/*!
 * \file msg_impl.h
 *
 * Contain all the implementation specific types
 *
 * \author: Christos Choutouridis 8997 <cchoutou@ece.auth.gr>
 */

#ifndef __msg_impl__
#define __msg_impl__

#include <stdint.h>
#include <stdbool.h>
#include <time.h>
#include <netinet/ip_icmp.h>

/*!
 * General options
 */
//! @{
#define  LISTENER_PORT        2288        //!< The server port
#define  MSG_TEXT_SIZE        256         //!< Maximum size of each message
#define  MSG_LIST_SIZE        2000        //!< Maximum size of message history buffer
#define  DEVICE_LIST_SIZE     100         //!< Maximum size of the device list

#define  MSG_DELIMITER        '_'         //!< Message delimiter
#define  ADHOC_NET_A          10          //!< [A.B.C.D]
#define  ADHOC_NET_B           0
#define  ADHOC_NET_C           0
#define  ADHOC_NET_D           0

//#define  NO_DEBUG             1

//! @}

/*!
 * Helper macros
 */
#define _MK_ADHOC_SUBNET(A, B, C, D)   (((A)<<24) | ((B)<<16) | ((C)<<8) | (D))
#define _adhoc_subnet         _MK_ADHOC_SUBNET(ADHOC_NET_A, ADHOC_NET_B, ADHOC_NET_C, ADHOC_NET_D)
/*!
 * Messenger types
 */

//! @{

/*!
 * Application status type
 */
typedef enum {
   MSG_OK =0,  //!< Indicate success
   MSG_ERROR   //!< Indicate error
} status_t;

typedef  bool        bool_t;        //!< Boolean type
typedef  char        char_t;        //!< Application wide character type
typedef  uint32_t    aem_t;         //!< AEM data type
typedef  int64_t     tstamp_t;      //!< UNIX time in 64 bit wide signed integer

/*!
 * IP wrapper type
 */
typedef struct {
   uint16_t A, B, C, D;
}devIP_t;

/*!
 * A RTES node device representation
 * \note
 *    Objects of this type are also acting as fwd list nodes.
 */
typedef struct device {
   aem_t             id;      //!< AEM of the device
   struct device*    next;    //!< link to the next linked device on the chain
} device_t;

typedef device_t*    devList_t;     //!< device list alias


/*!
 * \brief
 *    Core message representation as it described in the requirements
 *
 * Object of this type constructed upon creation or when receiving a message.
 * \note
 *    associate functions -- mutable-like interface:
 *    \sa cMsg_parse() used for parsing and creation
 *    \sa cMsg_getFromAEM() used as fromAEM getter
 *    \sa cMsg_getToAEM() used as toAEM getter
 *    \sa cMsg_getTs() used as timestamp getter
 *    \sa cMsg_getText() used as text getter
 */
typedef struct {
   aem_t       from;       //!< sender's AEM
   aem_t       to;         //!< destination AEM
   tstamp_t    ts;         //!< UNIX timestamp compatible
   size_t      text;       //!< text offset
   char_t      msg[MSG_TEXT_SIZE];    //!< The actual message stream
} cMsg_t;


/*!
 * \brief
 *    Mid and application layer message representation
 *
 * This type
 */
typedef struct {
   device_t    sender;        //!< The sender's device
   devList_t   recipients;    //!< List of all devices the message has reach
   cMsg_t      cMsg;          //!< actual message payload
} msg_t;

typedef int32_t mIter_t;      //!< message list iterator type

/*!
 * \brief Message list
 *
 * This holds the last \a MSG_LIST_SIZE messages exchanged from this
 * device(including the ones we have create).
 *
 * With this we create a 2 dimensional map of msg/dev where each item
 * of the list is linked with all the devices reached by us as a fwd-list.
 * The items on the msgList are:
 *  - Messages we create
 *  - Messages received by the listener
 *
 * Here we define 2 directions for iteration. The message direction and the device
 * direction.
 *
 * Every node on the msgList.m array represents a message. Every node in the device
 * list inside msgList[m].recipients represent devices we don't anymore need to send
 * the current message to them.
 *
 * Layout example:
 *
 *           msgList.m
 *             [ 0 ]  --> [devx] --> [devy] -- >0
 *         |   [ 1 ]  --> [devy] -- > 0
 *   time  |   [ 2 ]  -->  0
 *   [*1]  |   [ 3 ]       ...
 *        \|/
 *              ...
 *
 *             [MAX]
 *
 * [*1]: msgList is actually implemented as a ring buffer so in that
 *       content, "time is a loop".
 */
typedef struct {
   msg_t    m[MSG_LIST_SIZE];    //!< The actual data representation
   mIter_t  last;                //!< A ring buffer iterator marking the last item on .m
   size_t   size;
} msgList_t;

//! @}

/*!
 * Client types
 */
//! @{

#define PING_PKT_S   (64)
#define PING_MSG_S   (PING_PKT_S - sizeof(struct icmphdr))
typedef struct {
    struct icmphdr hdr;
    char           msg[PING_MSG_S];
}ping_pkt_t;

//! @}



/*!
 * Application settings
 */
//! @{

typedef enum {
   OUTLEVEL_0,    //!< Output only results [default]
   OUTLEVEL_1,    //!< Output results and every message also
   OUTLEVEL_2     //!< Debug level, use with care!
}outLevel_en;


typedef struct {
   uint16_t          port;
   time_t            duration;
   time_t            msgInterval;
   outLevel_en       outLevel;
}settings_t;

extern settings_t settings;

#define settings_init(s) s = {         \
   .port = 2288,                       \
   .duration = 7200,                   \
   .msgInterval = 60,                  \
   .outLevel = OUTLEVEL_1              \
}

//! @}

#endif /* __msg_impl__ */