#pragma once

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

#ifndef __has_include
#define __has_include(s) 0
#endif

#if GCC_VERSION >= GCC_VER(4,4,0) && __GXX_EXPERIMENTAL_CXX0X__
// GCC 4.4 provides <thread>
#ifndef _GLIBCXX_USE_SCHED_YIELD
#define _GLIBCXX_USE_SCHED_YIELD
#endif
#include <thread>
#elif __has_include(<thread>) && !ANDROID
// Clang + libc++
#include <thread>
#else

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

#include <algorithm>

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

#ifdef __APPLE__
#import <Foundation/NSAutoreleasePool.h>
#endif

#if defined(_WIN32)
// WIN32

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>

#if defined(_MSC_VER) && defined(_MT)
// When linking with LIBCMT (the multithreaded C library), Microsoft recommends
// using _beginthreadex instead of CreateThread.
#define USE_BEGINTHREADEX
#include <process.h>
#endif

#ifdef USE_BEGINTHREADEX
#define THREAD_ID unsigned
#define THREAD_RETURN unsigned __stdcall
#else
#define THREAD_ID DWORD
#define THREAD_RETURN DWORD WINAPI
#endif
#define THREAD_HANDLE HANDLE

#else
// PTHREAD

#include <unistd.h>

#ifndef _POSIX_THREADS
#error unsupported platform (no pthreads?)
#endif

#include <pthread.h>

#define THREAD_ID pthread_t
#define THREAD_HANDLE pthread_t
#define THREAD_RETURN void*

#endif

namespace std
{

class thread
{
public:
    typedef THREAD_HANDLE native_handle_type;

    class id
    {
        friend class thread;
    public:
        id() : m_thread(0) {}
        id(THREAD_ID _id) : m_thread(_id) {}

        bool operator==(const id& rhs) const
        {
            return m_thread == rhs.m_thread;
        }

        bool operator!=(const id& rhs) const
        {
            return !(*this == rhs);
        }

        bool operator<(const id& rhs) const
        {
            return m_thread < rhs.m_thread;
        }

    private:
        THREAD_ID m_thread;
    };

    // no variadic template support in msvc
    //template <typename C, typename... A>
    //thread(C&& func, A&&... args);

    template <typename C>
    thread(C func)
    {
        StartThread(new Func<C>(func));
    }

    template <typename C, typename A>
    thread(C func, A arg)
    {
        StartThread(new FuncArg<C, A>(func, arg));
    }

    thread() /*= default;*/ {}

#ifdef USE_RVALUE_REFERENCES
    thread(const thread&) /*= delete*/;

    thread(thread&& other)
    {
#else
    thread(const thread& t)
    {
        // ugly const_cast to get around lack of rvalue references
        thread& other = const_cast<thread&>(t);
#endif
        swap(other);
    }

#ifdef USE_RVALUE_REFERENCES
    thread& operator=(const thread&) /*= delete*/;

    thread& operator=(thread&& other)
    {
#else
    thread& operator=(const thread& t)
    {
        // ugly const_cast to get around lack of rvalue references
        thread& other = const_cast<thread&>(t);
#endif
        if (joinable())
            detach();
        swap(other);
        return *this;
    }

    ~thread()
    {
        if (joinable())
            detach();
    }

    bool joinable() const
    {
        return m_id != id();
    }

    id get_id() const
    {
        return m_id;
    }

    native_handle_type native_handle()
    {
#ifdef _WIN32
        return m_handle;
#else
        return m_id.m_thread;
#endif
    }

    void join()
    {
#ifdef _WIN32
        WaitForSingleObject(m_handle, INFINITE);
        detach();
#else
        pthread_join(m_id.m_thread, NULL);
        m_id = id();
#endif
    }

    void detach()
    {
#ifdef _WIN32
        CloseHandle(m_handle);
#else
        pthread_detach(m_id.m_thread);
#endif
        m_id = id();
    }

    void swap(thread& other)
    {
        std::swap(m_id, other.m_id);
#ifdef _WIN32
        std::swap(m_handle, other.m_handle);
#endif
    }
    
    static unsigned hardware_concurrency()
    {
#ifdef _WIN32
        SYSTEM_INFO sysinfo;
        GetSystemInfo(&sysinfo);
        return static_cast<unsigned>(sysinfo.dwNumberOfProcessors);
#else
        return 0;
#endif
    }

private:
    id m_id;
    
#ifdef _WIN32
    native_handle_type m_handle;
#endif

    template <typename F>
    void StartThread(F* param)
    {
#ifdef USE_BEGINTHREADEX
        m_handle = (HANDLE)_beginthreadex(NULL, 0, &RunAndDelete<F>, param, 0, &m_id.m_thread);
#elif defined(_WIN32)
        m_handle = CreateThread(NULL, 0, &RunAndDelete<F>, param, 0, &m_id.m_thread);
#else
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setstacksize(&attr, 1024 * 1024);
        if (pthread_create(&m_id.m_thread, &attr, &RunAndDelete<F>, param))
            m_id = id();
#endif
    }
    
    template <typename C>
    class Func
    {
    public:
        Func(C _func) : func(_func) {}

        void Run() { func(); }

    private:
        C const func;
    };

    template <typename C, typename A>
    class FuncArg
    {
    public:
        FuncArg(C _func, A _arg) : func(_func), arg(_arg) {}

        void Run() { func(arg); }

    private:
        C const func;
        A arg;
    };

    template <typename F>
    static THREAD_RETURN RunAndDelete(void* param)
    {
#ifdef __APPLE__
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
#endif
        static_cast<F*>(param)->Run();
        delete static_cast<F*>(param);
#ifdef __APPLE__
        [pool release];
#endif
        return 0;
    }
};

namespace this_thread
{

inline void yield()
{
#ifdef _WIN32
    SwitchToThread();
#else
    sleep(0);
#endif
}

inline thread::id get_id()
{
#ifdef _WIN32
    return GetCurrentThreadId();
#else
    return pthread_self();
#endif
}

}    // namespace this_thread

}    // namespace std

#undef USE_RVALUE_REFERENCES
#undef USE_BEGINTHREADEX
#undef THREAD_ID
#undef THREAD_RETURN
#undef THREAD_HANDLE

#endif
