/*-
 * Copyright (c) 2014 Pedro Souza <pedrosouza@freebsd.org>
 * All rights reserved.
 *
 * 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 "lua.h"
#include "lauxlib.h"
#include "lstd.h"
#include "lutils.h"
#include "bootstrap.h"

/*
 * Like loader.perform, except args are passed already parsed
 * on the stack.
 */
static int
lua_command(lua_State *L)
{
        int     i;
        int     res = 1;
        int     argc = lua_gettop(L);
        char    **argv;

        argv = malloc(sizeof(char *) * (argc + 1));
        if (argv == NULL)
                return 0;
        for (i = 0; i < argc; i++)
                argv[i] = (char *)(intptr_t)luaL_checkstring(L, i + 1);
        argv[argc] = NULL;
        res = interp_builtin_cmd(argc, argv);
        free(argv);
        lua_pushinteger(L, res);

        return 1;
}

static int
lua_has_command(lua_State *L)
{
        const char      *cmd;

        cmd = luaL_checkstring(L, 1);
        if (interp_has_builtin_cmd(cmd)) {
                lua_pushboolean(L, 1);
                return 1;
        }

        lua_pushnil(L);
        lua_pushstring(L, "Builtin command not found");
        return 2;
}

static int
lua_has_feature(lua_State *L)
{
        const char      *feature;
        char *msg;

        feature = luaL_checkstring(L, 1);

        if (feature_name_is_enabled(feature)) {
                lua_pushboolean(L, 1);
                return 1;
        }

        lua_pushnil(L);
        lua_pushstring(L, "Feature not enabled");
        return 2;
}


static int
lua_perform(lua_State *L)
{
        int     argc;
        char    **argv;
        int     res = 1;

        if (parse(&argc, &argv, luaL_checkstring(L, 1)) == 0) {
                res = interp_builtin_cmd(argc, argv);
                free(argv);
        }
        lua_pushinteger(L, res);

        return 1;
}

static int
lua_exit(lua_State *L)
{
        exit(luaL_checkinteger(L, 1));
        return 0;
}

static int
lua_command_error(lua_State *L)
{

        lua_pushstring(L, command_errbuf);
        return 1;
}

/*
 * Accepts a space-delimited loader command and runs it through the standard
 * loader parsing, as if it were executed at the loader prompt by the user.
 */
static int
lua_interpret(lua_State *L)
{
        const char      *interp_string;

        if (lua_gettop(L) != 1) {
                lua_pushnil(L);
                return 1;
        }

        interp_string = luaL_checkstring(L, 1);
        lua_pushinteger(L, interp_run(interp_string));
        return 1;
}

static int
lua_parse(lua_State *L)
{
        int     argc, nargc;
        char    **argv;

        if (parse(&argc, &argv, luaL_checkstring(L, 1)) == 0) {
                for (nargc = 0; nargc < argc; ++nargc) {
                        lua_pushstring(L, argv[nargc]);
                }
                free(argv);
                return nargc;
        }

        lua_pushnil(L);
        return 1;
}

static int
lua_getchar(lua_State *L)
{

        lua_pushinteger(L, getchar());
        return 1;
}

static int
lua_ischar(lua_State *L)
{

        lua_pushboolean(L, ischar());
        return 1;
}

static int
lua_gets(lua_State *L)
{
        char    buf[129];

        ngets(buf, 128);
        lua_pushstring(L, buf);
        return 1;
}

static int
lua_time(lua_State *L)
{

        lua_pushinteger(L, time(NULL));
        return 1;
}

static int
lua_delay(lua_State *L)
{

        delay((int)luaL_checknumber(L, 1));
        return 0;
}

static int
lua_getenv(lua_State *L)
{
        lua_pushstring(L, getenv(luaL_checkstring(L, 1)));

        return 1;
}

static int
lua_setenv(lua_State *L)
{
        const char *key, *val;

        key = luaL_checkstring(L, 1);
        val = luaL_checkstring(L, 2);
        lua_pushinteger(L, setenv(key, val, 1));

        return 1;
}

static int
lua_unsetenv(lua_State *L)
{
        const char      *ev;

        ev = luaL_checkstring(L, 1);
        lua_pushinteger(L, unsetenv(ev));

        return 1;
}

static int
lua_printc(lua_State *L)
{
        ssize_t cur, l;
        const char *s = luaL_checklstring(L, 1, &l);

        for (cur = 0; cur < l; ++cur)
                putchar((unsigned char)*(s++));

        return 1;
}

static int
lua_openfile(lua_State *L)
{
        const char      *mode, *str;
        int     nargs;

        nargs = lua_gettop(L);
        if (nargs < 1 || nargs > 2) {
                lua_pushnil(L);
                return 1;
        }
        str = lua_tostring(L, 1);
        mode = "r";
        if (nargs > 1) {
                mode = lua_tostring(L, 2);
                if (mode == NULL) {
                        lua_pushnil(L);
                        return 1;
                }
        }
        FILE * f = fopen(str, mode);
        if (f != NULL) {
                FILE ** ptr = (FILE**)lua_newuserdata(L, sizeof(FILE**));
                *ptr = f;
        } else
                lua_pushnil(L);
        return 1;
}

static int
lua_closefile(lua_State *L)
{
        FILE ** f;
        if (lua_gettop(L) != 1) {
                lua_pushboolean(L, 0);
                return 1;
        }

        f = (FILE**)lua_touserdata(L, 1);
        if (f != NULL && *f != NULL) {
                lua_pushboolean(L, fclose(*f) == 0 ? 1 : 0);
                *f = NULL;
        } else
                lua_pushboolean(L, 0);

        return 1;
}

static int
lua_readfile(lua_State *L)
{
        FILE    **f;
        size_t  size, r;
        char * buf;

        if (lua_gettop(L) < 1 || lua_gettop(L) > 2) {
                lua_pushnil(L);
                lua_pushinteger(L, 0);
                return 2;
        }

        f = (FILE**)lua_touserdata(L, 1);

        if (f == NULL || *f == NULL) {
                lua_pushnil(L);
                lua_pushinteger(L, 0);
                return 2;
        }

        if (lua_gettop(L) == 2)
                size = (size_t)lua_tonumber(L, 2);
        else
                size = (*f)->size;


        buf = (char*)malloc(size);
        r = fread(buf, 1, size, *f);
        lua_pushlstring(L, buf, r);
        free(buf);
        lua_pushinteger(L, r);

        return 2;
}

/*
 * Implements io.write(file, ...)
 * Any number of string and number arguments may be passed to it,
 * and it will return the number of bytes written, or nil, an error string, and
 * the errno.
 */
static int
lua_writefile(lua_State *L)
{
        FILE    **f;
        const char      *buf;
        int     i, nargs;
        size_t  bufsz, w, wrsz;

        buf = NULL;
        bufsz = 0;
        w = 0;
        wrsz = 0;
        nargs = lua_gettop(L);
        if (nargs < 2) {
                errno = EINVAL;
                return luaL_fileresult(L, 0, NULL);
        }

        f = (FILE**)lua_touserdata(L, 1);

        if (f == NULL || *f == NULL) {
                errno = EINVAL;
                return luaL_fileresult(L, 0, NULL);
        }

        /* Do a validation pass first */
        for (i = 0; i < nargs - 1; i++) {
                /*
                 * With Lua's API, lua_isstring really checks if the argument
                 * is a string or a number.  The latter will be implicitly
                 * converted to a string by our later call to lua_tolstring.
                 */
                if (!lua_isstring(L, i + 2)) {
                        errno = EINVAL;
                        return luaL_fileresult(L, 0, NULL);
                }
        }
        for (i = 0; i < nargs - 1; i++) {
                /* We've already validated; there's no chance of failure */
                buf = lua_tolstring(L, i + 2, &bufsz);
                wrsz = fwrite(buf, 1, bufsz, *f);
                if (wrsz < bufsz)
                        return luaL_fileresult(L, 0, NULL);
                w += wrsz;
        }
        lua_pushinteger(L, w);
        return 1;
}

#define REG_SIMPLE(n)   { #n, lua_ ## n }
static const struct luaL_Reg loaderlib[] = {
        REG_SIMPLE(command),
        REG_SIMPLE(command_error),
        REG_SIMPLE(delay),
        REG_SIMPLE(exit),
        REG_SIMPLE(getenv),
        REG_SIMPLE(has_command),
        REG_SIMPLE(has_feature),
        REG_SIMPLE(interpret),
        REG_SIMPLE(parse),
        REG_SIMPLE(perform),
        REG_SIMPLE(printc),     /* Also registered as the global 'printc' */
        REG_SIMPLE(setenv),
        REG_SIMPLE(time),
        REG_SIMPLE(unsetenv),
        { NULL, NULL },
};

static const struct luaL_Reg iolib[] = {
        { "close", lua_closefile },
        REG_SIMPLE(getchar),
        REG_SIMPLE(gets),
        REG_SIMPLE(ischar),
        { "open", lua_openfile },
        { "read", lua_readfile },
        { "write", lua_writefile },
        { NULL, NULL },
};
#undef REG_SIMPLE

static void
lua_add_feature(void *cookie, const char *name, const char *desc, bool enabled)
{
        lua_State *L = cookie;

        /*
         * The feature table consists solely of features that are enabled, and
         * their associated descriptions for debugging purposes.
         */
        lua_pushstring(L, desc);
        lua_setfield(L, -2, name);
}

static void
lua_add_features(lua_State *L)
{

        lua_newtable(L);
        feature_iter(&lua_add_feature, L);

        /*
         * We should still have just the table on the stack after we're done
         * iterating.
         */
        lua_setfield(L, -2, "features");
}

int
luaopen_loader(lua_State *L)
{
        luaL_newlib(L, loaderlib);
        /* Add loader.machine and loader.machine_arch properties */
        lua_pushstring(L, MACHINE);
        lua_setfield(L, -2, "machine");
        lua_pushstring(L, MACHINE_ARCH);
        lua_setfield(L, -2, "machine_arch");
        lua_pushstring(L, LUA_PATH);
        lua_setfield(L, -2, "lua_path");
        lua_pushinteger(L, bootprog_rev);
        lua_setfield(L, -2, "version");
        lua_pushinteger(L, CMD_OK);
        lua_setfield(L, -2, "CMD_OK");
        lua_pushinteger(L, CMD_WARN);
        lua_setfield(L, -2, "CMD_WARN");
        lua_pushinteger(L, CMD_ERROR);
        lua_setfield(L, -2, "CMD_ERROR");
        lua_pushinteger(L, CMD_CRIT);
        lua_setfield(L, -2, "CMD_CRIT");
        lua_pushinteger(L, CMD_FATAL);
        lua_setfield(L, -2, "CMD_FATAL");
        lua_add_features(L);
        /* Set global printc to loader.printc */
        lua_register(L, "printc", lua_printc);
        return 1;
}

int
luaopen_io(lua_State *L)
{
        luaL_newlib(L, iolib);
        return 1;
}