#pragma once

#include <bitset>
#include <iomanip>

#include <arpa/inet.h>
#include <ifaddrs.h>
#include <iwlib.h>
#include <limits.h>
#include <linux/ethtool.h>
#include <linux/if_link.h>
#include <linux/sockios.h>
#include <net/if.h>
#include <netinet/in.h>
#include <signal.h>
#include <sys/socket.h>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <iostream>
#include <memory>
#include <memory>
#include <sstream>
#include <string>
#include <string>

#ifdef inline
#undef inline
#endif

#include "common.hpp"
#include "config.hpp"
#include "utils/command.hpp"
#include "utils/file.hpp"
#include "utils/string.hpp"

LEMONBUDDY_NS

namespace net {
  DEFINE_ERROR(network_error);

  // types {{{

  struct quality_range {
    int val = 0;
    int max = 0;

    int percentage() const {
      if (max < 0)
        return 2 * (val + 100);
      return static_cast<float>(val) / max * 100.0f + 0.5f;
    }
  };

  using bytes_t = unsigned int;

  struct link_activity {
    bytes_t transmitted = 0;
    bytes_t received = 0;
    chrono::system_clock::time_point time;
  };

  struct link_status {
    string ip;
    link_activity previous;
    link_activity current;
  };

  // }}}
  // class: network {{{

  class network {
   public:
    /**
     * Construct network interface
     */
    explicit network(string interface) : m_interface(interface) {
      if (if_nametoindex(m_interface.c_str()) == 0)
        throw network_error("Invalid network interface \"" + m_interface + "\"");
      if ((m_socketfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
        throw network_error("Failed to open socket");
    }

    /**
     * Destruct network interface
     */
    virtual ~network() {
      if (m_socketfd != -1)
        close(m_socketfd);
    }

    /**
     * Query device driver for information
     */
    virtual bool query() {
      struct ifaddrs* ifaddr;

      if (getifaddrs(&ifaddr) == -1)
        return false;

      for (auto ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
        if (m_interface.compare(0, m_interface.length(), ifa->ifa_name) != 0)
          continue;

        switch (ifa->ifa_addr->sa_family) {
          case AF_INET:
            char ip_buffer[NI_MAXHOST];
            getnameinfo(ifa->ifa_addr, sizeof(sockaddr_in), ip_buffer, NI_MAXHOST, nullptr, 0,
                NI_NUMERICHOST);
            m_status.ip = string{ip_buffer};
            break;

          case AF_PACKET:
            if (ifa->ifa_data == nullptr)
              continue;
            struct rtnl_link_stats* link_state =
                reinterpret_cast<decltype(link_state)>(ifa->ifa_data);
            m_status.previous = m_status.current;
            m_status.current.transmitted = link_state->tx_bytes;
            m_status.current.received = link_state->rx_bytes;
            m_status.current.time = chrono::system_clock::now();
            break;
        }
      }

      freeifaddrs(ifaddr);

      return true;
    }

    /**
     * Check current connection state
     */
    virtual bool connected() const = 0;

    /**
     * Run ping command to test internet connectivity
     */
    virtual bool ping() const {
      try {
        auto exec = "ping -c 2 -W 2 -I " + m_interface + " " + string(CONNECTION_TEST_IP);
        auto ping = command_util::make_command(exec);
        return ping && ping->exec(true) == EXIT_SUCCESS;
      } catch (const std::exception& err) {
        return false;
      }
    }

    /**
     * Get interface ip address
     */
    string ip() const {
      return m_status.ip;
    }

    /**
     * Get download speed rate
     */
    string downspeed(int minwidth = 3) const {
      float bytes_diff = m_status.current.received - m_status.previous.received;
      return format_speedrate(bytes_diff, minwidth);
    }

    /**
     * Get upload speed rate
     */
    string upspeed(int minwidth = 3) const {
      float bytes_diff = m_status.current.transmitted - m_status.previous.transmitted;
      return format_speedrate(bytes_diff, minwidth);
    }

   protected:
    /**
     * Test if the network interface is in a valid state
     */
    bool test_interface() const {
      auto operstate = file_util::get_contents("/sys/class/net/" + m_interface + "/operstate");
      return operstate.compare(0, 2, "up") == 0;
    }

    /**
     * Format up- and download speed
     */
    string format_speedrate(float bytes_diff, int minwidth) const {
      const auto duration = m_status.current.time - m_status.previous.time;
      float time_diff = chrono::duration_cast<chrono::seconds>(duration).count();
      float speedrate = bytes_diff / (time_diff ? time_diff : 1);

      vector<string> suffixes{"GB", "MB"};
      string suffix{"KB"};

      while ((speedrate /= 1000) > 999) {
        suffix = suffixes.back();
        suffixes.pop_back();
      }

      return string_util::from_stream(stringstream() << std::setw(minwidth) << std::setfill(' ')
                                                     << std::setprecision(0) << std::fixed
                                                     << speedrate << " " << suffix << "/s");
    }

    int m_socketfd = 0;
    link_status m_status;
    string m_interface;
  };

  // }}}
  // class: wired_network {{{

  class wired_network : public network {
   public:
    explicit wired_network(string interface) : network(interface) {}

    /**
     * Query device driver for information
     */
    bool query() override {
      if (!network::query())
        return false;

      struct ethtool_cmd ethernet_data;
      ethernet_data.cmd = ETHTOOL_GSET;

      struct ifreq request;
      strncpy(request.ifr_name, m_interface.c_str(), IFNAMSIZ - 1);
      request.ifr_data = reinterpret_cast<caddr_t>(&ethernet_data);

      if (ioctl(m_socketfd, SIOCETHTOOL, &request) == -1)
        return false;

      m_linkspeed = ethernet_data.speed;

      return true;
    }

    /**
     * Check current connection state
     */
    bool connected() const override {
      if (!network::test_interface())
        return false;

      struct ifreq request;
      struct ethtool_value ethernet_data;

      strncpy(request.ifr_name, m_interface.c_str(), IFNAMSIZ - 1);
      ethernet_data.cmd = ETHTOOL_GLINK;
      request.ifr_data = reinterpret_cast<caddr_t>(&ethernet_data);

      if (ioctl(m_socketfd, SIOCETHTOOL, &request) != -1)
        return ethernet_data.data != 0;

      return false;
    }

    /**
     *
     * about the current connection
     */
    string linkspeed() const {
      return (m_linkspeed == 0 ? "???" : to_string(m_linkspeed)) + " Mbit/s";
    }

   private:
    int m_linkspeed = 0;
  };

  // }}}
  // class: wireless_network {{{

  class wireless_network : public network {
   public:
    wireless_network(string interface) : network(interface) {}

    /**
     * Query the wireless device for information
     * about the current connection
     */
    bool query() override {
      if (!network::query())
        return false;

      auto socket_fd = iw_sockets_open();

      if (socket_fd == -1)
        return false;

      struct iwreq req;

      if (iw_get_ext(socket_fd, m_interface.c_str(), SIOCGIWMODE, &req) == -1)
        return false;

      // Ignore interfaces in ad-hoc mode
      if (req.u.mode == IW_MODE_ADHOC)
        return false;

      query_essid(socket_fd);
      query_quality(socket_fd);

      iw_sockets_close(socket_fd);

      return true;
    }

    /**
     * Check current connection state
     */
    bool connected() const override {
      if (!network::test_interface())
        return false;

      struct ifreq request;
      strncpy(request.ifr_name, m_interface.c_str(), IFNAMSIZ - 1);

      if ((ioctl(m_socketfd, SIOCGIFFLAGS, &request)) == -1)
        return false;
      if (m_essid.empty())
        return false;

      return true;
    }

    /**
     * ESSID reported by last query
     */
    string essid() const {
      return m_essid;
    }

    /**
     * Signal strength percentage reported by last query
     */
    int signal() const {
      return m_signalstrength.percentage();
    }

    /**
     * Link quality percentage reported by last query
     */
    int quality() const {
      return m_linkquality.percentage();
    }

   protected:
    /**
     * Query for ESSID
     */
    void query_essid(const int& socket_fd) {
      char essid[IW_ESSID_MAX_SIZE + 1];

      struct iwreq req;
      req.u.essid.pointer = &essid;
      req.u.essid.length = sizeof(essid);
      req.u.essid.flags = 0;

      if (iw_get_ext(socket_fd, m_interface.c_str(), SIOCGIWESSID, &req) != -1) {
        m_essid = string{essid};
      } else {
        m_essid.clear();
      }
    }

    /**
     * Query for device driver quality values
     */
    void query_quality(const int& socket_fd) {
      iwrange range;
      iwstats stats;

      // Fill range
      if (iw_get_range_info(socket_fd, m_interface.c_str(), &range) == -1)
        return;
      // Fill stats
      if (iw_get_stats(socket_fd, m_interface.c_str(), &stats, &range, 1) == -1)
        return;

      // Check if the driver supplies the quality value
      if (stats.qual.updated & IW_QUAL_QUAL_INVALID)
        return;
      // Check if the driver supplies the quality level value
      if (stats.qual.updated & IW_QUAL_LEVEL_INVALID)
        return;

      // Check if the link quality has been uodated
      if (stats.qual.updated & IW_QUAL_QUAL_UPDATED) {
        m_linkquality.val = stats.qual.qual;
        m_linkquality.max = range.max_qual.qual;
      }

      // Check if the signal strength has been uodated
      if (stats.qual.updated & IW_QUAL_LEVEL_UPDATED) {
        m_signalstrength.val = stats.qual.level;
        m_signalstrength.max = range.max_qual.level;

        // Check if the values are defined in dBm
        if (stats.qual.level > range.max_qual.level) {
          m_signalstrength.val -= 0x100;
          m_signalstrength.max -= 0x100;
        }
      }
    }

   private:
    shared_ptr<wireless_info> m_info;
    string m_essid;
    quality_range m_signalstrength;
    quality_range m_linkquality;
  };

  // }}}

  /**
   * Test if interface with given name is a wireless device
   */
  inline bool is_wireless_interface(string ifname) {
    return file_util::exists("/sys/class/net/" + ifname + "/wireless");
  }

  using wireless_t = unique_ptr<wireless_network>;
  using wired_t = unique_ptr<wired_network>;
}

LEMONBUDDY_NS_END