#ifndef CONDITION_VARIABLE_H_
#define CONDITION_VARIABLE_H_

#define GCC_VER(x,y,z)	((x) * 10000 + (y) * 100 + (z))
#define GCC_VERSION GCC_VER(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)

#if GCC_VERSION >= GCC_VER(4,4,0) && __GXX_EXPERIMENTAL_CXX0X__
// GCC 4.4 provides <condition_variable>
#include <condition_variable>
#else

// partial std::condition_variable implementation for win32/pthread

#include "std_mutex.h"

#if (_MSC_VER >= 1600) || (GCC_VERSION >= GCC_VER(4,3,0) && __GXX_EXPERIMENTAL_CXX0X__)
#define USE_RVALUE_REFERENCES
#endif

#if defined(_WIN32) && defined(_M_X64)
#define USE_CONDITION_VARIABLES
#elif defined(_WIN32)
#define USE_EVENTS
#endif

namespace std
{

class condition_variable
{
#if defined(_WIN32) && defined(USE_CONDITION_VARIABLES)
    typedef CONDITION_VARIABLE native_type;
#elif defined(_WIN32)
    typedef HANDLE native_type;
#else
    typedef pthread_cond_t native_type;
#endif

public:

#ifdef USE_EVENTS
    typedef native_type native_handle_type;
#else
    typedef native_type* native_handle_type;
#endif

    condition_variable()
    {
#if defined(_WIN32) && defined(USE_CONDITION_VARIABLES)
        InitializeConditionVariable(&m_handle);
#elif defined(_WIN32)
        m_handle = CreateEvent(NULL, false, false, NULL);
#else
        pthread_cond_init(&m_handle, NULL);
#endif
    }

    ~condition_variable()
    {
#if defined(_WIN32) && !defined(USE_CONDITION_VARIABLES)
        CloseHandle(m_handle);
#elif !defined(_WIN32)
        pthread_cond_destroy(&m_handle);
#endif
    }

    condition_variable(const condition_variable&) /*= delete*/;
    condition_variable& operator=(const condition_variable&) /*= delete*/;

    void notify_one()
    {
#if defined(_WIN32) && defined(USE_CONDITION_VARIABLES)
        WakeConditionVariable(&m_handle);
#elif defined(_WIN32)
        SetEvent(m_handle);
#else
        pthread_cond_signal(&m_handle);
#endif
    }

    void notify_all()
    {
#if defined(_WIN32) && defined(USE_CONDITION_VARIABLES)
        WakeAllConditionVariable(&m_handle);
#elif defined(_WIN32)
        // TODO: broken
        SetEvent(m_handle);
#else
        pthread_cond_broadcast(&m_handle);
#endif
    }

    void wait(unique_lock<mutex>& lock)
    {
#ifdef _WIN32
#ifdef USE_SRWLOCKS
        SleepConditionVariableSRW(&m_handle, lock.mutex()->native_handle(), INFINITE, 0);
#elif defined(USE_CONDITION_VARIABLES)
        SleepConditionVariableCS(&m_handle, lock.mutex()->native_handle(), INFINITE);
#else
        // TODO: broken, the unlock and wait need to be atomic
        lock.unlock();
        WaitForSingleObject(m_handle, INFINITE);
        lock.lock();
#endif
#else
        pthread_cond_wait(&m_handle, lock.mutex()->native_handle());
#endif
    }

    template <class Predicate>
    void wait(unique_lock<mutex>& lock, Predicate pred)
    {
        while (!pred())
            wait(lock);
    }

    //template <class Clock, class Duration>
    //cv_status wait_until(unique_lock<mutex>& lock,
    //	const chrono::time_point<Clock, Duration>& abs_time);

    //template <class Clock, class Duration, class Predicate>
    //	bool wait_until(unique_lock<mutex>& lock,
    //	const chrono::time_point<Clock, Duration>& abs_time,
    //	Predicate pred);

    //template <class Rep, class Period>
    //cv_status wait_for(unique_lock<mutex>& lock,
    //	const chrono::duration<Rep, Period>& rel_time);

    //template <class Rep, class Period, class Predicate>
    //	bool wait_for(unique_lock<mutex>& lock,
    //	const chrono::duration<Rep, Period>& rel_time,
    //	Predicate pred);

    native_handle_type native_handle()
    {
#ifdef USE_EVENTS
        return m_handle;
#else
        return &m_handle;
#endif
    }

private:
    native_type m_handle;
};

}

#endif
#endif