Add ticker for suspending coroutines for a specific amount of ticks

blokk-api/build.gradle.kts

@@ -41,6 +41,9 @@ dependencies {
 tasks {
     compileKotlin {
         kotlinOptions.jvmTarget = "1.8"
+        kotlinOptions.freeCompilerArgs = listOf(
+            "-Xopt-in=kotlinx.coroutines.ExperimentalCoroutinesApi"
+        )
     }
 
     compileTestKotlin {

blokk-api/src/main/kotlin/space/blokk/Blokk.kt

@@ -9,6 +9,9 @@ import space.blokk.utils.UUIDAdapter
 import space.blokk.utils.UUIDWithoutHyphensAdapter
 
 interface BlokkProvider {
+    /**
+     * The [Server] instance.
+     */
     val server: Server
 
     /**

blokk-api/src/main/kotlin/space/blokk/net/protocols/play/JoinGamePacket.kt

@@ -1,11 +1,11 @@
 package space.blokk.net.protocols.play
 
 import io.netty.buffer.ByteBuf
-import space.blokk.GameMode
 import space.blokk.net.MinecraftDataTypes.writeString
 import space.blokk.net.MinecraftDataTypes.writeVarInt
 import space.blokk.net.protocols.OutgoingPacket
 import space.blokk.net.protocols.OutgoingPacketCompanion
+import space.blokk.players.GameMode
 import space.blokk.worlds.WorldDimension
 import space.blokk.worlds.WorldType
 

blokk-api/src/main/kotlin/space/blokk/players/GameMode.kt

@@ -1,4 +1,4 @@
-package space.blokk
+package space.blokk.players
 
 enum class GameMode {
     SURVIVAL,

blokk-api/src/main/kotlin/space/blokk/server/Server.kt

@@ -1,6 +1,7 @@
 package space.blokk.server
 
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.ReceiveChannel
 import space.blokk.events.EventBus
 import space.blokk.events.EventTarget
 import space.blokk.server.events.ServerEvent
@@ -8,4 +9,10 @@ import space.blokk.server.events.ServerEvent
 interface Server : EventTarget<ServerEvent> {
     override val eventBus: EventBus<ServerEvent>
     val scope: CoroutineScope
+
+    fun createTickChannel(): ReceiveChannel<Unit>
+
+    companion object {
+        const val TICKS_PER_SECOND = 20
+    }
 }

blokk-api/src/main/kotlin/space/blokk/utils/DelayTicks.kt

@@ -0,0 +1,17 @@
+package space.blokk.utils
+
+import space.blokk.Blokk
+
+/**
+ * Suspends for [ticks].
+ */
+suspend fun delayTicks(ticks: Long) {
+    val channel = Blokk.server.createTickChannel()
+    (0..ticks).forEach { _ -> channel.receive() }
+    channel.cancel()
+}
+
+/**
+ * Suspends for one tick.
+ */
+suspend fun delayTick() = delayTicks(1)

blokk-api/src/main/kotlin/space/blokk/worlds/World.kt

@@ -0,0 +1,16 @@
+package space.blokk.worlds
+
+/**
+ * A minecraft world, sometimes also called level.
+ */
+interface World {
+    /**
+     * The [dimension][WorldDimension] of the world.
+     */
+    var dimension: WorldDimension
+
+    /**
+     * The [type][WorldType] of the world.
+     */
+    var type: WorldType
+}

blokk-server/build.gradle.kts

@@ -48,6 +48,9 @@ dependencies {
 tasks {
     compileKotlin {
         kotlinOptions.jvmTarget = "1.8"
+        kotlinOptions.freeCompilerArgs = listOf(
+            "-Xopt-in=kotlinx.coroutines.ExperimentalCoroutinesApi"
+        )
     }
 
     shadowJar {

blokk-server/src/main/kotlin/space/blokk/BlokkServer.kt

@@ -17,6 +17,7 @@ import space.blokk.net.events.ServerListInfoRequestEvent
 import space.blokk.server.Server
 import space.blokk.server.events.ServerEvent
 import space.blokk.utils.EncryptionUtils
+import space.blokk.utils.Ticker
 import java.io.File
 import java.security.KeyPair
 import kotlin.system.exitProcess
@@ -28,7 +29,8 @@ class BlokkServer internal constructor() : Server {
 
     override val scope = CoroutineScope(CoroutineName("BlokkServer"))
     override val eventBus = EventBus(ServerEvent::class, scope)
-    val logger = Logger("BlokkServer")
+
+    val logger = Logger("Server")
     var socketServer = BlokkSocketServer(); private set
 
     val keyPair: KeyPair
@@ -64,7 +66,14 @@ class BlokkServer internal constructor() : Server {
         )
         .build().loadConfigOrThrow<BlokkConfig>()
 
+    private val ticker = Ticker(scope)
+    override fun createTickChannel() = ticker.createTickChannel()
+
     init {
+        setProvider()
+    }
+
+    private fun setProvider() {
         val providerField = Blokk::class.java.getDeclaredField("provider")
         providerField.isAccessible = true
         providerField.set(Blokk, object : BlokkProvider {
@@ -86,6 +95,8 @@ class BlokkServer internal constructor() : Server {
 
         socketServer.bind()
         logger info "Listening on ${config.host}:${config.port}"
+
+        ticker.start()
     }
 
     companion object {

blokk-server/src/main/kotlin/space/blokk/net/JoinProcedure.kt

@@ -2,7 +2,6 @@ package space.blokk.net
 
 import io.netty.buffer.Unpooled
 import space.blokk.BlokkServer
-import space.blokk.GameMode
 import space.blokk.chat.TextComponent
 import space.blokk.net.MinecraftDataTypes.writeString
 import space.blokk.net.protocols.login.EncryptionRequestPacket
@@ -13,6 +12,7 @@ import space.blokk.net.protocols.play.JoinGamePacket
 import space.blokk.net.protocols.play.PlayProtocol
 import space.blokk.net.protocols.play.PlayerAbilitiesPacket
 import space.blokk.net.protocols.play.ServerDifficultyPacket
+import space.blokk.players.GameMode
 import space.blokk.utils.AuthenticationHelper
 import space.blokk.utils.EncryptionUtils
 import space.blokk.worlds.WorldDifficulty

blokk-server/src/main/kotlin/space/blokk/utils/Ticker.kt

@@ -0,0 +1,32 @@
+package space.blokk.utils
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.channels.ReceiveChannel
+import space.blokk.server.Server
+import java.util.*
+import java.util.concurrent.Executors
+
+class Ticker(serverScope: CoroutineScope) {
+    private val scope = serverScope + Executors
+        .newSingleThreadExecutor { Thread(it).also { thread -> thread.name = "Ticker" } }
+        .asCoroutineDispatcher()
+
+    private val channels: MutableSet<Channel<Unit>> = Collections.synchronizedSet(mutableSetOf<Channel<Unit>>())
+
+    fun createTickChannel(): ReceiveChannel<Unit> {
+        return Channel<Unit>().also { channel ->
+            channel.invokeOnClose { channels.remove(channel) }
+            channels.add(channel)
+        }
+    }
+
+    fun start() {
+        scope.launch {
+            while (true) {
+                channels.toSet().forEach { it.send(Unit) }
+                delay(1000L / Server.TICKS_PER_SECOND)
+            }
+        }
+    }
+}

build.gradle.kts

@@ -9,17 +9,3 @@ version = "0.0.1"
 repositories {
     mavenCentral()
 }
-
-dependencies {
-
-}
-
-tasks {
-    compileKotlin {
-        kotlinOptions.jvmTarget = "1.8"
-    }
-
-    compileTestKotlin {
-        kotlinOptions.jvmTarget = "1.8"
-    }
-}

settings.gradle.kts

@@ -3,7 +3,6 @@ pluginManagement {
         mavenCentral()
         gradlePluginPortal()
     }
-
 }
 
 rootProject.name = "blokk"