#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/stat.h>

char *make_path(const char *src, const char *dst) {
	size_t len = strlen(src) + strlen(dst) + 2;
	char *full_path = malloc(len + 1);
	if (full_path == NULL) {
		fprintf(stderr, "cp: malloc() returned NULL\n");
		return NULL;
	}

	snprintf(full_path, len, "%s/%s", src, dst);
	return full_path;
}


int write_to_file(const char *src, const char *dst) {
	int ifd = open(src, O_RDONLY);
	if (ifd < 0)
		return 1;

	int ofd = open(dst, O_CREAT | O_TRUNC | O_WRONLY, 0666);
	if (ofd < 0) {
		close(ifd);
		return 1;
	}

	char buf[4096];
	ssize_t len = 0;
	while ((len = read(ifd, buf, sizeof(buf))))
		write(ofd, buf, len);

	close(ifd);
	close(ofd);
	return 0;
}

int copyf(const char *src, const char *dst) {
	char *copy = strdup(src);
	if (!copy)
		return 1;

	char *bname = basename(copy);
	char *new_path = make_path(bname, dst);
	if (new_path == NULL)
		return 1;

	int ret = write_to_file(src, new_path);

	free(new_path);
	free(copy);

	return ret;
}

int copy(const char *src, const char *dst){
	if (write_to_file(src, dst)) {
		if (copyf(src, dst)) {
			fprintf(stderr, "cp: (%s %s) %s\n", src, dst, strerror(errno));
			return 1;
		}
	}

	return 0;
}

int get_stat(const char *path, struct stat *stat_path) {
	if (stat(path, stat_path)) {
		fprintf(stderr, "cp: unable to stat %s: %s\n", path, strerror(errno));
		return 1;
	}

	return 0;
}

int cptree(const char *src, const char *dst) {
	printf("%s %s\n", src, dst);

	struct stat stat_path;
	get_stat(src, &stat_path);

	if (S_ISDIR(stat_path.st_mode) == 0) {
		if (copy(src, dst)) {
			fprintf(stderr, "cp: %s: is not directory\n", src);
			return 1;
		}

		return 0;
	}

	else {
		if (mkdir(dst, 0777) < 0) {
			fprintf(stderr, "cp: %s\n", strerror(errno));
			return 1;
		}
	}

	DIR *dir = opendir(src);
	if (dir == NULL) {
		fprintf(stderr, "cp: %s: Can`t open directory\n", src);
		return -1;
        }

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

		char *src_path = make_path(src, ep->d_name);
		if (src_path == NULL)
			return 1;

		char *dst_path = make_path(dst, ep->d_name);
		if (dst_path == NULL)
			return 1;

		cptree(src_path, dst_path);

		free(src_path);
		free(dst_path);
	}

	closedir(dir);
	return 0;
}

int main(const int argc, const char **argv) {
	/* Recursion */
	unsigned int r_flag;

	int i;
	for (i = 1; i < argc; i++) {
		if (argv[i][0] != '-')
			break;

		else if (!strcmp(argv[i], "-r"))
			r_flag = 1;

		else if (!strcmp(argv[i], "-h")) {
			printf("cp [-r] [Src] [Dst]\n");
			return 0;
		}
	}

	if (argc - i >= 2) {
		if (r_flag)
			return cptree(argv[i], argv[argc - 1]);
		else
			return copy(argv[i], argv[argc - 1]);
	}

	return 0;
}