/*
    Copyright (c) 2007-2010 iMatix Corporation

    This file is part of 0MQ.

    0MQ is free software; you can redistribute it and/or modify it under
    the terms of the Lesser GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    0MQ is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    Lesser GNU General Public License for more details.

    You should have received a copy of the Lesser GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <vector>
#include <string>
#include <memory>

#include "../include/zmq.hpp"
#include "../foreign/xmlParser/xmlParser.cpp"

class device_cfg_t
{

    enum endpoint_direction {connect, bind};

    typedef std::pair <endpoint_direction, std::string> sock_details_t;

    typedef std::vector <sock_details_t> vsock_dets_t;

public:

    explicit device_cfg_t (int type) :
        device_type (type),
        context (0),
        in_socket (0),
        out_socket (0)
    {
    }

    virtual ~device_cfg_t()
    {
        delete out_socket;
        delete in_socket;
    }

    bool init (XMLNode &device)
    {
        XMLNode in_node = device.getChildNode ("in");
        if (in_node.isEmpty ()) {
            fprintf (stderr,
                "'in' node is missing in the configuration file\n");
            return false;
        }

        XMLNode out_node = device.getChildNode ("out");
        if (out_node.isEmpty ()) {
            fprintf (stderr,
                "'out' node is missing in the configuration file\n");
            return false;
        }

        if (!process_node (in_node, true, device_cfg_t::bind))
            return false;
        if (!process_node (in_node, true, device_cfg_t::connect))
            return false;
        if (!process_node (out_node, false, device_cfg_t::bind))
            return false;
        if (!process_node (out_node, false, device_cfg_t::connect))
            return false;

        return true;
    }

    void set_context(zmq::context_t *context_)
    {
        context = context_;
    }

    zmq::context_t *get_context () const
    {
        return context;
    }

    virtual bool make_sockets () = 0;

    bool set_up_connections ()
    {
        for (vsock_dets_t::const_iterator i = in.begin (); i != in.end ();
              ++i) {
            switch (i->first)
            {
                case device_cfg_t::connect:
                    in_socket->connect (i->second.c_str ());
                    break;
                case device_cfg_t::bind:
                    in_socket->bind (i->second.c_str ());
            }
        }

        for (vsock_dets_t::const_iterator i = out.begin (); i != out.end ();
              ++i) {
            switch (i->first)
            {
                case device_cfg_t::connect:
                    out_socket->connect (i->second.c_str ());
                    break;
                case device_cfg_t::bind:
                    out_socket->bind (i->second.c_str ());
            }

        }
        return true;
    }

    void run() 
    {
        zmq::device(device_type, *in_socket, *out_socket);
    }


protected:

    bool make_sockets (int in_type, int out_type)
    {
        in_socket = new (std::nothrow) zmq::socket_t (*context, in_type);
        if (!in_socket) 
            return false;
        out_socket = new (std::nothrow) zmq::socket_t (*context, out_type);
        if (!out_socket) {
            return false;
        }
        return true;
    }

    int process_node (XMLNode& target_, bool in_,
        device_cfg_t::endpoint_direction ept_)
    {
        const char *name =
            (ept_ == device_cfg_t::connect) ? "connect" : "bind";
        int n = 0;
        while (true) {
            XMLNode connect = target_.getChildNode (name, n);
            if (connect.isEmpty ())
                break;
            const char *addr = connect.getAttribute ("addr");
            if (!addr) {
                fprintf (stderr, "'%s' node is missing 'addr' attribute\n",
                    name);
                return 0;
            }

            if (in_) 
                in.push_back (sock_details_t (ept_, addr));
            else
                out.push_back (sock_details_t (ept_, addr));

            n++;
        }

        return 1;
    }


protected:

    int device_type;
    zmq::context_t *context;
    vsock_dets_t in;
    vsock_dets_t out;
    zmq::socket_t *in_socket;
    zmq::socket_t *out_socket;

private:

    device_cfg_t (device_cfg_t const&);
    void operator = (device_cfg_t const&);
};

class queue_device_cfg_t : public device_cfg_t
{
public:

    queue_device_cfg_t () :
        device_cfg_t (ZMQ_QUEUE)
    {
    }

    virtual bool make_sockets ()
    {
        return device_cfg_t::make_sockets (ZMQ_XREP, ZMQ_XREQ);
    }
};


class streamer_device_cfg_t : public device_cfg_t
{
public:

    streamer_device_cfg_t () : 
        device_cfg_t (ZMQ_STREAMER)
    {
    }

    virtual bool make_sockets ()
    {
        return device_cfg_t::make_sockets (ZMQ_UPSTREAM, ZMQ_DOWNSTREAM);
    }
};

class forwarder_device_cfg_t : public device_cfg_t
{
public:

    forwarder_device_cfg_t() :
        device_cfg_t (ZMQ_FORWARDER)
    {
    }

    virtual bool make_sockets()
    {
        if (!device_cfg_t::make_sockets (ZMQ_SUB, ZMQ_PUB) ) {
            return false;
        }
        in_socket->setsockopt (ZMQ_SUBSCRIBE, "", 0);
        return true;
    }
};


device_cfg_t *make_device_config (XMLNode& device)
{
    const char *dev_type = device.getAttribute ("type");

    if (!dev_type) {
        fprintf (stderr, "'device' node is missing 'type' attribute\n");
        return NULL;
    }

    if (strcmp (dev_type, "forwarder") == 0) {
        return new (std::nothrow) forwarder_device_cfg_t;
    }
    else if (strcmp (dev_type, "streamer") == 0) {
        return new (std::nothrow) streamer_device_cfg_t;
    }
    else if (strcmp (dev_type, "queue") == 0) {
        return new (std::nothrow) queue_device_cfg_t;
    }
    
    fprintf (stderr, "type attribute in the device configuration file "
             "should be named 'forwarder', 'streamer' or 'queue'\n");

    return NULL;
}


extern "C" void* worker_function(void *arg)
{
    if (!arg) {
        fprintf (stderr, "arg is null, returning \n");
        return 0;
    }

    std::auto_ptr <device_cfg_t> cfg ((device_cfg_t*) arg);

    zmq::context_t *ctx = cfg->get_context ();

    if (!ctx) {
        fprintf (stderr, "no context, returning \n");
        return 0;
    }

    if (!cfg->make_sockets ()) {
        fprintf (stderr, "failed to make sockets, returning \n");
        return 0;
    }


    if (!cfg->set_up_connections ()) {
        fprintf (stderr, "failed to set up connections, returning \n");
        return 0;         
    }

    cfg->run();

    return 0;
}

int main (int argc, char *argv [])
{
    if (argc != 2) {
        fprintf (stderr, "usage: zmqd <config-file>\n");
        return 1;
    }

    XMLNode root = XMLNode::parseFile (argv [1]);

    if (root.isEmpty ()) {
        fprintf (stderr, "configuration file not found or not an XML file\n");
        return 1;
    }

    if (strcmp (root.getName (), "config") != 0) {
        fprintf (stderr, "root element in the configuration file should be "
            "named 'config'\n");
        return 1;
    }

    std::vector <device_cfg_t*> vdev;

    while (true) {

        XMLNode device = root.getChildNode ("device", vdev.size());

        if (device.isEmpty())
            break;

        device_cfg_t* dev = make_device_config (device);

        if (!dev) {
            fprintf(stderr, "failed to create device config\n");
            return 1;
        }
        
        if (!dev->init (device)) {
            fprintf(stderr,"error with initialising device configuration\n");
            delete dev;
            return 1;
        }
    
        vdev.push_back (dev);
    }

    std::vector <device_cfg_t*>::size_type num_devices = vdev.size ();

    if (num_devices == 0) {
        fprintf(stderr,"no devices in the config file\n");
        return 1;
    }

    zmq::context_t ctx (num_devices, 1);

    for (unsigned int i = 0 ; i < num_devices ; ++i) {

        vdev [i]->set_context (&ctx);
        
        if (i)  {
            pthread_t worker;
            int rc = pthread_create (&worker, NULL, &worker_function,
                (void*) vdev [i]);
            assert (rc == 0);
        }
    }

    worker_function ((void*) vdev [0]);

    return 0;
}