/*
** $Id: lua.c,v 1.206.1.1 2013/04/12 18:48:47 roberto Exp $
** Lua stand-alone interpreter
** See Copyright Notice in lua.h
*/

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

#define lua_c

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

#if !defined(LUA_PROMPT)
#define LUA_PROMPT "> "
#define LUA_PROMPT2 ">> "
#endif

#if !defined(LUA_PROGNAME)
#define LUA_PROGNAME "lua"
#endif

#if !defined(LUA_MAXINPUT)
#define LUA_MAXINPUT 512
#endif

#if !defined(LUA_INIT)
#define LUA_INIT "LUA_INIT"
#endif

#define LUA_INITVERSION \
	LUA_INIT "_" LUA_VERSION_MAJOR "_" LUA_VERSION_MINOR

/*
** lua_stdin_is_tty detects whether the standard input is a 'tty' (that
** is, whether we're running lua interactively).
*/
#if defined(LUA_USE_ISATTY)
#include <unistd.h>
#define lua_stdin_is_tty() isatty(0)
#elif defined(LUA_WIN)
#include <io.h>
#include <stdio.h>
#define lua_stdin_is_tty() _isatty(_fileno(stdin))
#else
#define lua_stdin_is_tty() 1 /* assume stdin is a tty */
#endif

/*
** lua_readline defines how to show a prompt and then read a line from
** the standard input.
** lua_saveline defines how to "save" a read line in a "history".
** lua_freeline defines how to free a line read by lua_readline.
*/
#if defined(LUA_USE_READLINE)

#include <stdio.h>
#include <readline/readline.h>
#include <readline/history.h>
#define lua_readline(L, b, p) ((void)L, ((b) = readline(p)) != NULL)
#define lua_saveline(L, idx)                                     \
	if (lua_rawlen(L, idx) > 0)            /* non-empty line? */ \
		add_history(lua_tostring(L, idx)); /* add it to history */
#define lua_freeline(L, b) ((void)L, free(b))

#elif !defined(lua_readline)

#define lua_readline(L, b, p)                                     \
	((void)L, fputs(p, stdout), fflush(stdout), /* show prompt */ \
	 fgets(b, LUA_MAXINPUT, stdin) != NULL)     /* get line */
#define lua_saveline(L, idx) \
	{                        \
		(void)L;             \
		(void)idx;           \
	}
#define lua_freeline(L, b) \
	{                      \
		(void)L;           \
		(void)b;           \
	}

#endif

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(const char *badoption)
{
	luai_writestringerror("%s: ", progname);
	if (badoption[1] == 'e' || badoption[1] == 'l')
		luai_writestringerror("'%s' needs argument\n", badoption);
	else
		luai_writestringerror("unrecognized option '%s'\n", badoption);
	luai_writestringerror(
		"usage: %s [options] [script [args]]\n"
		"Available options are:\n"
		"  -e stat  execute string " LUA_QL("stat")
			"\n"
			"  -i       enter interactive mode after executing " LUA_QL("script")
				"\n"
				"  -l name  require library " LUA_QL("name")
					"\n"
					"  -v       show version information\n"
					"  -E       ignore environment variables\n"
					"  --       stop handling options\n"
					"  -        stop handling options and execute stdin\n",
		progname);
}

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

static int report(lua_State *L, int status)
{
	if (status != LUA_OK && !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);
		/* force a complete garbage collection in case of errors */
		lua_gc(L, LUA_GCCOLLECT, 0);
	}
	return status;
}

/* the next function is called unprotected, so it must avoid errors */
static void finalreport(lua_State *L, int status)
{
	if (status != LUA_OK)
	{
		const char *msg = (lua_type(L, -1) == LUA_TSTRING) ? lua_tostring(L, -1)
														   : NULL;
		if (msg == NULL) msg = "(error object is not a string)";
		l_message(progname, msg);
		lua_pop(L, 1);
	}
}

static int traceback(lua_State *L)
{
	const char *msg = lua_tostring(L, 1);
	if (msg)
		luaL_traceback(L, L, msg, 1);
	else if (!lua_isnoneornil(L, 1))
	{                                           /* is there an error object? */
		if (!luaL_callmeta(L, 1, "__tostring")) /* try its 'tostring' metamethod */
			lua_pushliteral(L, "(no error message)");
	}
	return 1;
}

static int docall(lua_State *L, int narg, int nres)
{
	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 */
	globalL = L;                     /* to be available to 'laction' */
	signal(SIGINT, laction);
	status = lua_pcall(L, narg, nres, base);
	signal(SIGINT, SIG_DFL);
	lua_remove(L, base); /* remove traceback function */
	return status;
}

static void print_version(void)
{
	luai_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
	luai_writeline();
}

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);
	if (status == LUA_OK) status = docall(L, 0, 0);
	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);
	if (status == LUA_OK) status = docall(L, 0, 0);
	return report(L, status);
}

static int dolibrary(lua_State *L, const char *name)
{
	int status;
	lua_getglobal(L, "require");
	lua_pushstring(L, name);
	status = docall(L, 1, 1); /* call 'require(name)' */
	if (status == LUA_OK)
		lua_setglobal(L, name); /* global[name] = require return */
	return report(L, status);
}

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

/* mark in error messages for incomplete statements */
#define EOFMARK "<eof>"
#define marklen (sizeof(EOFMARK) / sizeof(char) - 1)

static int incomplete(lua_State *L, int status)
{
	if (status == LUA_ERRSYNTAX)
	{
		size_t lmsg;
		const char *msg = lua_tolstring(L, -1, &lmsg);
		if (lmsg >= marklen && strcmp(msg + lmsg - marklen, EOFMARK) == 0)
		{
			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);
	int readstatus = lua_readline(L, b, prmt);
	lua_pop(L, 1); /* remove result from 'get_prompt' */
	if (readstatus == 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 */
		size_t l;
		const char *line = lua_tolstring(L, 1, &l);
		status = luaL_loadbuffer(L, line, l, "=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 == LUA_OK) status = docall(L, 0, LUA_MULTRET);
		report(L, status);
		if (status == LUA_OK && lua_gettop(L) > 0)
		{ /* any result to print? */
			luaL_checkstack(L, LUA_MINSTACK, "too many results to print");
			lua_getglobal(L, "print");
			lua_insert(L, 1);
			if (lua_pcall(L, lua_gettop(L) - 1, 0, 0) != LUA_OK)
				l_message(progname, lua_pushfstring(L,
													"error calling " LUA_QL("print") " (%s)",
													lua_tostring(L, -1)));
		}
	}
	lua_settop(L, 0); /* clear stack */
	luai_writeline();
	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 == LUA_OK)
		status = docall(L, narg, LUA_MULTRET);
	else
		lua_pop(L, narg);
	return report(L, status);
}

/* check that argument has no extra characters at the end */
#define noextrachars(x)                \
	{                                  \
		if ((x)[2] != '\0') return -1; \
	}

/* indices of various argument indicators in array args */
#define has_i 0 /* -i */
#define has_v 1 /* -v */
#define has_e 2 /* -e */
#define has_E 3 /* -E */

#define num_has 4 /* number of 'has_*' */

static int collectargs(char **argv, int *args)
{
	int i;
	for (i = 1; argv[i] != NULL; i++)
	{
		if (argv[i][0] != '-') /* not an option? */
			return i;
		switch (argv[i][1])
		{ /* option */
			case '-':
				noextrachars(argv[i]);
				return (argv[i + 1] != NULL ? i + 1 : 0);
			case '\0':
				return i;
			case 'E':
				args[has_E] = 1;
				break;
			case 'i':
				noextrachars(argv[i]);
				args[has_i] = 1; /* go through */
			case 'v':
				noextrachars(argv[i]);
				args[has_v] = 1;
				break;
			case 'e':
				args[has_e] = 1; /* go through */
			case 'l':            /* both options need an argument */
				if (argv[i][2] == '\0')
				{        /* no concatenated argument? */
					i++; /* try next 'argv' */
					if (argv[i] == NULL || argv[i][0] == '-')
						return -(i - 1); /* no next argument or it is another option */
				}
				break;
			default:       /* invalid option; return its index... */
				return -i; /* ...as a negative value */
		}
	}
	return 0;
}

static int runargs(lua_State *L, char **argv, int n)
{
	int i;
	for (i = 1; i < n; i++)
	{
		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)") != LUA_OK)
					return 0;
				break;
			}
			case 'l':
			{
				const char *filename = argv[i] + 2;
				if (*filename == '\0') filename = argv[++i];
				lua_assert(filename != NULL);
				if (dolibrary(L, filename) != LUA_OK)
					return 0; /* stop if file fails */
				break;
			}
			default:
				break;
		}
	}
	return 1;
}

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

static int pmain(lua_State *L)
{
	int argc = (int)lua_tointeger(L, 1);
	char **argv = (char **)lua_touserdata(L, 2);
	int script;
	int args[num_has];
	args[has_i] = args[has_v] = args[has_e] = args[has_E] = 0;
	if (argv[0] && argv[0][0]) progname = argv[0];
	script = collectargs(argv, args);
	if (script < 0)
	{ /* invalid arg? */
		print_usage(argv[-script]);
		return 0;
	}
	if (args[has_v]) print_version();
	if (args[has_E])
	{                          /* option '-E'? */
		lua_pushboolean(L, 1); /* signal for libraries to ignore env. vars. */
		lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
	}
	/* open standard libraries */
	luaL_checkversion(L);
	lua_gc(L, LUA_GCSTOP, 0); /* stop collector during initialization */
	luaL_openlibs(L);         /* open libraries */
	lua_gc(L, LUA_GCRESTART, 0);
	if (!args[has_E] && handle_luainit(L) != LUA_OK)
		return 0; /* error running LUA_INIT */
	/* execute arguments -e and -l */
	if (!runargs(L, argv, (script > 0) ? script : argc)) return 0;
	/* execute main script (if there is one) */
	if (script && handle_script(L, argv, script) != LUA_OK) return 0;
	if (args[has_i]) /* -i option? */
		dotty(L);
	else if (script == 0 && !args[has_e] && !args[has_v])
	{ /* no arguments? */
		if (lua_stdin_is_tty())
		{
			print_version();
			dotty(L);
		}
		else
			dofile(L, NULL); /* executes stdin as a file */
	}
	lua_pushboolean(L, 1); /* signal no errors */
	return 1;
}

int main(int argc, char **argv)
{
	int status, result;
	lua_State *L = luaL_newstate(); /* create state */
	if (L == NULL)
	{
		l_message(argv[0], "cannot create state: not enough memory");
		return EXIT_FAILURE;
	}
	/* call 'pmain' in protected mode */
	lua_pushcfunction(L, &pmain);
	lua_pushinteger(L, argc);       /* 1st argument */
	lua_pushlightuserdata(L, argv); /* 2nd argument */
	status = lua_pcall(L, 2, 1, 0);
	result = lua_toboolean(L, -1); /* get result */
	finalreport(L, status);
	lua_close(L);
	return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
}
