/*
 * file:        dc320.c
 # description: download program for Polaroid DC320 POS camera
 * author:      Peter Desnoyers, pjd@fred.cambridge.ma.us
 */

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

#define E6_4 0xe6, 0xe6, 0xe6, 0xe6
#define E6_8 E6_4, E6_4

void printhex(int n, unsigned char *buf)
{
    int i;
    for (i = 0; i < n; i++) {
	if (i > 0 && (i%16) == 0)
	    printf("\n");
	printf(" %02X", buf[i]);
    }
    printf("\n");
}

/*
  need better read and write routines.  In particular, read needs to
  use select() for timeout, and retry a few times in the camera find
  routine.  Other routines can bail on timeout.  Write should
  calculate the checksum for us; reads should verify the checksum and
  data received.
*/

void hdr(int fd)
{
    char cmd1[] = {E6_8, 0, 0xff, 0xff};
    char cmd2[] = {E6_4, 1, 0xfe, 0xff};
    char cmd3[] = {E6_4, 2, 0xfd, 0xff};
    char cmd4[] = {E6_4, 0xa, 0xf5, 0xff};
    unsigned char buf[32];
    int n;
    
    write(fd, cmd1, sizeof(cmd1));
    n = read(fd, buf, sizeof(buf));
    //    printhex(n, buf);

    write(fd, cmd2, sizeof(cmd2));
    n = read(fd, buf, sizeof(buf));
    //    printhex(n, buf);

    write(fd, cmd3, sizeof(cmd3));
    n = read(fd, buf, sizeof(buf));
    //    printhex(n, buf);

    write(fd, cmd4, sizeof(cmd4));
    n = read(fd, buf, sizeof(buf));
    //    printhex(n, buf);
    printf("found camera\n");
}

int npics(int fd)
{
    char cmd1[] = {E6_4, 3, 0xfc, 0xff};
    unsigned char buf[32];
    int n;
    
    write(fd, cmd1, sizeof(cmd1));
    n = read(fd, buf, sizeof(buf));
    printhex(n, buf);

    return buf[1];
}

int picsiz(int fd, int i)
{
    char cmd1[] = {E6_4, 4, 1, 0xfb, 0xfe};
    unsigned char buf[32];
    int n, len;

    cmd1[5] += (i-1);
    cmd1[7] -= (i-1);
    
    
    write(fd, cmd1, sizeof(cmd1));
    n = read(fd, buf, sizeof(buf));
    printhex(n, buf);

    len = (buf[1] << 24) + (buf[2] << 16) + (buf[3] << 8) + buf[4];
    printf("pic(%d) = %d bytes\n", i, len);
    return len;
}

/*
  packet checksum:
    1s complement sum of bytes, then subtract from 255 (like IP
    checksum, but 8 bits) so 1s complement sum of all bytes=0.
*/

/* 
   Unknown data.  It may be needed to interpret the image - it's
   identical for images with about the same brightness, but differs
   between varied images.

   Format is :

   07 00 06 aa aa 7f bb bb ?? xx

   aa aa, bb bb = data
   ?? - not sure if data or checksum
   xx - packet checksum
*/

void getxxx(int fd, int i)
{
    char cmd[] = {E6_4, 0x0c, 01, 0xf3, 0xfe};
    unsigned char buf[32];
    int n;

    cmd[5] += (i-1);
    cmd[7] -= (i-1);
    write(fd, cmd, sizeof(cmd));
    n = read(fd, buf, sizeof(buf));
    printf("unknown: "), printhex(n, buf);
}

void getpic(int fd, int i, int len, char *name)
{
    char cmd1[] = {E6_4, 5, 1, 0xfa, 0xfe};
    unsigned char buf[2048], *p;
    int n, j, cksum, f1, f2;
    FILE *fp;

    printf("reading picture %d (%s)\n", i, name);
    fp = fopen(name, "w");
    
    cmd1[5] += (i-1);
    cmd1[7] -= (i-1);

    write(fd, cmd1, sizeof(cmd1));

    while (len > 0) {
	j = (len>2000) ? 2000 : len;
	usleep(10000);
	n = read(fd, buf, 5);
	f1 = (buf[1]<<8) + buf[2];
	f2 = (buf[3]<<8) + buf[4];
	printf("frame %d (%d)\n", f1, f2);
	
	for (p = buf; n > 0 && j > 0; p += n, j -= n) {
	    usleep(1000);
	    n = read(fd, p, j);
	}
	fwrite(buf, p-buf, 1, fp);
	len -= (p-buf);
	
	n = read(fd, buf, 2);
	cksum = (buf[0]<<8) + buf[1];
    }
    fclose(fp);
}

void delpics(int fd)
{
    char cmd[] = {E6_4, 7, 0xf8, 0xff};
    unsigned char buf[32];
    int n;
    
    write(fd, cmd, sizeof(cmd));
    n = read(fd, buf, sizeof(buf));
    printf("delete complete: "), printhex(n, buf);
}
    
int main(int argc, char **argv)
{
    int fd;
    struct termios ti;
    int n, size, i;
    int getpics=0, delete=0;
    char nbuf[32];
    
    if (argc == 2 && !strcmp(argv[1], "-get"))
	getpics++;
    if (argc == 2 && !strcmp(argv[1], "-delete"))
	delete=1;
    
    if ((fd = open("/dev/ttyS0", O_RDWR)) < 0)
	perror("can't open tty\n"), exit(1);

    if (tcgetattr(fd, &ti) < 0)
	perror("can't get attr\n"), exit(1);
    
    cfmakeraw(&ti);

    cfsetospeed(&ti, B115200);
    cfsetispeed(&ti, B115200);
    if (tcsetattr(fd, TCSANOW, &ti) < 0)
	perror("can't set attr\n"), exit(1);

    hdr(fd);

    if (delete) 
	delpics(fd);
    else {
	n = npics(fd);
	printf("%d pictures\n", n);
	for (i = 1; i <= n; i++) {
	    size = picsiz(fd, i);
	    printf("picture %d: %d bytes\n", i, size);
	    if (getpics) {
		sprintf(nbuf, "pic.%d.dat", i);
		getpic(fd, i, size, nbuf);
	    }
	    getxxx(fd, i);
	}
    }
    
    close(fd);
    return 0;
}