/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2019 Netflix, Inc
 *
 * 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 AUTHOR 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 <sys/ioccom.h>

#include <ctype.h>
#include <dirent.h>
#include <dlfcn.h>
#include <err.h>
#include <fcntl.h>
#include <getopt.h>
#include <libutil.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#include "comnd.h"

static struct cmd top;

static void
print_tree(const struct cmd *f)
{

        if (f->parent != NULL)
                print_tree(f->parent);
        if (f->name != NULL)
                fprintf(stderr, " %s", f->name);
}

static void
print_usage(const struct cmd *f)
{

        fprintf(stderr, "    %s", getprogname());
        print_tree(f->parent);
        fprintf(stderr, " %-15s - %s\n", f->name, f->descr);
}

static void
gen_usage(const struct cmd *t)
{
        struct cmd *walker;

        fprintf(stderr, "usage:\n");
        SLIST_FOREACH(walker, &t->subcmd, link) {
                print_usage(walker);
        }
        exit(EX_USAGE);
}

int
cmd_dispatch(int argc, char *argv[], const struct cmd *t)
{
        struct cmd *walker;

        if (t == NULL)
                t = &top;

        if (argv[1] == NULL) {
                gen_usage(t);
                return (1);
        }
        SLIST_FOREACH(walker, &t->subcmd, link) {
                if (strcmp(argv[1], walker->name) == 0) {
                        walker->fn(walker, argc-1, &argv[1]);
                        return (0);
                }
        }
        fprintf(stderr, "Unknown command: %s\n", argv[1]);
        gen_usage(t);
        return (1);
}

static void
arg_suffix(char *buf, size_t len, arg_type at)
{
        switch (at) {
        case arg_none:
                break;
        case arg_string:
                strlcat(buf, "=<STRING>", len);
                break;
        case arg_path:
                strlcat(buf, "=<FILE>", len);
                break;
        default:
                strlcat(buf, "=<NUM>", len);
                break;
        }
}

void
arg_help(int argc __unused, char * const *argv, const struct cmd *f)
{
        int i;
        char buf[31];
        const struct opts *opts = f->opts;
        const struct args *args = f->args;

        // XXX walk up the cmd list...
        if (argv[optind])
                fprintf(stderr, "Unknown argument: %s\n", argv[optind]);
        fprintf(stderr, "Usage:\n    %s", getprogname());
        print_tree(f);
        if (opts)
                fprintf(stderr, " <args>");
        if (args) {
                while (args->descr != NULL) {
                        fprintf(stderr, " %s", args->descr);
                        args++;
                }
        }
        fprintf(stderr, "\n\n%s\n", f->descr);
        if (opts != NULL) {
                fprintf(stderr, "Options:\n");
                for (i = 0; opts[i].long_arg != NULL; i++) {
                        *buf = '\0';
                        if (isprint(opts[i].short_arg)) {
                                snprintf(buf, sizeof(buf), " -%c, ", opts[i].short_arg);
                        } else {
                                strlcpy(buf, "    ", sizeof(buf));
                        }
                        strlcat(buf, "--", sizeof(buf));
                        strlcat(buf, opts[i].long_arg, sizeof(buf));
                        arg_suffix(buf, sizeof(buf), opts[i].at);
                        fprintf(stderr, "%-30.30s - %s\n", buf, opts[i].descr);
                }
        }
        exit(EX_USAGE);
}

static int
find_long(struct option *lopts, int ch)
{
        int i;

        for (i = 0; lopts[i].val != ch && lopts[i].name != NULL; i++)
                continue;
        return (i);
}

int
arg_parse(int argc, char * const * argv, const struct cmd *f)
{
        int i, n, idx, ch;
        uint64_t v;
        struct option *lopts;
        char *shortopts, *p;
        const struct opts *opts = f->opts;
        const struct args *args = f->args;

        if (opts == NULL)
                n = 0;
        else
                for (n = 0; opts[n].long_arg != NULL;)
                        n++;
        lopts = malloc((n + 2) * sizeof(struct option));
        if (lopts == NULL)
                err(EX_OSERR, "option memory");
        p = shortopts = malloc((2 * n + 3) * sizeof(char));
        if (shortopts == NULL)
                err(EX_OSERR, "shortopts memory");
        idx = 0;
        for (i = 0; i < n; i++) {
                lopts[i].name = opts[i].long_arg;
                lopts[i].has_arg = opts[i].at == arg_none ? no_argument : required_argument;
                lopts[i].flag = NULL;
                lopts[i].val = opts[i].short_arg;
                if (isprint(opts[i].short_arg)) {
                        *p++ = opts[i].short_arg;
                        if (lopts[i].has_arg)
                                *p++ = ':';
                }
        }
        lopts[n].name = "help";
        lopts[n].has_arg = no_argument;
        lopts[n].flag = NULL;
        lopts[n].val = '?';
        *p++ = '?';
        *p++ = '\0';
        memset(lopts + n + 1, 0, sizeof(struct option));
        while ((ch = getopt_long(argc, argv, shortopts, lopts, &idx)) != -1) {
                /*
                 * If ch != 0, we've found a short option, and we have to
                 * look it up lopts table. Otherwise idx is valid.
                 */
                if (ch != 0)
                        idx = find_long(lopts, ch);
                if (idx == n)
                        arg_help(argc, argv, f);
                switch (opts[idx].at) {
                case arg_none:
                        *(bool *)opts[idx].ptr = true;
                        break;
                case arg_string:
                case arg_path:
                        *(const char **)opts[idx].ptr = optarg;
                        break;
                case arg_uint8:
                        v = strtoul(optarg, NULL, 0);
                        if (v > 0xff)
                                goto bad_arg;
                        *(uint8_t *)opts[idx].ptr = v;
                        break;
                case arg_uint16:
                        v = strtoul(optarg, NULL, 0);
                        if (v > 0xffff)
                                goto bad_arg;
                        *(uint16_t *)opts[idx].ptr = v;
                        break;
                case arg_uint32:
                        v = strtoul(optarg, NULL, 0);
                        if (v > 0xffffffffu)
                                goto bad_arg;
                        *(uint32_t *)opts[idx].ptr = v;
                        break;
                case arg_uint64:
                        v = strtoul(optarg, NULL, 0);
                        if (v > 0xffffffffffffffffull)
                                goto bad_arg;
                        *(uint64_t *)opts[idx].ptr = v;
                        break;
                case arg_size:
                        if (expand_number(optarg, &v) < 0)
                                goto bad_arg;
                        *(uint64_t *)opts[idx].ptr = v;
                        break;
                }
        }
        if (args) {
                while (args->descr) {
                        if (optind >= argc) {
                                fprintf(stderr, "Missing arg %s\n", args->descr);
                                arg_help(argc, argv, f);
                                free(lopts);
                                free(shortopts);
                                return (1);
                        }
                        *(char **)args->ptr = argv[optind++];
                        args++;
                }
        }
        free(lopts);
        free(shortopts);
        return (0);
bad_arg:
        fprintf(stderr, "Bad value to --%s: %s\n", opts[idx].long_arg, optarg);
        free(lopts);
        free(shortopts);
        exit(EX_USAGE);
}

/*
 * Loads all the .so's from the specified directory.
 */
void
cmd_load_dir(const char *dir, cmd_load_cb_t cb, void *argp)
{
        DIR *d;
        struct dirent *dent;
        char *path = NULL;
        void *h;

        d = opendir(dir);
        if (d == NULL)
                return;
        for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
                if (strcmp(".so", dent->d_name + dent->d_namlen - 3) != 0)
                        continue;
                asprintf(&path, "%s/%s", dir, dent->d_name);
                if (path == NULL)
                        err(EX_OSERR, "Can't malloc for path, giving up.");
                if ((h = dlopen(path, RTLD_NOW | RTLD_GLOBAL)) == NULL)
                        warnx("Can't load %s: %s", path, dlerror());
                else {
                        if (cb != NULL)
                                cb(argp, h);
                }
                free(path);
                path = NULL;
        }
        closedir(d);
}

void
cmd_register(struct cmd *up, struct cmd *cmd)
{
        struct cmd *walker, *last;

        if (up == NULL)
                up = &top;
        SLIST_INIT(&cmd->subcmd);
        cmd->parent = up;
        last = NULL;
        SLIST_FOREACH(walker, &up->subcmd, link) {
                if (strcmp(walker->name, cmd->name) > 0)
                        break;
                last = walker;
        }
        if (last == NULL) {
                SLIST_INSERT_HEAD(&up->subcmd, cmd, link);
        } else {
                SLIST_INSERT_AFTER(last, cmd, link);
        }
}

void
cmd_init(void)
{

}