Added basic TCP networking for the server.

The client's networking is still very experimental and
the actual protocol is not yet specified for either side.

1 files changed, 90 insertions, 0 deletions

diff --git a/src/main/scala/Server/Server.scala b/src/main/scala/Server/Server.scala
new file mode 100644
index 0000000..829010c
--- /dev/null
+++ b/src/main/scala/Server/Server.scala
@@ -0,0 +1,90 @@
+package o1game.Server
+
+
+// TODO: TLS/SSL / import javax.net.ssl.SSLServerSocketFactory
+
+import java.io.IOException
+import java.lang.Thread.sleep
+import java.net.{ServerSocket, Socket}
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.concurrent.Future
+import scala.util.{Failure, Success, Try}
+import o1game.constants.*
+
+/** `Server` exists to initialize a server for the game
+ *  and run it with its method `startServer`.
+ */
+class Server(port: Int, maxClients: Int):
+	private val socket = ServerSocket(port)
+	private val clientGetter = ConnectionGetter(socket)
+	private val clients: Clients = Clients(maxClients)
+	private val buffer: Array[Byte] = Array.ofDim(1024)
+	private var bufferIndex = 0
+
+	/** Starts the server. Won't terminate under normal circumstances. */
+	def startServer(): Unit =
+		while true do
+			sleep(POLL_INTERVAL)
+			this.receiveNewClient()
+			this.writeToAll("Test message.")
+			this.readFromAll()
+			clients.foreach(_.executeActions())
+
+	/** Receives a new client and stores it in `clients`.
+	 *
+	 *  @return describes if a client was added
+	 */
+	private def receiveNewClient(): Boolean =
+		clientGetter.newClient() match
+			case Some(c) =>
+				clients.addClient(Client(c, None))
+				true
+			case None =>
+				false
+
+	/** Sends `message` to all clients
+	 *
+	 *  @param message the message to send
+	 */
+	private def writeToAll(message: String): Unit =
+		clients.removeNonSatisfying((c: Client) =>
+			try
+				val output = c.socket.getOutputStream
+				output.write(message.toVector.map(_.toByte).toArray)
+				output.flush()
+				true
+			catch
+				case e: IOException => false
+		)
+
+	/** Reads data sent by clients and stores it in the `Client`s of `clients` */
+	private def readFromAll(): Unit =
+		clients.removeNonSatisfying((c: Client) =>
+			try
+				val input = c.socket.getInputStream
+				while input.available() != 0 do
+					val bytesRead = input.read(buffer)
+					if bytesRead != -1 then
+						c.receiveData(buffer.take(bytesRead).toVector)
+				true
+			catch
+				case e: IOException => false
+		)
+
+end Server
+
+class ConnectionGetter(val socket: ServerSocket):
+
+	private var nextClient: Future[Socket] = Future.failed(IOException())
+
+	def newClient(): Option[Socket] =
+		this.nextClient.value match
+			case Some(Success(s)) =>
+				nextClient = Future(socket.accept())
+				Some(s)
+			case Some(Failure(e)) =>
+				nextClient = Future(socket.accept())
+				None
+			case None => None
+
+end ConnectionGetter