package net.vulkanmod.gl;

import it.unimi.dsi.fastutil.ints.Int2ReferenceOpenHashMap;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import org.lwjgl.system.MemoryUtil;

public class VkGlBuffer {
   private static int ID_COUNTER = 1;
   private static final Int2ReferenceOpenHashMap<VkGlBuffer> map = new Int2ReferenceOpenHashMap();
   private static int boundId = 0;
   private static VkGlBuffer boundBuffer;
   private static VkGlBuffer arrayBufferBound;
   private static VkGlBuffer pixelPackBufferBound;
   private static VkGlBuffer pixelUnpackBufferBound;
   int id;
   int target;
   ByteBuffer data;

   public static int glGenBuffers() {
      int id = ID_COUNTER;
      map.put(id, new VkGlBuffer(id));
      ++ID_COUNTER;
      return id;
   }

   public static void glBindBuffer(int target, int buffer) {
      boundId = buffer;
      VkGlBuffer glBuffer = (VkGlBuffer)map.get(buffer);
      if (buffer > 0 && glBuffer == null) {
         throw new NullPointerException("bound texture is null");
      } else {
         if (glBuffer != null) {
            glBuffer.target = target;
         }

         switch (target) {
            case 34962 -> arrayBufferBound = glBuffer;
            case 35051 -> pixelPackBufferBound = glBuffer;
            case 35052 -> pixelUnpackBufferBound = glBuffer;
            default -> throw new IllegalStateException("Unexpected value: " + target);
         }

      }
   }

   public static void glBufferData(int target, ByteBuffer byteBuffer, int usage) {
      checkTarget(target);
      pixelUnpackBufferBound = boundBuffer;
   }

   public static void glBufferData(int target, long size, int usage) {
      VkGlBuffer var10000;
      switch (target) {
         case 35051 -> var10000 = pixelPackBufferBound;
         case 35052 -> var10000 = pixelUnpackBufferBound;
         default -> throw new IllegalStateException("Unexpected value: " + target);
      }

      VkGlBuffer buffer = var10000;
      buffer.allocate((int)size);
   }

   public static ByteBuffer glMapBuffer(int target, int access) {
      VkGlBuffer var10000;
      switch (target) {
         case 35051 -> var10000 = pixelPackBufferBound;
         case 35052 -> var10000 = pixelUnpackBufferBound;
         default -> throw new IllegalStateException("Unexpected value: " + target);
      }

      VkGlBuffer buffer = var10000;
      ByteBuffer mappedBuffer = buffer.data;
      mappedBuffer.position(0);
      return mappedBuffer;
   }

   public static boolean glUnmapBuffer(int i) {
      return true;
   }

   public static void glDeleteBuffers(IntBuffer intBuffer) {
      for(int i = intBuffer.position(); i < intBuffer.limit(); ++i) {
         glDeleteBuffers(intBuffer.get(i));
      }

   }

   public static void glDeleteBuffers(int id) {
      VkGlBuffer buffer = (VkGlBuffer)map.remove(id);
      if (buffer != null) {
         buffer.freeData();
      }

   }

   public static VkGlBuffer getPixelUnpackBufferBound() {
      return pixelUnpackBufferBound;
   }

   public static VkGlBuffer getPixelPackBufferBound() {
      return pixelPackBufferBound;
   }

   private static void checkTarget(int target) {
      if (target != 35052 && target != 35051) {
         throw new IllegalArgumentException("target %d not supported".formatted(target));
      }
   }

   public VkGlBuffer(int id) {
      this.id = id;
   }

   private void allocate(int size) {
      if (this.data != null) {
         this.freeData();
      }

      this.data = MemoryUtil.memAlloc(size);
   }

   private ByteBuffer getData() {
      return this.data;
   }

   private void freeData() {
      MemoryUtil.memFree(this.data);
   }
}