/*
 * UNG's Not GNU
 *
 * Copyright (c) 2011-2019, Jakob Kaivo <jkk@ung.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#define _XOPEN_SOURCE 700
#include <errno.h>
#include <ftw.h>
#include <libgen.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#ifndef OPEN_MAX
#define OPEN_MAX _POSIX_OPEN_MAX
#endif

static enum { DEFAULT, INTERACTIVE, FORCE } mode = DEFAULT;
static int recursive = 0;
static int retval = 0;

static int rm_prompt(const char *p)
{
	if (mode == FORCE) {
		return 1;
	}

	if (!((access(p, W_OK) != 0 && isatty(STDIN_FILENO)) || mode == INTERACTIVE)) {
		return 1;
	}

	char *buf = NULL;
	size_t len = 0;

	if (errno == ENOENT)	// FIXME: this is probably wrong
		return 1;

	fprintf(stderr, "remove %s? ", p);
	getline(&buf, &len, stdin);
	if (!strcasecmp("yes\n", buf) || !(strcasecmp("y\n", buf))) {
		free(buf);
		return 1;
	}
	return 0;
}

int rm(const char *p, const struct stat *st, int typeflag, struct FTW *f)
{
	(void)typeflag; (void)f;

	if (st == NULL) {
		/* TODO: proper error, or should there be one? */
		printf("st is null\n");
		retval = 1;
		return 0;
	}

	if (S_ISDIR(st->st_mode)) {
		if (!recursive) {
			fprintf(stderr, "%s: %s\n", p, strerror(EISDIR));
			retval = 1;
			return 0;
		}

		if (!rm_prompt(p)) {
			return 0;
		}

		if (rmdir(p) != 0) {
			perror(p);
			retval = 1;
			return 0;
		}
		return 0;
	}

	if (!rm_prompt(p)) {
		return 0;
	}

	if (unlink(p) != 0) {
		perror(p);
		retval = 1;
	}

	return 0;
}

int main(int argc, char **argv)
{
	int c;
	while ((c = getopt(argc, argv, "fiRr")) != -1) {
		switch (c) {
		case 'f':
			mode = FORCE;
			break;

		case 'i':
			mode = INTERACTIVE;
			break;

		case 'r':
		case 'R':
			recursive = 1;
			break;

		default:
			return 1;
		}
	}

	if (optind >= argc) {
		return mode == FORCE ? 0 : 1;
	}

	do {
		char base[strlen(argv[optind]) + 1];
		strcpy(base, argv[optind]);
		char *b = basename(base);

		if (strcmp(b, "/") == 0 || strcmp(b, ".") == 0 || strcmp(b, "..") == 0) {
			fprintf(stderr, "rm: deleting %s not allowed\n", argv[optind]);
			retval = 1;
			continue;
		}

		struct stat st;
		if (lstat(argv[optind], &st) != 0) {
			if (mode != FORCE) {
				perror(argv[optind]);
				retval = 1;
			}
			continue;
		}

		if (recursive) {
			nftw(argv[optind], rm, OPEN_MAX, FTW_DEPTH | FTW_PHYS);
		} else {
			rm(argv[optind], &st, 0, NULL);
		}
	} while (++optind < argc);

	return retval;
}