#include <poll.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/mman.h>
#include <sys/socket.h>

#include "display-X.h"
#include "ycbcr-rgb-cvt.h"

extern const char *__progname;

#define FRAMESIZE 640*480*2

static unsigned char *framebuf;
static int dpipe;

#define wrt(fd,buf,len) wrt_(#fd "," #buf "," #len,(fd),(buf),len)
static void wrt_(const char *s, int fd, const void *buf, int len)
{
 int n;

 n = write(fd,buf,len);
 if (n < 0)
  { fprintf(stderr,"write(%s): %s\n",s,strerror(errno));
    exit(1);
  }
 if (n != len)
  { fprintf(stderr,"write(%s): wrote %d not %d\n",s,n,len);
    exit(1);
  }
}

static void setup_frame(void)
{
 void *mmrv;

 mmrv = mmap(0,FRAMESIZE*2,PROT_READ|PROT_WRITE,MAP_ANON|MAP_SHARED,-1,0);
 if (mmrv == MAP_FAILED)
  { fprintf(stderr,"%s: buffer mmap (%u): %s\n",__progname,(unsigned int)(FRAMESIZE*2),strerror(errno));
    exit(1);
  }
 framebuf = mmrv;
 bzero(framebuf,FRAMESIZE*2);
}

static void displayer_main(void)
{
 unsigned char c;
 CVTPARAMS p;

 static void dpr(void *buf, int len)
  { int nr;
    nr = recv(dpipe,buf,len,MSG_WAITALL);
    if (nr == len)
     { return;
     }
    else if (nr < 0)
     { fprintf(stderr,"%s: displayer pipe read: %s\n",__progname,strerror(errno));
     }
    else if (nr == 0)
     { fprintf(stderr,"%s: displayer pipe read EOF\n",__progname);
     }
    else if (nr < len)
     { fprintf(stderr,"%s: displayer pipe short read (%d, wanted %d)\n",__progname,nr,len);
     }
    else
     { fprintf(stderr,"%s: impossible displayer pipe read: %d\n",__progname,nr);
     }
    exit(1);
  }

 setup_X();
 p.Kr = .299;
 p.Kb = .114;
 p.minY = 0;
 p.maxY = 255;
 p.maxCC = 127;
 reset_cvt(&p);
 while (1)
  { dpr(&c,1);
    display_frame(framebuf+(c*FRAMESIZE));
    wrt(dpipe,&c,1);
  }
}

static void fork_displayer(void)
{
 int p[2];
 int pid;

 if (socketpair(AF_LOCAL,SOCK_STREAM,0,&p[0]) < 0)
  { fprintf(stderr,"%s: socketpair: %s\n",__progname,strerror(errno));
    exit(1);
  }
 wrt(p[1],"\0\1",2);
 fflush(0);
 pid = fork();
 if (pid == 0)
  { close(p[0]);
    dpipe = p[1];
    displayer_main();
    _exit(0);
  }
 close(p[1]);
 dpipe = p[0];
// fcntl(dpipe,F_SETFL,fcntl(dpipe,F_GETFL,0)|O_NONBLOCK);
}

static int rd(int fd, void *data, int len)
{
 int r;
 unsigned char *dp;
 int l;

 dp = data;
 l = len;
 while (l > 0)
  { r = read(fd,dp,l);
    if (r < 0)
     { fprintf(stderr,"%s: read: %s\n",__progname,strerror(errno));
       exit(1);
     }
    if (r == 0) return(0);
    if (r > l) abort();
    dp += r;
    l -= r;
  }
 return(1);
}

int main(void);
int main(void)
{
 unsigned char bno;

 setup_frame();
 fork_displayer();
 while (1)
  { if (! rd(dpipe,&bno,1))
     { fprintf(stderr,"%s: displayer pipe EOF\n",__progname);
       exit(1);
     }
    if (! rd(0,&framebuf[bno*FRAMESIZE],640*480*2)) break;
    wrt(dpipe,&bno,1);
  }
 return(0);
}