#ifndef COMMON_H
#define COMMON_H

#include <memory>
#include <optional>
#include <windows.h>

#ifdef UNICODE
#define WA "W"
#else
#define WA "A"
#endif

struct Win32Error : public std::exception
{
	Win32Error(DWORD);
	~Win32Error(void);
	virtual const char *what(void) const noexcept override;
private:
	DWORD m_dwErr;
	char *m_szMsg = NULL;
};

struct Library
{
	Library(const TCHAR *);
	~Library(void);
	FARPROC GetProcAddress(const char *);
private:
	HMODULE m_hModule;
};

inline int Cmp(const int a, const int b)
{
	if (a == b) return 0;
	if (a > b) return 1;
	return -1;
}

/* Return integer scaled for current DPI. */
inline int Dpi(const int i)
{
	extern int g_iDPI;
	return MulDiv(i, g_iDPI, 96);
}

/* Create and return an object of type C. If construction fails,
 * return nothing. The returned value must be checked before being
 * used, as dereferencing is undefined if the value is empty. */
template <class C, typename ...T>
std::optional<C> try_make(T ...args)
{
	try {
		return C(args...);
	} catch (...) {
		return {};
	}
}

#endif