newsystem.performanceinstruments.MemInstrument;
import com.hypixel.hytale.math.vector.Vector3i;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.annotation.Nonnull;

public class NBufferBundle implements MemInstrument {
   private final Map<NBufferType, NBufferBundle.Grid> grids = new HashMap<>();

   @Nonnull
   public NBufferBundle.Grid createGrid(@Nonnull NBufferType bufferType, int capacity) {
      assert capacity >= 0;

      assert !this.grids.containsKey(bufferType);

      assert !this.existingGridHasBufferTypeIndex(bufferType.index);

      NBufferBundle.Grid grid = new NBufferBundle.Grid(bufferType, capacity);
      this.grids.put(bufferType, grid);
      return grid;
   }

   @Nonnull
   public NBufferBundle.Access createBufferAccess(@Nonnull NBufferType bufferType, @Nonnull Bounds3i bounds_bufferGrid) {
      assert bounds_bufferGrid.isCorrect();

      return this.getGrid(bufferType).openAccess(bounds_bufferGrid);
   }

   public void closeALlAccesses() {
      for (NBufferBundle.Grid grid : this.grids.values()) {
         grid.closeAllAccesses();
      }
   }

   @Nonnull
   public NBufferBundle.Grid getGrid(@Nonnull NBufferType contentType) {
      NBufferBundle.Grid grid = this.grids.get(contentType);

      assert grid != null;

      return grid;
   }

   @Nonnull
   @Override
   public MemInstrument.Report getMemoryUsage() {
      long size_bytes = 16L;

      for (Entry<NBufferType, NBufferBundle.Grid> entry : this.grids.entrySet()) {
         size_bytes += entry.getValue().getMemoryUsage().size_bytes();
      }

      return new MemInstrument.Report(size_bytes);
   }

   private boolean existingGridHasBufferTypeIndex(int bufferTypeIndex) {
      for (NBufferBundle.Grid grid : this.grids.values()) {
         if (grid.bufferType.index == bufferTypeIndex) {
            return true;
         }
      }

      return false;
   }

   @Nonnull
   public NBufferBundle.MemoryReport createMemoryReport() {
      NBufferBundle.MemoryReport memoryReport = new NBufferBundle.MemoryReport();

      for (NBufferBundle.Grid grid : this.grids.values()) {
         MemInstrument.Report gridUsage = grid.getMemoryUsage();
         int gridBufferCount = grid.buffers.size();
         memoryReport.gridEntries.add(new NBufferBundle.MemoryReport.GridEntry(gridUsage, gridBufferCount, grid.bufferType));
      }

      return memoryReport;
   }

   public static class Access implements MemInstrument {
      private final NBufferBundle.Grid grid;
      private final Bounds3i bounds_bufferGrid;
      private final NBufferBundle.Grid.TrackedBuffer[] buffers;
      private boolean isClosed;

      private Access(@Nonnull NBufferBundle.Grid grid, @Nonnull Bounds3i bounds_bufferGrid) {
         assert bounds_bufferGrid.isCorrect();

         this.grid = grid;
         this.bounds_bufferGrid = bounds_bufferGrid.clone();
         this.bounds_bufferGrid.min.y = 0;
         this.bounds_bufferGrid.max.y = 40;
         Vector3i boundsSize_bufferGrid = this.bounds_bufferGrid.getSize();
         int bufferCount = boundsSize_bufferGrid.x * boundsSize_bufferGrid.y * boundsSize_bufferGrid.z;
         this.buffers = new NBufferBundle.Grid.TrackedBuffer[bufferCount];
         this.isClosed = false;
      }

      @Nonnull
      public NBufferBundle.Access.View createView(@Nonnull Bounds3i viewBounds_bufferGrid) {
         assert this.bounds_bufferGrid.contains(viewBounds_bufferGrid);

         return new NBufferBundle.Access.View(this, viewBounds_bufferGrid);
      }

      @Nonnull
      public NBufferBundle.Access.View createView() {
         return new NBufferBundle.Access.View(this, this.bounds_bufferGrid);
      }

      @Nonnull
      public NBufferBundle.Grid.TrackedBuffer getBuffer(@Nonnull Vector3i position_bufferGrid) {
         assert !this.isClosed;

         assert this.bounds_bufferGrid.contains(position_bufferGrid);

         int index = GridUtils.toIndexFromPositionYXZ(position_bufferGrid, this.bounds_bufferGrid);
         return this.buffers[index];
      }

      @Nonnull
      public Bounds3i getBounds_bufferGrid() {
         return this.bounds_bufferGrid.clone();
      }

      public void close() {
         this.grid.accessors.remove(this);
         this.isClosed = true;
         Arrays.fill(this.buffers, null);
      }

      @Nonnull
      @Override
      public MemInstrument.Report getMemoryUsage() {
         long size_bytes = 8L + this.bounds_bufferGrid.getMemoryUsage().size_bytes();
         return new MemInstrument.Report(size_bytes);
      }

      private void loadGrid() {
         assert !this.isClosed;

         assert this.bounds_bufferGrid.min.y == 0 && this.bounds_bufferGrid.max.y == 40;

         Vector3i position_bufferGrid = this.bounds_bufferGrid.min.clone();
         position_bufferGrid.setY(0);
         NBufferBundle.Grid.TrackedBuffer[] trackedBuffersOutput = new NBufferBundle.Grid.TrackedBuffer[40];

         for (position_bufferGrid.z = this.bounds_bufferGrid.min.z; position_bufferGrid.z < this.bounds_bufferGrid.max.z; position_bufferGrid.z++) {
            for (position_bufferGrid.x = this.bounds_bufferGrid.min.x; position_bufferGrid.x < this.bounds_bufferGrid.max.x; position_bufferGrid.x++) {
               position_bufferGrid.setY(0);
               this.grid.ensureBufferColumnExists(position_bufferGrid, trackedBuffersOutput);
               int i = 0;

               for (position_bufferGrid.y = 0; position_bufferGrid.y < 40; position_bufferGrid.y++) {
                  position_bufferGrid.dropHash();
                  int index = GridUtils.toIndexFromPositionYXZ(position_bufferGrid, this.bounds_bufferGrid);
                  this.buffers[index] = trackedBuffersOutput[i];
                  i++;
               }
            }
         }
      }

      public static class View {
         private final NBufferBundle.Access access;
         private final Bounds3i bounds_bufferGrid;

         private View(@Nonnull NBufferBundle.Access access, @Nonnull Bounds3i bounds_bufferGrid) {
            assert access.bounds_bufferGrid.contains(bounds_bufferGrid);

            this.access = access;
            this.bounds_bufferGrid = bounds_bufferGrid;
         }

         @Nonnull
         public NBufferBundle.Grid.TrackedBuffer getBuffer(@Nonnull Vector3i position_bufferGrid) {
            assert !this.access.isClosed;

            assert this.bounds_bufferGrid.contains(position_bufferGrid);

            return this.access.getBuffer(position_bufferGrid);
         }

         @Nonnull
         public Bounds3i getBounds_bufferGrid() {
            return this.bounds_bufferGrid.clone();
         }
      }
   }

   public static class Grid implements MemInstrument {
      private final NBufferType bufferType;
      private final Map<Vector3i, NBufferBundle.Grid.TrackedBuffer> buffers;
      private final Deque<Vector3i> oldestColumnEntryDeque_bufferGrid;
      private final int capacity;
      private final List<NBufferBundle.Access> accessors;

      private Grid(@Nonnull NBufferType bufferType, int capacity) {
         this.bufferType = bufferType;
         this.buffers = new HashMap<>();
         this.oldestColumnEntryDeque_bufferGrid = new ArrayDeque<>();
         this.capacity = Math.max(capacity, 0);
         this.accessors = new ArrayList<>();
      }

      @Nonnull
      public NBufferType getBufferType() {
         return this.bufferType;
      }

      @Nonnull
      public NBufferBundle.Access openAccess(@Nonnull Bounds3i bounds_bufferGrid) {
         NBufferBundle.Access access = new NBufferBundle.Access(this, bounds_bufferGrid);
         this.accessors.add(access);
         access.loadGrid();
         return access;
      }

      public void closeAllAccesses() {
         for (int i = this.accessors.size() - 1; i >= 0; i--) {
            NBufferBundle.Access access = this.accessors.get(i);
            access.close();
         }
      }

      @Nonnull
      @Override
      public MemInstrument.Report getMemoryUsage() {
         long size_bytes = 68L;
         size_bytes += 28L * this.buffers.size();
         size_bytes += 4L * this.buffers.size();
         size_bytes += 32L * this.buffers.size();

         for (NBufferBundle.Grid.TrackedBuffer buffer : this.buffers.values()) {
            size_bytes += buffer.getMemoryUsage().size_bytes();
         }

         size_bytes += 8L * this.accessors.size();

         for (NBufferBundle.Access access : this.accessors) {
            size_bytes += access.getMemoryUsage().size_bytes();
         }

         return new MemInstrument.Report(size_bytes);
      }

      private void ensureBufferColumnExists(@Nonnull Vector3i position_bufferGrid, @Nonnull NBufferBundle.Grid.TrackedBuffer[] trackedBuffersOut) {
         assert position_bufferGrid.y == 0;

         assert trackedBuffersOut.length == 40;

         NBufferBundle.Grid.TrackedBuffer buffer = this.buffers.get(position_bufferGrid);
         if (buffer == null) {
            this.createBufferColumn(position_bufferGrid, trackedBuffersOut);
         } else {
            Vector3i positionClone_bufferGrid = new Vector3i(position_bufferGrid);

            for (int i = 0; i < trackedBuffersOut.length; i++) {
               positionClone_bufferGrid.setY(i + 0);
               trackedBuffersOut[i] = this.buffers.get(positionClone_bufferGrid);

               assert trackedBuffersOut[i] != null;
            }
         }
      }

      private void createBufferColumn(@Nonnull Vector3i position_bufferGrid, @Nonnull NBufferBundle.Grid.TrackedBuffer[] trackedBuffersOut) {
         assert !this.buffers.containsKey(position_bufferGrid);

         assert trackedBuffersOut.length == 40;

         this.tryTrimSurplus(40);
         int i = 0;

         for (int y = 0; y < 40; y++) {
            Vector3i finalPosition_bufferGrid = new Vector3i(position_bufferGrid.x, y, position_bufferGrid.z);
            NBufferBundle.Tracker tracker = new NBufferBundle.Tracker();
            NBuffer buffer = this.bufferType.bufferSupplier.get();

            assert this.bufferType.isValid(buffer);

            trackedBuffersOut[i] = new NBufferBundle.Grid.TrackedBuffer(tracker, buffer);
            this.buffers.put(finalPosition_bufferGrid, trackedBuffersOut[i]);
            i++;
         }

         Vector3i tilePosition_bufferGrid = new Vector3i(position_bufferGrid.x, 0, position_bufferGrid.z);
         this.oldestColumnEntryDeque_bufferGrid.addLast(tilePosition_bufferGrid);
      }

      private void tryTrimSurplus(int extraRoom) {
         int surplusCount = Math.max(0, this.buffers.size() - this.capacity - extraRoom);
         int surplusColumnsCount = surplusCount == 0 ? 0 : surplusCount / 40 + 1;

         for (int i = 0; i < surplusColumnsCount; i++) {
            if (!this.destroyOldestBufferColumn()) {
               return;
            }
         }
      }

      private boolean destroyOldestBufferColumn() {
         assert !this.oldestColumnEntryDeque_bufferGrid.isEmpty();

         for (int i = 0; i < this.oldestColumnEntryDeque_bufferGrid.size(); i++) {
            Vector3i oldest_bufferGrid = this.oldestColumnEntryDeque_bufferGrid.removeFirst();
            if (!this.isBufferColumnInAccess(oldest_bufferGrid)) {
               this.removeBufferColumn(oldest_bufferGrid);
               return true;
            }

            this.oldestColumnEntryDeque_bufferGrid.addLast(oldest_bufferGrid);
         }

         return false;
      }

      private void removeBufferColumn(@Nonnull Vector3i position_bufferGrid) {
         assert position_bufferGrid.y == 0;

         Vector3i removalPosition_bufferGrid = new Vector3i(position_bufferGrid);

         for (int y = 0; y < 40; y++) {
            removalPosition_bufferGrid.setY(y);
            this.buffers.remove(removalPosition_bufferGrid);
         }
      }

      private boolean isBufferColumnInAccess(@Nonnull Vector3i position_bufferGrid) {
         assert position_bufferGrid.y == 0;

         for (NBufferBundle.Access access : this.accessors) {
            if (access.bounds_bufferGrid.contains(position_bufferGrid)) {
               return true;
            }
         }

         return false;
      }

      public record TrackedBuffer(@Nonnull NBufferBundle.Tracker tracker, @Nonnull NBuffer buffer) implements MemInstrument {
         @Nonnull
         @Override
         public MemInstrument.Report getMemoryUsage() {
            long size_bytes = 16L + this.tracker.getMemoryUsage().size_bytes() + this.buffer.getMemoryUsage().size_bytes();
            return new MemInstrument.Report(size_bytes);
         }
      }
   }

   public static class MemoryReport {
      public final List<NBufferBundle.MemoryReport.GridEntry> gridEntries = new ArrayList<>();

      @Nonnull
      @Override
      public String toString() {
         this.gridEntries.sort((o1, o2) -> {
            if (o1.bufferType().index > o2.bufferType().index) {
               return 1;
            } else {
               return o1.bufferType().index < o2.bufferType().index ? -1 : 0;
            }
         });
         StringBuilder builder = new StringBuilder();
         long total_mb = 0L;

         for (NBufferBundle.MemoryReport.GridEntry entry : this.gridEntries) {
            total_mb += entry.report.size_bytes();
         }

         total_mb /= 1000000L;
         builder.append("Memory Usage Report\n");
         builder.append("Buffers Memory Usage: ").append(total_mb).append(" mb\n");

         for (NBufferBundle.MemoryReport.GridEntry entry : this.gridEntries) {
            builder.append(entry.toString(1));
         }

         return builder.toString();
      }

      public record GridEntry(MemInstrument.Report report, int bufferCount, @Nonnull NBufferType bufferType) {
         @Nonnull
         public String toString(int indentation) {
            long size_mb = this.report.size_bytes() / 1000000L;
            StringBuilder builder = new StringBuilder();
            builder.append("\t".repeat(indentation)).append(this.bufferType.name + " Grid (Index ").append(this.bufferType().index).append("):\n");
            builder.append("\t".repeat(indentation + 1)).append("Memory Footprint: ").append(size_mb).append(" mb\n");
            builder.append("\t".repeat(indentation + 1)).append("Buffer Count: ").append(this.bufferCount).append("\n");
            return builder.toString();
         }
      }
   }

   public static class Tracker implements MemInstrument {
      public final int INITIAL_STAGE_INDEX = -1;
      public int stageIndex = -1;

      @Nonnull
      @Override
      public MemInstrument.Report getMemoryUsage() {
         return new MemInstrument.Report(4L);
      }
   }
}