/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2024, Baptiste Daroussin <bapt@FreeBSD.org>
 */

#include <errno.h>
#include <kenv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

#include "bootstrap.h"

int luaopen_freebsd_kenv(lua_State *L);

static int
lua_kenv_get(lua_State *L)
{
        const char *env;
        int ret, n;
        char value[1024];

        n = lua_gettop(L);
        if (n == 0) {
                char *buf, *bp, *cp;
                int size;

                size = kenv(KENV_DUMP, NULL, NULL, 0);
                if (size < 0) {
                        lua_pushnil(L);
                        lua_pushstring(L, strerror(errno));
                        lua_pushinteger(L, errno);
                        return (3);
                }
                size += 1;
                buf = malloc(size);
                if (buf == NULL) {
                        lua_pushnil(L);
                        lua_pushstring(L, strerror(errno));
                        lua_pushinteger(L, errno);
                        return (3);
                }
                if (kenv(KENV_DUMP, NULL, buf, size) < 0) {
                        free(buf);
                        lua_pushnil(L);
                        lua_pushstring(L, strerror(errno));
                        lua_pushinteger(L, errno);
                        return (3);
                }

                lua_newtable(L);
                for (bp = buf; *bp != '\0'; bp += strlen(bp) + 1) {
                        cp = strchr(bp, '=');
                        if (cp == NULL)
                                continue;
                        *cp++ = '\0';
                        lua_pushstring(L, cp);
                        lua_setfield(L, -2, bp);
                        bp = cp;
                }
                free(buf);
                return (1);
        }
        env = luaL_checkstring(L, 1);
        ret = kenv(KENV_GET, env, value, sizeof(value));
        if (ret == -1) {
                if (errno == ENOENT) {
                        lua_pushnil(L);
                        return (1);
                }
                lua_pushnil(L);
                lua_pushstring(L, strerror(errno));
                lua_pushinteger(L, errno);
                return (3);
        }
        lua_pushstring(L, value);
        return (1);
}

#define REG_SIMPLE(n)   { #n, lua_kenv_ ## n }
static const struct luaL_Reg freebsd_kenv[] = {
        REG_SIMPLE(get),
        { NULL, NULL },
};
#undef REG_SIMPLE

int
luaopen_freebsd_kenv(lua_State *L)
{
        luaL_newlib(L, freebsd_kenv);

        return (1);
}

FLUA_MODULE_NAMED(freebsd_kenv, "freebsd.kenv");