#include "error.h"

static __thread char errorbuf[NNWT_ERROR_STR_MAXLEN];
#ifdef NAUNET_ON_WINDOWS
static __thread wchar_t errorbufw[NNWT_ERROR_STR_MAXLEN];
#endif

char *nn_strerror(s32 errnum)
{
#ifdef NAUNET_ON_WINDOWS
    strerror_s(errorbuf, NNWT_ERROR_STR_MAXLEN, errnum);
#else
#if (_POSIX_C_SOURCE >= 200112L) && ! _GNU_SOURCE
    if (strerror_r(errnum, errorbuf, NNWT_ERROR_STR_MAXLEN) != 0) errorbuf[0] = '\0';
#else
    return strerror_r(errnum, errorbuf, NNWT_ERROR_STR_MAXLEN);
#endif
#endif
    return errorbuf;
}

#ifdef NAUNET_ON_WINDOWS
#include "../winwrap.h"

#include <wchar.h>

// https://stackoverflow.com/a/46104456
char *nn_win32_error_message(s32 err)
{
    DWORD ret = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        err,
        0,
        errorbufw,
        NNWT_ERROR_STR_MAXLEN,
        NULL);
    if (!ret) {
        return NULL;
    }
    errorbufw[ret] = L'\0';
    mbstate_t mbstate = { 0 };
    wchar_t *wc = errorbufw;
    size_t length = wcsrtombs(NULL, (const wchar_t **)&wc, 0, &mbstate);
    if (length == (size_t)-1) {
        return NULL;
    }
    length = wcsrtombs(errorbuf, (const wchar_t **)&wc, length, &mbstate);
    al_assert(length < NNWT_ERROR_STR_MAXLEN);
    errorbuf[length] = L'\0';
    return errorbuf;
}
#endif