/*
 * Copyright (c) 2014 Jonas 'Sortie' Termansen.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * basename.c
 * Strip directory and suffix from filenames.
 */

#include <errno.h>
#include <error.h>
#include <libgen.h>
#include <locale.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void do_basename(char* path, const char* suffix, bool zero)
{
	if ( path[0] )
	{
		const char* name = basename(path);
		size_t name_length = strlen(name);
		size_t suffix_length = suffix ? strlen(suffix) : 0;
		if ( suffix && suffix_length <= name_length &&
			 !strcmp(name + name_length - suffix_length, suffix) )
			name_length -= suffix_length;
		fwrite(name, sizeof(char), name_length, stdout);
	}
	fputc(zero ? '\0' : '\n', stdout);
}

static void compact_arguments(int* argc, char*** argv)
{
	for ( int i = 0; i < *argc; i++ )
	{
		while ( i < *argc && !(*argv)[i] )
		{
			for ( int n = i; n < *argc; n++ )
				(*argv)[n] = (*argv)[n+1];
			(*argc)--;
		}
	}
}

static void help(FILE* fp, const char* argv0)
{
	fprintf(fp, "Usage: %s NAME [SUFFIX]\n", argv0);
	fprintf(fp, "  or:  %s OPTION... NAME...\n", argv0);
	fprintf(fp, "Print NAME with any leading directory components removed.\n");
	fprintf(fp, "If specified, also remove a trailing SUFFIX.\n");
	fprintf(fp, "\n");
	fprintf(fp, "  -a, --multiple       support multiple arguments and treat each as a NAME\n");
	fprintf(fp, "  -s, --suffix=SUFFIX  remove a trailing SUFFIX\n");
	fprintf(fp, "  -z, --zero           separate output with NUL rather than newline\n");
	fprintf(fp, "      --help           display this help and exit\n");
	fprintf(fp, "      --version        output version information and exit\n");
	fprintf(fp, "\n");
	fprintf(fp, "Examples:\n");
	fprintf(fp, "  %s /usr/bin/sort          -> \"sort\"\n", argv0);
	fprintf(fp, "  %s include/stdio.h .h     -> \"stdio\"\n", argv0);
	fprintf(fp, "  %s -s .h include/stdio.h  -> \"stdio\"\n", argv0);
	fprintf(fp, "  %s -a any/str1 any/str2   -> \"str1\" followed by \"str2\"\n", argv0);

}

static void version(FILE* fp, const char* argv0)
{
	fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
}

int main(int argc, char* argv[])
{
	setlocale(LC_ALL, "");

	bool multiple = false;
	const char* suffix = NULL;
	bool zero = false;

	const char* argv0 = argv[0];
	for ( int i = 1; i < argc; i++ )
	{
		const char* arg = argv[i];
		if ( arg[0] != '-' || !arg[1] )
			break; /* Stop after first non-option. */
		argv[i] = NULL;
		if ( !strcmp(arg, "--") )
			break;
		if ( arg[1] != '-' )
		{
			char c;
			while ( (c = *++arg) ) switch ( c )
			{
			case 'a': multiple = true; break;
			case 's':
				if ( !*(suffix = arg + 1) )
				{
					if ( i + 1 == argc )
					{
						error(0, 0, "option requires an argument -- 's'");
						fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
						exit(1);
					}
					suffix = argv[i+1];
					argv[++i] = NULL;
				}
				arg = "s";
				break;
			case 'z': zero = true; break;
			default:
				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
				help(stderr, argv0);
				exit(1);
			}
		}
		else if ( !strcmp(arg, "--help") )
			help(stdout, argv0), exit(0);
		else if ( !strcmp(arg, "--version") )
			version(stdout, argv0), exit(0);
		else if ( !strcmp(arg, "--multiple") )
			multiple = true;
		else if ( !strncmp(arg, "--suffix=", strlen("--suffix=")) )
			suffix = arg + strlen("--suffix=");
		else if ( !strcmp(arg, "--suffix") )
		{
			if ( i + 1 == argc )
			{
				error(0, 0, "option '--suffix' requires an argument");
				fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
				exit(125);
			}
			suffix = argv[i+1];
			argv[++i] = NULL;
		}
		else if ( !strcmp(arg, "--zero") )
			zero = true;
		else
		{
			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
			help(stderr, argv0);
			exit(1);
		}
	}

	compact_arguments(&argc, &argv);

	if ( argc <= 1 )
	{
		error(0, 0, "missing operand");
		fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
		exit(1);
	}

	if ( multiple || suffix )
	{
		for ( int i = 1; i < argc; i++ )
			do_basename(argv[i], suffix, zero);
	}
	else
	{
		if ( 4 <= argc )
		{
			error(0, 0, "extra operand `%s'", argv[3]);
			fprintf(stderr, "Try `%s --help' for more information.\n", argv[0]);
			exit(1);
		}

		if ( 3 <= argc )
			suffix = argv[2];

		do_basename(argv[1], suffix, zero);
	}

	if ( fflush(stdout) == EOF )
		return 1;
	if ( ferror(stdout) )
		return 1;

	return 0;
}