/**
 * @file
 * PacketEngine packet format.
 */

/******************************************************************************
 * Copyright (c) 2011-2012, AllSeen Alliance. All rights reserved.
 *
 *    Permission to use, copy, modify, and/or distribute this software for any
 *    purpose with or without fee is hereby granted, provided that the above
 *    copyright notice and this permission notice appear in all copies.
 *
 *    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 ******************************************************************************/
#ifndef _ALLJOYN_PACKET_H
#define _ALLJOYN_PACKET_H

#include <qcc/platform.h>
#include <qcc/String.h>
#include <qcc/IPAddress.h>
#include <alljoyn/Status.h>

namespace ajn {

/* Packet flag bit definitions */
#define PACKET_FLAG_CONTROL    0x01     /* Packet is a control (non data) packet */
#define PACKET_FLAG_BOM        0x02     /* Packet is the beginning of a potentially multi-packet message (data only) */
#define PACKET_FLAG_EOM        0x04     /* Packet is the end of a potentially multi-packet message (data only) */
#define PACKET_FLAG_DELAY_ACK  0x08     /* Data packet may be acked by the receiver in a delayed manner */
#define PACKET_FLAG_FLOW_OFF   0x10     /* Transmitter is XOFF (and will be expecting XON) */

/* Control packet command types (payload offset = 0, size = BYTE) */
#define PACKET_COMMAND_CONNECT_REQ         0x01
#define PACKET_COMMAND_CONNECT_RSP         0x02
#define PACKET_COMMAND_CONNECT_RSP_ACK     0x03
#define PACKET_COMMAND_DISCONNECT_REQ      0x04
#define PACKET_COMMAND_DISCONNECT_RSP      0x05
#define PACKET_COMMAND_DISCONNECT_RSP_ACK  0x06
#define PACKET_COMMAND_ACK                 0x07
#define PACKET_COMMAND_XON                 0x08
#define PACKET_COMMAND_XON_ACK             0x09

/* Forward Declarations */
class PacketSource;
class PacketEngineStream;

/* Types */
struct PacketDest {
    uint8_t ip[qcc::IPAddress::IPv6_SIZE];
    uint16_t port;
    uint16_t addrSize;
};

/** Construct a PacketDest from a addr,port */
PacketDest GetPacketDest(const qcc::String& addr, uint16_t port);

PacketDest GetPacketDest(const qcc::IPAddress& addr, uint16_t port);

/** Get the addr,port from a PacketDest */
void GetAddressAndPort(const PacketDest& dest, qcc::IPAddress& addr, uint16_t& port);

class Packet {
  public:
    static const size_t payloadOffset;

    uint32_t chanId;       /* Channel Id */
    uint16_t seqNum;       /* Incrementing packet sequence number */
    uint16_t gap;          /* # of missing packets prior to this packet */
    uint8_t flags;         /* Message flags */
    size_t payloadLen;     /* Payload length */
    uint32_t* payload;     /* Pointer to payload */
    uint32_t* buffer;      /* Pointer to beginning of packet */
    uint64_t expireTs;     /* Packet expiration timestamp */
    uint64_t sendTs;       /* Timestampe when packet was last sent */
    uint16_t sendAttempts; /* Number of times this packet has been sent */
    bool fastRetransmit;   /* true iff packet has been fast retransmitted */

    /** Constructor */
    Packet(size_t mtu);

    /** Copy constructor */
    Packet(const Packet& other);

    /** Assignment operator */
    Packet& operator=(const Packet& other);

    /** Destructor */
    ~Packet();

    size_t SetPayload(const void* payload, size_t payloadLen);
    void SetSender(const PacketDest& sender) { this->sender = sender; }
    const PacketDest& GetSender() const { return sender; }

    /**
     * Unmarshal serialized packet state into object form.
     *
     * @param source   Serial data source use to populate packet state.
     * @return ER_OK if successful.
     */
    QStatus Unmarshal(PacketSource& source);

    /**
     * Marshal packet state into serialized form.
     * After calling this method, the packet's object state will be serialized into the buffer member.
     */
    void Marshal();

    /**
     * Reinitialize state of packet.
     */
    void Clean();

  private:
    size_t mtu;
    uint16_t crc16;
    uint8_t version;
    PacketDest sender;

    Packet();
};

class PacketReceiver {
  public:
    virtual ~PacketReceiver() { }
    virtual QStatus PushPacket(const Packet& packet) = 0;
};

}

#endif