#include "socket.h"

#include <fmt/core.h>

#include <filesystem>
#include <iostream>

namespace fs = std::filesystem;
using namespace std::string_literals;

std::mutex& Socket::getMutex()
{
 return m_mutex;
}

FCGI_ID& Socket::fcgi_id()
{
 return m_fcgi_id;
}

SocketFactory::SocketFactory()
{
}

std::shared_ptr<Socket> SocketFactory::create(const std::string& app_addr)
{
 std::error_code ec;
 size_t pos { app_addr.find_last_of(':') };
 if (pos != app_addr.npos) { // tcp socket: host:port

  return std::make_shared<TCPSocket>(app_addr.substr(0, pos), app_addr.substr(pos + 1), m_io_context);
 
 } else if (fs::is_socket(fs::path{app_addr}, ec)) { // Unix domain socket
  return std::make_shared<FileSocket>(app_addr, m_io_context);
 } else if (fs::is_regular_file(fs::path{app_addr}, ec)) { // Executable to start
  return std::make_shared<FileSocketApp>(app_addr, m_io_context);
 } else {
  std::cerr << "FCGI Error: Invalid app_addr type." << std::endl;
 }

 return {}; 
}

TCPSocket::TCPSocket(const std::string& host, const std::string& port, boost::asio::io_context& io_context)
 : m_io_context(io_context)
 , m_host(host)
 , m_port(port)
 , m_socket(io_context)
{
}

TCPSocket::~TCPSocket()
{
}

void TCPSocket::open()
{
 boost::asio::ip::tcp::resolver resolver(m_io_context);
 auto endpoints{resolver.resolve(m_host, m_port)};
 try {
  boost::asio::connect(m_socket, endpoints);
 } catch(const std::exception& ex) {
  std::cerr << "FCGI Error: Error on connecting to " << m_host << ":" << m_port << ": " << ex.what() << std::endl;
  return;
 }

 boost::asio::socket_base::keep_alive keepAlive(true);
 m_socket.set_option(keepAlive);

 struct timeval tv;
 tv.tv_sec  = 0; // infinite
 tv.tv_usec = 0;
 if (setsockopt(m_socket.native_handle(), SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
  std::cerr << "FCGI Error: SO_RCVTIMEO" << std::endl;

 if (setsockopt(m_socket.native_handle(), SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv)))
  std::cerr << "FCGI Error: SO_SNDTIMEO" << std::endl;

 int val{1};
 if (setsockopt(m_socket.native_handle(), SOL_SOCKET, SO_KEEPALIVE, &val, sizeof(val)))
  std::cerr << "FCGI Error: SO_KEEPALIVE" << std::endl;
}

bool TCPSocket::is_open()
{
 if (m_socket.is_open()) {
  std::vector<char> inbuf;

  int error;
  socklen_t len = sizeof (error);
  int retval {getsockopt(m_socket.native_handle(), SOL_SOCKET, SO_ERROR, &error, &len)};

  if (retval) {
   std::cerr << "FCGI Error: getsockopt() error in is_open(): " << strerror(errno) << std::endl;
   try {
    // for graceful shutdown, according to
    // https://www.boost.org/doc/libs/1_66_0/doc/html/boost_asio/reference/basic_stream_socket/close/overload1.html
    m_socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
    m_socket.close(); // correct state
   } catch (...) {
    std::cerr << "Error on shutdown/close" << std::endl;
   }
   return false;
  }

  if (error != 0) {
   try {
    m_socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
    m_socket.close(); // correct state
   } catch (...) {
    std::cerr << "Error on shutdown/close" << std::endl;
   }
   return false;
  }

  return true;
 } else
  return false;
}

void TCPSocket::close()
{
 m_socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
 m_socket.close();
}

size_t TCPSocket::write(const std::vector<char>& data)
{
 try {
  return m_socket.write_some(boost::asio::buffer(data));
 } catch (const boost::system::system_error& ex) {
  if (ex.code() == boost::asio::error::eof) {
   throw fcgi_eof_error("EOF on write");
  } else if (ex.code() == boost::asio::error::broken_pipe) {
   throw fcgi_broken_pipe_error("Application server connection broken");
  } else
   throw std::runtime_error("FCGI Error: Unknown boost asio exception on write: "s + ex.what());
 } catch (const std::exception& ex) {
  throw std::runtime_error("FCGI Error: Unknown exception on write: "s + ex.what());
 }
}

size_t TCPSocket::read(std::vector<char>& data)
{
 try {
  size_t result{0};

  do {
   std::vector<char> inbuf_part(1024);
   size_t got { m_socket.read_some(boost::asio::buffer(inbuf_part))};
   data.insert(data.end(), inbuf_part.begin(), inbuf_part.begin() + got);
   result += got;
  } while (m_socket.available());

  return result;

 } catch (const boost::system::system_error& ex) {
  if (ex.code() == boost::asio::error::eof) {
   throw fcgi_eof_error("EOF on read");
  } else
   throw std::runtime_error("FCGI Error: Unknown boost asio exception on read: "s + ex.what());
 } catch (const std::exception& ex) {
  throw std::runtime_error("FCGI Error: Unknown exception on read: "s + ex.what());
 }
}

FileSocket::FileSocket(const std::string& app_addr, boost::asio::io_context& io_context)
 : m_app_addr(app_addr)
 , m_socket(io_context)
{
}

FileSocket::~FileSocket()
{
}

void FileSocket::open()
{
 try {
  boost::asio::local::stream_protocol::endpoint ep(m_app_addr);
  m_socket.connect(ep);
 } catch(const std::exception& ex) {
  std::cerr << "FCGI Error: Error on connecting to " << m_app_addr << ": " << ex.what() << std::endl;
  return;
 }
}

bool FileSocket::is_open()
{
 return m_socket.is_open();
}

void FileSocket::close()
{
 m_socket.close();
}

size_t FileSocket::write(const std::vector<char>& data)
{
 try {
  return m_socket.write_some(boost::asio::buffer(data));
 } catch (const boost::system::system_error& ex) {
  if (ex.code() == boost::asio::error::eof) {
   throw fcgi_eof_error("EOF on write");
  } else if (ex.code() == boost::asio::error::broken_pipe) {
   throw fcgi_broken_pipe_error("Application server connection broken");
  } else
   throw std::runtime_error("FCGI Error: Unknown boost asio exception on write: "s + ex.what());
 } catch (const std::exception& ex) {
  throw std::runtime_error("FCGI Error: Unknown exception on write: "s + ex.what());
 }
}

size_t FileSocket::read(std::vector<char>& data)
{
 try {
  size_t result{0};

  do { 
   std::vector<char> inbuf_part(1024);
   size_t got { m_socket.read_some(boost::asio::buffer(inbuf_part))};
   data.insert(data.end(), inbuf_part.begin(), inbuf_part.begin() + got);
   result += got;
  } while (m_socket.available());

  return result;
 } catch (const boost::system::system_error& ex) {
  if (ex.code() == boost::asio::error::eof) {
   throw fcgi_eof_error("EOF on read");
  } else
   throw std::runtime_error("FCGI Error: Unknown boost asio exception on read: "s + ex.what());
 } catch (const std::exception& ex) {
  throw std::runtime_error("FCGI Error: Unknown exception on read: "s + ex.what());
 }
}

std::string generate_unix_domain_socket(const std::string& directory)
{
 for (int i = 0; i < 10000; i++) {
  std::string path{fmt::format("{}/fcgi-socket{}", directory, i)};
  if (fs::exists(path))
   continue;
  return path;
 }
 throw std::runtime_error("dynamic unix domain socket couldn't be generated.");
}

FileSocketApp::FileSocketApp(const std::string& app_addr, boost::asio::io_context& io_context):
 m_socket_file{generate_unix_domain_socket(fs::exists("/var/lib/webserver") ? "/var/lib/webserver" : ".")},
 m_fcgi_process{app_addr, m_socket_file},
 m_file_socket{m_socket_file, io_context}
{
}

FileSocketApp::~FileSocketApp()
{
 std::error_code ec;
 fs::remove(m_socket_file, ec);
}

void FileSocketApp::open()
{
 m_file_socket.open();
}

void FileSocketApp::close()
{
 m_file_socket.close();
}

bool FileSocketApp::is_open()
{
 return m_file_socket.is_open();
}

size_t FileSocketApp::write(const std::vector<char>& data)
{
 return m_file_socket.write(data);
}

size_t FileSocketApp::read(std::vector<char>& data)
{
 return m_file_socket.read(data);
}