/*
** $Id: liolib.c,v 1.19 1998/06/02 21:20:54 roberto Exp roberto $
** Standard I/O (and system) library
** See Copyright Notice in lua.h
*/


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

#include "lauxlib.h"
#include "lua.h"
#include "luadebug.h"
#include "lualib.h"


#ifndef OLD_ANSI
#include <locale.h>
#else
#define setlocale(a,b)	0
#define LC_ALL		0
#define LC_COLLATE	0
#define LC_CTYPE	0
#define LC_MONETARY	0
#define LC_NUMERIC	0
#define LC_TIME		0
#define strerror(e)	"(no error message provided by operating system)"
#endif


#define CLOSEDTAG	2
#define IOTAG		1

#define FIRSTARG      3  /* 1st and 2nd are upvalues */

#define FINPUT		"_INPUT"
#define FOUTPUT		"_OUTPUT"


#ifdef POPEN
FILE *popen();
int pclose();
#else
#define popen(x,y) NULL  /* that is, popen always fails */
#define pclose(x)  (-1)
#endif


static int gettag (int i)
{
  return lua_getnumber(lua_getparam(i));
}


static void pushresult (int i)
{
  if (i)
    lua_pushuserdata(NULL);
  else {
    lua_pushnil();
    lua_pushstring(strerror(errno));
  }
}


static int ishandler (lua_Object f)
{
  if (lua_isuserdata(f)) {
    if (lua_tag(f) == gettag(CLOSEDTAG))
      lua_error("cannot access a closed file");
    return lua_tag(f) == gettag(IOTAG);
  }
  else return 0;
}

static FILE *getfile (char *name)
{
  lua_Object f = lua_getglobal(name);
  if (!ishandler(f))
      luaL_verror("global variable `%.50s' is not a file handle", name);
  return lua_getuserdata(f);
}


static FILE *getfileparam (char *name, int *arg)
{
  lua_Object f = lua_getparam(*arg);
  if (ishandler(f)) {
    (*arg)++;
    return lua_getuserdata(f);
  }
  else
    return getfile(name);
}


static void closefile (char *name)
{
  FILE *f = getfile(name);
  if (f == stdin || f == stdout) return;
  if (pclose(f) == -1)
    fclose(f);
  lua_pushobject(lua_getglobal(name));
  lua_settag(gettag(CLOSEDTAG));
}


static void setfile (FILE *f, char *name, int tag)
{
  lua_pushusertag(f, tag);
  lua_setglobal(name);
}


static void setreturn (FILE *f, char *name)
{
  int tag = gettag(IOTAG);
  setfile(f, name, tag);
  lua_pushusertag(f, tag);
}


static void io_readfrom (void)
{
  FILE *current;
  lua_Object f = lua_getparam(FIRSTARG);
  if (f == LUA_NOOBJECT) {
    closefile(FINPUT);
    current = stdin;
  }
  else if (lua_tag(f) == gettag(IOTAG))
    current = lua_getuserdata(f);
  else {
    char *s = luaL_check_string(FIRSTARG);
    current = (*s == '|') ? popen(s+1, "r") : fopen(s, "r");
    if (current == NULL) {
      pushresult(0);
      return;
    }
  }
  setreturn(current, FINPUT);
}


static void io_writeto (void)
{
  FILE *current;
  lua_Object f = lua_getparam(FIRSTARG);
  if (f == LUA_NOOBJECT) {
    closefile(FOUTPUT);
    current = stdout;
  }
  else if (lua_tag(f) == gettag(IOTAG))
    current = lua_getuserdata(f);
  else {
    char *s = luaL_check_string(FIRSTARG);
    current = (*s == '|') ? popen(s+1,"w") : fopen(s,"w");
    if (current == NULL) {
      pushresult(0);
      return;
    }
  }
  setreturn(current, FOUTPUT);
}


static void io_appendto (void)
{
  char *s = luaL_check_string(FIRSTARG);
  FILE *fp = fopen (s, "a");
  if (fp != NULL)
    setreturn(fp, FOUTPUT);
  else
    pushresult(0);
}


#define NEED_OTHER (EOF-1)  /* just some flag different from EOF */


static void read_until (FILE *f, int lim) {
  int l = 0;
  int c;
  for (c = getc(f); c != EOF && c != lim; c = getc(f)) {
    luaL_addchar(c);
    l++;
  }
  if (l > 0 || c == lim)  /* read anything? */
    lua_pushlstring(luaL_buffer(), l);
}

static void io_read (void) {
  int arg = FIRSTARG;
  FILE *f = getfileparam(FINPUT, &arg);
  char *p = luaL_opt_string(arg, NULL);
  luaL_resetbuffer();
  if (p == NULL)  /* default: read a line */
    read_until(f, '\n');
  else if (p[0] == '.' && p[1] == '*' && p[2] == 0)  /* p = ".*" */
    read_until(f, EOF);
  else {
    int l = 0;  /* number of chars read in buffer */
    int inskip = 0;  /* to control {skips} */
    int c = NEED_OTHER;
    while (*p) {
      switch (*p) {
        case '{':
          inskip++;
          p++;
          continue;
        case '}':
          if (inskip == 0)
            lua_error("unbalanced braces in read pattern");
          inskip--;
          p++;
          continue;
        default: {
          char *ep;  /* get what is next */
          int m;  /* match result */
          if (c == NEED_OTHER) c = getc(f);
          if (c == EOF) {
            luaI_singlematch(0, p, &ep);  /* to set "ep" */
            m = 0;
          }
          else {
            m = luaI_singlematch(c, p, &ep);
            if (m) {
              if (inskip == 0) {
                luaL_addchar(c);
                l++;
              }
              c = NEED_OTHER;
            }
          }
          switch (*ep) {
            case '*':  /* repetition */
              if (!m) p = ep+1;  /* else stay in (repeat) the same item */
              continue;
            case '?':  /* optional */
              p = ep+1;  /* continues reading the pattern */
              continue;
            default:
              if (m) p = ep;  /* continues reading the pattern */
              else
                goto break_while;   /* pattern fails */
          }
        }
      }
    } break_while:
    if (c >= 0)  /* not EOF nor NEED_OTHER? */
       ungetc(c, f);
    if (l > 0 || *p == 0)  /* read something or did not fail? */
      lua_pushlstring(luaL_buffer(), l);
  }
}


static void io_write (void)
{
  int arg = FIRSTARG;
  FILE *f = getfileparam(FOUTPUT, &arg);
  int status = 1;
  char *s;
  long l;
  while ((s = luaL_opt_lstr(arg++, NULL, &l)) != NULL)
    status = status && (fwrite(s, 1, l, f) == l);
  pushresult(status);
}


static void io_execute (void)
{
  lua_pushnumber(system(luaL_check_string(1)));
}


static void io_remove  (void)
{
  pushresult(remove(luaL_check_string(1)) == 0);
}


static void io_rename (void)
{
  pushresult(rename(luaL_check_string(1),
                    luaL_check_string(2)) == 0);
}


static void io_tmpname (void)
{
  lua_pushstring(tmpnam(NULL));
}



static void io_getenv (void)
{
  lua_pushstring(getenv(luaL_check_string(1)));  /* if NULL push nil */
}


static void io_clock (void) {
  lua_pushnumber(((double)clock())/CLOCKS_PER_SEC);
}


static void io_date (void)
{
  time_t t;
  struct tm *tm;
  char *s = luaL_opt_string(1, "%c");
  char b[BUFSIZ];
  time(&t); tm = localtime(&t);
  if (strftime(b,sizeof(b),s,tm))
    lua_pushstring(b);
  else
    lua_error("invalid `date' format");
}


static void setloc (void)
{
  static int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC,
                      LC_TIME};
  int op = (int)luaL_opt_number(2, 0);
  luaL_arg_check(0 <= op && op <= 5, 2, "invalid option");
  lua_pushstring(setlocale(cat[op], luaL_check_string(1)));
}


static void io_exit (void)
{
  lua_Object o = lua_getparam(1);
  exit(lua_isnumber(o) ? (int)lua_getnumber(o) : 1);
}


static void io_debug (void)
{
  while (1) {
    char buffer[250];
    fprintf(stderr, "lua_debug> ");
    if (fgets(buffer, sizeof(buffer), stdin) == 0) return;
    if (strcmp(buffer, "cont\n") == 0) return;
    lua_dostring(buffer);
  }
}


static void lua_printstack (FILE *f)
{
  int level = 1;  /* skip level 0 (it's this function) */
  lua_Object func;
  while ((func = lua_stackedfunction(level++)) != LUA_NOOBJECT) {
    char *name;
    int currentline;
    char *filename;
    int linedefined;
    lua_funcinfo(func, &filename, &linedefined);
    fprintf(f, (level==2) ? "Active Stack:\n\t" : "\t");
    switch (*lua_getobjname(func, &name)) {
      case 'g':
        fprintf(f, "function %s", name);
        break;
      case 't':
        fprintf(f, "`%s' tag method", name);
        break;
      default: {
        if (linedefined == 0)
          fprintf(f, "main of %s", filename);
        else if (linedefined < 0)
          fprintf(f, "%s", filename);
        else
          fprintf(f, "function (%s:%d)", filename, linedefined);
        filename = NULL;
      }
    }
    if ((currentline = lua_currentline(func)) > 0)
      fprintf(f, " at line %d", currentline);
    if (filename)
      fprintf(f, " [in file %s]", filename);
    fprintf(f, "\n");
  }
}


static void errorfb (void)
{
  fprintf(stderr, "lua: %s\n", lua_getstring(lua_getparam(1)));
  lua_printstack(stderr);
}



static struct luaL_reg iolib[] = {
{"setlocale", setloc},
{"execute",  io_execute},
{"remove",   io_remove},
{"rename",   io_rename},
{"tmpname",   io_tmpname},
{"getenv",   io_getenv},
{"date",     io_date},
{"clock",     io_clock},
{"exit",     io_exit},
{"debug",    io_debug},
{"print_stack", errorfb}
};

static struct luaL_reg iolibtag[] = {
{"readfrom", io_readfrom},
{"writeto",  io_writeto},
{"appendto", io_appendto},
{"read",     io_read},
{"write",    io_write}
};

static void openwithtags (void)
{
  int iotag = lua_newtag();
  int closedtag = lua_newtag();
  int i;
  for (i=0; i<sizeof(iolibtag)/sizeof(iolibtag[0]); i++) {
    /* put both tags as upvalues for these functions */
    lua_pushnumber(iotag);
    lua_pushnumber(closedtag);
    lua_pushcclosure(iolibtag[i].func, 2);
    lua_setglobal(iolibtag[i].name);
  }
  setfile(stdin, FINPUT, iotag);
  setfile(stdout, FOUTPUT, iotag);
  setfile(stdin, "_STDIN", iotag);
  setfile(stdout, "_STDOUT", iotag);
  setfile(stderr, "_STDERR", iotag);
}

void lua_iolibopen (void)
{
  luaL_openlib(iolib, (sizeof(iolib)/sizeof(iolib[0])));
  openwithtags();
  lua_pushcfunction(errorfb);
  lua_seterrormethod();
}