/** 
 @file  enet.h
 @brief ENet public header file
*/
#ifndef __ENET_ENET_H__
#define __ENET_ENET_H__

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdlib.h>

#ifdef WIN32
#include "enet/win32.h"
#else
#include "enet/unix.h"
#endif

#include "enet/types.h"
#include "enet/protocol.h"
#include "enet/list.h"
#include "enet/callbacks.h"

#define ENET_VERSION_MAJOR 1
#define ENET_VERSION_MINOR 3
#define ENET_VERSION_PATCH 3
#define ENET_VERSION_CREATE(major, minor, patch) (((major)<<16) | ((minor)<<8) | (patch))
#define ENET_VERSION ENET_VERSION_CREATE(ENET_VERSION_MAJOR, ENET_VERSION_MINOR, ENET_VERSION_PATCH)

typedef enet_uint32 ENetVersion;

typedef enum _ENetSocketType
{
   ENET_SOCKET_TYPE_STREAM   = 1,
   ENET_SOCKET_TYPE_DATAGRAM = 2
} ENetSocketType;

typedef enum _ENetSocketWait
{
   ENET_SOCKET_WAIT_NONE    = 0,
   ENET_SOCKET_WAIT_SEND    = (1 << 0),
   ENET_SOCKET_WAIT_RECEIVE = (1 << 1)
} ENetSocketWait;

typedef enum _ENetSocketOption
{
   ENET_SOCKOPT_NONBLOCK  = 1,
   ENET_SOCKOPT_BROADCAST = 2,
   ENET_SOCKOPT_RCVBUF    = 3,
   ENET_SOCKOPT_SNDBUF    = 4,
   ENET_SOCKOPT_REUSEADDR = 5
} ENetSocketOption;

enum
{
   ENET_HOST_ANY       = 0,            /**< specifies the default server host */
   ENET_HOST_BROADCAST = 0xFFFFFFFF,   /**< specifies a subnet-wide broadcast */

   ENET_PORT_ANY       = 0             /**< specifies that a port should be automatically chosen */
};

/**
 * Portable internet address structure. 
 *
 * The host must be specified in network byte-order, and the port must be in host 
 * byte-order. The constant ENET_HOST_ANY may be used to specify the default 
 * server host. The constant ENET_HOST_BROADCAST may be used to specify the
 * broadcast address (255.255.255.255).  This makes sense for enet_host_connect,
 * but not for enet_host_create.  Once a server responds to a broadcast, the
 * address is updated from ENET_HOST_BROADCAST to the server's actual IP address.
 */
typedef struct _ENetAddress
{
   enet_uint32 host;
   enet_uint16 port;
} ENetAddress;

/**
 * Packet flag bit constants.
 *
 * The host must be specified in network byte-order, and the port must be in
 * host byte-order. The constant ENET_HOST_ANY may be used to specify the
 * default server host.
 
   @sa ENetPacket
*/
typedef enum _ENetPacketFlag
{
   /** packet must be received by the target peer and resend attempts should be
     * made until the packet is delivered */
   ENET_PACKET_FLAG_RELIABLE    = (1 << 0),
   /** packet will not be sequenced with other packets
     * not supported for reliable packets
     */
   ENET_PACKET_FLAG_UNSEQUENCED = (1 << 1),
   /** packet will not allocate data, and user must supply it instead */
   ENET_PACKET_FLAG_NO_ALLOCATE = (1 << 2),
   /** packet will be fragmented using unreliable (instead of reliable) sends
     * if it exceeds the MTU */
   ENET_PACKET_FLAG_UNRELIABLE_FRAGMENT = (1 << 3)
} ENetPacketFlag;

struct _ENetPacket;
typedef void (ENET_CALLBACK * ENetPacketFreeCallback) (struct _ENetPacket *);

/**
 * ENet packet structure.
 *
 * An ENet data packet that may be sent to or received from a peer. The shown 
 * fields should only be read and never modified. The data field contains the 
 * allocated data for the packet. The dataLength fields specifies the length 
 * of the allocated data.  The flags field is either 0 (specifying no flags), 
 * or a bitwise-or of any combination of the following flags:
 *
 *    ENET_PACKET_FLAG_RELIABLE - packet must be received by the target peer
 *    and resend attempts should be made until the packet is delivered
 *
 *    ENET_PACKET_FLAG_UNSEQUENCED - packet will not be sequenced with other packets 
 *    (not supported for reliable packets)
 *
 *    ENET_PACKET_FLAG_NO_ALLOCATE - packet will not allocate data, and user must supply it instead
 
   @sa ENetPacketFlag
 */
typedef struct _ENetPacket
{
   size_t                   referenceCount;  /**< internal use only */
   enet_uint32              flags;           /**< bitwise-or of ENetPacketFlag constants */
   enet_uint8 *             data;            /**< allocated data for packet */
   size_t                   dataLength;      /**< length of data */
   ENetPacketFreeCallback   freeCallback;    /**< function to be called when the packet is no longer in use */
} ENetPacket;

typedef struct _ENetAcknowledgement
{
   ENetListNode acknowledgementList;
   enet_uint32  sentTime;
   ENetProtocol command;
} ENetAcknowledgement;

typedef struct _ENetOutgoingCommand
{
   ENetListNode outgoingCommandList;
   enet_uint16  reliableSequenceNumber;
   enet_uint16  unreliableSequenceNumber;
   enet_uint32  sentTime;
   enet_uint32  roundTripTimeout;
   enet_uint32  roundTripTimeoutLimit;
   enet_uint32  fragmentOffset;
   enet_uint16  fragmentLength;
   enet_uint16  sendAttempts;
   ENetProtocol command;
   ENetPacket * packet;
} ENetOutgoingCommand;

typedef struct _ENetIncomingCommand
{  
   ENetListNode     incomingCommandList;
   enet_uint16      reliableSequenceNumber;
   enet_uint16      unreliableSequenceNumber;
   ENetProtocol     command;
   enet_uint32      fragmentCount;
   enet_uint32      fragmentsRemaining;
   enet_uint32 *    fragments;
   ENetPacket *     packet;
} ENetIncomingCommand;

typedef enum _ENetPeerState
{
   ENET_PEER_STATE_DISCONNECTED                = 0,
   ENET_PEER_STATE_CONNECTING                  = 1,
   ENET_PEER_STATE_ACKNOWLEDGING_CONNECT       = 2,
   ENET_PEER_STATE_CONNECTION_PENDING          = 3,
   ENET_PEER_STATE_CONNECTION_SUCCEEDED        = 4,
   ENET_PEER_STATE_CONNECTED                   = 5,
   ENET_PEER_STATE_DISCONNECT_LATER            = 6,
   ENET_PEER_STATE_DISCONNECTING               = 7,
   ENET_PEER_STATE_ACKNOWLEDGING_DISCONNECT    = 8,
   ENET_PEER_STATE_ZOMBIE                      = 9 
} ENetPeerState;

#ifndef ENET_BUFFER_MAXIMUM
#define ENET_BUFFER_MAXIMUM (1 + 2 * ENET_PROTOCOL_MAXIMUM_PACKET_COMMANDS)
#endif

enum
{
   ENET_HOST_RECEIVE_BUFFER_SIZE          = 256 * 1024,
   ENET_HOST_SEND_BUFFER_SIZE             = 256 * 1024,
   ENET_HOST_BANDWIDTH_THROTTLE_INTERVAL  = 1000,
   ENET_HOST_DEFAULT_MTU                  = 1400,

   ENET_PEER_DEFAULT_ROUND_TRIP_TIME      = 500,
   ENET_PEER_DEFAULT_PACKET_THROTTLE      = 32,
   ENET_PEER_PACKET_THROTTLE_SCALE        = 32,
   ENET_PEER_PACKET_THROTTLE_COUNTER      = 7, 
   ENET_PEER_PACKET_THROTTLE_ACCELERATION = 2,
   ENET_PEER_PACKET_THROTTLE_DECELERATION = 2,
   ENET_PEER_PACKET_THROTTLE_INTERVAL     = 5000,
   ENET_PEER_PACKET_LOSS_SCALE            = (1 << 16),
   ENET_PEER_PACKET_LOSS_INTERVAL         = 10000,
   ENET_PEER_WINDOW_SIZE_SCALE            = 64 * 1024,
   ENET_PEER_TIMEOUT_LIMIT                = 32,
   ENET_PEER_TIMEOUT_MINIMUM              = 5000,
   ENET_PEER_TIMEOUT_MAXIMUM              = 30000,
   ENET_PEER_PING_INTERVAL                = 500,
   ENET_PEER_UNSEQUENCED_WINDOWS          = 64,
   ENET_PEER_UNSEQUENCED_WINDOW_SIZE      = 1024,
   ENET_PEER_FREE_UNSEQUENCED_WINDOWS     = 32,
   ENET_PEER_RELIABLE_WINDOWS             = 16,
   ENET_PEER_RELIABLE_WINDOW_SIZE         = 0x1000,
   ENET_PEER_FREE_RELIABLE_WINDOWS        = 8
};

typedef struct _ENetChannel
{
   enet_uint16  outgoingReliableSequenceNumber;
   enet_uint16  outgoingUnreliableSequenceNumber;
   enet_uint16  usedReliableWindows;
   enet_uint16  reliableWindows [ENET_PEER_RELIABLE_WINDOWS];
   enet_uint16  incomingReliableSequenceNumber;
   enet_uint16  incomingUnreliableSequenceNumber;
   ENetList     incomingReliableCommands;
   ENetList     incomingUnreliableCommands;
} ENetChannel;

/**
 * An ENet peer which data packets may be sent or received from. 
 *
 * No fields should be modified unless otherwise specified. 
 */
typedef struct _ENetPeer
{ 
   ENetListNode  dispatchList;
   struct _ENetHost * host;
   enet_uint16   outgoingPeerID;
   enet_uint16   incomingPeerID;
   enet_uint32   connectID;
   enet_uint8    outgoingSessionID;
   enet_uint8    incomingSessionID;
   ENetAddress   address;            /**< Internet address of the peer */
   void *        data;               /**< Application private data, may be freely modified */
   ENetPeerState state;
   ENetChannel * channels;
   size_t        channelCount;       /**< Number of channels allocated for communication with peer */
   enet_uint32   incomingBandwidth;  /**< Downstream bandwidth of the client in bytes/second */
   enet_uint32   outgoingBandwidth;  /**< Upstream bandwidth of the client in bytes/second */
   enet_uint32   incomingBandwidthThrottleEpoch;
   enet_uint32   outgoingBandwidthThrottleEpoch;
   enet_uint32   incomingDataTotal;
   enet_uint32   outgoingDataTotal;
   enet_uint32   lastSendTime;
   enet_uint32   lastReceiveTime;
   enet_uint32   nextTimeout;
   enet_uint32   earliestTimeout;
   enet_uint32   packetLossEpoch;
   enet_uint32   packetsSent;
   enet_uint32   packetsLost;
   enet_uint32   packetLoss;          /**< mean packet loss of reliable packets as a ratio with respect to the constant ENET_PEER_PACKET_LOSS_SCALE */
   enet_uint32   packetLossVariance;
   enet_uint32   packetThrottle;
   enet_uint32   packetThrottleLimit;
   enet_uint32   packetThrottleCounter;
   enet_uint32   packetThrottleEpoch;
   enet_uint32   packetThrottleAcceleration;
   enet_uint32   packetThrottleDeceleration;
   enet_uint32   packetThrottleInterval;
   enet_uint32   lastRoundTripTime;
   enet_uint32   lowestRoundTripTime;
   enet_uint32   lastRoundTripTimeVariance;
   enet_uint32   highestRoundTripTimeVariance;
   enet_uint32   roundTripTime;            /**< mean round trip time (RTT), in milliseconds, between sending a reliable packet and receiving its acknowledgement */
   enet_uint32   roundTripTimeVariance;
   enet_uint32   mtu;
   enet_uint32   windowSize;
   enet_uint32   reliableDataInTransit;
   enet_uint16   outgoingReliableSequenceNumber;
   ENetList      acknowledgements;
   ENetList      sentReliableCommands;
   ENetList      sentUnreliableCommands;
   ENetList      outgoingReliableCommands;
   ENetList      outgoingUnreliableCommands;
   ENetList      dispatchedCommands;
   int           needsDispatch;
   enet_uint16   incomingUnsequencedGroup;
   enet_uint16   outgoingUnsequencedGroup;
   enet_uint32   unsequencedWindow [ENET_PEER_UNSEQUENCED_WINDOW_SIZE / 32]; 
   enet_uint32   eventData;
} ENetPeer;

/** An ENet packet compressor for compressing UDP packets before socket sends or receives.
 */
typedef struct _ENetCompressor
{
   /** Context data for the compressor. Must be non-NULL. */
   void * context;
   /** Compresses from inBuffers[0:inBufferCount-1], containing inLimit bytes, to outData, outputting at most outLimit bytes. Should return 0 on failure. */
   size_t (ENET_CALLBACK * compress) (void * context, const ENetBuffer * inBuffers, size_t inBufferCount, size_t inLimit, enet_uint8 * outData, size_t outLimit);
   /** Decompresses from inData, containing inLimit bytes, to outData, outputting at most outLimit bytes. Should return 0 on failure. */
   size_t (ENET_CALLBACK * decompress) (void * context, const enet_uint8 * inData, size_t inLimit, enet_uint8 * outData, size_t outLimit);
   /** Destroys the context when compression is disabled or the host is destroyed. May be NULL. */
   void (ENET_CALLBACK * destroy) (void * context);
} ENetCompressor;

/** Callback that computes the checksum of the data held in buffers[0:bufferCount-1] */
typedef enet_uint32 (ENET_CALLBACK * ENetChecksumCallback) (const ENetBuffer * buffers, size_t bufferCount);
 
/** An ENet host for communicating with peers.
  *
  * No fields should be modified unless otherwise stated.

    @sa enet_host_create()
    @sa enet_host_destroy()
    @sa enet_host_connect()
    @sa enet_host_service()
    @sa enet_host_flush()
    @sa enet_host_broadcast()
    @sa enet_host_compress()
    @sa enet_host_compress_with_range_coder()
    @sa enet_host_channel_limit()
    @sa enet_host_bandwidth_limit()
    @sa enet_host_bandwidth_throttle()
  */
typedef struct _ENetHost
{
   ENetSocket           socket;
   ENetAddress          address;                     /**< Internet address of the host */
   enet_uint32          incomingBandwidth;           /**< downstream bandwidth of the host */
   enet_uint32          outgoingBandwidth;           /**< upstream bandwidth of the host */
   enet_uint32          bandwidthThrottleEpoch;
   enet_uint32          mtu;
   enet_uint32          randomSeed;
   int                  recalculateBandwidthLimits;
   ENetPeer *           peers;                       /**< array of peers allocated for this host */
   size_t               peerCount;                   /**< number of peers allocated for this host */
   size_t               channelLimit;                /**< maximum number of channels allowed for connected peers */
   enet_uint32          serviceTime;
   ENetList             dispatchQueue;
   int                  continueSending;
   size_t               packetSize;
   enet_uint16          headerFlags;
   ENetProtocol         commands [ENET_PROTOCOL_MAXIMUM_PACKET_COMMANDS];
   size_t               commandCount;
   ENetBuffer           buffers [ENET_BUFFER_MAXIMUM];
   size_t               bufferCount;
   ENetChecksumCallback checksum;                    /**< callback the user can set to enable packet checksums for this host */
   ENetCompressor       compressor;
   enet_uint8           packetData [2][ENET_PROTOCOL_MAXIMUM_MTU];
   ENetAddress          receivedAddress;
   enet_uint8 *         receivedData;
   size_t               receivedDataLength;
   enet_uint32          totalSentData;               /**< total data sent, user should reset to 0 as needed to prevent overflow */
   enet_uint32          totalSentPackets;            /**< total UDP packets sent, user should reset to 0 as needed to prevent overflow */
   enet_uint32          totalReceivedData;           /**< total data received, user should reset to 0 as needed to prevent overflow */
   enet_uint32          totalReceivedPackets;        /**< total UDP packets received, user should reset to 0 as needed to prevent overflow */
} ENetHost;

/**
 * An ENet event type, as specified in @ref ENetEvent.
 */
typedef enum _ENetEventType
{
   /** no event occurred within the specified time limit */
   ENET_EVENT_TYPE_NONE       = 0,  

   /** a connection request initiated by enet_host_connect has completed.  
     * The peer field contains the peer which successfully connected. 
     */
   ENET_EVENT_TYPE_CONNECT    = 1,  

   /** a peer has disconnected.  This event is generated on a successful 
     * completion of a disconnect initiated by enet_pper_disconnect, if 
     * a peer has timed out, or if a connection request intialized by 
     * enet_host_connect has timed out.  The peer field contains the peer 
     * which disconnected. The data field contains user supplied data 
     * describing the disconnection, or 0, if none is available.
     */
   ENET_EVENT_TYPE_DISCONNECT = 2,  

   /** a packet has been received from a peer.  The peer field specifies the
     * peer which sent the packet.  The channelID field specifies the channel
     * number upon which the packet was received.  The packet field contains
     * the packet that was received; this packet must be destroyed with
     * enet_packet_destroy after use.
     */
   ENET_EVENT_TYPE_RECEIVE    = 3
} ENetEventType;

/**
 * An ENet event as returned by enet_host_service().
   
   @sa enet_host_service
 */
typedef struct _ENetEvent 
{
   ENetEventType        type;      /**< type of the event */
   ENetPeer *           peer;      /**< peer that generated a connect, disconnect or receive event */
   enet_uint8           channelID; /**< channel on the peer that generated the event, if appropriate */
   enet_uint32          data;      /**< data associated with the event, if appropriate */
   ENetPacket *         packet;    /**< packet associated with the event, if appropriate */
} ENetEvent;

/** @defgroup global ENet global functions
    @{ 
*/

/** 
  Initializes ENet globally.  Must be called prior to using any functions in
  ENet.
  @returns 0 on success, < 0 on failure
*/
ENET_API int enet_initialize (void);

/** 
  Initializes ENet globally and supplies user-overridden callbacks. Must be called prior to using any functions in ENet. Do not use enet_initialize() if you use this variant. Make sure the ENetCallbacks structure is zeroed out so that any additional callbacks added in future versions will be properly ignored.

  @param version the constant ENET_VERSION should be supplied so ENet knows which version of ENetCallbacks struct to use
  @param inits user-overriden callbacks where any NULL callbacks will use ENet's defaults
  @returns 0 on success, < 0 on failure
*/
ENET_API int enet_initialize_with_callbacks (ENetVersion version, const ENetCallbacks * inits);

/** 
  Shuts down ENet globally.  Should be called when a program that has
  initialized ENet exits.
*/
ENET_API void enet_deinitialize (void);

/** @} */

/** @defgroup private ENet private implementation functions */

/**
  Returns the wall-time in milliseconds.  Its initial value is unspecified
  unless otherwise set.
  */
ENET_API enet_uint32 enet_time_get (void);
/**
  Sets the current wall-time in milliseconds.
  */
ENET_API void enet_time_set (enet_uint32);

/** @defgroup socket ENet socket functions
    @{
*/
ENET_API ENetSocket enet_socket_create (ENetSocketType);
ENET_API int        enet_socket_bind (ENetSocket, const ENetAddress *);
ENET_API int        enet_socket_listen (ENetSocket, int);
ENET_API ENetSocket enet_socket_accept (ENetSocket, ENetAddress *);
ENET_API int        enet_socket_connect (ENetSocket, const ENetAddress *);
ENET_API int        enet_socket_send (ENetSocket, const ENetAddress *, const ENetBuffer *, size_t);
ENET_API int        enet_socket_receive (ENetSocket, ENetAddress *, ENetBuffer *, size_t);
ENET_API int        enet_socket_wait (ENetSocket, enet_uint32 *, enet_uint32);
ENET_API int        enet_socket_set_option (ENetSocket, ENetSocketOption, int);
ENET_API void       enet_socket_destroy (ENetSocket);
ENET_API int        enet_socketset_select (ENetSocket, ENetSocketSet *, ENetSocketSet *, enet_uint32);

/** @} */

/** @defgroup Address ENet address functions
    @{
*/
/** Attempts to resolve the host named by the parameter hostName and sets
    the host field in the address parameter if successful.
    @param address destination to store resolved address
    @param hostName host name to lookup
    @retval 0 on success
    @retval < 0 on failure
    @returns the address of the given hostName in address on success
*/
ENET_API int enet_address_set_host (ENetAddress * address, const char * hostName);

/** Gives the printable form of the ip address specified in the address parameter.
    @param address    address printed
    @param hostName   destination for name, must not be NULL
    @param nameLength maximum length of hostName.
    @returns the null-terminated name of the host in hostName on success
    @retval 0 on success
    @retval < 0 on failure
*/
ENET_API int enet_address_get_host_ip (const ENetAddress * address, char * hostName, size_t nameLength);

/** Attempts to do a reverse lookup of the host field in the address parameter.
    @param address    address used for reverse lookup
    @param hostName   destination for name, must not be NULL
    @param nameLength maximum length of hostName.
    @returns the null-terminated name of the host in hostName on success
    @retval 0 on success
    @retval < 0 on failure
*/
ENET_API int enet_address_get_host (const ENetAddress * address, char * hostName, size_t nameLength);

/** @} */

ENET_API ENetPacket * enet_packet_create (const void *, size_t, enet_uint32);
ENET_API void         enet_packet_destroy (ENetPacket *);
ENET_API int          enet_packet_resize  (ENetPacket *, size_t);
extern enet_uint32    enet_crc32 (const ENetBuffer *, size_t);
                
ENET_API ENetHost * enet_host_create (const ENetAddress *, size_t, size_t, enet_uint32, enet_uint32);
ENET_API void       enet_host_destroy (ENetHost *);
ENET_API ENetPeer * enet_host_connect (ENetHost *, const ENetAddress *, size_t, enet_uint32);
ENET_API int        enet_host_check_events (ENetHost *, ENetEvent *);
ENET_API int        enet_host_service (ENetHost *, ENetEvent *, enet_uint32);
ENET_API void       enet_host_flush (ENetHost *);
ENET_API void       enet_host_broadcast (ENetHost *, enet_uint8, ENetPacket *);
ENET_API void       enet_host_compress (ENetHost *, const ENetCompressor *);
ENET_API int        enet_host_compress_with_range_coder (ENetHost * host);
ENET_API void       enet_host_channel_limit (ENetHost *, size_t);
ENET_API void       enet_host_bandwidth_limit (ENetHost *, enet_uint32, enet_uint32);
extern   void       enet_host_bandwidth_throttle (ENetHost *);

ENET_API int                 enet_peer_send (ENetPeer *, enet_uint8, ENetPacket *);
ENET_API ENetPacket *        enet_peer_receive (ENetPeer *, enet_uint8 * channelID);
ENET_API void                enet_peer_ping (ENetPeer *);
ENET_API void                enet_peer_reset (ENetPeer *);
ENET_API void                enet_peer_disconnect (ENetPeer *, enet_uint32);
ENET_API void                enet_peer_disconnect_now (ENetPeer *, enet_uint32);
ENET_API void                enet_peer_disconnect_later (ENetPeer *, enet_uint32);
ENET_API void                enet_peer_throttle_configure (ENetPeer *, enet_uint32, enet_uint32, enet_uint32);
extern int                   enet_peer_throttle (ENetPeer *, enet_uint32);
extern void                  enet_peer_reset_queues (ENetPeer *);
extern void                  enet_peer_setup_outgoing_command (ENetPeer *, ENetOutgoingCommand *);
extern ENetOutgoingCommand * enet_peer_queue_outgoing_command (ENetPeer *, const ENetProtocol *, ENetPacket *, enet_uint32, enet_uint16);
extern ENetIncomingCommand * enet_peer_queue_incoming_command (ENetPeer *, const ENetProtocol *, ENetPacket *, enet_uint32);
extern ENetAcknowledgement * enet_peer_queue_acknowledgement (ENetPeer *, const ENetProtocol *, enet_uint16);
extern void                  enet_peer_dispatch_incoming_unreliable_commands (ENetPeer *, ENetChannel *);
extern void                  enet_peer_dispatch_incoming_reliable_commands (ENetPeer *, ENetChannel *);

ENET_API void * enet_range_coder_create (void);
ENET_API void   enet_range_coder_destroy (void *);
ENET_API size_t enet_range_coder_compress (void *, const ENetBuffer *, size_t, size_t, enet_uint8 *, size_t);
ENET_API size_t enet_range_coder_decompress (void *, const enet_uint8 *, size_t, enet_uint8 *, size_t);
   
extern size_t enet_protocol_command_size (enet_uint8);

#ifdef __cplusplus
}
#endif

#endif /* __ENET_ENET_H__ */

