#define _POSIX_C_SOURCE 2

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

/* for quoting against the shell replace ' with '\'' and surround with
 * single quotes
 */

char *quote(char *s, int chi, char *repl, int addquotes) {
	size_t size = 0, rsize = 0;
	char *d, *q, *r;
	char ch = chi;

	if (!s) return NULL;
	if (!repl) return NULL;

	rsize = strlen(repl);

	for (d = s; *d; d++) {
		if (*d == ch) {
			size += rsize-1;
		}
		size++;
	}

	if (addquotes) {
		size += 2;
	}

	d = q = malloc(size+1);

	if (q) {
		if (addquotes) {
			*d++ = ch;
		}

		while (*s) {
			if (*s == ch) {
				r = repl;
				while (*r) {
					*d++ = *r++;
				}
				s++;
			} else {
				*d++ = *s++;
			}
			*d = 0;
		}

		if (addquotes) {
			*d++ = ch;
		}
		*d = 0;
	}

	return q;
}

int main(int ac, char **av) {
	char *quoted;
	int i;
	int ch = '\'';
	int opt, shellmode = 0, addquotes = 0, ident = 0;
	char *repl = "''";
	int count = 0;
	char *separator = "\n";

	while ((opt = getopt(ac, av, "sqid:")) != -1) {
		switch (opt) {
			case 's': shellmode = 1; break;
			case 'q': addquotes = 1; break;
			case 'i': ident = 1; break;
			case 'd': separator = optarg; break;
			default:
				  exit(EXIT_FAILURE);
				  break;
		}
	}
	int argn = optind;

	if (shellmode) {
		repl = "'\\''";
	} else if (ident) {
		ch = '"';
		repl = "\"\"";
	}

	count = 0;
	for (i=argn;i<ac;i++) {
		quoted = quote(av[i], ch, repl, addquotes);
		printf("%s%s", count > 0 ? separator : "", quoted);
		free(quoted);
		count++;
	}
	if (count > 0) {
		printf("\n");
	}
	return 0;
}