/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Maxim Shishmarev <maxim.shishmarev@monash.edu>
 *
 *  Contributing authors:
 *     Kevin Leo <kevin.leo@monash.edu>
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Kevin Leo, 2017
 *     Christian Schulte, 2017
 *     Maxim Shishmarev, 2017
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  Permission is hereby granted, free of charge, to any person obtaining
 *  a copy of this software and associated documentation files (the
 *  "Software"), to deal in the Software without restriction, including
 *  without limitation the rights to use, copy, modify, merge, publish,
 *  distribute, sublicense, and/or sell copies of the Software, and to
 *  permit persons to whom the Software is furnished to do so, subject to
 *  the following conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <iostream>
#include <sstream>
#include <vector>
#include <cstring>

#ifdef WIN32

#include <winsock2.h>
#include <ws2tcpip.h>
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "Mswsock.lib")
#pragma comment(lib, "AdvApi32.lib")

#include <basetsd.h>
typedef SSIZE_T ssize_t;

#else

#include <netdb.h>
#include <unistd.h>
#include <sys/socket.h>

#endif

namespace Gecode { namespace CPProfiler {

  class Node {
    NodeUID node_;
    NodeUID parent_;
    int alt_;
    int kids_;
    
    NodeStatus status_;
    
    Option<std::string> label_;
    Option<std::string> nogood_;
    Option<std::string> info_;
    
  public:
    Node(NodeUID node, NodeUID parent,
         int alt, int kids, NodeStatus status);
    Node& set_node_thread_id(int tid);
    const Option<std::string>& label() const;
    Node& set_label(const std::string& label);
    const Option<std::string>& nogood() const;
    Node& set_nogood(const std::string& nogood);
    const Option<std::string>& info() const;
    Node& set_info(const std::string& info);
    int alt() const;
    int kids() const;
    NodeStatus status() const;
    NodeUID nodeUID() const;
    NodeUID parentUID() const;
    int node_id() const;
    int parent_id() const;
    int node_thread_id() const;
    int node_restart_id() const;
    int parent_thread_id() const;
    int parent_restart_id() const;
  };

  class Connector {
  private:
    MessageMarshalling marshalling;
    
    const unsigned int port;
    
    int sockfd;
    bool _connected;
    
    static int sendall(int s, const char* buf, int* len);
    void sendOverSocket(void);
    void sendRawMsg(const std::vector<char>& buf);
  public:    
    Connector(unsigned int port);
    
    bool connected() const;
    
    /// connect to a socket via port specified in the construction (6565 by
    /// default)
    void connect(void);
    
    // sends START_SENDING message to the Profiler with a model name
    void start(const std::string& file_path = "",
               int execution_id = -1, bool has_restarts = false);
    void restart(int restart_id = -1);
    void done();
    
    /// disconnect from a socket
    void disconnect(void);
    
    void sendNode(const Node& node);
    Node createNode(NodeUID node, NodeUID parent,
                    int alt, int kids, NodeStatus status);
  };
  

  /*
   * Nodes
   */
  inline
  Node::Node(NodeUID node, NodeUID parent,
             int alt, int kids, NodeStatus status)
    : node_{node}, parent_{parent},
    alt_(alt), kids_(kids), status_(status) {}
    
  inline Node&
  Node::set_node_thread_id(int tid) {
    node_.tid = tid;
    return *this;
  }
    
  inline const Option<std::string>&
  Node::label() const { return label_; }
    
  inline Node&
  Node::set_label(const std::string& label) {
    label_.set(label);
    return *this;
  }
    
  inline const Option<std::string>&
  Node::nogood() const { 
    return nogood_;
  }
    
  inline Node&
  Node::set_nogood(const std::string& nogood) {
    nogood_.set(nogood);
    return *this;
  }
    
  inline const Option<std::string>&
  Node::info() const { return info_; }

  inline Node&
  Node::set_info(const std::string& info) {
    info_.set(info);
    return *this;
  }
    
  inline int
  Node::alt() const { return alt_; }
  inline int
  Node::kids() const { return kids_; }
    
  inline NodeStatus
  Node::status() const { return status_; }
    
  inline NodeUID
  Node::nodeUID() const { return node_; }
  inline NodeUID
  Node::parentUID() const { return parent_; }
    
  inline int
  Node::node_id() const { return node_.nid; }
  inline int
  Node::parent_id() const { return parent_.nid; }
  inline int
  Node::node_thread_id() const {  return node_.tid; }
  inline int
  Node::node_restart_id() const { return node_.rid; }
  inline int
  Node::parent_thread_id() const {  return parent_.tid; }
  inline int
  Node::parent_restart_id() const { return parent_.rid; }

  
  /*
   * Connector
   */
  inline
  Connector::Connector(unsigned int port) : port(port), _connected(false) {}

  inline bool Connector::connected() const { return _connected; }


  /*
   * The following code is taken from:
   *   Beej's Guide to Network Programming
   *   http://beej.us/guide/bgnet/
   * with the folloiwng license:
   *
   * Beej's Guide to Network Programming is Copyright © 2015 Brian "Beej Jorgensen" Hall.
   * With specific exceptions for source code and translations, below, this work is licensed under the Creative Commons Attribution- Noncommercial- No Derivative Works 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA.
   * One specific exception to the "No Derivative Works" portion of the license is as follows: this guide may be freely translated into any language, provided the translation is accurate, and the guide is reprinted in its entirety. The same license restrictions apply to the translation as to the original guide. The translation may also include the name and contact information for the translator.
   * The C source code presented in this document is hereby granted to the public domain, and is completely free of any license restriction.
   * Educators are freely encouraged to recommend or supply copies of this guide to their students.
   * Contact beej@beej.us for more information. 
   */
  inline int
  Connector::sendall(int s, const char* buf, int* len) {
    int total = 0;         // how many bytes we've sent
    int bytesleft = *len;  // how many we have left to send
    ssize_t n;
    
    while (total < *len) {
      n = send(s, buf + total, static_cast<size_t>(bytesleft), 0);
      if (n == -1) {
        break;
      }
      total += static_cast<int>(n);
      bytesleft -= static_cast<int>(n);
    }

    *len = static_cast<int>(total);  // return number actually sent here
    
    return (n == -1) ? -1 : 0;  // return -1 on failure, 0 on success
  }

  inline void
  Connector::sendRawMsg(const std::vector<char>& buf) {
    uint32_t bufSize = static_cast<uint32_t>(buf.size());
    int bufSizeLen = sizeof(uint32_t);
    sendall(sockfd, reinterpret_cast<char*>(&bufSize), &bufSizeLen);
    int bufSizeInt = static_cast<int>(bufSize);
    sendall(sockfd, reinterpret_cast<const char*>(buf.data()), &bufSizeInt);
  }
    
  inline void
  Connector::sendOverSocket(void) {
    if (!_connected) return;
      
    std::vector<char> buf = marshalling.serialize();
      
    sendRawMsg(buf);
  }
    
  inline void
  Connector::connect(void) {
    struct addrinfo hints, *servinfo, *p;
    int rv;
      
#ifdef WIN32
    // Initialise Winsock.
    WSADATA wsaData;
    int startupResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (startupResult != 0) {
      printf("WSAStartup failed with error: %d\n", startupResult);
    }
#endif
    
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    
    if ((rv = getaddrinfo("localhost", std::to_string(port).c_str(), &hints,
                          &servinfo)) != 0) {
      std::cerr << "getaddrinfo: " << gai_strerror(rv) << "\n";
      goto giveup;
    }
    
    // loop through all the results and connect to the first we can
    for (p = servinfo; p != nullptr; p = p->ai_next) {
      if ((sockfd = static_cast<int>(socket(p->ai_family, p->ai_socktype, p->ai_protocol))) == -1) {
        // errno is set here, but we don't examine it.
        continue;
      }
      
      if (::connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
#ifdef WIN32
        closesocket(sockfd);
#else
        close(sockfd);
#endif
        // errno is set here, but we don't examine it.
        continue;
      }
      
      break;
    }
    
    // Connection failed; give up.
    if (p == nullptr) {
      goto giveup;
    }
      
    freeaddrinfo(servinfo);  // all done with this structure
    
    _connected = true;
    
    return;
  giveup:
    _connected = false;
    return;
    
  }
  
  inline void
  Connector::start(const std::string& file_path,
                   int execution_id, bool has_restarts) {
    /// extract fzn file name
    std::string base_name(file_path);
    {
      size_t pos = base_name.find_last_of('/');
      if (pos != static_cast<size_t>(-1)) {
        base_name = base_name.substr(pos + 1, base_name.length() - pos - 1);
      }
    }
    
    std::string info{""};
    {
      std::stringstream ss;
      ss << "{";
      ss << "\"has_restarts\": " << (has_restarts ? "true" : "false")  << "\n";
      ss << ",\"name\": " << "\"" << base_name << "\"" << "\n";
      if (execution_id != -1) {
        ss << ",\"execution_id\": " << execution_id;
      }
      ss << "}";
      info = ss.str();
    }
    
    marshalling.makeStart(info);
    sendOverSocket();
  }

  inline void
  Connector::restart(int restart_id) {
      
    std::string info{""};
    {
      std::stringstream ss;
      ss << "{";
      ss << "\"restart_id\": " << restart_id << "\n";
      ss << "}";
      info = ss.str();
    }
    
    marshalling.makeRestart(info);
    sendOverSocket();
  }
  
  inline void
  Connector::done() {
    marshalling.makeDone();
    sendOverSocket();
  }
  
  inline void
  Connector::disconnect() {
#ifdef WIN32
    closesocket(sockfd);
#else
    close(sockfd);
#endif
  }
  
  inline void
  Connector::sendNode(const Node& node) {
    if (!_connected) return;
    
    auto& msg = marshalling.makeNode(node.nodeUID(), node.parentUID(),
                                     node.alt(), node.kids(), node.status());
    
    if (node.label().valid()) msg.set_label(node.label().value());
    if (node.nogood().valid()) msg.set_nogood(node.nogood().value());
    if (node.info().valid()) msg.set_info(node.info().value());
    
    sendOverSocket();
  }

  inline Node
  Connector::createNode(NodeUID node, NodeUID parent,
                        int alt, int kids, NodeStatus status) {
    return Node(node, parent, alt, kids, status);
  }
  
}}

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