#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>
#include "make_path.h"
#include "get_stat.h"

int (*get_stat)(const char *prog_name, const char *path, struct stat *stat_path);
unsigned int r_flag;
unsigned int s_flag;

int change(const char *file, const struct group *grp) {
	struct stat stat_path;
	if (mu_get_stat("chgrp", file, &stat_path))
		return 1;

	if (lchown(file, stat_path.st_uid, grp->gr_gid)) {
		if (!s_flag)
			fprintf(stderr, "chgrp: %s: %s\n", file, strerror(errno));

		return 1;
	}

	return 0;
}

int chtree(const char *dst, const struct group *grp) {
	int ret = change(dst, grp);

	struct stat stat_path;
	if (get_stat("chgrp", dst, &stat_path))
		return 1;

	if (!S_ISDIR(stat_path.st_mode) || !r_flag)
		return ret;

	DIR *dir = opendir(dst);
	if (dir == NULL) {
		if (!s_flag)
			fprintf(stderr, "chgrp: %s: Can`t open directory\n", dst);

		return 1;
	}

	struct dirent *ep;
	while ((ep = readdir(dir)) != NULL) {
		if (!strcmp(ep->d_name, ".") || !strcmp(ep->d_name, ".."))
			continue;

		char *full_path = mu_make_path("chgrp", dst, ep->d_name);
		if (full_path == NULL)
			continue;

		if (chtree(full_path, grp))
			ret = 1;

		free(full_path);
	}

	closedir(dir);
	return ret;
}

int main(int argc, char **argv) {
	get_stat = mu_get_lstat;

	int opt;
	while ((opt = getopt(argc, argv, "RfH") != -1)) {
		switch (opt) {
			case 'R':
				r_flag = 1;
				break;

			case 'f':
				s_flag = 1;
				break;

			case 'H':
				get_stat = mu_get_stat;
				break;

			default:
				printf("chgrp [group] [file1 file2...]\n\t[-H if a command line argument is a symbolic link]\n\t[-R Recursive] [-f Silent]\n");
				return 0;
		}
	}

	if (argv[optind] == NULL) {
		fprintf(stderr, "chgrp: missing operand\n");
		return 1;
	}

	struct group *grp = getgrnam(argv[optind]);
	if (!grp) {
		fprintf(stderr, "chgrp: unknow group\n");
		return 1;
	}

	argv += optind;
	argc -= optind;

	int ret = 0;
	for (int i = 1; i < argc; i++)
		if (chtree(argv[i], grp))
			ret = 1;

	return ret;
}