Refactor update player resource packs

src/main/kotlin/one/oktw/galaxy/proxy/resourcepack/ResourcePackManager.kt

@@ -3,35 +3,35 @@ package one.oktw.galaxy.proxy.resourcepack
 import com.velocitypowered.api.proxy.Player
 import com.velocitypowered.api.proxy.player.ResourcePackInfo
 import one.oktw.galaxy.proxy.Main.Companion.main
-import kotlin.math.max
+import kotlin.math.min
 
 class ResourcePackManager {
     private val appliedPacks: MutableMap<Player, List<ResourcePackInfo>> = mutableMapOf()
 
     fun updatePlayerResourcePacks(player: Player, galaxy: String) {
-        val targetResourcePacks = main.config.galaxies[galaxy]?.ResourcePacks?.distinct()?.mapNotNull { main.config.resourcePacks[it]?.packInfo() } ?: return
-        val appliedResourcePacks = this.appliedPacks.getOrPut(player) { listOf() }
-
-        var skipFurtherCheck = false
-        val packsToQueue = mutableListOf<ResourcePackInfo>()
-        val packsToRemove = mutableListOf<ResourcePackInfo>()
-
-        for (index in 0..max(targetResourcePacks.size, appliedResourcePacks.size)) {
-            // Skip applied pack on same position
-            val targetPack = targetResourcePacks.getOrNull(index)
-            val appliedPack = appliedResourcePacks.getOrNull(index)
-            if (targetPack?.id == appliedPack?.id && !skipFurtherCheck) continue
-
-            skipFurtherCheck = true
-            if (index < appliedResourcePacks.size) packsToRemove.add(appliedResourcePacks[index])
-            if (index < targetResourcePacks.size) packsToQueue.add(targetResourcePacks[index])
+        val new = main.config.galaxies[galaxy]?.ResourcePacks?.mapNotNull { main.config.resourcePacks[it]?.packInfo() } ?: emptyList()
+        val old = this.appliedPacks.getOrElse(player) { listOf() }
+
+        // Matching new resource packs
+        var updateIndex = old.lastIndex
+        for (i in 0..min(old.size, new.size)) {
+            if (old.getOrNull(i)?.hash != new.getOrNull(i)?.hash) {
+                updateIndex = i
+                break
+            }
         }
 
-        packsToRemove.forEach { pack -> player.removeResourcePacks(pack) }
-        packsToQueue.forEach { pack -> player.sendResourcePacks(pack) }
-        appliedPacks[player] = targetResourcePacks.toList()
+        // Remove not match resource packs
+        old.subList(updateIndex, old.size).forEach(player::removeResourcePacks)
+
+        // Add new resource packs
+        new.subList(updateIndex, new.size).forEach(player::sendResourcePacks)
+
+        // Save player resource packs state
+        appliedPacks[player] = new.toList()
     }
 
+    // Remove player resource packs state
     fun removePlayer(player: Player) {
         appliedPacks.remove(player)
     }