dnetd/source/dnetd/dlink.d

module dnetd.dlink;

import dnetd.dconnection;
import core.sync.mutex : Mutex;
import std.stdio;
import std.conv;
import dnetd.dserver;
import dnetd.dconfig;
import std.socket : Address;
import core.thread : Thread;
import std.socket;
import gogga;
import core.thread;
import tristanable.encoding : DataMessage;
import bmessage : bSendMessage = sendMessage, bReceiveMessage = receiveMessage;
import std.string : cmp;

/**
* Link manager
*
* Given a set of original DLink objects, it will open connections to them
* It also facilitates DConnection making a call to `.addLink` here when an
* inbound peering request comes in
*/
public final class DLinkManager
{

    this(DServer server)
    {
        
    }

    /**
    * Goes through the DConnection[] array in DServer and returns
    * all connections that are SERVER connections
    */
    public DConnection[] getLinkedServers()
    {
        DConnection[] links;

        /* TODO: Implement me */


        return links;
    }

}











/**
* Represents a server link
*
* Either used for inbound or outbound
*/
public final class DLink : Thread
{
    /* Associated server */
    private DServer server;

    /* The connection */
    private DConnection connection;

    /**
    * Links details
    */
    private string name;
    private Address address;

    /**
    * Outbound utilities
    */
    private Socket outboundSocket;

    /**
    * Constructs a DLink for an outbound peering
    */
    this(DServer server, string name, Address address)
    {
        /* Set the worker thread for outbound connections */
        super(&outboundWorker);

        this.server = server;
        this.name = name;
        this.address = address;

        /* Create an outbound connection */
        /* TODO: Fuuuuuuuuuuuuuuuuuuuck handling of shit here bababooey and not in dconnection.d as we would have done below */

        
    }

    /**
    * Initializes a new outbound connection
    */
    private void initializeOutboundConnection()
    {
        /* Open a connection to the server */
        outboundSocket = new Socket(address.addressFamily, SocketType.STREAM, ProtocolType.TCP);

        gprintln(address);



        while(true)
        {
            try
            {
                outboundSocket.connect(address);
                break;
            }
            catch(SocketOSException)
            {
                gprintln("Could not link with server "~name~"!", DebugType.ERROR);
                Thread.sleep(dur!("seconds")(3));
            }
        }
        


        
    }

    private void outboundWorker()
    {
        /* Initialize a new outbound connection */
        initializeOutboundConnection();

        bool status = linkHandshake();

        /* TODO: Implement me */
        while(true)
        {
            byte[] dataIn;
            bool statusRecv = bReceiveMessage(outboundSocket, dataIn);

            if(statusRecv)
            {

            }
            else
            {
                /* TODO: Connection error */
                gprintln("Outbound server communication error, breaking", DebugType.ERROR);
                break;
            }
        }

        /* TODO: Clean up connection */
        server.getLinkManager().removeLinkOutbounded(name);
    }

    /**
    * Performs the server LINK command and makes sure
    * the server accepts the linking and also that the
    * links name on our local server match up
    */
    private bool linkHandshake()
    {
        bool status = true;

        /* TODO: Send LINK (1) command */
        byte[] data;
        data ~= [1];

        gprintln("Here", DebugType.WARNING);

        /* TODO: Encode [serverNameLen, serverName] */
        string serverName = server.getGeneralConfig().getName();
        data ~= [cast(byte)serverName.length];
        data ~= serverName;

        /* Encode and send LINK command */     
        DataMessage message = new DataMessage(0, data);
        bSendMessage(outboundSocket, message.encode());

        /* TODO: Await an acknowledgement [status] */
        byte[] receivedResponseBytes;
        bool recvStatus = bReceiveMessage(outboundSocket, receivedResponseBytes);
        gprintln("Recev status: "~to!(string)(recvStatus), DebugType.WARNING);

        DataMessage receivedResponse = DataMessage.decode(receivedResponseBytes);

        ubyte[] dataReply = cast(ubyte[])receivedResponse.getData();

        /* TODO: 0 is good, 1 is bad */
        if(dataReply[0] == 0)
        {
            /* TODO: Get server name, makes sure it matches on in config file */
            ubyte nameLen = dataReply[1];
            string name = cast(string)dataReply[2..2+nameLen];
            gprintln("Server said his name is '"~name~"'", DebugType.WARNING);


            /* Attempt to attach server */
            status = server.getMeyer().attachLink(name, this);
            gprintln("Outbound link status: "~to!(string)(status));

        }
        else if(dataReply[0] == 1)
        {
            /* TODO: Handle this case */
            gprintln("Server linking rejected", DebugType.ERROR);
            status = false;
        }
        else
        {
            /* TODO: Handle this case */
            status = false;
        }
        /* TODO: If 0, then expect following [nameLen, name] */


        return status;
    }


    override public string toString()
    {
        return name~"(DConnection: "~to!(string)(connection)~", Socket: "~to!(string)(outboundSocket)~")";
    }


    /**
    * Constructs a DLink for an inbound peering
    */
    this(DServer server, string name, DConnection connection)
    {
        /* Save the server and name  */
        this(server, name, address=null);

        /* Save connection */
        this.connection = connection;
    }

    public string getName()
    {
        return name;
    }
}

/* TODO: Remove this from here and put it in DServer */
public final class DMeyer : Thread
{
    /* Direct peers */
    private DLink[] links;
    private Mutex linksMutex;

    /* Associated server */
    private DServer server;

    this(DServer server)
    {
        super(&worker);

        /* save shit */
        this.server = server;
        
        /* Initialize the locks */
        initLocks();

        start();
    }

    /**
    * Every 3 seconds information on what servers are linked will be printed out
    */
    private void worker()
    {
        while(true)
        {
            linksMutex.lock();
            gprintln("Linked servers: "~to!(string)(links), DebugType.WARNING);
            linksMutex.unlock();

            Thread.sleep(dur!("seconds")(3));
        }
    }

    /* Initialize locks */
    private void initLocks()
    {
        linksMutex = new Mutex();
    }


    public void removeLinkOutbounded(string serverName)
    {
        /* Lock the links list */
        linksMutex.lock();

        DLink[] newList;
        DLink removedLink;
        foreach(DLink link; links)
        {
            if(cmp(link.getName(), serverName) != 0)
            {
                newList ~= link;
            }
            else
            {
                removedLink = link;
            }
        }


        links = newList;


        /* Unlock the links list */
        linksMutex.unlock();


        gprintln("Removed outbounded peer "~to!(string)(removedLink), DebugType.WARNING);
    }

    public bool attachLink(string serverName, DLink link)
    {
        /* Link exists? */
        bool linkGood = true;

        /* Lock the links list */
        linksMutex.lock();

        /* Search for this entry, only add it if it doens't exist */
        foreach(DLink currentLink; links)
        {
            if(cmp(currentLink.getName(), serverName) == 0)
            {
                linkGood = false;
                break;
            }
        }

        if(linkGood)
        {
            links ~= link;
        }

        /* Unlock the links list */
        linksMutex.unlock();

        return linkGood;
    }




    /**
    * Remove a link via DConnection (inbounded)
    */
    public void removeLinkInbounded(DConnection connection)
    {
        linksMutex.lock();

        DLink[] newList;
        DLink removedLink;
        foreach(DLink link; links)
        {
            if(link.connection != connection)
            {
                newList ~= link;
            }
            else
            {
                removedLink = link;
            }
        }

        links = newList;

        linksMutex.unlock();

        gprintln("Removed inbounded peer from link manager "~to!(string)(removedLink), DebugType.WARNING);
    }


    public DLink[] getLinks()
    {
        return links;
    }
}

/**
* Broadcast a message to the given server
*/
public void broadcastMessage_toLink(Socket linkedServer, byte[] data)
{
    
}

/**
* Given a server link this will send the users
* this server is aware of
*/
public string[] getUsers(DLink link)
{
    
}