/**
 * @file
 * @brief General game bindings.
**/

/*
--- General game bindings

module "crawl"
*/

#include "AppHdr.h"

#include "dlua.h"
#include "cluautil.h"
#include "l_libs.h"

#include "chardump.h"
#include "cio.h"
#include "command.h"
#include "delay.h"
#include "directn.h"
#include "end.h"
#include "format.h"
#include "hiscores.h"
#include "hints.h"
#include "initfile.h"
#include "itemname.h"
#include "libutil.h"
#include "macro.h"
#include "menu.h"
#include "message.h"
#include "notes.h"
#include "options.h"
#include "ouch.h"
#include "output.h"
#include "perlin.h"
#include "player.h"
#include "prompt.h"
#include "random.h"
#include "religion.h"
#include "state.h"
#include "stringutil.h"
#include "tutorial.h"
#include "view.h"
#include "worley.h"

#ifdef TARGET_OS_WINDOWS
# include "windows.h"
#else
# include <sys/time.h>
# include <time.h>
#endif

/////////////////////////////////////////////////////////////////////
// User accessible
//

/*
--- Print a message.
-- @param message message to print
-- @channel channel to print on; defaults to 0 (<code>MSGCH_PLAIN</code>)
function mpr(message, channel) */
static int crawl_mpr(lua_State *ls)
{
    if (!crawl_state.io_inited)
        return 0;

    const char *message = luaL_checkstring(ls, 1);
    if (!message)
        return 0;

    int ch = MSGCH_PLAIN;
    if (lua_isnumber(ls, 2))
        ch = luaL_checkint(ls, 2);
    else
    {
        const char *channel = lua_tostring(ls, 2);
        if (channel)
            ch = str_to_channel(channel);
    }

    if (ch < 0 || ch >= NUM_MESSAGE_CHANNELS)
        ch = MSGCH_PLAIN;

    mprf(static_cast<msg_channel_type>(ch), "%s", message);
    return 0;
}

/*
---
function formatted_mpr(message, channel) */
static int crawl_formatted_mpr(lua_State *ls)
{
    if (!crawl_state.io_inited)
        return 0;

    const char *message = luaL_checkstring(ls, 1);
    if (!message)
        return 0;

    int ch = MSGCH_PLAIN;
    if (lua_isnumber(ls, 2))
        ch = luaL_checkint(ls, 2);
    else
    {
        const char *channel = lua_tostring(ls, 2);
        if (channel)
            ch = str_to_channel(channel);
    }

    if (ch < 0 || ch >= NUM_MESSAGE_CHANNELS)
        ch = MSGCH_PLAIN;

    formatted_mpr(formatted_string::parse_string(message),
                  static_cast<msg_channel_type>(ch));
    return 0;
}

/*
--- Print to stderr for debugging hooks.
function stderr(text) */
LUAFN(crawl_stderr)
{
    const char *text = luaL_checkstring(ls, 1);
    fprintf(stderr, "%s\n", text);
    return 0;
}

/*
--- Debugging spew.
function dpr(text) */
LUAFN(crawl_dpr)
{
#ifdef DEBUG_DIAGNOSTICS
    const char *text = luaL_checkstring(ls, 1);
    if (crawl_state.io_inited)
        dprf("%s", text);
#endif
    return 0;
}

/*
---
function delay(ms) */
LUAWRAP(crawl_delay, delay(luaL_checkint(ls, 1)))
/*
---
function more() */
LUAWRAP(crawl_more, more())
/*
---
function flush_prev_message() */
LUAWRAP(crawl_flush_prev_message, flush_prev_message())
/*
---
function clear_messages(force) */
LUAWRAP(crawl_clear_messages,
clear_messages(lua_isboolean(ls, 1) ? lua_toboolean(ls, 1) : false))
/*
---
function redraw_screen() */
LUAWRAP(crawl_redraw_screen, redraw_screen())

/*
---
function set_more_autoclear(flag) */
static int crawl_set_more_autoclear(lua_State *ls)
{
    if (lua_isnone(ls, 1))
    {
        luaL_argerror(ls, 1, "needs a boolean argument");
        return 0;
    }
    set_more_autoclear(lua_toboolean(ls, 1));

    return 0;
}

/*
---
function enable_more(flag) */
static int crawl_enable_more(lua_State *ls)
{
    if (lua_isnone(ls, 1))
    {
        luaL_argerror(ls, 1, "needs a boolean argument");
        return 0;
    }
    crawl_state.show_more_prompt = lua_toboolean(ls, 1);

    return 0;
}

/*
--- Wrapper for <code>cancellable_get_line()</code>.  Since that takes
-- a pre-allocated buffer, an arbitrary 500-character limit is
-- currently imposed.
-- @return Either a string if one is input, or nil if input is cancelled
function c_input_line() */
static int crawl_c_input_line(lua_State *ls)
{
    char linebuf[500];

    bool valid = !cancellable_get_line(linebuf, sizeof linebuf);
    if (valid)
        lua_pushstring(ls, linebuf);
    else
        lua_pushnil(ls);
    return 1;
}

/*
--- Get input key (combo).
-- @return integer representing the key (combo) input
function getch() */
LUARET1(crawl_getch, number, getchm())
/*
--- Check for pending input.
-- @return 1 if there is, 0 otherwise
function kbhit() */
LUARET1(crawl_kbhit, number, kbhit())
/*
--- Flush the input buffer (typeahead).
function flush_input() */
LUAWRAP(crawl_flush_input, flush_input_buffer(FLUSH_LUA))

static char _lua_char(lua_State *ls, int ndx, char defval = 0)
{
    return lua_isnone(ls, ndx) || !lua_isstring(ls, ndx)? defval
           : lua_tostring(ls, ndx)[0];
}

/*
--- Ask the player a yes/no question.
-- The player is supposed to answer by pressing Y or N.
-- @param prompt question for the user
-- @param safe accept lowercase answers?
-- @param safeanswer if a letter, this will be considered a safe default
-- @param clear_after clear the question after the user answers?
-- @param noprompt if true, skip asking the question; just wait for the answer
function yesno(prompt, safe, safeanswer, clear_after, interrupt_delays, noprompt) */
static int crawl_yesno(lua_State *ls)
{
    const char *prompt = luaL_checkstring(ls, 1);
    const bool safe = lua_toboolean(ls, 2);
    const int safeanswer = _lua_char(ls, 3);
    const bool clear_after =
        lua_isnone(ls, 4) ? true : lua_toboolean(ls, 4);
    const bool interrupt_delays =
        lua_isnone(ls, 5) ? true : lua_toboolean(ls, 5);
    const bool noprompt =
        lua_isnone(ls, 6) ? false : lua_toboolean(ls, 6);

    lua_pushboolean(ls, yesno(prompt, safe, safeanswer, clear_after,
                              interrupt_delays, noprompt));
    return 1;
}

/*
--- Ask the player a yes/no/quit question.
-- Mostly like <code>yesno()</code>, but doesn't yet support as many
-- parameters in this Lua binding.
-- @param allow_all actually ask a yes/no/quit/all question
function yesnoquit(prompt, safe, safeanswer, allow_all, clear_after) */
static int crawl_yesnoquit(lua_State *ls)
{
    const char *prompt = luaL_checkstring(ls, 1);
    const bool safe = lua_toboolean(ls, 2);
    const int safeanswer = _lua_char(ls, 3);
    const bool allow_all =
        lua_isnone(ls, 4) ? false : lua_toboolean(ls, 4);
    const bool clear_after =
        lua_isnone(ls, 5) ? true : lua_toboolean(ls, 5);

    // Skipping the other params until somebody needs them.

    lua_pushnumber(ls, yesnoquit(prompt, safe, safeanswer, allow_all,
                                 clear_after));
    return 1;
}

static void crawl_sendkeys_proc(lua_State *ls, int argi)
{
    if (lua_isstring(ls, argi))
    {
        const char *keys = luaL_checkstring(ls, argi);
        if (!keys)
            return;

        for (; *keys; ++keys)
            macro_sendkeys_end_add_expanded(*keys);
    }
    else if (lua_istable(ls, argi))
    {
        for (int i = 1; ; ++i)
        {
            lua_rawgeti(ls, argi, i);
            if (lua_isnil(ls, -1))
            {
                lua_pop(ls, 1);
                return;
            }

            crawl_sendkeys_proc(ls, lua_gettop(ls));
            lua_pop(ls, 1);
        }
    }
    else if (lua_isnumber(ls, argi))
        macro_sendkeys_end_add_expanded(luaL_checkint(ls, argi));
}

/*
--- XXX vararg function
--
function sendkeys() */
static int crawl_sendkeys(lua_State *ls)
{
    int top = lua_gettop(ls);
    for (int i = 1; i <= top; ++i)
        crawl_sendkeys_proc(ls, i);
    return 0;
}

/*
--- Tell Crawl to process one command.
-- @return whether it will actually do so?
function process_command() */
static int crawl_process_command(lua_State *ls)
{
    const bool will_process =
        current_delay_action() == DELAY_MACRO || !you_are_delayed();

    if (will_process)
    {
        // This should only be called from a macro delay, but run_macro
        // may not have started the macro delay; do so now.
        if (!you_are_delayed())
            start_delay(DELAY_MACRO, 1);
        start_delay(DELAY_MACRO_PROCESS_KEY, 1);
    }

    lua_pushboolean(ls, will_process);
    return 1;
}

/*
---
function process_keys() */
static int crawl_process_keys(lua_State *ls)
{
    const delay_type current_delay = current_delay_action();
    if (current_delay && current_delay != DELAY_MACRO)
    {
        luaL_error(ls, "Cannot currently process new keys (%s delay active)",
                   delay_name(current_delay));
        return 0;
    }

    if (you.turn_is_over)
    {
        luaL_error(ls, "Cannot currently process new keys (turn is over)");
        return 0;
    }

    const char* keys = luaL_checkstring(ls, 1);

    if (strlen(keys) == 0)
    {
        luaL_argerror(ls, 1, "Must have at least one key to process.");
        return 0;
    }

    command_type cmd = key_to_command(keys[0], KMC_DEFAULT);

    if (cmd == CMD_NO_CMD)
    {
        luaL_argerror(ls, 1, "First key is invalid command");
        return 0;
    }

    flush_input_buffer(FLUSH_BEFORE_COMMAND);
    for (int i = 1, len = strlen(keys); i < len; i++)
        macro_sendkeys_end_add_expanded(keys[i]);

    process_command(cmd);

    return 0;
}

/*
--- Play a sound.
-- @param sf filename of sound to play
function playsound(sf) */
static int crawl_playsound(lua_State *ls)
{
    const char *sf = luaL_checkstring(ls, 1);
    if (!sf)
        return 0;
    play_sound(sf);
    return 0;
}

/*
--- Run a macro.
-- @param macroname name of macro to run
function runmacro(macroname) */
static int crawl_runmacro(lua_State *ls)
{
    const char *macroname = luaL_checkstring(ls, 1);
    if (!macroname)
        return 0;
    run_macro(macroname);
    return 0;
}

/*
--- Set user options from string.
-- @param s string of options to set, in same format as <tt>init.txt</tt>/<tt>.crawlrc</tt>.
function setopt(s) */
static int crawl_setopt(lua_State *ls)
{
    if (!lua_isstring(ls, 1))
        return 0;

    const char *s = lua_tostring(ls, 1);
    if (s)
    {
        // Note that the conditional script can contain nested Lua[ ]Lua code.
        read_options(s, true);
    }

    return 0;
}

/*
--- Read options from file.
-- @param filename name of file to read from
function read_options(filename) */
static int crawl_read_options(lua_State *ls)
{
    if (!lua_isstring(ls, 1))
        return 0;

    const char* filename = lua_tostring(ls, 1);
    Options.include(filename, true, true);
    return 0;
}

static int crawl_bindkey(lua_State *ls)
{
    const char *s = NULL;
    if (lua_isstring(ls, 1))
        s = lua_tostring(ls, 1);

    if (!s || !lua_isfunction(ls, 2) || lua_gettop(ls) != 2)
        return 0;

    lua_pushvalue(ls, 2);
    string name = clua.setuniqregistry();
    if (lua_gettop(ls) != 2)
    {
        fprintf(stderr, "Stack top has changed!\n");
        lua_settop(ls, 2);
    }
    macro_userfn(s, name.c_str());
    return 0;
}

static int crawl_msgch_num(lua_State *ls)
{
    const char *s = luaL_checkstring(ls, 1);
    if (!s)
        return 0;
    int ch = str_to_channel(s);
    if (ch == -1)
        return 0;

    lua_pushnumber(ls, ch);
    return 1;
}

static int crawl_msgch_name(lua_State *ls)
{
    int num = luaL_checkint(ls, 1);
    string name = channel_to_str(num);
    lua_pushstring(ls, name.c_str());
    return 1;
}

static int crawl_take_note(lua_State *ls)
{
    const char* msg = luaL_checkstring(ls, 1);
    take_note(Note(NOTE_MESSAGE, 0, 0, msg));
    return 0;
}

static int crawl_messages(lua_State *ls)
{
    const int count = luaL_checkint(ls, 1);
    lua_pushstring(ls, get_last_messages(count).c_str());
    return 1;
}

#define REGEX_METATABLE "crawl.regex"
#define MESSF_METATABLE "crawl.messf"

static int crawl_regex(lua_State *ls)
{
    const char *s = luaL_checkstring(ls, 1);
    if (!s)
        return 0;

    text_pattern **tpudata =
            clua_new_userdata< text_pattern* >(ls, REGEX_METATABLE);
    if (tpudata)
    {
        *tpudata = new text_pattern(s);
        return 1;
    }
    return 0;
}

static int crawl_regex_find(lua_State *ls)
{
    text_pattern **pattern =
            clua_get_userdata< text_pattern* >(ls, REGEX_METATABLE);
    if (!pattern)
        return 0;

    const char *text = luaL_checkstring(ls, -1);
    if (!text)
        return 0;

    lua_pushboolean(ls, (*pattern)->matches(text));
    return 1;
}

static int crawl_regex_equals(lua_State *ls)
{
    text_pattern **pattern =
            clua_get_userdata< text_pattern* >(ls, REGEX_METATABLE);
    text_pattern **arg =
            clua_get_userdata< text_pattern* >(ls, REGEX_METATABLE, 2);
    lua_pushboolean(ls, pattern && arg && **pattern == **arg);
    return 1;
}

static const luaL_reg crawl_regex_ops[] =
{
    { "matches",        crawl_regex_find },
    { "equals",         crawl_regex_equals },
    { NULL, NULL }
};

static int crawl_message_filter(lua_State *ls)
{
    const char *pattern = luaL_checkstring(ls, 1);
    if (!pattern)
        return 0;

    int num = lua_isnumber(ls, 2)? luaL_checkint(ls, 2) : -1;
    message_filter **mf =
            clua_new_userdata< message_filter* >(ls, MESSF_METATABLE);
    if (mf)
    {
        *mf = new message_filter(num, pattern);
        return 1;
    }
    return 0;
}

static int crawl_messf_matches(lua_State *ls)
{
    message_filter **mf =
            clua_get_userdata< message_filter* >(ls, MESSF_METATABLE);
    if (!mf)
        return 0;

    const char *pattern = luaL_checkstring(ls, 2);
    int ch = luaL_checkint(ls, 3);
    if (pattern)
    {
        bool filt = (*mf)->is_filtered(ch, pattern);
        lua_pushboolean(ls, filt);
        return 1;
    }
    return 0;
}

static int crawl_messf_equals(lua_State *ls)
{
    message_filter **mf =
            clua_get_userdata< message_filter* >(ls, MESSF_METATABLE);
    message_filter **arg =
            clua_get_userdata< message_filter* >(ls, MESSF_METATABLE, 2);
    lua_pushboolean(ls, mf && arg && **mf == **arg);
    return 1;
}

static const luaL_reg crawl_messf_ops[] =
{
    { "matches",        crawl_messf_matches },
    { "equals",         crawl_messf_equals },
    { NULL, NULL }
};

static int crawl_trim(lua_State *ls)
{
    const char *s = luaL_checkstring(ls, 1);
    if (!s)
        return 0;
    string text = s;
    trim_string(text);
    lua_pushstring(ls, text.c_str());
    return 1;
}

static int crawl_split(lua_State *ls)
{
    const char *s = luaL_checkstring(ls, 1),
               *token = luaL_checkstring(ls, 2);
    if (!s || !token)
        return 0;

    vector<string> segs = split_string(token, s);
    if (lua_isboolean(ls, 3) && lua_toboolean(ls, 3))
        reverse(segs.begin(), segs.end());
    lua_newtable(ls);
    for (int i = 0, count = segs.size(); i < count; ++i)
    {
        lua_pushstring(ls, segs[i].c_str());
        lua_rawseti(ls, -2, i + 1);
    }
    return 1;
}

static int _crawl_grammar(lua_State *ls)
{
    description_level_type ndesc = DESC_PLAIN;
    if (lua_isstring(ls, 2))
        ndesc = description_type_by_name(lua_tostring(ls, 2));
    PLUARET(string,
            thing_do_grammar(ndesc, false,
                             false, luaL_checkstring(ls, 1)).c_str());
}

static int crawl_article_a(lua_State *ls)
{
    const char *s = luaL_checkstring(ls, 1);

    bool lowercase = true;
    if (lua_isboolean(ls, 2))
        lowercase = lua_toboolean(ls, 2);

    lua_pushstring(ls, article_a(s, lowercase).c_str());

    return 1;
}

LUARET1(crawl_game_started, boolean, crawl_state.need_save
                                     || crawl_state.map_stat_gen
                                     || crawl_state.obj_stat_gen
                                     || crawl_state.test)
LUARET1(crawl_stat_gain_prompt, boolean, crawl_state.stat_gain_prompt)
LUARET1(crawl_random2, number, random2(luaL_checkint(ls, 1)))
LUARET1(crawl_one_chance_in, boolean, one_chance_in(luaL_checkint(ls, 1)))
LUARET1(crawl_random2avg, number,
        random2avg(luaL_checkint(ls, 1), luaL_checkint(ls, 2)))
LUARET1(crawl_random_range, number,
        random_range(luaL_checkint(ls, 1), luaL_checkint(ls, 2),
                      lua_isnumber(ls, 3)? luaL_checkint(ls, 3) : 1))
LUARET1(crawl_coinflip, boolean, coinflip())
LUARET1(crawl_roll_dice, number,
        lua_gettop(ls) == 1
        ? roll_dice(1, luaL_checkint(ls, 1))
        : roll_dice(luaL_checkint(ls, 1), luaL_checkint(ls, 2)))
LUARET1(crawl_x_chance_in_y, boolean, x_chance_in_y(luaL_checkint(ls, 1),
                                                    luaL_checkint(ls, 2)))
LUARET1(crawl_div_rand_round, number, div_rand_round(luaL_checkint(ls, 1),
                                                     luaL_checkint(ls, 2)))
LUARET1(crawl_random_real, number, random_real())

// Get the full worley noise datum for a given point
static int crawl_worley(lua_State *ls)
{
    double px = lua_tonumber(ls,1);
    double py = lua_tonumber(ls,2);
    double pz = lua_tonumber(ls,3);

    worley::noise_datum n = worley::noise(px,py,pz);
    lua_pushnumber(ls, n.distance[0]);
    lua_pushnumber(ls, n.distance[1]);
    lua_pushnumber(ls, n.id[0]);
    lua_pushnumber(ls, n.id[1]);
    lua_pushnumber(ls, n.pos[0][0]);
    lua_pushnumber(ls, n.pos[0][1]);
    lua_pushnumber(ls, n.pos[0][2]);
    lua_pushnumber(ls, n.pos[1][0]);
    lua_pushnumber(ls, n.pos[1][1]);
    lua_pushnumber(ls, n.pos[1][2]);
    return 10;
}

// Simpler return value for normal situations where we just
// want the difference between the nearest point distances.
// Also returns the id in case we want a per-node number.
static int crawl_worley_diff(lua_State *ls)
{
    double px = lua_tonumber(ls,1);
    double py = lua_tonumber(ls,2);
    double pz = lua_tonumber(ls,3);

    worley::noise_datum n = worley::noise(px,py,pz);
    lua_pushnumber(ls, n.distance[1]-n.distance[0]);
    lua_pushnumber(ls, n.id[0]);

    return 2;
}

// Splits a 32-bit integer into four bytes. This is useful
// in conjunction with worley ids to get four random numbers
// instead of one from the current node id.
static int crawl_split_bytes(lua_State *ls)
{
    uint32_t val = lua_tonumber(ls,1);
    uint8_t bytes[4] =
    {
        (uint8_t)(val >> 24),
        (uint8_t)(val >> 16),
        (uint8_t)(val >> 8),
        (uint8_t)(val)
    };
    lua_pushnumber(ls, bytes[0]);
    lua_pushnumber(ls, bytes[1]);
    lua_pushnumber(ls, bytes[2]);
    lua_pushnumber(ls, bytes[3]);
    return 4;
}

// Supports 2D-4D Simplex noise. The first two parameters are required
// for 2D noise, the next two are optional for 3D or 4D.
// TODO: Could support octaves here but maybe it can be handled more
// flexibly in lua
static int crawl_simplex(lua_State *ls)
{
    int dims = 0;
    double vals[4];
    if (lua_isnumber(ls,1))
    {
        vals[dims] = lua_tonumber(ls,1);
        dims++;
    }
    if (lua_isnumber(ls,2))
    {
        vals[dims] = lua_tonumber(ls,2);
        dims++;
    }
    if (lua_isnumber(ls,3))
    {
        vals[dims] = lua_tonumber(ls,3);
        dims++;
    }
    if (lua_isnumber(ls,4))
    {
        vals[dims] = lua_tonumber(ls,4);
        dims++;
    }

    double result;
    switch (dims)
    {
    case 2:
        result = perlin::noise(vals[0],vals[1]);
        break;
    case 3:
        result = perlin::noise(vals[0],vals[1],vals[2]);
        break;
    case 4:
        result = perlin::noise(vals[0],vals[1],vals[2],vals[3]);
        break;
    default:
        return 0; // TODO: Throw error?
    }
    lua_pushnumber(ls, result);

    return 1;
}

static int crawl_is_tiles(lua_State *ls)
{
    lua_pushboolean(ls, is_tiles());

    return 1;
}

static int crawl_is_webtiles(lua_State *ls)
{
#ifdef USE_TILE_WEB
    lua_pushboolean(ls, true);
#else
    lua_pushboolean(ls, false);
#endif

    return 1;
}

static int crawl_is_touch_ui(lua_State *ls)
{
#ifdef TOUCH_UI
    lua_pushboolean(ls, true);
#else
    lua_pushboolean(ls, false);
#endif

    return 1;
}

static int crawl_get_command(lua_State *ls)
{
    if (lua_gettop(ls) == 0)
    {
        lua_pushnil(ls);
        return 1;
    }

    const command_type cmd = name_to_command(luaL_checkstring(ls, 1));

    string cmd_name = command_to_string(cmd, true);
    if (strcmp(cmd_name.c_str(), "<") == 0)
        cmd_name = "<<";

    lua_pushstring(ls, cmd_name.c_str());
    return 1;
}

LUAWRAP(crawl_endgame, screen_end_game(luaL_checkstring(ls, 1)))
LUAWRAP(crawl_tutorial_hunger, set_tutorial_hunger(luaL_checkint(ls, 1)))
LUAWRAP(crawl_tutorial_skill, set_tutorial_skill(luaL_checkstring(ls, 1), luaL_checkint(ls, 2)))
LUAWRAP(crawl_tutorial_hint, tutorial_init_hint(luaL_checkstring(ls, 1)))
LUAWRAP(crawl_print_hint, print_hint(luaL_checkstring(ls, 1)))

static int crawl_random_element(lua_State *ls)
{
    const int table_idx = 1;
    const int value_idx = 2;

    if (lua_gettop(ls) == 0)
    {
        lua_pushnil(ls);
        return 1;
    }

    // Only the first arg does anything now.  Maybe this should
    // select from a variable number of table args?
    lua_pop(ls, lua_gettop(ls) - 1);

    // Keep max value on the stack, as it could be any type of value.
    lua_pushnil(ls);
    int rollsize = 0;

    lua_pushnil(ls);
    while (lua_next(ls, table_idx) != 0)
    {
        const int weight_idx = -1;
        const int key_idx = -2;

        int this_weight = lua_isnil(ls, weight_idx) ?
            1 : (int)lua_tonumber(ls, weight_idx);

        if (rollsize > 0)
        {
            rollsize += this_weight;
            if (x_chance_in_y(this_weight, rollsize))
            {
                lua_pushvalue(ls, key_idx);
                lua_replace(ls, value_idx);
            }
        }
        else
        {
            lua_pushvalue(ls, key_idx);
            lua_replace(ls, value_idx);
            rollsize = this_weight;
        }

        lua_pop(ls, 1);
    }

    lua_pushvalue(ls, value_idx);

    return 1;
}

static int crawl_err_trace(lua_State *ls)
{
    const int nargs = lua_gettop(ls);
    const int err = lua_pcall(ls, nargs - 1, LUA_MULTRET, 0);

    if (err)
    {
        // This code from lua.c:traceback() (mostly)
        const char *errs = lua_tostring(ls, 1);
        string errstr = errs? errs : "";
        lua_getfield(ls, LUA_GLOBALSINDEX, "debug");
        if (!lua_istable(ls, -1))
        {
            lua_pop(ls, 1);
            return lua_error(ls);
        }
        lua_getfield(ls, -1, "traceback");
        if (!lua_isfunction(ls, -1))
        {
            lua_pop(ls, 2);
            return lua_error(ls);
        }
        lua_pushvalue(ls, 1);
        lua_pushinteger(ls, 2); // Skip crawl_err_trace and traceback.
        lua_call(ls, 2, 1);

        // What's on top should be the error.
        lua_error(ls);
    }

    return lua_gettop(ls);
}

static int crawl_tutorial_msg(lua_State *ls)
{
    const char *key = luaL_checkstring(ls, 1);
    if (!key)
        return 0;
    tutorial_msg(key, lua_isboolean(ls, 2) && lua_toboolean(ls, 2));
    return 0;
}

LUAWRAP(crawl_dump_char, dump_char(you.your_name, true))

#ifdef WIZARD
static int crawl_call_dlua(lua_State *ls)
{
    if (!you.wizard)
        luaL_error(ls, "This function is wizard mode only.");

    const char* code = luaL_checkstring(ls, 1);
    if (!code)
        return 0;

    luaL_loadbuffer(dlua, code, strlen(code), "call_dlua");
    int status = lua_pcall(dlua, 0, LUA_MULTRET, 0);

    if (status)
    {
        if (!lua_isnil(dlua, -1))
        {
            const char *msg = lua_tostring(dlua, -1);
            if (msg == NULL)
                msg = "(error object is not a string)";
            mprf(MSGCH_ERROR, "%s", msg);
        }

        lua_settop(dlua, 0); // don't bother unwinding, just nuke the stack
        return 0;
    }

    if (lua_gettop(dlua) > 0)
    {
        // TODO: shuttle things other than a single scalar value
        if (lua_isnil(dlua, -1))
            lua_pushnil(ls);
        else if (lua_isboolean(dlua, -1))
            lua_pushboolean(ls, lua_toboolean(dlua, -1));
        else if (lua_isnumber(dlua, -1))
            lua_pushnumber(ls, lua_tonumber(dlua, -1));
        else if (const char *ret = lua_tostring(dlua, -1))
            lua_pushstring(ls, ret);
        else
        {
            mprf(MSGCH_ERROR, "call_dlua: cannot pass non-scalars yet (TODO)");
            lua_pushnil(ls);
        }

        lua_settop(dlua, 0); // clear the stack
        return 1;
    }

    return 0;
}
#endif

static const struct luaL_reg crawl_clib[] =
{
    { "mpr",                crawl_mpr },
    { "formatted_mpr",      crawl_formatted_mpr },
    { "dpr",                crawl_dpr },
    { "stderr",             crawl_stderr },
    { "more",               crawl_more },
    { "more_autoclear",     crawl_set_more_autoclear },
    { "enable_more",        crawl_enable_more },
    { "flush_prev_message", crawl_flush_prev_message },
    { "clear_messages",     crawl_clear_messages },
    { "delay",              crawl_delay },
    { "random2",            crawl_random2 },
    { "one_chance_in",      crawl_one_chance_in },
    { "random2avg",         crawl_random2avg },
    { "coinflip",           crawl_coinflip },
    { "roll_dice",          crawl_roll_dice },
    { "x_chance_in_y",      crawl_x_chance_in_y },
    { "random_range",       crawl_random_range },
    { "random_element",     crawl_random_element },
    { "div_rand_round",     crawl_div_rand_round },
    { "random_real",        crawl_random_real },
    { "worley",             crawl_worley },
    { "worley_diff",        crawl_worley_diff },
    { "split_bytes",        crawl_split_bytes },
    { "simplex",            crawl_simplex },

    { "redraw_screen",      crawl_redraw_screen },
    { "c_input_line",       crawl_c_input_line},
    { "getch",              crawl_getch },
    { "yesno",              crawl_yesno },
    { "yesnoquit",          crawl_yesnoquit },
    { "kbhit",              crawl_kbhit },
    { "flush_input",        crawl_flush_input },
    { "sendkeys",           crawl_sendkeys },
    { "process_command",    crawl_process_command },
    { "process_keys",       crawl_process_keys },
    { "playsound",          crawl_playsound },
    { "runmacro",           crawl_runmacro },
    { "bindkey",            crawl_bindkey },
    { "setopt",             crawl_setopt },
    { "read_options",       crawl_read_options },
    { "msgch_num",          crawl_msgch_num },
    { "msgch_name",         crawl_msgch_name },
    { "take_note",          crawl_take_note },
    { "messages",           crawl_messages },

    { "regex",              crawl_regex },
    { "message_filter",     crawl_message_filter },
    { "trim",               crawl_trim },
    { "split",              crawl_split },
    { "grammar",            _crawl_grammar },
    { "article_a",          crawl_article_a },
    { "game_started",       crawl_game_started },
    { "stat_gain_prompt",   crawl_stat_gain_prompt },
    { "is_tiles",           crawl_is_tiles },
    { "is_webtiles",        crawl_is_webtiles },
    { "is_touch_ui",        crawl_is_touch_ui },
    { "err_trace",          crawl_err_trace },
    { "get_command",        crawl_get_command },
    { "endgame",            crawl_endgame },
    { "tutorial_msg",       crawl_tutorial_msg },
    { "dump_char",          crawl_dump_char },
#ifdef WIZARD
    { "call_dlua",          crawl_call_dlua },
#endif

    { NULL, NULL },
};

void cluaopen_crawl(lua_State *ls)
{
    clua_register_metatable(ls, REGEX_METATABLE, crawl_regex_ops,
                            lua_object_gc<text_pattern>);
    clua_register_metatable(ls, MESSF_METATABLE, crawl_messf_ops,
                            lua_object_gc<message_filter>);

    luaL_openlib(ls, "crawl", crawl_clib, 0);
}

/////////////////////////////////////////////////////////////////////
// Non-user-accessible bindings (dlua).
//

LUAFN(_crawl_args)
{
    return clua_stringtable(ls, SysEnv.cmd_args);
}

LUAFN(_crawl_milestone)
{
    mark_milestone(luaL_checkstring(ls, 1),
                   luaL_checkstring(ls, 2),
                   luaL_checkstring(ls, 3));
    return 0;
}

LUAFN(_crawl_redraw_view)
{
    viewwindow();
    return 0;
}

LUAFN(_crawl_redraw_stats)
{
    you.wield_change        = true;
    you.redraw_title        = true;
    you.redraw_quiver       = true;
    you.redraw_hit_points   = true;
    you.redraw_magic_points = true;
    you.redraw_stats.init(true);
    you.redraw_experience   = true;
    you.redraw_armour_class = true;
    you.redraw_evasion      = true;
    you.redraw_status_flags = 0xFFFFFFFF;

    print_stats();
    return 0;
}

LUAFN(_crawl_millis)
{
#ifdef TARGET_OS_WINDOWS
    // MSVC has no gettimeofday().
    FILETIME ft;
    GetSystemTimeAsFileTime(&ft);
    uint64_t tt = ft.dwHighDateTime;
    tt <<= 32;
    tt |= ft.dwLowDateTime;
    tt /= 10000;
    tt -= 11644473600000ULL;
    lua_pushnumber(ls, tt);
#else
    struct timeval tv;
    gettimeofday(&tv, nullptr);
    lua_pushnumber(ls, tv.tv_sec * 1000 + tv.tv_usec / 1000);
#endif
    return 1;
}

static string _crawl_make_name(lua_State *ls)
{
    // A quick wrapper around itemname:make_name. Seed is random_int().
    // Possible parameters: all caps, max length, char start. By default
    // these are false, -1, and 0 as per make_name.
    bool all_caps = false;
    int maxlen = -1;
    char start = 0;
    if (lua_gettop(ls) >= 1 && lua_isboolean(ls, 1))
        all_caps = lua_toboolean(ls, 1);
    if (lua_gettop(ls) >= 2 && lua_isnumber(ls, 2))
        maxlen = luaL_checkint(ls, 2);
    if (lua_gettop(ls) >= 3 && lua_isstring(ls, 3))
    {
        const char* s = luaL_checkstring(ls, 3);
        if (s && *s)
            start = *s;
    }
    return make_name(random_int(), all_caps, maxlen, start);
}

LUARET1(crawl_make_name, string, _crawl_make_name(ls).c_str())

// FIXME: factor out the duplicated code in the next two functions.
LUAFN(_crawl_unavailable_god)
{
    const char *god_name = luaL_checkstring(ls, 1);
    if (!god_name)
    {
        string err = "unavailable_god requires a god!";
        return luaL_argerror(ls, 1, err.c_str());
    }
    god_type god = str_to_god(god_name);
    if (god == GOD_NO_GOD)
    {
        string err = make_stringf("'%s' matches no god.", god_name);
        return luaL_argerror(ls, 1, err.c_str());
    }
    lua_pushboolean(ls, is_unavailable_god(god));
    return 1;
}

static int _crawl_god_speaks(lua_State *ls)
{
    if (!crawl_state.io_inited)
        return 0;

    const char *god_name = luaL_checkstring(ls, 1);
    if (!god_name)
    {
        string err = "god_speaks requires a god!";
        return luaL_argerror(ls, 1, err.c_str());
    }

    god_type god = str_to_god(god_name);
    if (god == GOD_NO_GOD)
    {
        string err = make_stringf("'%s' matches no god.", god_name);
        return luaL_argerror(ls, 1, err.c_str());
    }

    const char *message = luaL_checkstring(ls, 2);
    if (!message)
        return 0;

    god_speaks(god, message);
    return 0;
}

LUAFN(_crawl_set_max_runes)
{
    int max_runes = luaL_checkinteger(ls, 1);
    if (max_runes < 0 || max_runes > NUM_RUNE_TYPES)
        luaL_error(ls, make_stringf("Bad number of max runes: %d", max_runes).c_str());
    else
        you.obtainable_runes = max_runes;
    return 0;
}

LUAWRAP(_crawl_mark_game_won, crawl_state.mark_last_game_won())

LUAFN(crawl_hints_type)
{
    if (crawl_state.game_is_tutorial())
        lua_pushstring(ls, "tutorial");
    else if (!crawl_state.game_is_hints())
        lua_pushstring(ls, "");
    else
        switch (Hints.hints_type)
        {
        case HINT_BERSERK_CHAR:
            lua_pushstring(ls, "berserk");
            break;
        case HINT_RANGER_CHAR:
            lua_pushstring(ls, "ranger");
            break;
        case HINT_MAGIC_CHAR:
            lua_pushstring(ls, "magic");
            break;
        default:
            die("invalid hints_type");
        }
    return 1;
}

static const struct luaL_reg crawl_dlib[] =
{
{ "args", _crawl_args },
{ "mark_milestone", _crawl_milestone },
{ "redraw_view", _crawl_redraw_view },
{ "redraw_stats", _crawl_redraw_stats },
{ "god_speaks", _crawl_god_speaks },
{ "millis", _crawl_millis },
{ "make_name", crawl_make_name },
{ "set_max_runes", _crawl_set_max_runes },
{ "tutorial_hunger", crawl_tutorial_hunger },
{ "tutorial_skill",  crawl_tutorial_skill },
{ "tutorial_hint",   crawl_tutorial_hint },
{ "print_hint", crawl_print_hint },
{ "mark_game_won", _crawl_mark_game_won },
{ "hints_type", crawl_hints_type },
{ "unavailable_god", _crawl_unavailable_god },

{ NULL, NULL }
};

void dluaopen_crawl(lua_State *ls)
{
    luaL_openlib(ls, "crawl", crawl_dlib, 0);
}
