/*
** $Id: lua.c,v 1.157 2005/12/29 16:23:32 roberto Exp $
** Lua stand-alone interpreter
** See Copyright Notice in lua.h
*/

#ifdef _MSC_VER
// disable warning about using getenv
#  define _CRT_SECURE_NO_WARNINGS
#endif


#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>

#include <sitkVersion.h>

#define lua_c

#if !defined(_WIN32)
#  define LUA_USE_POSIX
#endif


extern "C"
{
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}

static lua_State * globalL = NULL;

static const char * progname = LUA_PROGNAME;

static void
lstop(lua_State * L, lua_Debug * ar)
{
  (void)ar; /* unused arg. */
  lua_sethook(L, NULL, 0, 0);
  luaL_error(L, "interrupted!");
}


static void
laction(int i)
{
  signal(i, SIG_DFL); /* if another SIGINT happens before lstop,
                              terminate process (default action) */
  lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
}


static void
print_usage(void)
{
  fprintf(stderr,
          "usage: %s [options] [script [args]].\n"
          "Available options are:\n"
          "  -e stat  execute string " LUA_QL(
            "stat") "\n"
                    "  -l name  require library " LUA_QL(
                      "name") "\n"
                              "  -c conf  configure logger from file " LUA_QL(
                                "config") "\n"
                                          "  -i       enter interactive mode after executing " LUA_QL(
                                            "script") "\n"
                                                      "  -v       show version information\n"
                                                      "  --       stop handling options\n"
                                                      "  -        execute stdin and stop handling options\n",
          progname);
  fflush(stderr);
}


static void
l_message(const char * pname, const char * msg)
{
  if (pname)
    fprintf(stderr, "%s: ", pname);
  fprintf(stderr, "%s\n", msg);
  fflush(stderr);
}


static int
report(lua_State * L, int status)
{
  if (status && !lua_isnil(L, -1))
  {
    const char * msg = lua_tostring(L, -1);
    if (msg == NULL)
      msg = "(error object is not a string)";
    l_message(progname, msg);
    lua_pop(L, 1);
  }
  return status;
}


static int
traceback(lua_State * L)
{
  lua_getfield(L, LUA_GLOBALSINDEX, "debug");
  if (!lua_istable(L, -1))
  {
    lua_pop(L, 1);
    return 1;
  }
  lua_getfield(L, -1, "traceback");
  if (!lua_isfunction(L, -1))
  {
    lua_pop(L, 2);
    return 1;
  }
  lua_pushvalue(L, 1);   /* pass error message */
  lua_pushinteger(L, 2); /* skip this function and traceback */
  lua_call(L, 2, 1);     /* call debug.traceback */
  return 1;
}


static int
docall(lua_State * L, int narg, int clear)
{
  int status;
  int base = lua_gettop(L) - narg; /* function index */
  lua_pushcfunction(L, traceback); /* push traceback function */
  lua_insert(L, base);             /* put it under chunk and args */
  signal(SIGINT, laction);
  status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base);
  signal(SIGINT, SIG_DFL);
  lua_remove(L, base); /* remove traceback function */
  /* force a complete garbage collection in case of errors */
  if (status != 0)
    lua_gc(L, LUA_GCCOLLECT, 0);
  return status;
}

static void
print_version(void)
{
  fprintf(stdout, LUA_VERSION "  " LUA_COPYRIGHT "\n");
  fprintf(stdout, "Simple ITK:\n%s\n", itk::simple::Version::ExtendedVersionString().c_str());
}


static int
getargs(lua_State * L, char ** argv, int n)
{
  int narg;
  int i;
  int argc = 0;
  while (argv[argc])
    argc++;              /* count total number of arguments */
  narg = argc - (n + 1); /* number of arguments to the script */
  luaL_checkstack(L, narg + 3, "too many arguments to script");
  for (i = n + 1; i < argc; i++)
    lua_pushstring(L, argv[i]);
  lua_createtable(L, narg, n + 1);
  for (i = 0; i < argc; i++)
  {
    lua_pushstring(L, argv[i]);
    lua_rawseti(L, -2, i - n);
  }
  return narg;
}


static int
dofile(lua_State * L, const char * name)
{
  int status = luaL_loadfile(L, name) || docall(L, 0, 1);
  return report(L, status);
}


static int
dostring(lua_State * L, const char * s, const char * name)
{
  int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1);
  return report(L, status);
}


static int
dolibrary(lua_State * L, const char * name)
{
  lua_getglobal(L, "require");
  lua_pushstring(L, name);
  return report(L, lua_pcall(L, 1, 0, 0));
}


static const char *
get_prompt(lua_State * L, int firstline)
{
  const char * p;
  lua_getfield(L, LUA_GLOBALSINDEX, firstline ? "_PROMPT" : "_PROMPT2");
  p = lua_tostring(L, -1);
  if (p == NULL)
    p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
  lua_pop(L, 1); /* remove global */
  return p;
}


static int
incomplete(lua_State * L, int status)
{
  if (status == LUA_ERRSYNTAX)
  {
    size_t       lmsg;
    const char * msg = lua_tolstring(L, -1, &lmsg);
    const char * tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
    if (strstr(msg, LUA_QL("<eof>")) == tp)
    {
      lua_pop(L, 1);
      return 1;
    }
  }
  return 0; /* else... */
}


static int
pushline(lua_State * L, int firstline)
{
  char         buffer[LUA_MAXINPUT];
  char *       b = buffer;
  size_t       l;
  const char * prmt = get_prompt(L, firstline);
  if (lua_readline(L, b, prmt) == 0)
    return 0; /* no input */
  l = strlen(b);
  if (l > 0 && b[l - 1] == '\n')            /* line ends with newline? */
    b[l - 1] = '\0';                        /* remove it */
  if (firstline && b[0] == '=')             /* first line starts with `=' ? */
    lua_pushfstring(L, "return %s", b + 1); /* change it to `return' */
  else
    lua_pushstring(L, b);
  lua_freeline(L, b);
  return 1;
}


static int
loadline(lua_State * L)
{
  int status;
  lua_settop(L, 0);
  if (!pushline(L, 1))
    return -1; /* no input */
  for (;;)
  { /* repeat until gets a complete line */
    status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=stdin");
    if (!incomplete(L, status))
      break;             /* cannot try to add lines? */
    if (!pushline(L, 0)) /* no more input? */
      return -1;
    lua_pushliteral(L, "\n"); /* add a new line... */
    lua_insert(L, -2);        /* ...between the two lines */
    lua_concat(L, 3);         /* join them */
  }
  lua_saveline(L, 1);
  lua_remove(L, 1); /* remove line */
  return status;
}


static void
dotty(lua_State * L)
{
  int          status;
  const char * oldprogname = progname;
  progname = NULL;
  while ((status = loadline(L)) != -1)
  {
    if (status == 0)
      status = docall(L, 0, 0);
    report(L, status);
    if (status == 0 && lua_gettop(L) > 0)
    { /* any result to print? */
      lua_getglobal(L, "print");
      lua_insert(L, 1);
      if (lua_pcall(L, lua_gettop(L) - 1, 0, 0) != 0)
        l_message(progname, lua_pushfstring(L, "error calling " LUA_QL("print") " (%s)", lua_tostring(L, -1)));
    }
  }
  lua_settop(L, 0); /* clear stack */
  fputs("\n", stdout);
  fflush(stdout);
  progname = oldprogname;
}


static int
handle_script(lua_State * L, char ** argv, int n)
{
  int          status;
  const char * fname;
  int          narg = getargs(L, argv, n); /* collect arguments */
  lua_setglobal(L, "arg");
  fname = argv[n];
  if (strcmp(fname, "-") == 0 && strcmp(argv[n - 1], "--") != 0)
    fname = NULL; /* stdin */
  status = luaL_loadfile(L, fname);
  lua_insert(L, -(narg + 1));
  if (status == 0)
    status = docall(L, narg, 0);
  else
    lua_pop(L, narg);
  return report(L, status);
}


static int
collectargs(char ** argv, int * pi, int * pv, int * pe)
{
  int i;
  for (i = 1; argv[i] != NULL; i++)
  {
    if (argv[i][0] != '-') /* not an option? */
      return i;
    switch (argv[i][1])
    { /* option */
      case '-':
        return (argv[i + 1] != NULL ? i + 1 : 0);
      case '\0':
        return i;
      case 'i':
        *pi = 1; /* go through */
      case 'v':
        *pv = 1;
        break;
      case 'e':
        *pe = 1; /* go through */
      case 'c':
      case 'l':
        if (argv[i][2] == '\0')
        {
          i++;
          if (argv[i] == NULL)
            return -1;
        }
        break;
      default:
        return -1; /* invalid option */
    }
  }
  return 0;
}


std::string LogConfigFilename("");

static int
runargs(lua_State * L, char ** argv, int n)
{
  int i;
  for (i = 1; i < n; i++)
  {
    if (argv[i] == NULL)
      continue;
    lua_assert(argv[i][0] == '-');
    switch (argv[i][1])
    { /* option */
      case 'e':
      {
        const char * chunk = argv[i] + 2;
        if (*chunk == '\0')
          chunk = argv[++i];
        lua_assert(chunk != NULL);
        if (dostring(L, chunk, "=(command line)") != 0)
          return 1;
        break;
      }
      case 'l':
      {
        const char * filename = argv[i] + 2;
        if (*filename == '\0')
          filename = argv[++i];
        lua_assert(filename != NULL);
        if (dolibrary(L, filename))
          return 1; /* stop if file fails */
        break;
      }
      case 'c':
      {
        const char * filename = argv[i] + 2;
        if (*filename == '\0')
          filename = argv[++i];
        lua_assert(filename != NULL);
        LogConfigFilename = filename;
        break;
      }
      default:
        break;
    }
  }
  return 0;
}


static int
handle_luainit(lua_State * L)
{
  const char * init = getenv("LUA_INIT");
  if (init == NULL)
    return 0; /* status OK */
  else if (init[0] == '@')
    return dofile(L, init + 1);
  else
    return dostring(L, init, "=LUA_INIT");
}


struct Smain
{
  int     argc;
  char ** argv;
  int     status;
};


extern "C" int
luaopen_SimpleITK(lua_State * L);

static int
pmain(lua_State * L)
{
  struct Smain * s = (struct Smain *)lua_touserdata(L, 1);
  char **        argv = s->argv;
  int            script;
  int            has_i = 0, has_v = 0, has_e = 0;
  globalL = L;
  if (argv[0] && argv[0][0])
    progname = argv[0];
  lua_gc(L, LUA_GCSTOP, 0); /* stop collector during initialization */
  luaL_openlibs(L);         /* open libraries */

  // Insert our custom code
  luaopen_SimpleITK(L);

  lua_gc(L, LUA_GCRESTART, 0);
  s->status = handle_luainit(L);
  if (s->status != 0)
    return 0;
  script = collectargs(argv, &has_i, &has_v, &has_e);
  if (script < 0)
  { /* invalid args? */
    print_usage();
    s->status = 1;
    return 0;
  }
  if (has_v)
    print_version();
  s->status = runargs(L, argv, (script > 0) ? script : s->argc);
  if (s->status != 0)
    return 0;

  // See if we have OMP_NUM_THREADS set, and if so, make ITK obey
  // std::string NumThreads;
  // if ( itksys::SystemTools::GetEnv ( "OMP_NUM_THREADS", NumThreads ) ) {
  //   itk::MultiThreader::SetGlobalDefaultNumberOfThreads ( atoi ( NumThreads.c_str() ) );
  // }

  if (script)
    s->status = handle_script(L, argv, script);
  if (s->status != 0)
    return 0;
  if (has_i)
    dotty(L);
  else if (script == 0 && !has_e && !has_v)
  {
    if (lua_stdin_is_tty())
    {
      print_version();
      dotty(L);
    }
    else
      dofile(L, NULL); /* executes stdin as a file */
  }
  return 0;
}


int
main(int argc, char ** argv)
{
  int status = 0;

  struct Smain s;
  lua_State *  L = lua_open(); /* create state */
  if (L == NULL)
  {
    l_message(argv[0], "cannot create state: not enough memory");
    return EXIT_FAILURE;
  }
#ifdef USE_TECLA
  // Initialize Tecla
  gl = new_GetLine(16 * 1024, 2048);
  gl_configure_getline(gl, "", "", "~/.SimpleITKLua");
  gl_load_history(gl, "~/.SimpleITK.history", "--");
#endif


  s.argc = argc;
  s.argv = argv;
  try
  {
    status = lua_cpcall(L, &pmain, &s);
    report(L, status);
    lua_close(L);
  }
  catch (...)
  {}

#ifdef USE_TECLA
  gl_save_history(gl, "~/.SimpleITK.history", "--", 1000);
  del_GetLine(gl);
#endif
  return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;
}
