/**
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef LIBMINIFI_INCLUDE_IO_POSIX_CLIENTSOCKET_H_
#define LIBMINIFI_INCLUDE_IO_POSIX_CLIENTSOCKET_H_


#include <cstdint>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#include <mutex>
#include <atomic>
#include "io/BaseStream.h"
#include "core/Core.h"
#include "core/logging/Logger.h"
#include "io/validation.h"
#include "properties/Configure.h"
#include "io/NetworkPrioritizer.h"

namespace org {
namespace apache {
namespace nifi {
namespace minifi {
namespace io {

/**
 * Context class for socket. This is currently only used as a parent class for TLSContext.  It is necessary so the Socket and TLSSocket constructors
 * can be the same.  It also gives us a common place to set timeouts, etc from the Configure object in the future.
 */
class SocketContext {
 public:
  SocketContext(const std::shared_ptr<Configure> &configure) {
  }
};
/**
 * Socket class.
 * Purpose: Provides a general purpose socket interface that abstracts
 * connecting information from users
 * Design: Extends DataStream and allows us to perform most streaming
 * operations against a BSD socket
 *
 *
 */
class Socket : public BaseStream {
 public:
  /**
   * Constructor that creates a client socket.
   * @param context the SocketContext
   * @param hostname hostname we are connecting to.
   * @param port port we are connecting to.
   */
  explicit Socket(const std::shared_ptr<SocketContext> &context, const std::string &hostname, const uint16_t port);

  /**
   * Move constructor.
   */
  explicit Socket(const Socket &&);

  /**
   * Static function to return the current machine's host name
   */
  static std::string getMyHostName() {
    static std::string HOSTNAME = init_hostname();
    return HOSTNAME;
  }

  /**
   * Destructor
   */

  virtual ~Socket();

  virtual void closeStream();
  /**
   * Initializes the socket
   * @return result of the creation operation.
   */
  virtual int16_t initialize();

  virtual void setInterface(io::NetworkInterface &&interface) {
    local_network_interface_ = std::move(interface);
  }

  /**
   * Sets the non blocking flag on the file descriptor.
   */
  void setNonBlocking();

  std::string getHostname() const;

  /**
   * Return the port for this socket
   * @returns port
   */
  uint16_t getPort() const {
    return port_;
  }

  // data stream extensions
  /**
   * Reads data and places it into buf
   * @param buf buffer in which we extract data
   * @param buflen
   * @param retrieve_all_bytes determines if we should read all bytes before returning
   */
  virtual int readData(std::vector<uint8_t> &buf, int buflen) {
    return readData(buf, buflen, true);
  }
  /**
   * Reads data and places it into buf
   * @param buf buffer in which we extract data
   * @param buflen
   * @param retrieve_all_bytes determines if we should read all bytes before returning
   */
  virtual int readData(uint8_t *buf, int buflen) {
    return readData(buf, buflen, true);
  }

  /**
   * Reads data and places it into buf
   * @param buf buffer in which we extract data
   * @param buflen
   * @param retrieve_all_bytes determines if we should read all bytes before returning
   */
  virtual int readData(std::vector<uint8_t> &buf, int buflen, bool retrieve_all_bytes);
  /**
   * Reads data and places it into buf
   * @param buf buffer in which we extract data
   * @param buflen
   * @param retrieve_all_bytes determines if we should read all bytes before returning
   */
  virtual int readData(uint8_t *buf, int buflen, bool retrieve_all_bytes);

  /**
   * Write value to the stream using std::vector
   * @param buf incoming buffer
   * @param buflen buffer to write
   *
   */
  virtual int writeData(std::vector<uint8_t> &buf, int buflen);

  /**
   * writes value to stream
   * @param value value to write
   * @param size size of value
   */
  virtual int writeData(uint8_t *value, int size);

  /**
   * Writes a system word
   * @param value value to write
   */
  virtual int write(uint64_t value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Writes a uint32_t
   * @param value value to write
   */
  virtual int write(uint32_t value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Writes a system short
   * @param value value to write
   */
  virtual int write(uint16_t value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Reads a system word
   * @param value value to write
   */
  virtual int read(uint64_t &value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Reads a uint32_t
   * @param value value to write
   */
  virtual int read(uint32_t &value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Reads a system short
   * @param value value to write
   */
  virtual int read(uint16_t &value, bool is_little_endian = EndiannessCheck::IS_LITTLE);

  /**
   * Returns the underlying buffer
   * @return vector's array
   **/
  const uint8_t *getBuffer() const {
    return DataStream::getBuffer();
  }

  /**
   * Retrieve size of data stream
   * @return size of data stream
   **/
  const uint64_t getSize() const {
    return DataStream::getSize();
  }

 protected:

  /**
   * Constructor that accepts host name, port and listeners. With this
   * contructor we will be creating a server socket
   * @param context the SocketContext
   * @param hostname our host name
   * @param port connecting port
   * @param listeners number of listeners in the queue
   */
  explicit Socket(const std::shared_ptr<SocketContext> &context, const std::string &hostname, const uint16_t port, const uint16_t listeners);

  /**
   * Creates a vector and returns the vector using the provided
   * type name.
   * @param t incoming object
   * @returns vector.
   */
  template<typename T>
  std::vector<uint8_t> readBuffer(const T&);

  /**
   * Creates a connection using the address info object.
   * @param p addrinfo structure.
   * @returns fd.
   */
  virtual int8_t createConnection(const addrinfo *p, in_addr_t &addr);

  /**
   * Sets socket options depending on the instance.
   * @param sock socket file descriptor.
   */
  virtual int16_t setSocketOptions(const int sock);

  /**
   * Attempt to select the socket file descriptor
   * @param msec timeout interval to wait
   * @returns file descriptor
   */
  virtual int16_t select_descriptor(const uint16_t msec);

  addrinfo *addr_info_;

  std::recursive_mutex selection_mutex_;

  std::string requested_hostname_;
  std::string canonical_hostname_;
  uint16_t port_;

  bool is_loopback_only_;
  io::NetworkInterface local_network_interface_;

  // connection information
  int32_t socket_file_descriptor_;

  fd_set total_list_;
  fd_set read_fds_;
  std::atomic<uint16_t> socket_max_;
  std::atomic<uint64_t> total_written_;
  std::atomic<uint64_t> total_read_;
  uint16_t listeners_;


  bool nonBlocking_;

  std::shared_ptr<logging::Logger> logger_;

  void setPort(uint16_t port) {
    port_ = port;
  }

 private:
  static std::string init_hostname() {
    char hostname[1024];
    gethostname(hostname, 1024);
    Socket mySock(nullptr, hostname, 0);
    mySock.initialize();
    auto resolved_hostname = mySock.getHostname();
    return !IsNullOrEmpty(resolved_hostname) ? resolved_hostname : hostname;
  }
};

} /* namespace io */
} /* namespace minifi */
} /* namespace nifi */
} /* namespace apache */
} /* namespace org */
#endif /* LIBMINIFI_INCLUDE_IO_POSIX_CLIENTSOCKET_H_ */