#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/file.h>

#include "tiles.h"
#include "strings.h"

int tile_ncol;
int tile_nbacks;
unsigned short int (*tile_cmap)[3] = 0;
unsigned char tile_pics[TILE__N][TILE_YSIZE][TILE_XSIZE];
unsigned char (*tile_backs)[TILE_YSIZE][TILE_XSIZE] = 0;

static int Read(int fd, void *buf, int nb)
{
 int left;
 int did;
 char *bp;

 left = nb;
 bp = buf;
 do
  { did = read(fd,bp,left);
    if (did < 0) return(-1);
    if (did == 0) break;
    left -= did;
    bp += did;
  } while (left > 0);
 return(nb-left);
}

#define Write write

static int getcment(int fd, unsigned short int *ep)
{
 unsigned char buf[6];

 if (Read(fd,&buf[0],6) != 6) return(-1);
 ep[0] = (buf[0] << 8) | buf[1];
 ep[1] = (buf[2] << 8) | buf[3];
 ep[2] = (buf[4] << 8) | buf[5];
 return(0);
}

static int putcment(int fd, unsigned short int *ep)
{
 unsigned char buf[6];

 buf[0] = ep[0] >> 8;
 buf[1] = ep[0] & 0xff;
 buf[2] = ep[1] >> 8;
 buf[3] = ep[1] & 0xff;
 buf[4] = ep[2] >> 8;
 buf[5] = ep[2] & 0xff;
 if (Write(fd,&buf[0],6) != 6) return(-1);
 return(0);
}

static int getbm_c(int fd, unsigned char (*bm)[TILE_XSIZE])
{
 if (Read(fd,bm,TILE_XSIZE*TILE_YSIZE) != TILE_XSIZE*TILE_YSIZE) return(-1);
 return(0);
}

static int putbm_c(int fd, unsigned char (*bm)[TILE_XSIZE])
{
 if (Write(fd,bm,TILE_XSIZE*TILE_YSIZE) != TILE_XSIZE*TILE_YSIZE) return(-1);
 return(0);
}

/* tiles_c would be auto [][][], except that if they are
   then the stack takes too big a step and we drop core. */
int tile_loaddeck(const char *path)
{
 int errsave;
 int fd;
 unsigned char buf;
 int i;
 int ncol;
 int nbacks;
 unsigned short int (*cmap)[3];
 unsigned char (*tiles_c)[TILE_YSIZE][TILE_XSIZE];
 unsigned char (*backs_c)[TILE_YSIZE][TILE_XSIZE];

 errno = 0;
 cmap = 0;
 tiles_c = 0;
 backs_c = 0;
 fd = open(path,O_RDONLY,0);
 if (fd < 0) goto err;
 if (Read(fd,&buf,1) != 1) goto err;
 ncol = buf;
 if (Read(fd,&buf,1) != 1) goto err;
 nbacks = buf;
 cmap = malloc(ncol*sizeof(*cmap));
 if (cmap == 0)
  { errno = ENOMEM;
    goto err;
  }
 tiles_c = malloc(TILE__N*sizeof(*tiles_c));
 if (tiles_c == 0)
  { errno = ENOMEM;
    goto err;
  }
 backs_c = malloc(nbacks*sizeof(*backs_c));
 if (backs_c == 0)
  { errno = ENOMEM;
    goto err;
  }
 for (i=0;i<ncol;i++) if (getcment(fd,&cmap[i][0]) < 0) goto err;
 for (i=0;i<nbacks;i++) if (getbm_c(fd,&backs_c[i][0]) < 0) goto err;
 for (i=0;i<TILE__N;i++) if (getbm_c(fd,&tiles_c[i][0]) < 0) goto err;
 if (tile_cmap) free(tile_cmap);
 if (tile_backs) free(tile_backs);
 tile_ncol = ncol;
 tile_nbacks = nbacks;
 tile_cmap = cmap;
 bcopy(tiles_c,tile_pics,TILE__N*sizeof(*tiles_c));
 tile_backs = backs_c;
 free(tiles_c);
 close(fd);
 return(0);
err:;
 errsave = errno;
 if (fd >= 0) close(fd);
 if (cmap) free(cmap);
 if (tiles_c) free(tiles_c);
 if (backs_c) free(backs_c);
 errno = errsave ? errsave : EIO;
 return(-1);
}

int tile_savedeck(const char *path)
{
 int fd;
 unsigned char buf;
 int i;
 int errsave;
 off_t len;

 if ( (tile_ncol < 0) ||
      (tile_ncol > 255) ||
      (tile_nbacks < 0) ||
      (tile_nbacks > 255) )
  { errno = EINVAL;
    return(-1);
  }
 fd = open(path,O_RDWR|O_CREAT,0666);
 if (fd < 0) goto err;
 buf = tile_ncol;
 if (Write(fd,&buf,1) != 1) goto err;
 buf = tile_nbacks;
 if (Write(fd,&buf,1) != 1) goto err;
 for (i=0;i<tile_ncol;i++) if (putcment(fd,&tile_cmap[i][0]) < 0) goto err;
 for (i=0;i<tile_nbacks;i++) if (putbm_c(fd,&tile_backs[i][0]) < 0) goto err;
 for (i=0;i<TILE__N;i++) if (putbm_c(fd,&tile_pics[i][0]) < 0) goto err;
 len = lseek(fd,0,SEEK_CUR);
 ftruncate(fd,len);
 close(fd);
 return(0);
err:;
 errsave = errno;
 if (fd >= 0) close(fd);
 errno = errsave ? errsave : EIO;
 return(-1);
}