#include "irc.h"

#include <boost/algorithm/string.hpp>
#include <iostream>

void string_toupper(std::string &str) {
  std::transform(str.begin(), str.end(), str.begin(), ::toupper);
}

/**
 * @brief remove channel modes (op,voice,hop,...)
 *
 * @param nick
 */
void remove_channel_modes(std::string &nick) {
  // ~&@%+
  std::string remove("~&@%+");
  std::string::size_type pos;
  do {
    pos = remove.find(nick[0]);
    if (pos != std::string::npos)
      nick.erase(0, 1);
  } while (pos != std::string::npos);
}

/**
 * @brief split on spaces, with limit
 *
 * max is the maximum number of splits we will do.
 * default -1 is split all.
 *
 * "this is a test", 3  => [this][is][a test]
 *
 * @param text
 * @param max
 * @return std::vector<std::string>
 */
std::vector<std::string> split_limit(std::string &text, int max) {
  std::vector<std::string> ret;
  int t = 0;
  boost::split(ret, text, [&t, max](char c) {
    if (c == ' ') {
      ++t;
      return ((max == -1) or (t < max));
    };
    return false;
  });
  return ret;
}

/**
 * @brief irc split
 *
 * If it doesn't start with a ':', split into two parts.
 * Otherwise 4 parts
 * [from] [command] [to] [message]
 *
 * @param text
 * @return std::vector<std::string>
 */
std::vector<std::string> irc_split(std::string &text) {
  size_t msgpos = text.find(" :");
  std::string message;
  if (msgpos != std::string::npos) {
    message = text.substr(msgpos + 2);
    text.erase(msgpos);
  }
  std::vector<std::string> results;

  /*
  if (text[0] != ':')
    results = split_limit(text, 2);
  results = split_limit(text, 4);
  */
  results = split_limit(text, -1);
  if (!message.empty())
    results.push_back(message);
  return results;
}

/**
 * @brief parse_nick
 *
 * Parse out the nick from nick!username@host
 *
 * @param name
 * @return std::string
 */
std::string parse_nick(std::string &name) {
  std::string to = name;
  if (to[0] == ':')
    to.erase(0, 1);
  size_t pos = to.find('!');
  if (pos != std::string::npos) {
    to.erase(pos);
  }
  return to;
}

// namespace io = boost::asio;
// namespace ip = io::ip;
// using tcp = boost::asio::ip; // ip::tcp;

using error_code = boost::system::error_code;
using namespace std::placeholders;

// #define DEBUG_OUTPUT

typedef std::function<void(std::string &)> receiveFunction;

#ifdef SENDQ
ircClient::ircClient(boost::asio::io_context &io_context)
    : resolver{io_context}, ssl_context{boost::asio::ssl::context::tls},
      socket{io_context, ssl_context},
      sendq_timer{io_context}, context{io_context} {
#else
ircClient::ircClient(boost::asio::io_context &io_context)
    : resolver{io_context}, ssl_context{boost::asio::ssl::context::tls},
      socket{io_context, ssl_context}, context{io_context} {
#endif
  registered = false;
  nick_retry = 1;
  shutdown = false;
  logging = false;
  channels_updated = false;
  version = "Bugz IRC thing V0.1";
#ifdef SENDQ
  sendq_current = 0;
  sendq_active = false;
  sendq_ms = 500;
  sendq_current = 0;
#endif
}

std::ofstream &ircClient::log(void) {
  std::time_t t = std::time(nullptr);
  std::tm tm = *std::localtime(&t);
  debug_file << std::put_time(&tm, "%c ");
  return debug_file;
}

void ircClient::begin(void) {
  original_nick = nick;
  resolver.async_resolve(hostname, port,
                         std::bind(&ircClient::on_resolve, this, _1, _2));
  if (!debug_output.empty()) {
    debug_file.open(debug_output.c_str(),
                    std::ofstream::out | std::ofstream::app);
    logging = true;
  }
}

void ircClient::write(std::string output) {
  if (logging) {
    log() << "<< " << output << std::endl;
  }
  error_code error;
  socket.write_some(boost::asio::buffer(output + "\r\n"), error);
  if (error) {
    if (logging) {
      log() << "Write: " << error.message() << std::endl;
    }
  }
}

#ifdef SENDQ
/**
 * @brief Add to the sendq for async slow message sending.
 *
 * target is used (we cycle through sendq_targets) so no one person can clog up
 * the queue.
 *
 * @param target
 * @param output
 */
void ircClient::write_queue(std::string target, std::string output) {
  // is target in sendq_targets
  bool found = false;
  for (auto &t : sendq_targets) {
    if (t == target) {
      found = true;
      break;
    }
  }

  if (!found) {
    sendq_targets.push_back(target);
  };

  sendq[target].push_back(output);

  if (!sendq_active) {
    // async send is not active -- start the timer event
    sendq_active = true;
    sendq_current = 0;
    sendq_timer.expires_after(std::chrono::milliseconds(sendq_ms));
    sendq_timer.async_wait(std::bind(&ircClient::on_sendq, this, _1));
  }
}

/**
 * @brief async send buffer
 *
 * This sends lines out slowly to the ircd.  It uses the sendq_targets to
 * alternate between so one person can't clog up the buffer.
 *
 * TODO:  Add something that checks to see how many lines we have sent.
 * After 20 lines, increase the sendq_ms (maybe 2*sendq_ms?)  After 50, maybe
 * 3*sendq_ms.  We want to throttle ourselves and not have the ircd doing it.
 *
 * Currently, this is not thread-safe.  It's being used by code that isn't
 * running the io_context in another thread.
 * @param error
 */
void ircClient::on_sendq(error_code error) {
  std::string &target = sendq_targets[sendq_current];

  // calculate the next target
  ++sendq_current;
  if (sendq_current >= (int)sendq_targets.size())
    sendq_current = 0;

  std::string output = sendq[target].front();
  sendq[target].erase(sendq[target].begin());
  write(output);

  if (sendq[target].size() == 0) {
    // target queue is empty
    sendq.erase(target);

    // remove target from sendq_targets
    for (auto pos = sendq_targets.begin(); pos != sendq_targets.end(); ++pos) {
      // for (int x = 0; x < (int)sendq_targets.size(); ++x) {
      if (*pos == target) {
        sendq_targets.erase(pos);
        break;
      }
    }

    // verify the sendq_current is still valid
    if (sendq_current >= (int)sendq_targets.size())
      sendq_current = 0;
  }

  if (!sendq_targets.empty()) {
    // more to do, let's do it again!
    sendq_timer.expires_after(std::chrono::milliseconds(sendq_ms));
    sendq_timer.async_wait(std::bind(&ircClient::on_sendq, this, _1));
  } else {
    // let write_queue know we aren't running anymore.
    sendq_active = false;
  }
}
#endif

/**
 * @brief thread safe messages.push_back
 *
 * @param msg
 */
void ircClient::message_append(message_stamp &msg) {
  lock.lock();
  messages.push_back(msg);
  channels_updated = true;
  lock.unlock();
}

/**
 * @brief thread safe message_stamp pop
 *
 * @return boost::optional<message_stamp>
 */
boost::optional<message_stamp> ircClient::message_pop(void) {
  lock.lock();
  message_stamp msg;
  if (messages.empty()) {
    channels_updated = false;
    lock.unlock();
    return boost::optional<message_stamp>{};
  }
  msg = messages.front();
  messages.erase(messages.begin());
  lock.unlock();
  return msg;
}

void ircClient::on_resolve(
    error_code error, boost::asio::ip::tcp::resolver::results_type results) {
  if (logging) {
    log() << "Resolve: " << error.message() << std::endl;
  }
  if (error) {
    std::string output = "Unable to resolve (DNS Issue?): " + error.message();
    errors.push_back(output);
    message(output);
    socket.async_shutdown(std::bind(&ircClient::on_shutdown, this, _1));
  }
  boost::asio::async_connect(socket.next_layer(), results,
                             std::bind(&ircClient::on_connect, this, _1, _2));
}

void ircClient::on_connect(error_code error,
                           boost::asio::ip::tcp::endpoint const &endpoint) {
  if (logging) {
    log() << "Connect: " << error.message() << ", endpoint: " << endpoint
          << std::endl;
  }
  if (error) {
    std::string output = "Unable to connect: " + error.message();
    message(output);
    errors.push_back(output);
    socket.async_shutdown(std::bind(&ircClient::on_shutdown, this, _1));
  }

  socket.async_handshake(boost::asio::ssl::stream_base::client,
                         std::bind(&ircClient::on_handshake, this, _1));
}

void ircClient::on_handshake(error_code error) {
  if (logging) {
    log() << "Handshake: " << error.message() << std::endl;
  }
  if (error) {
    std::string output = "Handshake Failure: " + error.message();
    message(output);
    errors.push_back(output);
    socket.async_shutdown(std::bind(&ircClient::on_shutdown, this, _1));
  }

  write(registration());
  /*
  std::string request = registration();
  boost::asio::async_write(socket, boost::asio::buffer(request),
                           std::bind(&ircClient::on_write, this, _1, _2));
  // socket.async_shutdown(std::bind(&ircClient::on_shutdown, this, _1));
}

void ircClient::on_write(error_code error, std::size_t bytes_transferred) {
  if ((error) and (logging)) {
    log() << "Write: " << error.message() << std::endl;
  }
  */
  // << ", bytes transferred: " << bytes_transferred << "\n";
  boost::asio::async_read_until(
      socket, response, '\n', std::bind(&ircClient::read_until, this, _1, _2));
}

void ircClient::on_shutdown(error_code error) {
  if (logging) {
    log() << "SHUTDOWN: " << error.message() << std::endl;
  }
  shutdown = true;
  context.stop();
}

void ircClient::read_until(error_code error, std::size_t bytes) {
  // std::cout << "Read: " << bytes << ", " << error << "\n";
  // auto data = response.data();
  if (bytes == 0) {
    if (logging) {
      log() << "Read 0 bytes, shutdown..." << std::endl;
    }
    socket.async_shutdown(std::bind(&ircClient::on_shutdown, this, _1));
    return;
  };

  // Only try to get the data -- if we're read some bytes.
  auto data = response.data();
  response.consume(bytes);
  std::string text{(const char *)data.data(), bytes};

  while ((text[text.size() - 1] == '\r') or (text[text.size() - 1] == '\n'))
    text.erase(text.size() - 1);

  receive(text);

  // repeat until closed

  boost::asio::async_read_until(
      socket, response, '\n', std::bind(&ircClient::read_until, this, _1, _2));
}

/**
 * @brief Append a system message to the messages.
 *
 * @param msg
 */
void ircClient::message(std::string msg) {
  message_stamp ms;
  ms.buffer.push_back(msg);
  message_append(ms);
}

void ircClient::receive(std::string &text) {
  message_stamp ms;
  ms.buffer = irc_split(text);
  std::vector<std::string> &parts = ms.buffer;

  if (logging) {
    // this also shows our parser working
    std::ofstream &l = log();
    l << ">> ";
    for (auto &s : parts) {
      l << "[" << s << "] ";
    }
    l << std::endl;
  }

  // INTERNAL IRC PARSING/TRACKING

  if (parts.size() == 2) {
    // hide PING / PONG messages
    if (parts[0] == "PING") {
      std::string output = "PONG " + parts[1];
      write(output);
      return;
    }
  }

  if (parts.size() >= 3) {
    std::string source = parse_nick(parts[0]);
    std::string &cmd = parts[1];
    std::string &msg_to = parts[2];

    std::string msg;
    if (parts.size() >= 4) {
      msg = parts[parts.size() - 1];
    }

    if (logging) {
      // this also shows our parser working
      std::ofstream &l = log();
      l << "IRC: [SRC:" << source << "] [CMD:" << cmd << "] [TO:" << msg_to
        << "] [MSG:" << msg << "]" << std::endl;
    }

    if (cmd == "JOIN") {
      channels_lock.lock();
      if (nick == source) {
        // yes, we are joining
        std::string output = "You have joined " + msg_to;
        message(output);
        talkto(msg_to);
        // insert empty set here.
        std::set<std::string> empty;
        channels[msg_to] = empty;
      } else {
        // Someone else is joining
        std::string output = source + " has joined " += msg_to;
        message(output);
        channels[msg_to].insert(source);
        if ((int)source.size() > max_nick_length)
          max_nick_length = (int)source.size();
      }

      channels_lock.unlock();
    }

    if (cmd == "PART") {
      channels_lock.lock();
      if (nick == source) {
        std::string output = "You left " + msg_to;

        auto ch = channels.find(msg_to);
        if (ch != channels.end())
          channels.erase(ch);

        if (!channels.empty()) {
          talkto(channels.begin()->first);
          // output += " [talkto = " + talkto() + "]";
        } else {
          talkto("");
        }
        // message(output);

      } else {
        std::string output = source + " has left " + msg_to;
        if (!msg.empty()) {
          output += " " + msg;
        }
        message(output);
        channels[msg_to].erase(source);
      }

      find_max_nick_length();
      channels_lock.unlock();
    }

    if (cmd == "KICK") {
      std::string output =
          source + " has kicked " + parts[3] + " from " + msg_to;

      channels_lock.lock();
      if (parts[3] == nick) {
        channels.erase(msg_to);
        if (!channels.empty()) {
          talkto(channels.begin()->first);
          output += " [talkto = " + talkto() + "]";
        } else {
          talkto("");
        }
      } else {
        channels[msg_to].erase(parts[3]);
      }

      find_max_nick_length();
      channels_lock.unlock();
      message(output);
    }

    if (cmd == "QUIT") {
      std::string output = "* " + source + " has quit ";
      message(output);

      channels_lock.lock();
      if (source == nick) {
        // We've quit?
        channels.erase(channels.begin(), channels.end());
      } else {
        for (auto &c : channels) {
          c.second.erase(source);
          // would it be possible that channel is empty now?
          // no, because we're still in it.
        }
        find_max_nick_length();
      }
      channels_lock.unlock();
    }

    if (cmd == "353") {
      // NAMES list for channel
      std::vector<std::string> names_list = split_limit(msg);
      std::string channel = parts[4];

      channels_lock.lock();
      if (channels.find(channel) == channels.end()) {
        // does not exist
        channels.insert({channel, std::set<std::string>{}});
      }

      for (auto name : names_list) {
        remove_channel_modes(name);
        channels[channel].insert(name);
      }

      find_max_nick_length();
      channels_lock.unlock();
    }

    if (cmd == "NICK") {
      // msg_to.erase(0, 1);

      channels_lock.lock();
      for (auto &ch : channels) {
        if (ch.second.erase(source) == 1) {
          ch.second.insert(msg_to);
        }
      }
      // Is this us?  If so, change our nick.
      if (source == nick)
        nick = msg_to;

      find_max_nick_length();
      channels_lock.unlock();
    }

    if (cmd == "PRIVMSG") {
      // Possibly a CTCP request.  Let's see
      std::string message = msg;
      if ((message[0] == '\x01') and (message[message.size() - 1] == '\x01')) {
        // CTCP handler
        // NOTE:  When sent to a channel, the response is sent to the sender.

        // CTCP MESSAGE FOUND  strip \x01's
        message.erase(0, 1);
        message.erase(message.size() - 1);

        std::vector<std::string> ctcp_cmd = split_limit(message, 2);

        if (ctcp_cmd[0] != "ACTION") {
          std::string msg =
              "Received CTCP " + ctcp_cmd[0] + " from " + parse_nick(source);
          this->message(msg);
          if (logging) {
            log() << "CTCP : [" << message << "] from " + parse_nick(source)
                  << std::endl;
          }
        }

        if (message == "VERSION") {
          std::string reply_to = parse_nick(source);
          boost::format fmt = boost::format("NOTICE %1% :\x01VERSION %2%\x01") %
                              reply_to % version;
          std::string response = fmt.str();
          write(response);
          return;
        }

        if (message.substr(0, 5) == "PING ") {
          message.erase(0, 5);
          boost::format fmt = boost::format("NOTICE %1% :\x01PING %2%\x01") %
                              parse_nick(source) % message;
          std::string response = fmt.str();
          write(response);
          return;
        }

        if (message == "TIME") {
          auto now = std::chrono::system_clock::now();
          auto in_time_t = std::chrono::system_clock::to_time_t(now);
          std::string datetime = boost::lexical_cast<std::string>(
              std::put_time(std::localtime(&in_time_t), "%c"));

          boost::format fmt = boost::format("NOTICE %1% :\x01TIME %2%\x01") %
                              parse_nick(source) % datetime;
          std::string response = fmt.str();
          write(response);
          return;
        }

        if (message.substr(0, 7) == "ACTION ") {
          message.erase(0, 7);
          parts[1] = "ACTION"; // change PRIVMSG to ACTION
          parts[3] = message;
        } else {
          // What should I do with unknown CTCP commands?
          // Unknown CTCP command.  Eat it.
          return;
        }
      }
    }
  }

  if (!registered) {
    // We're not registered yet
    if (parts[1] == "433") {
      // nick collision!  Nick already in use
      if (nick == original_nick) {
        // try something basic
        nick += "_";
        std::string output = "NICK " + nick;
        write(output);
        return;
      } else {
        // Ok, go advanced
        nick = original_nick + "_" + std::to_string(nick_retry);
        ++nick_retry;
        std::string output = "NICK " + nick;
        write(output);
        return;
      }
    }

    // SASL Authentication
    if ((parts[1] == "CAP") and (parts[3] == "ACK")) {
      write("AUTHENTICATE PLAIN");
    }

    if ((parts[0] == "AUTHENTICATE") and (parts[1] == "+")) {
      std::string userpass;
      userpass.append(1, 0);
      userpass.append(nick);
      userpass.append(1, 0);
      userpass.append(sasl_plain_password);
      std::string asbase64 = base64encode(userpass);
      std::string auth = "AUTHENTICATE " + asbase64;
      write(auth);
    }

    if (parts[1] == "903") {
      // success SASL
      write("CAP END");
    }

    if (parts[1] == "904") {
      // SASL failed
      write("CAP END");
      // Should we close the connection if we can't authenticate?
    }

    if ((parts[1] == "376") or (parts[1] == "422")) {
      // END MOTD, or MOTD MISSING
      find_max_nick_length(); // start with ourself.
      registered = true;
      if (!autojoin.empty()) {
        std::string msg = "JOIN " + autojoin;
        write(msg);
      }
    }
  }

  message_append(ms);
}

/**
 * @brief find max nick length
 *
 * This is for formatting the messages.
 * We run through the channels checking all the users,
 * and also checking our own nick.
 *
 * This updates \ref max_nick_length
 */
void ircClient::find_max_nick_length(void) {
  int max = 0;
  for (auto const &ch : channels) {
    for (auto const &nick : ch.second) {
      if ((int)nick.size() > max)
        max = (int)nick.size();
    }
  }
  // check our nick against this too.
  if ((int)nick.size() > max)
    max = (int)nick.size();
  max_nick_length = max;
}

std::string ircClient::registration(void) {
  std::string text;

  // Initiate SASL authentication
  if (!sasl_plain_password.empty()) {
    text = "CAP REQ :sasl\r\n";
  }

  if (!server_password.empty()) {
    text += "PASS " + server_password + "\r\n";
  }

  text += "NICK " + nick + "\r\n" + "USER " + username + " 0 * :" + realname +
          "\r\n";
  return text;
}

#include <boost/archive/iterators/base64_from_binary.hpp>
#include <boost/archive/iterators/transform_width.hpp>

typedef boost::archive::iterators::base64_from_binary<
    boost::archive::iterators::transform_width<std::string::const_iterator, 6,
                                               8>>
    it_base64_t;

std::string base64encode(const std::string &str) {
  unsigned int writePaddChars = (3 - str.length() % 3) % 3;
  std::string base64(it_base64_t(str.begin()), it_base64_t(str.end()));
  base64.append(writePaddChars, '=');
  return base64;
}