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

#include <dirent.h>
#include <errno.h>

#include <bsd/string.h>
#include <sys/stat.h>
#include <sys/inotify.h>

int main(int argc, char *argv[]) {

    char *lex_path, *u_inp, *ful_p, *ev_buf, *parse_buf;
    DIR  *path;
    struct dirent *dent;
	struct inotify_event *event;
	int inotify_fd, watch_fd, rbts;

    extern int errno;

	lex_path = (char *) calloc(1, NAME_MAX + 1);

    if(argc == 1)
        lex_path = "./";

    else if(argc == 2)
        strlcpy(lex_path, argv[1], NAME_MAX + 1);

    else {

        printf("inappropriate number of args.\n");
        return 1;
    }

    if(!(path = opendir(lex_path))) {

        if(errno == EACCES)
            printf("improper permissions to read dir.\n");

        else if(errno == ENOENT)
            printf("given directory does not exist.\n");

        else if(errno == ENFILE)
            printf("we're out of fd's.\n");

        else if(errno == ENOTDIR)
            printf("argument is not a directory.\n");

        else
            printf("an unspecified error occurred.\n");

        return errno;
    }

	u_inp = (char *) calloc(1, NAME_MAX);
	ful_p = (char *) calloc(1, 8192); /* PATH_MAX workaround */ 

	while(dent) 
	    if((dent = readdir(path)) != NULL) 
			printf("%s\n", dent->d_name);
		
	closedir(path);

	printf("file to watch :: ");

	fgets(u_inp, NAME_MAX, stdin);
	strtok(u_inp, "\n"); /* trim newline */

	strlcat(ful_p, lex_path, 8192);
	strlcat(ful_p, "/", NAME_MAX + 1);
	strlcat(ful_p, u_inp, 8192);

	if(!(inotify_fd = inotify_init())) {

		printf("could not access inotify api\n");
		exit(1);
	}

	if((watch_fd = inotify_add_watch(inotify_fd, ful_p, IN_ACCESS | IN_MODIFY)) == -1) {

		printf("could not open watch on provided file\n");
		exit(1);
	}

	ev_buf    = (char *) calloc(1, 8192);
	parse_buf = (char *) calloc(1, 8192);

	for(;;) {

		rbts = read(inotify_fd, ev_buf, 8192);

		for(parse_buf = ev_buf; parse_buf < ev_buf + rbts;) {

			event = (struct inotify_event*) ev_buf;

			if(event->mask == 0x1)
				printf("file was read\n");
			else
				printf("file was written\n");

			parse_buf += sizeof(struct inotify_event) + event-> len;
		}
	}	

	free(u_inp);
	free(ful_p);
	free(lex_path);
	free(ev_buf);
	free(parse_buf);

    return 0;
}