/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>

#include "alloc-util.h"
#include "build.h"
#include "log.h"
#include "main-func.h"
#include "path-util.h"
#include "pretty-print.h"
#include "string-util.h"
#include "strv.h"
#include "unit-name.h"

static enum {
        ACTION_ESCAPE,
        ACTION_UNESCAPE,
        ACTION_MANGLE
} arg_action = ACTION_ESCAPE;
static const char *arg_suffix = NULL;
static const char *arg_template = NULL;
static bool arg_path = false;
static bool arg_instance = false;

static int help(void) {
        _cleanup_free_ char *link = NULL;
        int r;

        r = terminal_urlify_man("systemd-escape", "1", &link);
        if (r < 0)
                return log_oom();

        printf("%s [OPTIONS...] [NAME...]\n\n"
               "Escape strings for usage in systemd unit names.\n\n"
               "  -h --help               Show this help\n"
               "     --version            Show package version\n"
               "     --suffix=SUFFIX      Unit suffix to append to escaped strings\n"
               "     --template=TEMPLATE  Insert strings as instance into template\n"
               "     --instance           With --unescape, show just the instance part\n"
               "  -u --unescape           Unescape strings\n"
               "  -m --mangle             Mangle strings\n"
               "  -p --path               When escaping/unescaping assume the string is a path\n"
               "\nSee the %s for details.\n",
               program_invocation_short_name,
               link);

        return 0;
}

static int parse_argv(int argc, char *argv[]) {

        enum {
                ARG_VERSION = 0x100,
                ARG_SUFFIX,
                ARG_TEMPLATE
        };

        static const struct option options[] = {
                { "help",      no_argument,       NULL, 'h'           },
                { "version",   no_argument,       NULL, ARG_VERSION   },
                { "suffix",    required_argument, NULL, ARG_SUFFIX    },
                { "template",  required_argument, NULL, ARG_TEMPLATE  },
                { "unescape",  no_argument,       NULL, 'u'           },
                { "mangle",    no_argument,       NULL, 'm'           },
                { "path",      no_argument,       NULL, 'p'           },
                { "instance",  no_argument,       NULL, 'i'           },
                {}
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "hump", options, NULL)) >= 0)

                switch (c) {

                case 'h':
                        return help();

                case ARG_VERSION:
                        return version();

                case ARG_SUFFIX: {
                        UnitType t = unit_type_from_string(optarg);
                        if (t < 0)
                                return log_error_errno(t, "Invalid unit suffix type \"%s\".", optarg);

                        arg_suffix = optarg;
                        break;
                }

                case ARG_TEMPLATE:
                        if (!unit_name_is_valid(optarg, UNIT_NAME_TEMPLATE))
                                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                                       "Template name %s is not valid.", optarg);

                        arg_template = optarg;
                        break;

                case 'u':
                        arg_action = ACTION_UNESCAPE;
                        break;

                case 'm':
                        arg_action = ACTION_MANGLE;
                        break;

                case 'p':
                        arg_path = true;
                        break;

                case 'i':
                        arg_instance = true;
                        break;

                case '?':
                        return -EINVAL;

                default:
                        assert_not_reached();
                }

        if (optind >= argc)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "Not enough arguments.");

        if (arg_template && arg_suffix)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--suffix= and --template= may not be combined.");

        if ((arg_template || arg_suffix) && arg_action == ACTION_MANGLE)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--suffix= and --template= are not compatible with --mangle.");

        if (arg_suffix && arg_action == ACTION_UNESCAPE)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--suffix is not compatible with --unescape.");

        if (arg_path && !IN_SET(arg_action, ACTION_ESCAPE, ACTION_UNESCAPE))
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--path may not be combined with --mangle.");

        if (arg_instance && arg_action != ACTION_UNESCAPE)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--instance must be used in conjunction with --unescape.");

        if (arg_instance && arg_template)
                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                       "--instance may not be combined with --template.");

        return 1;
}

static int run(int argc, char *argv[]) {
        int r;

        log_setup();

        r = parse_argv(argc, argv);
        if (r <= 0)
                return r;

        STRV_FOREACH(i, argv + optind) {
                _cleanup_free_ char *e = NULL;

                switch (arg_action) {

                case ACTION_ESCAPE:
                        if (arg_path) {
                                r = unit_name_path_escape(*i, &e);
                                if (r < 0) {
                                        if (r == -EINVAL) {
                                                /* If escaping failed because the string was invalid, let's print a
                                                 * friendly message about it. Catch these specific error cases
                                                 * explicitly. */

                                                if (!path_is_valid(*i))
                                                        return log_error_errno(r, "Input '%s' is not a valid file system path, failed to escape.", *i);
                                                if (!path_is_absolute(*i))
                                                        return log_error_errno(r, "Input '%s' is not an absolute file system path, failed to escape.", *i);
                                                if (!path_is_normalized(*i))
                                                        return log_error_errno(r, "Input '%s' is not a normalized file system path, failed to escape.", *i);
                                        }

                                        /* All other error cases. */
                                        return log_error_errno(r, "Failed to escape string: %m");
                                }

                                /* If the escaping worked, then still warn if the path is not like we'd like
                                 * it. Because that means escaping is not necessarily reversible. */

                                if (!path_is_valid(*i))
                                        log_warning("Input '%s' is not a valid file system path, escaping is likely not going be reversible.", *i);
                                else if (!path_is_absolute(*i))
                                        log_warning("Input '%s' is not an absolute file system path, escaping is likely not going to be reversible.", *i);

                                /* Note that we don't complain about paths not being normalized here, because
                                 * some forms of non-normalization is actually OK, such as a series // and
                                 * unit_name_path_escape() will clean those up silently, and the reversal is
                                 * "close enough" to be OK. */
                        } else {
                                e = unit_name_escape(*i);
                                if (!e)
                                        return log_oom();
                        }

                        if (arg_template) {
                                char *x;

                                r = unit_name_replace_instance(arg_template, e, &x);
                                if (r < 0)
                                        return log_error_errno(r, "Failed to replace instance: %m");

                                free_and_replace(e, x);
                        } else if (arg_suffix) {
                                if (!strextend(&e, ".", arg_suffix))
                                        return log_oom();
                        }

                        break;

                case ACTION_UNESCAPE: {
                        _cleanup_free_ char *name = NULL;

                        if (arg_template || arg_instance) {
                                _cleanup_free_ char *template = NULL;

                                r = unit_name_to_instance(*i, &name);
                                if (r < 0)
                                        return log_error_errno(r, "Failed to extract instance: %m");
                                if (isempty(name))
                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                                               "Unit %s is missing the instance name.", *i);

                                r = unit_name_template(*i, &template);
                                if (r < 0)
                                        return log_error_errno(r, "Failed to extract template: %m");
                                if (arg_template && !streq(arg_template, template))
                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
                                                               "Unit %s template %s does not match specified template %s.",
                                                               *i, template, arg_template);
                        } else {
                                name = strdup(*i);
                                if (!name)
                                        return log_oom();
                        }

                        if (arg_path)
                                r = unit_name_path_unescape(name, &e);
                        else
                                r = unit_name_unescape(name, &e);
                        if (r < 0)
                                return log_error_errno(r, "Failed to unescape string: %m");

                        break;
                }

                case ACTION_MANGLE:
                        r = unit_name_mangle(*i, 0, &e);
                        if (r < 0)
                                return log_error_errno(r, "Failed to mangle name: %m");

                        break;
                }

                if (i != argv + optind)
                        fputc(' ', stdout);

                fputs(e, stdout);
        }

        fputc('\n', stdout);

        return 0;
}

DEFINE_MAIN_FUNCTION(run);