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

#define MAXLINE 1000

struct flags {
	unsigned int except : 1;
	unsigned int number : 1;
} flags;

void fpat(FILE *fp, char *fname, char *pattern, struct flags flags);

int main(int argc, char *argv[])
{
	FILE *fp;
	char pattern[MAXLINE];

	while (--argc > 0 && **++argv == '-') {
		while (*++*argv) {
			switch (**argv) {
			case 'x':
				flags.except = true;
				break;
			case 'n':
				flags.number = true;
				break;
			default:
				fprintf(stderr, "find: %c: unknown flag\n", **argv);
				exit(1);
				break;
			}
		}
	}

	if (argc >= 1) {
	 	strncpy(pattern, *argv, MAXLINE);
	} else {
		fprintf(stderr, "Usage: find -xn pattern [file ...]\n");
		exit(1);
	}

	if (argc == 1) {
		fpat(stdin, "", pattern, flags);
		fp = stdin;
	} else {
		while (--argc > 0) {
			if (!(fp = fopen(*++argv, "r"))) {
				fprintf(stderr, "find: can't open %s\n", *argv);
				exit (1);
			} else {
				fpat(fp, *argv, pattern, flags);
				fclose(fp);
			}
		}
	}

	return 0;
}

void fpat(FILE *fp, char *fname, char *pattern, struct flags flags)
{
	char line[MAXLINE];
	unsigned long lineno;

	lineno = 0;
	while (fgets(line, MAXLINE, fp) != NULL) {
		if (!!(strstr(line, pattern)) != flags.except) {
			if (*fname)
				printf("%s - ", fname);
			if (flags.number)
				printf("%5lu: ", ++lineno);
			printf("%s", line);
		}
	}
}