#include <cnet.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

//  This simple cnet "protocol" demonstrates the use of cnet's
//  debugging buttons, the Physical Layer, and checksums.

//  The function reboot_node() is first called for each node and
//  informs cnet that the node is interested in the EV_DEBUG0,
//  EV_DEBUG1 and EV_PHYSICALREADY events.
//  Strings are placed on the first and second debug buttons,
//  corresponding to the two interesting EV_DEBUGx events.

//  When EV_DEBUG0 is raised, cnet calls TX_reliable(), to format a
//  message in a frame and transmit that frame to the other node via link 1.
//  As the message will be assumed to be a C string (ending in a '\0'
//  byte), it is important to send the '\0' byte too (hence, strlen()+1 ).
//  Similarly, when EV_DEBUG1 occurs, TX_unreliable() is called.

//  When EV_PHYSICALREADY occurs, cnet calls RX_frame(),
//  to read the frame from the Physical Layer and report its contents.
//  If the frame was corrupted in transmit, any non-alphanumeric bytes
//  are printed as question marks.


char	*fruit[] = { "apple", "pineapple", "banana", "tomato", "plum" };
#define	NFRUITS	(sizeof(fruit) / sizeof(fruit[0]))

int	seqno    = 0;

// -----------------------------------------------------------------------

void describe_frame(char *frame, size_t length)
{
    printf("[\"");
    for(int n=0 ; n<length-1 ; ++n) {
	char byte = frame[n];

	if(isalnum(byte) || byte == ' ')
	    putchar(byte);
	else
	    putchar('?');
    }
    printf("\", ");
    printf("checksum=%5d]\n",CNET_IP_checksum((unsigned short *)frame,length));
}

EVENT_HANDLER(TX_reliable)
{
    char	frame[WAN_MAXFRAME];
    size_t	length;
    int		link	= 1;

    sprintf(frame, "message %d is %s", ++seqno, fruit[rand()%NFRUITS]);
    length	= strlen(frame) + 1;	// need to send the '\0' byte too

    printf("TX %zu bytes on link %d: ", length, link);
    describe_frame(frame, length);
    CHECK(CNET_write_physical_reliable(link, frame, &length));
}

EVENT_HANDLER(TX_unreliable)
{
    char	frame[WAN_MAXFRAME];
    size_t	length;
    int		link	= 1;

    sprintf(frame, "message %d is %s", ++seqno, fruit[rand()%NFRUITS]);
    length	= strlen(frame) + 1;	// need to send the '\0' byte too

    printf("TX %zu bytes on link %d: ", length, link);
    describe_frame(frame, length);
    CHECK(CNET_write_physical(link, frame, &length));
}

EVENT_HANDLER(RX_frame)
{
    char	frame[WAN_MAXFRAME];
    size_t	length	= sizeof(frame);
    int		link;

    CHECK(CNET_read_physical(&link, frame, &length));
    printf("RX %zu bytes on link %d: ", length, link);
    describe_frame(frame, length);
}

EVENT_HANDLER(reboot_node)
{
//  INDICATE OUR INTEREST in EV_PHYSICALREADY, EV_DEBUG0 and EV_DEBUG1 EVENTS
    CHECK(CNET_set_handler(EV_PHYSICALREADY,	RX_frame, 0));

    CHECK(CNET_set_handler(EV_DEBUG0,		TX_reliable, 0));
    CHECK(CNET_set_debug_string(EV_DEBUG0,	"Reliable"));

    CHECK(CNET_set_handler(EV_DEBUG1,		TX_unreliable, 0));
    CHECK(CNET_set_debug_string(EV_DEBUG1,	"Unreliable"));
}