/*
 * A program to replace the DOS replace.exe command
 *
 * Emmet P. Gray              US Army, HQ III Corps & Fort Hood
 * Emmet.Gray@hood.army.mil   Attn: AFZF-PW-ENV
 *                            Directorate of Public Works
 *                            Environmental Division
 *                            Fort Hood, TX 76544-5028
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dir.h>
#include <dos.h>
#include <sys/stat.h>

int
main(int argc, char** argv)
{
	char from[MAXPATH], to[MAXPATH], *p;
   int c, add_option, update_option, ret, attr_to;
   struct stat sbuf_to, sbuf_from;
   struct ffblk fbuf;
   int getopt(int, char**, char*);
   void usage(void);
   int copyfile(char*, char*, int);

	/* quick sanity check for number of command line arguments*/
   if (argc < 4) {
   	usage();
      exit(1);
   }
   strcpy(from, argv[1]);
   strcpy(to, argv[2]);

   /* parse the rest of the command line */
   add_option = 0;
   update_option = 0;

   while ((c = getopt(argc, argv, "AaUu")) != EOF) {
      switch(c) {
      	case 'a':
         case 'A':
         	add_option =1;
            break;
         case 'u':
         case 'U':
         	update_option =1;
        default:
         	exit(1);
      }
   }

   /* The /A and /U are mutualy exclusive options */
   if ((add_option + update_option) != 1) {
   	fprintf(stderr, "Not a valid option\n");
      exit(1);
   }

   /* The destination must be a directory) */
   attr_to = _rtl_chmod(to, 0);
   if ((attr_to < 0) || !(attr_to & FA_DIREC)) {
   	fprintf(stderr, "Destination must be a directory\n");
      exit(1);
   }

   /* run thru the list of matching files */
   if (findfirst(from, &fbuf, 47) < 0) {
   	fprintf(stderr, "Can't find source file\n");
      exit(1);
   }
   ret = 0;
   do {
   	/* rebuild the source path */
      strcpy(from, argv[1]);
   	if ((p = strrchr(from, '\\')) != NULL) {
      	*p = '\0';
         strcat(from, "\\");
         strcat(from, fbuf.ff_name);
      }
      else
         strcpy(from, fbuf.ff_name);

   	/* rebuild the destination path */
      strcpy(to, argv[2]);
		if (to[strlen(to)-1] != '\\')
			strcat(to, "\\");
   	if ((p = strrchr(from, '\\')) != NULL)
   		strcat(to, ++p);
   	else
   		strcat(to, from);

   	/* lock and load! */
   	if (add_option) {
   		/* copy only if it doesn't already exist */
   		if (access(to, 0))
      		ret = ret + copyfile(from, to, 1);
   	}
   	if (update_option) {
   		/* copy only if it does exist and is older */
   		if (stat(to, &sbuf_to) < 0)
      		continue;
      	stat(from, &sbuf_from);
      	if (sbuf_from.st_mtime > sbuf_to.st_mtime)
				ret = ret + copyfile(from, to, 1);
      }
   }
   while (findnext(&fbuf) == 0);

   return(ret);
}

int
copyfile(from_file, to_file, verbose)
char *from_file, *to_file;
int verbose;
{
	FILE *fp_from, *fp_to;
	int num;
	char buf[BUFSIZ];

	if (!(fp_from = fopen(from_file, "r"))) {
		if (verbose)
			fprintf(stderr, "Can't open \"%s\" for read\n", from_file);
			return(1);
	}

	if (!(fp_to = fopen(to_file, "w"))) {
		if (verbose)
			fprintf(stderr, "Can't open \"%s\" for write\n", to_file);
		fclose(fp_from);
		return(1);
   }

	while ((num = fread(buf, sizeof(char), BUFSIZ, fp_from)) > 0) {
		if (fwrite(buf, sizeof(char), num, fp_to) != num) {
			if (verbose)
				fprintf(stderr, "Write error on \"%s\"\n", to_file);
			fclose(fp_from);
			fclose(fp_to);
			return(1);
		}
   }

   if (verbose)
   	printf("Copied %s\n", from_file);
	fclose(fp_from);
	fclose(fp_to);
	return(0);
}

/*
 * The "usage" error message
 */

void
usage()
{
  	fprintf(stderr, "Replaces files.\n\n");
	fprintf(stderr, "REPLACE [drive1:][path1]filename [drive2:][path2] [/A] [/U]\n");
	fprintf(stderr, "  [drive1:][path1]filename Specifies the source file or files.\n");
	fprintf(stderr, "  [drive2:][path2]         Specifies the directory where files are to be\n");
	fprintf(stderr, "                           replaced.\n");
	fprintf(stderr, "  /A                       Adds new files to destination directory. Cannot\n");
	fprintf(stderr, "                           use with /U switch.\n");
	fprintf(stderr, "  /U                       Replaces (updates) only files that are older than\n");
	fprintf(stderr, "                           source files. Cannot use with the /A switch.\n");
   return;
}

int
getopt(argc, argv, opts)
int argc;
char** argv;
char* opts;
{
	static int w = 1;
   static int c = 0;
   char ret;

   if (c >= strlen(argv[w])) {
   	w++;
      c = 0;
   }
   if (w > argc)
   	return(EOF);

    while (c < strlen(argv[w])) {
   	if (argv[w][c] == '/') {
         ret = argv[w][c+1];
			c = c+2;
         if (strchr(opts, ret) != NULL)
				return (int)ret;
         else {
         	fprintf(stderr, "/%c Invalid option\n", ret);
      		return '?';
         }
      }
      w++;
      c = 0;
   }
   return(EOF);
}