/*-
 Author: Brian Tiffin
 Dedicated to the public domain
 
 Date: November 2016
 Modified: 2016-11-14/15:34-0500
+*/
/*
 unilua.c loadfunc a Lua interpreter in Unicon

 tectonics: gcc -o unilua.so -shared -fpic unilua.c \
                -I/usr/include/lua5.3 -llua5.3
*/
#include <stdio.h>
#include <string.h>
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>

#include "icall.h"

lua_State *uniLuaState;

/*
 unilua: execute Lua code from Unicon string
*/
int
unilua (int argc, descriptor argv[])
{
    int error;

    char *unibuf;
    int luaType;

    if (!uniLuaState) {
#ifdef LUA50
        uniLuaState = lua_open();     /* opens Lua */
        if (!uniLuaState) {
            Error(500);
        } 
        luaopen_base(uniLuaState);    /* opens the basic library */
        luaopen_table(uniLuaState);   /* opens the table library */
        luaopen_io(uniLuaState);      /* opens the I/O library */
        luaopen_string(uniLuaState);  /* opens the string lib. */
        luaopen_math(uniLuaState);    /* opens the math lib. */
#else
        uniLuaState = luaL_newstate();
        if (!uniLuaState) {
            Error(500);
        } 
        luaL_openlibs(uniLuaState);
#endif
    }

    /* ensure argv[1] is a string */
    ArgString(1);
    
    /* evaluate some Lua */
    unibuf = StringVal(argv[1]);
    error = luaL_loadbuffer(uniLuaState, unibuf, strlen(unibuf), "line") ||
            luaL_dostring(uniLuaState, unibuf);
    if (error) {
        fprintf(stderr, "%s", lua_tostring(uniLuaState, -1));
        lua_pop(uniLuaState, 1);  /* pop error message from the stack */
        Error(107);
    }

    luaType = lua_type(uniLuaState, -1);
    switch (luaType) {
        case LUA_TSTRING:
            RetString((char *)lua_tostring(uniLuaState, -1));
            break;
        case LUA_TNUMBER:
            if (lua_isinteger(uniLuaState, -1)) {
                RetInteger(lua_tointeger(uniLuaState, -1));
            } else {
                RetReal(lua_tonumber(uniLuaState, -1));
            }    
            break;
        default:
            RetString((char *)lua_typename(uniLuaState, luaType));
            break;
    }  
    return 0;
}

/*
 Close Lua state
*/
int
uniluaClose(int argc, descriptor argv[])
{
    lua_close(uniLuaState);
    RetNull();
    return 0;
}