From 78755b0e9a89e651ce8d16c9c6f1c099de18579f Mon Sep 17 00:00:00 2001
From: Auxilor <william.favierparsons1@gmail.com>
Date: Thu, 7 Oct 2021 14:34:40 +0100
Subject: [PATCH] (Hopefully) massively optimized display (PacketWindowItems)
 with DisplayFrame.kt

---
 .../proxy/v1_16_R3/fast/NMSFastItemStack.kt   | 12 ++++++++
 .../proxy/v1_17_R1/fast/NMSFastItemStack.kt   | 13 +++++++++
 .../eco/spigot/display/PacketWindowItems.kt   | 24 ++++++++++++----
 .../eco/spigot/display/frame/DisplayFrame.kt  | 28 +++++++++++++++++++
 4 files changed, 71 insertions(+), 6 deletions(-)
 create mode 100644 eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/frame/DisplayFrame.kt

diff --git a/eco-core/core-nms/v1_16_R3/src/main/kotlin/com/willfp/eco/proxy/v1_16_R3/fast/NMSFastItemStack.kt b/eco-core/core-nms/v1_16_R3/src/main/kotlin/com/willfp/eco/proxy/v1_16_R3/fast/NMSFastItemStack.kt
index c53e79d5..fe0f4293 100644
--- a/eco-core/core-nms/v1_16_R3/src/main/kotlin/com/willfp/eco/proxy/v1_16_R3/fast/NMSFastItemStack.kt
+++ b/eco-core/core-nms/v1_16_R3/src/main/kotlin/com/willfp/eco/proxy/v1_16_R3/fast/NMSFastItemStack.kt
@@ -150,6 +150,18 @@ class NMSFastItemStack(itemStack: org.bukkit.inventory.ItemStack) : EcoFastItemS
         handle.repairCost = cost
     }
 
+    override fun equals(other: Any?): Boolean {
+        if (other !is NMSFastItemStack) {
+            return false
+        }
+
+        return other.hashCode() == this.hashCode()
+    }
+
+    override fun hashCode(): Int {
+        return handle.tag.hashCode() * 31 + Item.getId(handle.item)
+    }
+
     private fun apply() {
         if (bukkit !is CraftItemStack) {
             bukkit.itemMeta = CraftItemStack.asCraftMirror(handle).itemMeta
diff --git a/eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/proxy/v1_17_R1/fast/NMSFastItemStack.kt b/eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/proxy/v1_17_R1/fast/NMSFastItemStack.kt
index e297c310..0873dbcd 100644
--- a/eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/proxy/v1_17_R1/fast/NMSFastItemStack.kt
+++ b/eco-core/core-nms/v1_17_R1/src/main/kotlin/com/willfp/eco/proxy/v1_17_R1/fast/NMSFastItemStack.kt
@@ -6,6 +6,7 @@ import net.minecraft.nbt.CompoundTag
 import net.minecraft.nbt.ListTag
 import net.minecraft.nbt.StringTag
 import net.minecraft.world.item.EnchantedBookItem
+import net.minecraft.world.item.Item
 import net.minecraft.world.item.ItemStack
 import net.minecraft.world.item.Items
 import org.bukkit.craftbukkit.v1_17_R1.inventory.CraftItemStack
@@ -170,6 +171,18 @@ class NMSFastItemStack(itemStack: org.bukkit.inventory.ItemStack) : EcoFastItemS
         handle.setRepairCost(cost)
     }
 
+    override fun equals(other: Any?): Boolean {
+        if (other !is NMSFastItemStack) {
+            return false
+        }
+
+        return other.hashCode() == this.hashCode()
+    }
+
+    override fun hashCode(): Int {
+        return handle.tag.hashCode() * 31 + Item.getId(handle.item)
+    }
+
     private fun apply() {
         if (bukkit !is CraftItemStack) {
             bukkit.itemMeta = CraftItemStack.asCraftMirror(handle).itemMeta
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/PacketWindowItems.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/PacketWindowItems.kt
index 38406e01..10ac3659 100644
--- a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/PacketWindowItems.kt
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/PacketWindowItems.kt
@@ -6,9 +6,11 @@ import com.comphenix.protocol.events.PacketEvent
 import com.willfp.eco.core.AbstractPacketAdapter
 import com.willfp.eco.core.EcoPlugin
 import com.willfp.eco.core.display.Display
+import com.willfp.eco.core.fast.FastItemStack
+import com.willfp.eco.spigot.display.frame.DisplayFrame
+import com.willfp.eco.spigot.display.frame.lastDisplayFrame
 import org.bukkit.entity.Player
 import org.bukkit.inventory.ItemStack
-import java.util.function.Consumer
 
 class PacketWindowItems(plugin: EcoPlugin) : AbstractPacketAdapter(plugin, PacketType.Play.Server.WINDOW_ITEMS, false) {
     override fun onSend(
@@ -20,11 +22,21 @@ class PacketWindowItems(plugin: EcoPlugin) : AbstractPacketAdapter(plugin, Packe
             if (itemStacks == null) {
                 return@modify null
             }
-            itemStacks.forEach(Consumer { item: ItemStack ->
-                Display.display(
-                    item, player
-                )
-            })
+            val frameMap = mutableMapOf<Byte, Int>()
+
+            for (index in itemStacks.indices) {
+                frameMap[index.toByte()] = FastItemStack.wrap(itemStacks[index]).hashCode()
+            }
+
+            val newFrame = DisplayFrame(frameMap)
+
+            val changes = player.lastDisplayFrame.getChangedSlots(newFrame)
+
+            player.lastDisplayFrame = newFrame
+
+            for (index in changes) {
+                Display.display(itemStacks[index.toInt()], player)
+            }
             itemStacks
         }
     }
diff --git a/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/frame/DisplayFrame.kt b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/frame/DisplayFrame.kt
new file mode 100644
index 00000000..c6ae0922
--- /dev/null
+++ b/eco-core/core-plugin/src/main/kotlin/com/willfp/eco/spigot/display/frame/DisplayFrame.kt
@@ -0,0 +1,28 @@
+package com.willfp.eco.spigot.display.frame
+
+import org.bukkit.entity.Player
+import java.util.*
+
+data class DisplayFrame(val items: Map<Byte, Int>) {
+    fun getChangedSlots(newFrame: DisplayFrame): List<Byte> {
+        val changes = mutableListOf<Byte>()
+
+        for ((slot, hash) in newFrame.items) {
+            if (items[slot] != hash) {
+                changes.add(slot)
+            }
+        }
+
+        return changes
+    }
+}
+
+val frames = mutableMapOf<UUID, DisplayFrame>()
+
+var Player.lastDisplayFrame: DisplayFrame
+    get() {
+        return frames[this.uniqueId] ?: DisplayFrame(emptyMap())
+    }
+    set(value) {
+        frames[this.uniqueId] = value
+    }