package com.hypixel.hytale.protocol.packets.setup;

import com.hypixel.hytale.protocol.Asset;
import com.hypixel.hytale.protocol.Packet;
import com.hypixel.hytale.protocol.io.ProtocolException;
import com.hypixel.hytale.protocol.io.ValidationResult;
import com.hypixel.hytale.protocol.io.VarInt;
import io.netty.buffer.ByteBuf;
import java.util.Arrays;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;

public class WorldSettings implements Packet {
   public static final int PACKET_ID = 20;
   public static final boolean IS_COMPRESSED = true;
   public static final int NULLABLE_BIT_FIELD_SIZE = 1;
   public static final int FIXED_BLOCK_SIZE = 5;
   public static final int VARIABLE_FIELD_COUNT = 1;
   public static final int VARIABLE_BLOCK_START = 5;
   public static final int MAX_SIZE = 1677721600;
   public int worldHeight;
   @Nullable
   public Asset[] requiredAssets;

   @Override
   public int getId() {
      return 20;
   }

   public WorldSettings() {
   }

   public WorldSettings(int worldHeight, @Nullable Asset[] requiredAssets) {
      this.worldHeight = worldHeight;
      this.requiredAssets = requiredAssets;
   }

   public WorldSettings(@Nonnull WorldSettings other) {
      this.worldHeight = other.worldHeight;
      this.requiredAssets = other.requiredAssets;
   }

   @Nonnull
   public static WorldSettings deserialize(@Nonnull ByteBuf buf, int offset) {
      WorldSettings obj = new WorldSettings();
      byte nullBits = buf.getByte(offset);
      obj.worldHeight = buf.getIntLE(offset + 1);
      int pos = offset + 5;
      if ((nullBits & 1) != 0) {
         int requiredAssetsCount = VarInt.peek(buf, pos);
         if (requiredAssetsCount < 0) {
            throw ProtocolException.negativeLength("RequiredAssets", requiredAssetsCount);
         }

         if (requiredAssetsCount > 4096000) {
            throw ProtocolException.arrayTooLong("RequiredAssets", requiredAssetsCount, 4096000);
         }

         int requiredAssetsVarLen = VarInt.size(requiredAssetsCount);
         if (pos + requiredAssetsVarLen + requiredAssetsCount * 64L > buf.readableBytes()) {
            throw ProtocolException.bufferTooSmall("RequiredAssets", pos + requiredAssetsVarLen + requiredAssetsCount * 64, buf.readableBytes());
         }

         pos += requiredAssetsVarLen;
         obj.requiredAssets = new Asset[requiredAssetsCount];

         for (int i = 0; i < requiredAssetsCount; i++) {
            obj.requiredAssets[i] = Asset.deserialize(buf, pos);
            pos += Asset.computeBytesConsumed(buf, pos);
         }
      }

      return obj;
   }

   public static int computeBytesConsumed(@Nonnull ByteBuf buf, int offset) {
      byte nullBits = buf.getByte(offset);
      int pos = offset + 5;
      if ((nullBits & 1) != 0) {
         int arrLen = VarInt.peek(buf, pos);
         pos += VarInt.length(buf, pos);

         for (int i = 0; i < arrLen; i++) {
            pos += Asset.computeBytesConsumed(buf, pos);
         }
      }

      return pos - offset;
   }

   @Override
   public void serialize(@Nonnull ByteBuf buf) {
      byte nullBits = 0;
      if (this.requiredAssets != null) {
         nullBits = (byte)(nullBits | 1);
      }

      buf.writeByte(nullBits);
      buf.writeIntLE(this.worldHeight);
      if (this.requiredAssets != null) {
         if (this.requiredAssets.length > 4096000) {
            throw ProtocolException.arrayTooLong("RequiredAssets", this.requiredAssets.length, 4096000);
         }

         VarInt.write(buf, this.requiredAssets.length);

         for (Asset item : this.requiredAssets) {
            item.serialize(buf);
         }
      }
   }

   @Override
   public int computeSize() {
      int size = 5;
      if (this.requiredAssets != null) {
         int requiredAssetsSize = 0;

         for (Asset elem : this.requiredAssets) {
            requiredAssetsSize += elem.computeSize();
         }

         size += VarInt.size(this.requiredAssets.length) + requiredAssetsSize;
      }

      return size;
   }

   public static ValidationResult validateStructure(@Nonnull ByteBuf buffer, int offset) {
      if (buffer.readableBytes() - offset < 5) {
         return ValidationResult.error("Buffer too small: expected at least 5 bytes");
      } else {
         byte nullBits = buffer.getByte(offset);
         int pos = offset + 5;
         if ((nullBits & 1) != 0) {
            int requiredAssetsCount = VarInt.peek(buffer, pos);
            if (requiredAssetsCount < 0) {
               return ValidationResult.error("Invalid array count for RequiredAssets");
            }

            if (requiredAssetsCount > 4096000) {
               return ValidationResult.error("RequiredAssets exceeds max length 4096000");
            }

            pos += VarInt.length(buffer, pos);

            for (int i = 0; i < requiredAssetsCount; i++) {
               ValidationResult structResult = Asset.validateStructure(buffer, pos);
               if (!structResult.isValid()) {
                  return ValidationResult.error("Invalid Asset in RequiredAssets[" + i + "]: " + structResult.error());
               }

               pos += Asset.computeBytesConsumed(buffer, pos);
            }
         }

         return ValidationResult.OK;
      }
   }

   public WorldSettings clone() {
      WorldSettings copy = new WorldSettings();
      copy.worldHeight = this.worldHeight;
      copy.requiredAssets = this.requiredAssets != null ? Arrays.stream(this.requiredAssets).map(e -> e.clone()).toArray(Asset[]::new) : null;
      return copy;
   }

   @Override
   public boolean equals(Object obj) {
      if (this == obj) {
         return true;
      } else {
         return !(obj instanceof WorldSettings other)
            ? false
            : this.worldHeight == other.worldHeight && Arrays.equals((Object[])this.requiredAssets, (Object[])other.requiredAssets);
      }
   }

   @Override
   public int hashCode() {
      int result = 1;
      result = 31 * result + Integer.hashCode(this.worldHeight);
      return 31 * result + Arrays.hashCode((Object[])this.requiredAssets);
   }
}