' This demonstrates how to perform a graceful disconnect, where data sending/receiving
' is allowed to complete before the client is disconnected.
' In this demo the server begins the graceful disconnect process
' It is also possible for a client to initiate a graceful disconnect
' mnClientConnected return value constants




Imports System.Threading

Module Module1
    Sub Main()

        Const C_NOT_CONNECTED As Integer = 0
        Const C_CONNECTED As Integer = 1
        Const C_NO_SEND As Integer = 2
        Const C_NO_RECV As Integer = 3
        Const C_NO_SEND_RECV As Integer = 4


        ' Setup server
        Dim iReturn As Integer = 0
        Console.WriteLine("DarkNet version: " + mn.GetVersion())

        Dim RecvPacket As Int64 = mn.CreatePacket()
        Dim SendPacket As Int64 = mn.CreatePacket()
        mn.SetMemorySize(SendPacket, 1024)
        mn.SetUsedSize(SendPacket, 1024)

        mn.Start(1, 0)

        mn.DisableUDP(0)
        mn.SetLocal(0, "127.0.0.1", 6565, "", 0)
        mn.EnableGracefulDisconnect(0) ' Enable graceful disconnect
        mn.StartServer(0, 50, 0, 0)

        Console.WriteLine("Server started on TCP port " + mn.GetLocalPortTCP(0).ToString())

        ' Send data to clients every SendFreq ms
        Dim SendTimer As Integer = 0
        Dim SendFreq As Integer = 100

        ' Disconnect a client every DisconnectFreq ms
        Dim DisconnectTimer As Integer = 0
        Dim DisconnectFreq As Integer = 3000

        ' Main loop
        Do
            ' Use less CPU
            Thread.Sleep(1)

            ' Graceful close
            For cl As Integer = 1 To mn.GetMaxClients(0)
                Dim iClientStatus As Integer = mn.ClientConnected(0, cl)
                Select Case (iClientStatus)
                    ' Shutdown client
                    ' Further send operations to this client will fail silently
                    ' mn.ClientConnected will now return 2
                    Case (C_CONNECTED)
                        If (System.DateTime.Now.Millisecond + (System.DateTime.Now.Second * 1000) + (System.DateTime.Now.Minute * 60 * 1000)) - DisconnectTimer > DisconnectFreq Then
                            mn.ShutdownClient(0, cl)
                            Console.WriteLine("Shut down client " + cl.ToString())

                            DisconnectTimer = System.DateTime.Now.Millisecond + (System.DateTime.Now.Second * 1000) + (System.DateTime.Now.Minute * 60 * 1000)
                        End If

                        ' Client is sending us data still
                        ' We will wait forever, but a robust server should
                        ' only wait for a set amount of time, and forcefully
                        ' disconnect clients that take too long
                    Case (C_NO_SEND)
                        ' Nothing to do while we wait


                        ' Client has finished sending us data
                        ' We must get it from packet queue
                        ' Once packet queue is empty, client
                        ' will be disconnected by mn.ClientConnected
                        ' and mn.ClientConnected will return 0
                    Case (C_NO_SEND_RECV)
                        Console.WriteLine("mn.ClientConnected (" + cl.ToString() + "): " + iClientStatus.ToString())
                        While (mn.RecvTCP(0, RecvPacket, cl) > 0)

                            Dim str As String = mn.GetString(RecvPacket, 0, True)
                            Console.WriteLine("Final string received from client " + cl.ToString() + ": " + str)
                        End While

                End Select
            Next cl

            ' New clients
            iReturn = mn.ClientJoined(0)
            If iReturn > 0 Then
                Console.WriteLine("New client joined, ID: " + iReturn.ToString())
                DisconnectTimer = System.DateTime.Now.Millisecond + (System.DateTime.Now.Second * 1000) + (System.DateTime.Now.Minute * 60 * 1000)
            End If

            ' Leaving clients
            iReturn = mn.ClientLeft(0)
            If iReturn > 0 Then
                Console.WriteLine("Client left, ID: " + iReturn.ToString())
            End If

            ' Receive data
            For cl As Integer = 1 To mn.GetMaxClients(0)
                If mn.ClientConnected(0, cl) = C_CONNECTED Then
                    ' TCP packets
                    iReturn = mn.RecvTCP(0, RecvPacket, cl)

                    If (iReturn > 0) Then
                        Dim str As String = mn.GetString(RecvPacket, 0, True)
                        Console.WriteLine("String received from client " + cl.ToString() + ": " + str)
                    End If
                End If
            Next cl

            ' Send data
            If (System.DateTime.Now.Millisecond + (System.DateTime.Now.Second * 1000) + (System.DateTime.Now.Minute * 60 * 1000)) - SendTimer > SendFreq Then
                For cl As Integer = 1 To mn.GetMaxClients(0)
                    If (mn.ClientConnected(0, cl) = C_CONNECTED) Then
                        mn.SendTCP(0, SendPacket, cl, True, True)
                        Console.WriteLine("Packet sent")
                    End If
                Next cl
                SendTimer = System.DateTime.Now.Millisecond + (System.DateTime.Now.Second * 1000) + (System.DateTime.Now.Minute * 60 * 1000)
            End If
        Loop
    End Sub

End Module