/*
 * Copyright (c) 2008 INRIA
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Mathieu Lacage <mathieu.lacage@cutebugs.net>
 */

#ifndef IPV4_INTERFACE_CONTAINER_H
#define IPV4_INTERFACE_CONTAINER_H

#include "ns3/ipv4-address.h"
#include "ns3/ipv4.h"

#include <stdint.h>
#include <vector>

namespace ns3
{

/**
 * @ingroup ipv4
 *
 * @brief holds a vector of std::pair of Ptr<Ipv4> and interface index.
 *
 * Typically ns-3 Ipv4Interfaces are installed on devices using an Ipv4 address
 * helper.  The helper's Assign() method takes a NetDeviceContainer which holds
 * some number of Ptr<NetDevice>.  For each of the NetDevices in the
 * NetDeviceContainer the helper will find the associated Ptr<Node> and
 * Ptr<Ipv4>.  It makes sure that an interface exists on the node for the
 * device and then adds an Ipv4Address according to the address helper settings
 * (incrementing the Ipv4Address somehow as it goes).  The helper then converts
 * the Ptr<Ipv4> and the interface index to a std::pair and adds them to a
 * container -- a container of this type.
 *
 * The point is then to be able to implicitly associate an index into the
 * original NetDeviceContainer (that identifies a particular net device) with
 * an identical index into the Ipv4InterfaceContainer that has a std::pair with
 * the Ptr<Ipv4> and interface index you need to play with the interface.
 *
 * @see Ipv4AddressHelper
 * @see Ipv4
 */
class Ipv4InterfaceContainer
{
  public:
    /**
     * @brief Container Const Iterator for pairs of Ipv4 smart pointer / Interface Index.
     */
    typedef std::vector<std::pair<Ptr<Ipv4>, uint32_t>>::const_iterator Iterator;

    /**
     * Create an empty Ipv4InterfaceContainer.
     */
    Ipv4InterfaceContainer();

    /**
     * Concatenate the entries in the other container with ours.
     * @param other container
     */
    void Add(const Ipv4InterfaceContainer& other);

    /**
     * @brief Get an iterator which refers to the first pair in the
     * container.
     *
     * Pairs can be retrieved from the container in two ways.  First,
     * directly by an index into the container, and second, using an iterator.
     * This method is used in the iterator method and is typically used in a
     * for-loop to run through the pairs
     *
     * @code
     *   for (auto i = container.Begin(); i != container.End(); ++i)
     *   {
     *       std::pair<Ptr<Ipv4>, uint32_t> pair = *i;
     *       method(pair.first, pair.second); // use the pair
     *   }
     * @endcode
     *
     * @returns an iterator which refers to the first pair in the container.
     */
    Iterator Begin() const;

    /**
     * @brief Get an iterator which indicates past-the-last Node in the
     * container.
     *
     * Nodes can be retrieved from the container in two ways.  First,
     * directly by an index into the container, and second, using an iterator.
     * This method is used in the iterator method and is typically used in a
     * for-loop to run through the Nodes
     *
     * @code
     *   for (auto i = container.Begin(); i != container.End(); ++i)
     *   {
     *       std::pair<Ptr<Ipv4>, uint32_t> pair = *i;
     *       method(pair.first, pair.second); // use the pair
     *   }
     * @endcode
     *
     * @returns an iterator which indicates an ending condition for a loop.
     */
    Iterator End() const;

    /**
     * @returns the number of Ptr<Ipv4> and interface pairs stored in this
     * Ipv4InterfaceContainer.
     *
     * Pairs can be retrieved from the container in two ways.  First,
     * directly by an index into the container, and second, using an iterator.
     * This method is used in the direct method and is typically used to
     * define an ending condition in a for-loop that runs through the stored
     * Nodes
     *
     * @code
     *   uint32_t nNodes = container.GetN ();
     *   for (uint32_t i = 0 i < nNodes; ++i)
     *     {
     *       std::pair<Ptr<Ipv4>, uint32_t> pair = container.Get (i);
     *       method (pair.first, pair.second);  // use the pair
     *     }
     * @endcode
     *
     * @returns the number of Ptr<Node> stored in this container.
     */
    uint32_t GetN() const;

    /**
     * @param i index of ipInterfacePair in container
     * @param j interface address index (if interface has multiple addresses)
     * @returns the IPv4 address of the j'th address of the interface
     *  corresponding to index i.
     *
     * If the second parameter is omitted, the zeroth indexed address of
     * the interface is returned.  Unless IP aliasing is being used on
     * the interface, the second parameter may typically be omitted.
     */
    Ipv4Address GetAddress(uint32_t i, uint32_t j = 0) const;

    /**
     * @brief Set a metric for the given interface
     * @param i Interface index
     * @param metric the interface metric
     */
    void SetMetric(uint32_t i, uint16_t metric);

    /**
     * Manually add an entry to the container consisting of the individual parts
     * of an entry std::pair.
     *
     * @param ipv4 pointer to Ipv4 object
     * @param interface interface index of the Ipv4Interface to add to the container
     */
    void Add(Ptr<Ipv4> ipv4, uint32_t interface);

    /**
     * Manually add an entry to the container consisting of a previously composed
     * entry std::pair.
     *
     * @param ipInterfacePair the pair of a pointer to Ipv4 object and interface index of the
     * Ipv4Interface to add to the container
     */
    void Add(std::pair<Ptr<Ipv4>, uint32_t> ipInterfacePair);

    /**
     * Manually add an entry to the container consisting of the individual parts
     * of an entry std::pair.
     *
     * @param ipv4Name std:string referring to the saved name of an Ipv4 Object that
     *        has been previously named using the Object Name Service.
     * @param interface interface index of the Ipv4Interface to add to the container
     */
    void Add(std::string ipv4Name, uint32_t interface);

    /**
     * Get the std::pair of an Ptr<Ipv4> and interface stored at the location
     * specified by the index.
     *
     * @param i the index of the container entry to retrieve.
     * @return the std::pair of a Ptr<Ipv4> and an interface index
     *
     * @note The returned Ptr<Ipv4> cannot be used directly to fetch the
     *       Ipv4Interface using the returned index (the GetInterface () method
     *       is provided in class Ipv4L3Protocol, and not class Ipv4). An
     *       example usage is provided below.
     *
     * @code
     *   Ipv4InterfaceContainer c;
     *   ...
     *   std::pair<Ptr<Ipv4>, uint32_t> returnValue = c.Get (0);
     *   Ptr<Ipv4> ipv4 = returnValue.first;
     *   uint32_t index = returnValue.second;
     *   Ptr<Ipv4Interface> iface =  DynamicCast<Ipv4L3Protocol> (ipv4)->GetInterface (index);
     * @endcode
     */
    std::pair<Ptr<Ipv4>, uint32_t> Get(uint32_t i) const;

  private:
    /**
     * @brief Container for pairs of Ipv4 smart pointer / Interface Index.
     */
    typedef std::vector<std::pair<Ptr<Ipv4>, uint32_t>> InterfaceVector;

    /**
     * @brief List of IPv4 stack and interfaces index.
     */
    InterfaceVector m_interfaces;
};

} // namespace ns3

#endif /* IPV4_INTERFACE_CONTAINER_H */
