Implement default available slots provider for surf servers

gradle.properties

@@ -4,6 +4,6 @@ org.gradle.configuration-cache=false
 kotlin.code.style=official
 kotlin.stdlib.default.dependency=false
 org.gradle.parallel=true
-version=1.1.3
+version=1.2.0
 
 authors=twisti,SLNE-Development

surf-queue-api/src/main/kotlin/dev/slne/surf/queue/api/SurfQueueAvailableSlotsProvider.kt

@@ -0,0 +1,41 @@
+package dev.slne.surf.queue.api
+
+import dev.slne.surf.core.api.common.server.SurfServer
+
+/**
+ * Provides the number of currently available slots for a given [SurfServer].
+ */
+interface SurfQueueAvailableSlotsProvider {
+
+    /**
+     * Returns the number of currently available slots on the given [server].
+     *
+     * @param server the server whose available slots should be resolved
+     * @return the amount of free slots on the server
+     */
+    suspend fun getAvailableSlots(server: SurfServer): Int
+
+    /**
+     * Holds global access to the currently configured [SurfQueueAvailableSlotsProvider].
+     */
+    companion object {
+        private lateinit var instance: SurfQueueAvailableSlotsProvider
+
+        /**
+         * Sets the global [SurfQueueAvailableSlotsProvider] instance.
+         *
+         * @param provider the provider instance to register
+         */
+        fun set(provider: SurfQueueAvailableSlotsProvider) {
+            instance = provider
+        }
+
+        /**
+         * Returns the globally configured [SurfQueueAvailableSlotsProvider] instance.
+         *
+         * @return the registered provider instance
+         * @throws UninitializedPropertyAccessException if no provider has been set yet
+         */
+        fun get() = instance
+    }
+}

surf-queue-paper/src/main/kotlin/dev/slne/surf/queue/paper/PaperSurfQueueInstance.kt

@@ -3,6 +3,7 @@ package dev.slne.surf.queue.paper
 import com.google.auto.service.AutoService
 import dev.slne.surf.api.paper.event.register
 import dev.slne.surf.core.api.common.server.SurfServer
+import dev.slne.surf.queue.api.SurfQueueAvailableSlotsProvider
 import dev.slne.surf.queue.common.QueueInstance
 import dev.slne.surf.queue.common.queue.AbstractQueue
 import dev.slne.surf.queue.common.queue.tick.QueueScheduler
@@ -11,6 +12,7 @@ import dev.slne.surf.queue.paper.config.SurfQueueConfig
 import dev.slne.surf.queue.paper.hook.startup.QueueStartHook
 import dev.slne.surf.queue.paper.listener.PlayerKickedDueToFullServerListener
 import dev.slne.surf.queue.paper.metrics.QueueMetricsLogger
+import dev.slne.surf.queue.paper.queue.DefaultSurfQueueAvailableSlotsProvider
 import dev.slne.surf.queue.paper.queue.PaperOwnedQueueImpl
 import dev.slne.surf.queue.paper.queue.PaperQueueImpl
 
@@ -25,6 +27,7 @@ class PaperSurfQueueInstance : QueueInstance() {
 
     override suspend fun load() {
         SurfQueueConfig.init()
+        SurfQueueAvailableSlotsProvider.set(DefaultSurfQueueAvailableSlotsProvider)
         super.load()
         QueueStartHook.get().onServerReady {
             isLoaded = true

surf-queue-paper/src/main/kotlin/dev/slne/surf/queue/paper/queue/DefaultSurfQueueAvailableSlotsProvider.kt

@@ -0,0 +1,15 @@
+package dev.slne.surf.queue.paper.queue
+
+import dev.slne.surf.core.api.common.server.SurfServer
+import dev.slne.surf.queue.api.SurfQueueAvailableSlotsProvider
+import org.bukkit.Bukkit
+
+object DefaultSurfQueueAvailableSlotsProvider : SurfQueueAvailableSlotsProvider {
+    override suspend fun getAvailableSlots(server: SurfServer): Int {
+        return if (SurfServer.current().name == server.name) {
+            Bukkit.getMaxPlayers() - Bukkit.getOnlinePlayers().size
+        } else {
+            server.maxPlayers - server.getPlayers().size
+        }
+    }
+}

surf-queue-paper/src/main/kotlin/dev/slne/surf/queue/paper/queue/transfer/PaperQueueTransfer.kt

@@ -7,6 +7,7 @@ import dev.slne.surf.core.api.common.server.connection.SurfServerConnectResult
 import dev.slne.surf.queue.paper.config.SurfQueueConfig
 import dev.slne.surf.queue.paper.listener.PlayerKickedDueToFullServerListener
 import dev.slne.surf.api.core.util.logger
+import dev.slne.surf.queue.api.SurfQueueAvailableSlotsProvider
 import kotlinx.coroutines.TimeoutCancellationException
 import kotlinx.coroutines.withTimeout
 import net.kyori.adventure.text.Component
@@ -26,10 +27,10 @@ class PaperQueueTransfer(
     }
 
     suspend fun tryTransfer(): Int {
-        val availableSlots = Bukkit.getMaxPlayers() - Bukkit.getOnlinePlayers().size
+        val coreServer = SurfServer[serverName] ?: return 0
+        val availableSlots = SurfQueueAvailableSlotsProvider.get().getAvailableSlots(coreServer)
 
         if (availableSlots <= 0) return 0
-        val coreServer = SurfServer[serverName] ?: return 0
         val maxTransfers = min(availableSlots, SurfQueueConfig.getConfig().maxTransfersPerSecond)
 
         return processor.processTransfers(maxTransfers) { (uuid) ->