#include <windows.h>

#include "common.h"

Win32Error::Win32Error(const DWORD dwErr) : m_dwErr(dwErr) {}

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

const char* Win32Error::what() const noexcept 
{
	if (!m_szMsg)
		FormatMessageA(
		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
		    NULL,
		    m_dwErr,
		    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		    (char*)&m_szMsg,
		    0, NULL
		);
	return m_szMsg;
}

const TCHAR* Win32Error::twhat() const noexcept 
{
#ifdef UNICODE
#define M m_wszMsg
#else
#define M m_szMsg
#endif
	if (!M)
		FormatMessage(
		    FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
		    NULL,
		    m_dwErr,
		    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		    (TCHAR*)&M,
		    0, NULL
		);
	return M;
#undef M
}

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

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

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