/**
 * @file    shellmatta_transport.h
 * @brief   transport layer functions of shellmatta
 * @author  Simon Fischer <fischer.simon.1991@gmail.com>
 */

#ifndef _SHELLMATTA_TRANSPORT_H_
#define _SHELLMATTA_TRANSPORT_H_

#include "shellmatta.h"

#define PROTOCOL_VERSION                    0x01u

/** @brief value of start-of-header character */
#define SHELLMATTA_START_OF_HEADER          0x01u

/* payload length defines */
/** @brief max length of a plain data payload */
#define SHELLMATTA_PAYLOAD_MAXLENGTH        ((uint8_t)(255))
/** @brief max length of a request sequence counters payload */
#define SHELLMATTA_PAYLOAD_LEN_SEQ_REQ      ((uint8_t)(0))
/** @brief max length of a respond sequence counters payload */
#define SHELLMATTA_PAYLOAD_LEN_SEQ_RES      ((uint8_t)(0))
/** @brief max length of a request buffersize payload */
#define SHELLMATTA_PAYLOAD_LEN_BUFSIZE_REQ  ((uint8_t)(1))
/** @brief max length of a respond buffersize payload */
#define SHELLMATTA_PAYLOAD_LEN_BUFSIZE_RES  ((uint8_t)(1))

/* header field length defines */
#define SHELLMATTA_HEADER_LENGTH            ((uint8_t)(8))
/** @brief length of headerfield: start of header */
#define SHELLMATTA_LENGTH_SOH               ((uint8_t)(1))
/** @brief length of headerfield: protocol version */
#define SHELLMATTA_LENGTH_PROT_VERSION      ((uint8_t)(1))
/** @brief length of headerfield: packet type */
#define SHELLMATTA_LENGTH_PACKET_TYPE       ((uint8_t)(1))
/** @brief length of headerfield: payload length */
#define SHELLMATTA_LENGTH_PAYLOAD_LENGTH    ((uint8_t)(1))
/** @brief length of headerfield: source */
#define SHELLMATTA_LENGTH_SOURCE            ((uint8_t)(1))
/** @brief length of headerfield: destination */
#define SHELLMATTA_LENGTH_DESTINATION       ((uint8_t)(1))
/** @brief length of headerfield: host to shell sequence counter */
#define SHELLMATTA_LENGTH_H2S_SEQUENCE_CNT  ((uint8_t)(1))
/** @brief length of headerfield: shell to host sequence counter */
#define SHELLMATTA_LENGTH_S2H_SEQUENCE_CNT  ((uint8_t)(1))
/** @brief length of headerfield: crc32 of header + payload without crc32 */
#define SHELLMATTA_LENGTH_CRC               ((uint8_t)(4))

/* positional defines */
#define SHELLMATTA_POS_SOH                  ((uint8_t)0)
#define SHELLMATTA_POS_PROT_VER             ((uint8_t)1)
#define SHELLMATTA_POS_PACKET_TYPE          ((uint8_t)2)
#define SHELLMATTA_POS_PAYLOAD_LEN          ((uint8_t)3)
#define SHELLMATTA_POS_SRC                  ((uint8_t)4)
#define SHELLMATTA_POS_DST                  ((uint8_t)5)
#define SHELLMATTA_POS_CNT_H2S              ((uint8_t)6)
#define SHELLMATTA_POS_CNT_S2H              ((uint8_t)7)
#define SHELLMATTA_POS_PAYLOAD              ((uint8_t)8)

/* utility defines */
#define SHELLMATTA_SHIFT_BY_1               ((uint8_t)(1))
#define SHELLMATTA_SHIFT_BY_2               ((uint8_t)(2))
#define SHELLMATTA_SHIFT_BY_3               ((uint8_t)(3))
#define SHELLMATTA_SHIFT_BY_8               ((uint8_t)(8))
#define SHELLMATTA_SHIFT_BY_16              ((uint8_t)(16))
#define SHELLMATTA_SHIFT_BY_24              ((uint8_t)(24))

/**
 * @brief definition of shellmatta transport layer states
 */
typedef enum
{
    STATE_GET_SOH                =0u,   /**< start of header state of transport layer */
    STATE_MANUAL_INPUT              ,
    STATE_GET_PROTOCOL_VERSION      ,   /**< protocol version state of transport layer */
    STATE_GET_PACKET_TYPE           ,   /**< packet type state of transport layer */
    STATE_GET_PAYLOAD_LENGTH        ,   /**< payload length state of transport layer */
    STATE_GET_SOURCE                ,   /**< source state of transport layer */
    STATE_GET_DESTINATION           ,   /**< destination state of transport layer */
    STATE_GET_H2S_SEQUENCE_CNT      ,   /**< host to shellmatta sequence counter state of transport layer */
    STATE_GET_S2H_SEQUENCE_CNT      ,   /**< shellmatta to host sequence counter state of transport layer */
    STATE_GET_PAYLOAD               ,   /**< payload state of transport layer */
    STATE_GET_CRC                   ,   /**< crc state of transport layer */
    STATE_PROCESS_PAYLOAD
} shellmatta_transport_state_t;

/**
 * @brief definition of shellmatta transport layer packet types
 */
typedef enum
{
    PACKET_DATA                     = 0x00u,    /**< packet type to send plain data */
    PACKET_SEQ_CNT_REQUEST          = 0x01u,    /**< packet type to request sequence counters */
    PACKET_SEQ_CNT_RESPOND          = 0x81u,    /**< packet type to respond with sequence counters */
    PACKET_MAX_BUFFERSIZE_REQUEST   = 0x02u,    /**< packet type to set and request max buffersize */
    PACKET_MAX_BUFFERSIZE_RESPOND   = 0x82u,    /**< packet type to respond with max buffersize */
    PACKET_SEARCH_DEVICE_REQUEST    = 0x03u,    /**< UNUSED: packet type to request search for a device by unique id */
    PACKET_SEARCH_DEVICE_RESPOND    = 0x83u,    /**< UNUSED: packet type to respond with search results */
    PACKET_SET_ADDRESS_REQUEST      = 0x04u,    /**< UNUSED: packet type to set and request an address */
    PACKET_SET_ADDRESS_RESPOND      = 0x84u     /**< UNUSED: packet type to respond with a set address */
} shellmatta_transport_packet_t;

typedef struct
{
    uint8_t h2s_sequenceCnt;                /**<  */
    uint8_t s2h_sequenceCnt;                /**<  */
    shellmatta_transport_state_t state;     /**<  */
    bool mandatory;                         /**<  */
    bool active;                            /**<  */
    bool continueStep;                      /**<  */
    shellmatta_write_t originalWrite;       /**<  */
} shellmatta_transport_layer_t;

extern uint8_t protocolVersion;
extern shellmatta_transport_packet_t packetType;
extern uint32_t payloadLength;
extern uint8_t source;
extern uint8_t destination;
extern uint32_t crc32;
extern uint8_t payloadCounter;
extern uint8_t crcCounter;
extern uint8_t packetSequenceCounter_h2s;
extern uint8_t packetSequenceCounter_s2h;
extern char payloadBuffer[SHELLMATTA_PAYLOAD_MAXLENGTH];

extern shellmatta_transport_layer_t transportLayerInst;

shellmatta_retCode_t shellmatta_reset_transport(void);

shellmatta_retCode_t shellmatta_init_transport_inst(void);

shellmatta_retCode_t shellmatta_handle_transport_fsm(char *data);

shellmatta_retCode_t shellmatta_write_transport(const char* data, uint32_t length);

#endif /* _SHELLMATTA_TRANSPORT_H_ */