/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022 The FreeBSD Foundation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <getopt.h>
#include <libgen.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>

extern int      main_decode(int, char *[]);
extern int      main_encode(int, char *[]);
extern int      main_base64_decode(const char *);
extern int      main_base64_encode(const char *, const char *);
extern int      main_quotedprintable(int, char*[]);

static int      search(const char *const);
static void     usage_base64(bool);
static void     version_base64(void);
static void     base64_encode_or_decode(int, char *[]);

enum coders {
        uuencode, uudecode, b64encode, b64decode, base64, qp
};

int
main(int argc, char *argv[])
{
        const char *const progname = getprogname();
        int coder = search(progname);

        if (coder == -1 && argc > 1) {
                argc--;
                argv++;
                coder = search(argv[0]);
        }
        switch (coder) {
        case uuencode:
        case b64encode:
                main_encode(argc, argv);
                break;
        case uudecode:
        case b64decode:
                main_decode(argc, argv);
                break;
        case base64:
                base64_encode_or_decode(argc, argv);
                break;
        case qp:
                main_quotedprintable(argc, argv);
                break;
        default:
                (void)fprintf(stderr,
                    "usage: %1$s <uuencode | uudecode> ...\n"
                    "       %1$s <b64encode | b64decode> ...\n"
                    "       %1$s <base64> ...\n"
                    "       %1$s <qp> ...\n",
                    progname);
                exit(EX_USAGE);
        }
}

static int
search(const char *const progname)
{
#define DESIGNATE(item) [item] = #item
        const char *const known[] = {
                DESIGNATE(uuencode),
                DESIGNATE(uudecode),
                DESIGNATE(b64encode),
                DESIGNATE(b64decode),
                DESIGNATE(base64),
                DESIGNATE(qp)
        };

        for (size_t i = 0; i < nitems(known); i++)
                if (strcmp(progname, known[i]) == 0)
                        return ((int)i);
        return (-1);
}

static void
usage_base64(bool failure)
{
        (void)fputs("usage: base64 [-w col | --wrap=col] "
            "[-d | --decode] [FILE]\n"
            "       base64 --help\n"
            "       base64 --version\n", stderr);
        exit(failure ? EXIT_FAILURE : EXIT_SUCCESS);
}

static void
version_base64(void)
{
        (void)fputs("FreeBSD base64\n", stderr);
        exit(EXIT_SUCCESS);
}

static void
base64_encode_or_decode(int argc, char *argv[])
{
        int ch;
        bool decode = false;
        const char *w = NULL;
        enum { HELP, VERSION };
        static const struct option opts[] =
        {
                {"decode",      no_argument,            NULL, 'd'},
                {"ignore-garbage",no_argument,          NULL, 'i'},
                {"wrap",        required_argument,      NULL, 'w'},
                {"help",        no_argument,            NULL, HELP},
                {"version",     no_argument,            NULL, VERSION},
                {NULL,          no_argument,            NULL, 0}
        };

        while ((ch = getopt_long(argc, argv, "+diw:", opts, NULL)) != -1)
                switch (ch) {
                case 'd':
                        decode = true;
                        break;
                case 'w':
                        w = optarg;
                        break;
                case 'i':
                        /* silently ignore */
                        break;
                case VERSION:
                        version_base64();
                        break;
                case HELP:
                default:
                        usage_base64(ch == '?');
                }

        if (decode)
                main_base64_decode(argv[optind]);
        else
                main_base64_encode(argv[optind], w);
}