#pragma once

// Simple cross platform mutex implementation.
// Similar to the new C++11 api.

// Windows and pthreads implementations in one.

// TODO: Need to clean up these primitives and put them in a reasonable namespace.

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <windows.h>

// Zap stupid windows defines
// Should move these somewhere clever.
#undef p
#undef DrawText
#undef itoa

#else
#include <pthread.h>
#include <errno.h>
#include <sys/time.h>
#endif

class recursive_mutex {
#ifdef _WIN32
	typedef CRITICAL_SECTION mutexType;
#else
	typedef pthread_mutex_t mutexType;
#endif
public:
	recursive_mutex() {
#ifdef _WIN32
		InitializeCriticalSection(&mut_);
#else
		// Critical sections are recursive so let's make these recursive too.
		pthread_mutexattr_t attr;
		pthread_mutexattr_init(&attr);
		pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
		pthread_mutex_init(&mut_, &attr);
#endif
	}
	~recursive_mutex() {
#ifdef _WIN32
		DeleteCriticalSection(&mut_);
#else
		pthread_mutex_destroy(&mut_);
#endif
	}

	bool trylock() {
#ifdef _WIN32
		return TryEnterCriticalSection(&mut_) == TRUE;
#else
		return pthread_mutex_trylock(&mut_) != EBUSY;
#endif
	}

	void lock() {
#ifdef _WIN32
		EnterCriticalSection(&mut_);
#else
		pthread_mutex_lock(&mut_);
#endif
	}

	void unlock() {
#ifdef _WIN32
		LeaveCriticalSection(&mut_);
#else
		pthread_mutex_unlock(&mut_);
#endif
	}

	mutexType &native_handle() {
		return mut_;
	}

private:
	mutexType mut_;
	recursive_mutex(const recursive_mutex &other);
};

class lock_guard {
public:
	lock_guard(recursive_mutex &mtx) : mtx_(mtx) {mtx_.lock();}
	~lock_guard() {mtx_.unlock();}

private:
	recursive_mutex &mtx_;
};


// Like a Windows event, or a modern condition variable.

class event {
public:
#ifdef _WIN32
#else
#endif
	event() {
#ifdef _WIN32
		event_ = CreateEvent(0, FALSE, FALSE, 0);
#else
		pthread_cond_init(&event_, NULL);
#endif
	}
	~event() {
#ifdef _WIN32
		CloseHandle(event_);
#else
		pthread_cond_destroy(&event_);
#endif
	}

	void notify_one() {
#ifdef _WIN32
		SetEvent(event_);
#else
		pthread_cond_signal(&event_);
#endif
	}

	// notify_all is not really possible to implement with win32 events?

	void wait(recursive_mutex &mtx) {
	// broken
#ifdef _WIN32
		// This has to be horribly racy.
		mtx.lock();
		WaitForSingleObject(event_, INFINITE);
		ResetEvent(event_); // necessary?
		mtx.unlock();
#else
		pthread_mutex_lock(&mtx.native_handle());
		pthread_cond_wait(&event_, &mtx.native_handle());
		pthread_mutex_unlock(&mtx.native_handle());
#endif
	}

	void wait_for(recursive_mutex &mtx, int milliseconds) {
#ifdef _WIN32
		//mtx.unlock();
		WaitForSingleObject(event_, milliseconds);
		ResetEvent(event_); // necessary?
		// mtx.lock();
#else
		timespec timeout;
		timeval tv;
		gettimeofday(&tv, NULL);
		timeout.tv_sec = tv.tv_sec;
		timeout.tv_nsec = tv.tv_usec * 1000;

		timeout.tv_sec += milliseconds / 1000;
		timeout.tv_nsec += milliseconds * 1000000;
		pthread_mutex_lock(&mtx.native_handle());
		pthread_cond_timedwait(&event_, &mtx.native_handle(), &timeout);
		pthread_mutex_unlock(&mtx.native_handle());
#endif
	}

	void reset() {
#ifdef _WIN32
		ResetEvent(event_);
#endif
	}
private:
#ifdef _WIN32
	HANDLE event_;
#else
	pthread_cond_t event_;
#endif
};


class condition_variable {
public:
#ifdef _WIN32
#else
#endif
	condition_variable() {
#ifdef _WIN32
		event_ = CreateEvent(0, FALSE, FALSE, 0);
#else
		pthread_cond_init(&event_, NULL);
#endif
	}
	~condition_variable() {
#ifdef _WIN32
		CloseHandle(event_);
#else
		pthread_cond_destroy(&event_);
#endif
	}

	void notify_one() {
#ifdef _WIN32
		SetEvent(event_);
#else
		pthread_cond_signal(&event_);
#endif
	}

	// notify_all is not really possible to implement with win32 events?

	void wait(recursive_mutex &mtx) {
		// broken
#ifdef _WIN32
		// This has to be horribly racy.
		mtx.unlock();
		WaitForSingleObject(event_, INFINITE);
		ResetEvent(event_); // necessary?
		mtx.lock();
#else
		pthread_cond_wait(&event_, &mtx.native_handle());
#endif
	}

	void wait_for(recursive_mutex &mtx, int milliseconds) {
#ifdef _WIN32
		//mtx.unlock();
		WaitForSingleObject(event_, milliseconds);
		ResetEvent(event_); // necessary?
		// mtx.lock();
#else
		timespec timeout;
#ifdef __APPLE__
		timeval tv;
		gettimeofday(&tv, NULL);
		timeout.tv_sec = tv.tv_sec;
		timeout.tv_nsec = tv.tv_usec * 1000;
#else
		clock_gettime(CLOCK_REALTIME, &timeout);
#endif
		timeout.tv_sec += milliseconds / 1000;
		timeout.tv_nsec += milliseconds * 1000000;
		pthread_cond_timedwait(&event_, &mtx.native_handle(), &timeout);
#endif
	}

private:
#ifdef _WIN32
	HANDLE event_;
#else
	pthread_cond_t event_;
#endif
};