/*
** $Id: lbaselib.c $
** Basic library
** See Copyright Notice in lua.h
*/

#define lbaselib_c
#define LUA_LIB

#include <ctype.h>
#include <locale.h>
#include <math.h> // HUGE_VAL
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <thread>
#include <unordered_set>

#include "lua.h"
#include "lprefix.h"
#include "lauxlib.h"
#include "lualib.h"
#include "lobject.h"
#include "lstate.h"

#include "vendor/Soup/soup/version_compare.hpp"


static int luaB_print (lua_State *L) {
#ifdef PLUTO_VMDUMP
  if (PLUTO_VMDUMP_COND(L)) {
    lua_writestring("<OUTPUT> ", 9);
  }
#endif
  int n = lua_gettop(L);  /* number of arguments */
  int i;
  for (i = 1; i <= n; i++) {  /* for each argument */
    size_t l;
    const char *s = luaL_tolstring(L, i, &l);  /* convert it to string */
    if (i > 1)  /* not the first element? */
      lua_writestring("\t", 1);  /* add a tab before it */
    lua_writestring(s, l);  /* print it */
    lua_pop(L, 1);  /* pop result */
  }
  lua_writeline();
  return 0;
}


/*
** Creates a warning with all given arguments.
** Check first for errors; otherwise an error may interrupt
** the composition of a warning, leaving it unfinished.
*/
static int luaB_warn (lua_State *L) {
  int n = lua_gettop(L);  /* number of arguments */
  int i;
  luaL_checkstring(L, 1);  /* at least one argument */
  for (i = 2; i <= n; i++)
    luaL_checkstring(L, i);  /* make sure all arguments are strings */
  for (i = 1; i < n; i++)  /* compose warning */
    lua_warning(L, lua_tostring(L, i), 1);
  lua_warning(L, lua_tostring(L, n), 0);  /* close warning */
  return 0;
}


static int luaB_wcall (lua_State *L) {
  luaL_checktype(L, 1, LUA_TFUNCTION);

  const auto og_ud_warn = G(L)->ud_warn;
  const auto og_warnf = G(L)->warnf;

  /* allocate buffer */
  auto str = pluto_newclassinst(L, std::string);

  /* write all warnings to buffer */
  lua_setwarnf(L, [](void *ud, const char *message, int tocont) {
    auto str = reinterpret_cast<std::string*>(ud);
    str->append(message);
    if (!tocont) {
      str->push_back('\n');
    }
  }, str);

  /* call provided function */
  lua_pushvalue(L, 1);
  lua_call(L, 0, 0);

  /* revert warnf */
  G(L)->ud_warn = og_ud_warn;
  G(L)->warnf = og_warnf;

  /* return warnings buffer */
  lua_pushlstring(L, str->data(), str->size());
  return 1;
}


#define SPACECHARS	" \f\n\r\t\v"

static const char *b_str2int (const char *s, int base, lua_Integer *pn) {
  lua_Unsigned n = 0;
  int neg = 0;
  s += strspn(s, SPACECHARS);  /* skip initial spaces */
  if (*s == '-') { s++; neg = 1; }  /* handle sign */
  else if (*s == '+') s++;
  if (!isalnum((unsigned char)*s))  /* no digit? */
    return NULL;
  do {
    int digit = (isdigit((unsigned char)*s)) ? *s - '0'
                   : (toupper((unsigned char)*s) - 'A') + 10;
    if (digit >= base) return NULL;  /* invalid numeral */
    n = n * base + digit;
    s++;
  } while (isalnum((unsigned char)*s));
  s += strspn(s, SPACECHARS);  /* skip trailing spaces */
  *pn = (lua_Integer)((neg) ? (0u - n) : n);
  return s;
}


int luaB_tonumber (lua_State *L) {
  if (lua_isnoneornil(L, 2)) {  /* standard conversion? */
    if (lua_type(L, 1) == LUA_TNUMBER) {  /* already a number? */
      lua_settop(L, 1);  /* yes; return it */
      return 1;
    }
    else {
      size_t l;
      const char *s = lua_tolstring(L, 1, &l);
      if (s != NULL && lua_stringtonumber(L, s) == l + 1)
        return 1;  /* successful conversion to number */
      /* else not a number */
      luaL_checkany(L, 1);  /* (but there must be some parameter) */
    }
  }
  else {
    size_t l;
    const char *s;
    lua_Integer n = 0;  /* to avoid warnings */
    lua_Integer base = luaL_checkinteger(L, 2);
    luaL_checktype(L, 1, LUA_TSTRING);  /* no numbers as strings */
    s = lua_tolstring(L, 1, &l);
    luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
    if (b_str2int(s, (int)base, &n) == s + l) {
      lua_pushinteger(L, n);
      return 1;
    }  /* else not a number */
  }  /* else not a number */
  luaL_pushfail(L);  /* not a number */
  return 1;
}


int luaB_utonumber(lua_State *L) {
  pluto_uwrap(L, luaB_tonumber, 1);
}


[[noreturn]] static int luaB_error (lua_State *L) {
  int level = (int)luaL_optinteger(L, 2, 1);
  lua_settop(L, 1);
  if (lua_type(L, 1) == LUA_TSTRING && level > 0) {
    luaL_where(L, level);   /* add extra information */
    lua_pushvalue(L, 1);
    lua_concat(L, 2);
  }
  lua_error(L);
}


static int luaB_getmetatable (lua_State *L) {
  luaL_checkany(L, 1);
  if (!lua_getmetatable(L, 1)) {
    lua_pushnil(L);
    return 1;  /* no metatable */
  }
  luaL_getmetafield(L, 1, "__metatable");
  return 1;  /* returns either __metatable field (if present) or metatable */
}


static int luaB_setmetatable (lua_State *L) {
  int t = lua_type(L, 2);
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table");
  if (l_unlikely(luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL))
    luaL_error(L, "cannot change a protected metatable");
  lua_settop(L, 2);
  lua_setmetatable(L, 1);
  return 1;
}


static int luaB_rawequal (lua_State *L) {
  luaL_checkany(L, 1);
  luaL_checkany(L, 2);
  lua_pushboolean(L, lua_rawequal(L, 1, 2));
  return 1;
}


static int luaB_rawlen (lua_State *L) {
  int t = lua_type(L, 1);
  luaL_argexpected(L, t == LUA_TTABLE || t == LUA_TSTRING, 1,
                      "table or string");
  lua_pushinteger(L, lua_rawlen(L, 1));
  return 1;
}


static int luaB_rawget (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_checkany(L, 2);
  lua_settop(L, 2);
  lua_rawget(L, 1);
  return 1;
}

static int luaB_rawset (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
#ifdef PLUTO_ENABLE_TABLE_FREEZING
  lua_erriffrozen(L, 1);
#endif
  luaL_checkany(L, 2);
  luaL_checkany(L, 3);
  lua_settop(L, 3);
  lua_rawset(L, 1);
  return 1;
}


static int pushmode (lua_State *L, int oldmode) {
  if (oldmode == -1)
    luaL_pushfail(L);  /* invalid call to 'lua_gc' */
  else
    lua_pushstring(L, (oldmode == LUA_GCINC) ? "incremental"
                                             : "generational");
  return 1;
}


/*
** check whether call to 'lua_gc' was valid (not inside a finalizer)
*/
#define checkvalres(res) { if (res == -1) break; }

static int luaB_collectgarbage (lua_State *L) {
  static const char *const opts[] = {"stop", "restart", "collect",
    "count", "step", "isrunning", "generational", "incremental",
    "param", NULL};
  static const char optsnum[] = {LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
    LUA_GCCOUNT, LUA_GCSTEP, LUA_GCISRUNNING, LUA_GCGEN, LUA_GCINC,
    LUA_GCPARAM};
  int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
  switch (o) {
    case LUA_GCCOUNT: {
      int k = lua_gc(L, o);
      int b = lua_gc(L, LUA_GCCOUNTB);
      checkvalres(k);
      lua_pushnumber(L, (lua_Number)k + ((lua_Number)b/1024));
      return 1;
    }
    case LUA_GCSTEP: {
      lua_Integer n = luaL_optinteger(L, 2, 0);
      int res = lua_gc(L, o, (int)n);
      checkvalres(res);
      lua_pushboolean(L, res);
      return 1;
    }
    case LUA_GCISRUNNING: {
      int res = lua_gc(L, o);
      checkvalres(res);
      lua_pushboolean(L, res);
      return 1;
    }
    case LUA_GCGEN: {
      return pushmode(L, lua_gc(L, o));
    }
    case LUA_GCINC: {
      return pushmode(L, lua_gc(L, o));
    }
    case LUA_GCPARAM: {
      static const char *const params[] = {
        "minormul", "majorminor", "minormajor",
        "pause", "stepmul", "stepsize", NULL};
      static const char pnum[] = {
        LUA_GCPMINORMUL, LUA_GCPMAJORMINOR, LUA_GCPMINORMAJOR,
        LUA_GCPPAUSE, LUA_GCPSTEPMUL, LUA_GCPSTEPSIZE};
      int p = pnum[luaL_checkoption(L, 2, NULL, params)];
      lua_Integer value = luaL_optinteger(L, 3, -1);
      lua_pushinteger(L, lua_gc(L, o, p, (int)value));
      return 1;
    }
    default: {
      int res = lua_gc(L, o);
      checkvalres(res);
      lua_pushinteger(L, res);
      return 1;
    }
  }
  luaL_pushfail(L);  /* invalid call (inside a finalizer) */
  return 1;
}


static int luaB_type (lua_State *L) {
  int t = lua_type(L, 1);
  luaL_argcheck(L, t != LUA_TNONE, 1, "value expected");
  lua_pushstring(L, lua_typename(L, t));
  return 1;
}

LUAI_FUNC int luaB_next(lua_State *L);
int luaB_next (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  lua_settop(L, 2);  /* create a 2nd argument if there isn't one */
  if (lua_next(L, 1))
    return 2;
  else {
    lua_pushnil(L);
    return 1;
  }
}


static int pairscont (lua_State *L, int status, lua_KContext k) {
  (void)L; (void)status; (void)k;  /* unused */
  return 3;
}

static int luaB_pairs (lua_State *L) {
  luaL_checkany(L, 1);
  if (luaL_getmetafield(L, 1, "__pairs") == LUA_TNIL) {  /* no metamethod? */
    lua_pushcfunction(L, luaB_next);  /* will return generator, */
    lua_pushvalue(L, 1);  /* state, */
    lua_pushnil(L);  /* and initial value */
  }
  else {
    lua_pushvalue(L, 1);  /* argument 'self' to metamethod */
    lua_callk(L, 1, 3, 0, pairscont);  /* get 3 values from metamethod */
  }
  return 3;
}


/*
** Traversal function for 'ipairs'
*/
static int ipairsaux (lua_State *L) {
  lua_Integer i = luaL_checkinteger(L, 2);
  i = luaL_intop(+, i, 1);
  lua_pushinteger(L, i);
  return (lua_geti(L, 1, i) == LUA_TNIL) ? 1 : 2;
}


/*
** 'ipairs' function. Returns 'ipairsaux', given "table", 0.
** (The given "table" may not be a table.)
*/
static int luaB_ipairs (lua_State *L) {
  luaL_checkany(L, 1);
  lua_pushcfunction(L, ipairsaux);  /* iteration function */
  lua_pushvalue(L, 1);  /* state */
  lua_pushinteger(L, 0);  /* initial value */
  return 3;
}


static int load_aux (lua_State *L, int status, int envidx) {
  if (l_likely(status == LUA_OK)) {
    if (envidx != 0) {  /* 'env' parameter? */
      lua_pushvalue(L, envidx);  /* environment for loaded function */
      if (!lua_setupvalue(L, -2, 1))  /* set it as 1st upvalue */
        lua_pop(L, 1);  /* remove 'env' if not used by previous call */
    }
    return 1;
  }
  else {  /* error (message is on top of the stack) */
    luaL_pushfail(L);
    lua_insert(L, -2);  /* put before error message */
    return 2;  /* return fail plus error message */
  }
}


static const char *getMode (lua_State *L, int idx) {
  const char *mode = luaL_optstring(L, idx, "bt");
  if (strchr(mode, 'B') != NULL)  /* Lua code cannot use fixed buffers */
    luaL_argerror(L, idx, "invalid mode");
  return mode;
}


static int luaB_loadfile (lua_State *L) {
  const char *fname = luaL_optstring(L, 1, NULL);
  const char *mode = getMode(L, 2);
  int env = (!lua_isnone(L, 3) ? 3 : 0);  /* 'env' index or 0 if no 'env' */
  int status = luaL_loadfilex(L, fname, mode);
  return load_aux(L, status, env);
}


/*
** {======================================================
** Generic Read function
** =======================================================
*/


/*
** reserved slot, above all arguments, to hold a copy of the returned
** string to avoid it being collected while parsed. 'load' has four
** optional arguments (chunk, source name, mode, and environment).
*/
#define RESERVEDSLOT	5


/*
** Reader for generic 'load' function: 'lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
*/
static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
  (void)(ud);  /* not used */
  luaL_checkstack(L, 2, "too many nested functions");
  lua_pushvalue(L, 1);  /* get function */
  lua_call(L, 0, 1);  /* call it */
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);  /* pop result */
    *size = 0;
    return NULL;
  }
  else if (l_unlikely(!lua_isstring(L, -1)))
    luaL_error(L, "reader function must return a string");
  lua_replace(L, RESERVEDSLOT);  /* save string in reserved slot */
  return lua_tolstring(L, RESERVEDSLOT, size);
}


#ifdef PLUTO_LOAD_HOOK
extern bool PLUTO_LOAD_HOOK(lua_State* L, const char* filename);
#endif

static int luaB_load (lua_State *L) {
  int status;
  size_t l;
#ifdef PLUTO_DISABLE_UNMODERATED_LOAD
  const char *s = luaL_checklstring(L, 1, &l);
#else
  const char *s = lua_tolstring(L, 1, &l);
#endif
  const char *mode = getMode(L, 3);
  int env = (!lua_isnone(L, 4) ? 4 : 0);  /* 'env' index or 0 if no 'env' */
#ifndef PLUTO_DISABLE_UNMODERATED_LOAD
  if (s != NULL) {  /* loading a string? */
#endif
#ifdef PLUTO_LOAD_HOOK
  if (!PLUTO_LOAD_HOOK(L, s))
    luaL_error(L, "disallowed by content moderation policy");
#endif
    const char *chunkname = luaL_optstring(L, 2, s);
    status = luaL_loadbufferx(L, s, l, chunkname, mode);
#ifndef PLUTO_DISABLE_UNMODERATED_LOAD
  }
  else {  /* loading from a reader function */
    const char *chunkname = luaL_optstring(L, 2, "=(load)");
    luaL_checktype(L, 1, LUA_TFUNCTION);
    lua_settop(L, RESERVEDSLOT);  /* create reserved slot */
    status = lua_load(L, generic_reader, NULL, chunkname, mode);
  }
#endif
  return load_aux(L, status, env);
}

/* }====================================================== */


static int dofilecont (lua_State *L, int d1, lua_KContext d2) {
  (void)d1;  (void)d2;  /* only to match 'lua_Kfunction' prototype */
  return lua_gettop(L) - 1;
}


static int luaB_dofile (lua_State *L) {
  const char *fname = luaL_optstring(L, 1, NULL);
  lua_settop(L, 1);
  if (l_unlikely(luaL_loadfile(L, fname) != LUA_OK))
    lua_error(L);
  lua_callk(L, 0, LUA_MULTRET, 0, dofilecont);
  return dofilecont(L, 0, 0);
}


int luaB_assert (lua_State *L) {
  if (l_likely(lua_toboolean(L, 1)))  /* condition is true? */
    return lua_gettop(L);  /* return all arguments */
  else {  /* error */
    luaL_checkany(L, 1);  /* there must be a condition */
    lua_remove(L, 1);  /* remove it */
    lua_pushliteral(L, "assertion failed!");  /* default message */
    lua_settop(L, 1);  /* leave only message (default if no other one) */
    luaB_error(L);  /* call 'error' */
  }
}


static int luaB_select (lua_State *L) {
  int n = lua_gettop(L);
  if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#') {
    lua_pushinteger(L, n-1);
    return 1;
  }
  else {
    lua_Integer i = luaL_checkinteger(L, 1);
    if (i < 0) i = n + i;
    else if (i > n) i = n;
    luaL_argcheck(L, 1 <= i, 1, "index out of range");
    return n - (int)i;
  }
}


/*
** Continuation function for 'pcall' and 'xpcall'. Both functions
** already pushed a 'true' before doing the call, so in case of success
** 'finishpcall' only has to return everything in the stack minus
** 'extra' values (where 'extra' is exactly the number of items to be
** ignored).
*/
static int finishpcall (lua_State *L, int status, lua_KContext extra) {
  if (l_unlikely(status != LUA_OK && status != LUA_YIELD)) {  /* error? */
    lua_pushboolean(L, 0);  /* first result (false) */
    lua_pushvalue(L, -2);  /* error message */
    return 2;  /* return false, msg */
  }
  else
    return lua_gettop(L) - (int)extra;  /* return all results */
}


static int luaB_pcall (lua_State *L) {
  int status;
  luaL_checkany(L, 1);
  lua_pushboolean(L, 1);  /* first result if no errors */
  lua_insert(L, 1);  /* put it in place */
  status = lua_pcallk(L, lua_gettop(L) - 2, LUA_MULTRET, 0, 0, finishpcall);
  return finishpcall(L, status, 0);
}


/*
** Do a protected call with error handling. After 'lua_rotate', the
** stack will have <f, err, true, f, [args...]>; so, the function passes
** 2 to 'finishpcall' to skip the 2 first values when returning results.
*/
static int luaB_xpcall (lua_State *L) {
  int status;
  int n = lua_gettop(L);
  luaL_checktype(L, 2, LUA_TFUNCTION);  /* check error function */
  lua_pushboolean(L, 1);  /* first result */
  lua_pushvalue(L, 1);  /* function */
  lua_rotate(L, 3, 2);  /* move them below function's arguments */
  status = lua_pcallk(L, n - 2, LUA_MULTRET, 2, 2, finishpcall);
  return finishpcall(L, status, 2);
}


int luaB_tostring (lua_State *L) {
  luaL_checkany(L, 1);
  luaL_tolstring(L, 1, NULL);
  return 1;
}


int luaB_utostring (lua_State *L) {
  pluto_uwrap(L, luaB_tostring, 1);
}


static int luaB_newuserdata (lua_State *L) {
  lua_newuserdata(L, 0);
  lua_newtable(L);
  lua_setmetatable(L, -2);
  return 1;
}


TValue *index2value (lua_State *L, int idx);
void addquoted (luaL_Buffer *b, const char *s, size_t len, bool must_be_valid_utf8);

struct FuncDumpWriter {
  int init;
  luaL_Buffer B;

  static int write (lua_State *L, const void *b, size_t size, void *ud) {
    auto state = (FuncDumpWriter*)ud;
    if (!state->init) {
      state->init = 1;
      luaL_buffinit(L, &state->B);
    }
    luaL_addlstring(&state->B, (const char *)b, size);
    return 0;
  }
};

static void luaB_dumpvar_impl (lua_State *L, std::string& dump, int indents, const std::unordered_set<Table*>& parents_base, bool is_export, bool is_key = false) {
  switch (lua_type(L, -1)) {
    default:
      if (is_export) {
        luaL_error(L, luaO_pushfstring(L, "can not export variables of type %s", ttypename(lua_type(L, -1))));
      }
      [[fallthrough]];
    case LUA_TBOOLEAN:
    case LUA_TNIL:
      dump.append(luaL_tolstring(L, -1, NULL));
      lua_pop(L, 1);
      return;

    case LUA_TNUMBER:
      if (is_export && !lua_isinteger(L, -1)) {
        auto n = lua_tonumber(L, -1);
        if (n == (lua_Number)HUGE_VAL) {
          dump.append("math.huge");
          return;
        }
        if (n == -(lua_Number)HUGE_VAL) {
          dump.append("-math.huge");
          return;
        }
        if (n != n) {
          dump.append("0/0");
          return;
        }
      }
      dump.append(luaL_tolstring(L, -1, NULL));
      lua_pop(L, 1);
      return;

    case LUA_TSTRING: {
      size_t l;
      const char *s = lua_tolstring(L, -1, &l);
      luaL_Buffer b;
      luaL_buffinit(L, &b);
      if (!is_export && !is_key) {
        luaL_addstring(&b, "string(");
        lua_pushinteger(L, l);
        luaL_addvalue(&b);
        luaL_addstring(&b, ") ");
      }
      addquoted(&b, s, l, true);
      luaL_pushresult(&b);
      dump.append(lua_tostring(L, -1));
      lua_pop(L, 1);
      return;
    }

    case LUA_TFUNCTION: {
      /* collect function dump */
      FuncDumpWriter state;
      state.init = 0;
      if (l_likely(lua_dump(L, FuncDumpWriter::write, &state, 0) == 0)) {
        luaL_pushresult(&state.B);
        size_t l;
        const char *s = lua_tolstring(L, -1, &l);
        lua_pop(L, 1);
        /* we have it as a single string now */
        luaL_Buffer b;
        luaL_buffinit(L, &b);
        if (!is_export) {
          luaL_addstring(&b, "function ");
        }
        else {
          luaL_addstring(&b, "load");
        }
        addquoted(&b, s, l, true);
        luaL_pushresult(&b);
        dump.append(lua_tostring(L, -1));
        lua_pop(L, 1);
        return;
      }
      else if (is_export)
        luaL_error(L, "Can't export C function");
      dump.append(luaL_tolstring(L, -1, NULL));
      lua_pop(L, 1);
      return;
    }

    case LUA_TTABLE:;
  }
  Table *h = hvalue(index2value(L, -1));
  if (indents != 1 && parents_base.count(h)) {
    if (is_export) {
      luaL_error(L, "Can't export recursive table");
    }
    dump.append("*RECURSION*");
    return;
  }
  lua_checkstack(L, 7);
  dump.push_back('{');
  std::unordered_set<Table*>& parents = *pluto_newclassinst(L, std::unordered_set<Table*>, parents_base);
  parents.emplace(h);
  lua_pushvalue(L, -2);
  lua_pushnil(L);
  bool empty = true;
  while (lua_next(L, -2)) {
    if (empty) {
      empty = false;
      if (!is_export && luaL_getmetafield(L, -3, "__name") != LUA_TNIL) {
        dump.append(" -- ");
        dump.append(luaL_tolstring(L, -1, NULL));
        lua_pop(L, 2);
      }
      dump.push_back('\n');
    }
    dump.append(indents, '\t');
    dump.push_back('[');

    lua_pushvalue(L, -2);
    luaE_incCstack(L);
    luaB_dumpvar_impl(L, dump, indents + 1, parents, is_export, true);
    L->nCcalls--;
    lua_pop(L, 1);
    dump.append("] = ");

    lua_pushvalue(L, -1);
    luaE_incCstack(L);
    luaB_dumpvar_impl(L, dump, indents + 1, parents, is_export);
    L->nCcalls--;
    lua_pop(L, 2);
    dump.append(",\n");
  }
  if (empty) {
    if (!is_export && luaL_getmetafield(L, -1, "__name") != LUA_TNIL) {
      dump.append(" --[[ ");
      dump.append(luaL_tolstring(L, -1, NULL));
      dump.append(" ]] ");
      lua_pop(L, 2);
    }
  }
  else {
    dump.append(indents - 1, '\t');
  }
  dump.push_back('}');
  lua_pop(L, 2);
}

static int luaB_dumpvar (lua_State *L) {
  if (lua_type(L, 1) == LUA_TNONE) {
    lua_pushliteral(L, "(no value)");
  }
  else {
    std::string& dump = *pluto_newclassinst(L, std::string);
    std::unordered_set<Table*>& parents = *pluto_newclassinst(L, std::unordered_set<Table*>);
    lua_pushvalue(L, 1);
    if (ttistable(index2value(L, -1)))
      parents.emplace(hvalue(index2value(L, -1)));
    luaB_dumpvar_impl(L, dump, 1, parents, false);
    pluto_pushstring(L, dump);
  }
  return 1;
}

static int luaB_exportvar (lua_State *L) {
  luaL_checkany(L, 1);
  std::string& dump = *pluto_newclassinst(L, std::string);
  std::unordered_set<Table*>& parents = *pluto_newclassinst(L, std::unordered_set<Table*>);
  lua_pushvalue(L, 1);
  if (ttistable(index2value(L, -1)))
    parents.emplace(hvalue(index2value(L, -1)));
  luaB_dumpvar_impl(L, dump, 1, parents, true);
  pluto_pushstring(L, dump);
  return 1;
}


static int luaB_compareversions (lua_State *L) {
  lua_pushinteger(L, SOUP_STRONG_ORDERING_TO_INT(soup::version_compare(luaL_checkstring(L, 1), luaL_checkstring(L, 2))));
  return 1;
}


static int luaB_range (lua_State *L) {
  lua_Integer start, end, step;
  if (!lua_isnoneornil(L, 2)) {
    start = luaL_checkinteger(L, 1);
    end = luaL_checkinteger(L, 2);
    step = luaL_optinteger(L, 3, 1);
  }
  else {
    start = 1;
    end = luaL_checkinteger(L, 1);
    step = 1;
  }

  lua_createtable(L, cast(int, end - start), 0);
  lua_Integer idx = 1;
  for (lua_Integer i = start; i <= end; i += step, ++idx) {
    lua_pushinteger(L, i);
    lua_rawseti(L, -2, idx);
    L->checkEtl();
  }
  return 1;
}


static int luaB_sdiv (lua_State *L) {
  lua_pushinteger(L, luaL_checkinteger(L, 1) / luaL_checkinteger(L, 2));
  return 1;
}


static int luaB_udiv (lua_State *L) {
  lua_pushinteger(L, static_cast<lua_Unsigned>(luaL_checkinteger(L, 1)) / static_cast<lua_Unsigned>(luaL_checkinteger(L, 2)));
  return 1;
}


static int luaB_smod (lua_State *L) {
  lua_pushinteger(L, luaL_checkinteger(L, 1) % luaL_checkinteger(L, 2));
  return 1;
}


static int luaB_umod (lua_State *L) {
  lua_pushinteger(L, static_cast<lua_Unsigned>(luaL_checkinteger(L, 1)) % static_cast<lua_Unsigned>(luaL_checkinteger(L, 2)));
  return 1;
}


static int luaB_callonce (lua_State *L) {
  luaL_checktype(L, 1, LUA_TFUNCTION);

  const auto caller_ci = L->ci->previous;
  const auto call_pc = caller_ci->u.l.savedpc;
  const auto call_id = static_cast<lua_Integer>(reinterpret_cast<uintptr_t>(call_pc));

  lua_pushinteger(L, call_id);
  if (lua_gettable(L, LUA_REGISTRYINDEX) <= LUA_TNIL) {
    lua_pushinteger(L, call_id + 1);
    if (lua_gettable(L, LUA_REGISTRYINDEX) <= LUA_TNIL) {
      lua_pushvalue(L, 1);
      lua_call(L, 0, 1);
      if (lua_type(L, -1) <= LUA_TNIL) {
        lua_pushinteger(L, call_id + 1);
        lua_pushvalue(L, true);
      }
      else {
        lua_pushinteger(L, call_id);
        lua_pushvalue(L, -2);
      }
      lua_settable(L, LUA_REGISTRYINDEX);
    }
    else {
      lua_pushnil(L);
    }
  }
  return 1;
}


static const luaL_Reg base_funcs[] = {
  {"callonce", luaB_callonce},
  {"sdiv", luaB_sdiv},
  {"udiv", luaB_udiv},
  {"smod", luaB_smod},
  {"umod", luaB_umod},
  {"range", luaB_range},
  {"compareversions", luaB_compareversions},
  {"exportvar", luaB_exportvar},
  {"dumpvar", luaB_dumpvar},
  {"newuserdata", luaB_newuserdata},
  {"assert", luaB_assert},
  {"collectgarbage", luaB_collectgarbage},
  {"dofile", luaB_dofile},
  {"error", luaB_error},
  {"getmetatable", luaB_getmetatable},
  {"ipairs", luaB_ipairs},
  {"loadfile", luaB_loadfile},
  {"load", luaB_load},
  {"next", luaB_next},
  {"pairs", luaB_pairs},
  {"pcall", luaB_pcall},
  {"print", luaB_print},
  {"warn", luaB_warn},
  {"wcall", luaB_wcall},
  {"rawequal", luaB_rawequal},
  {"rawlen", luaB_rawlen},
  {"rawget", luaB_rawget},
  {"rawset", luaB_rawset},
  {"select", luaB_select},
  {"setmetatable", luaB_setmetatable},
  {"tonumber", luaB_tonumber},
  {"utonumber", luaB_utonumber},
  {"tostring", luaB_tostring},
  {"utostring", luaB_utostring},
  {"type", luaB_type},
  {"xpcall", luaB_xpcall},
  /* placeholders */
  {LUA_GNAME, NULL},
  {"_VERSION", NULL},
  {NULL, NULL}
};


LUAMOD_API int luaopen_base (lua_State *L) {
  /* open lib into global table */
  lua_pushglobaltable(L);
  luaL_setfuncs(L, base_funcs, 0);
  /* set global _G */
  lua_pushvalue(L, -1);
  lua_setfield(L, -2, LUA_GNAME);
  /* set global _VERSION */
  lua_pushliteral(L, LUA_VERSION);
  lua_setfield(L, -2, "_VERSION");
  /* set global _PVERSION */
  lua_pushliteral(L, PLUTO_VERSION);
  lua_setfield(L, -2, "_PVERSION");
  return 1;
}

