/**
 * returns an absolute path from a relative file name
 */

#ifdef __cplusplus
  #include "lua.hpp"
#else
  #include "lua.h"
  #include "lualib.h"
  #include "lauxlib.h"
#endif
#include <math.h>

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

#include "libluaph1.h"

#ifdef __cplusplus
extern "C"{
#endif

static int os_setenv(lua_State* L) {
    const char* name = luaL_checkstring(L, 1);
    const char* value = luaL_checkstring(L, 2);

    int len = strlen(name) + strlen(value) + 2; //adding one char for '=' and another for '\0'
    char buffer[len];
    strcpy(buffer, name);
    strcat(buffer, "=");
    strcat(buffer, value);
    buffer[len] = 0;

    int res = putenv(buffer);
    printf("env (%d): %s, %s\n", res, buffer, getenv(name));
    if (res != 0) {
        lua_pushnil(L);
        lua_pushfstring(L, "unable to set environment variable '%s', errno %d : %s", name, errno, strerror(errno));
        return 2;
    }

    lua_pushnumber(L, res);
    return 1;
}

static int os_getenv(lua_State* L) {
    const char* name = luaL_checkstring(L, 1);

    char *buffer;
    printf("name: %s\n", name);
    buffer = getenv(name);
    printf("env: %s\n", buffer);
    if (buffer == NULL) {
        lua_pushnil(L);
        lua_pushfstring(L, "unable to get environment variable '%s'", name);
        return 2;
    }

    lua_pushstring(L, buffer);
    return 1;
}

static int os_realpath(lua_State* L) {
    char result[PH_PATH_MAX];
    int ok;

    const char* path = luaL_checkstring(L, 1);

#ifdef __MINGW32__
    ok = (_fullpath(result, path, PH_PATH_MAX) != NULL);
#else
    ok = (realpath(path, result) != NULL);
#endif

    if (!ok) {
        lua_pushnil(L);
        lua_pushfstring(L, "unable to fetch real path of '%s', errno %d : %s", path, errno, strerror(errno));
        return 2;
    }

    lua_pushstring(L, result);
    return 1;
}

//library to be registered
static const struct luaL_Reg libluaph1 [] = {
      {"realpath", os_realpath},
      {"setenv", os_setenv},
      {"getenv", os_getenv},
      {NULL, NULL}  /* sentinel */
    };

//name of this function is not flexible
int luaopen_libluaph1 (lua_State *L){
    luaL_newlib(L, libluaph1);
    return 1;
}

#ifdef __cplusplus
}
#endif