#include <stdexcept>
#include <memory>
#include <windows.h>
#include <SWI-Prolog.h>

#include "common.h"

/* Convert normal string to TSTR using given codepage. */
TCHAR *TszFromSz(const char *sz, int iCp)
{
	TCHAR *tsz;

#ifdef UNICODE
	int cbMultiByte, cchWideChar;

	cbMultiByte = strlen(sz)+1;
	cchWideChar = MultiByteToWideChar(iCp, 0, sz, cbMultiByte, NULL, 0);
	tsz = (TCHAR *)malloc(cchWideChar*sizeof(WCHAR));
	if (!tsz) return NULL;
	if (!MultiByteToWideChar(iCp, 0, sz, cbMultiByte, tsz, cchWideChar))
		return NULL;
#else
	tsz = malloc(strlen(sz)+1);
	if (!tsz) return NULL;
	strcpy(tsz, sz);
#endif

	return tsz;
}

Win32Error::Win32Error(DWORD dwErr)
{
	m_dwErr = dwErr;
	FormatMessageA(
	    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
	    NULL,
	    m_dwErr,
	    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
	    (LPSTR)&m_szMsg,
	    0, NULL
	);
}

Win32Error::~Win32Error()
{
	if (m_szMsg)
		HeapFree(GetProcessHeap(), 0, m_szMsg);
}

const char *Win32Error::what(void) const noexcept 
{
	return m_szMsg;
}

Library::Library(const TCHAR *tszLibrary)
{
	m_hModule = LoadLibrary(tszLibrary);
	if (!m_hModule)
		throw Win32Error(GetLastError());
}

Library::~Library()
{
	FreeLibrary(m_hModule);
}

FARPROC Library::GetProcAddress(const char *szProc)
{
	return ::GetProcAddress(m_hModule, szProc);
}