/*
 * =====================================================================================
 *
 *       Filename:  shm_queue.h
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  2021年03月25日 10时35分09秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Li Chao (), 
 *   Organization:  
 *
 * =====================================================================================
 */

#ifndef SHM_QUEUE_JE0OEUP3
#define SHM_QUEUE_JE0OEUP3

#include "msg.h"
#include "shm.h"
#include <boost/circular_buffer.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

namespace bhome_shm
{

template <class D>
using Circular = boost::circular_buffer<D, Allocator<D>>;

typedef boost::uuids::uuid MQId;

template <class D>
class SharedQueue : private Circular<D>
{
	typedef Circular<D> Super;
	Mutex mutex_;
	Cond cond_read_;
	Cond cond_write_;
	Mutex &mutex() { return mutex_; }

	static boost::posix_time::ptime MSFromNow(const int ms)
	{
		using namespace boost::posix_time;
		ptime cur = boost::posix_time::microsec_clock::universal_time();
		return cur + millisec(ms);
	}

	auto TimedReadPred(const int timeout_ms)
	{
		auto endtime = MSFromNow(timeout_ms);
		return [this, endtime](Guard &lock) {
			return (cond_read_.timed_wait(lock, endtime, [&]() { return !this->empty(); }));
		};
	}
	auto TryReadPred()
	{
		return [this](Guard &lock) { return !this->empty(); };
	}

	template <class Pred, class OnData>
	int ReadAllOnCond(Pred const &pred, OnData const &onData)
	{
		Guard lock(this->mutex());
		int n = 0;
		while (pred(lock)) {
			++n;
			onData(this->front());
			this->pop_front();
			this->cond_write_.notify_one();
		}
		return n;
	}

	template <class Pred>
	bool ReadOnCond(D &buf, Pred const &pred)
	{
		int flag = 0;
		auto only_once = [&](Guard &lock) { return flag++ == 0 && pred(lock); };
		auto onData = [&buf](D &d) {
			using std::swap;
			swap(buf, d);
		};
		return ReadAllOnCond(only_once, onData);
	}

	template <class Iter, class Pred, class OnWrite>
	int WriteAllOnCond(Iter begin, Iter end, Pred const &pred, OnWrite const &onWrite)
	{
		if (begin == end) { return 0; }

		int n = 0;
		Guard lock(mutex());
		while (pred(lock)) {
			onWrite(*begin);
			this->push_back(*begin);
			++n;
			cond_read_.notify_one();
			if (++begin == end) {
				break;
			}
		}
		return n;
	}

public:
	SharedQueue(const uint32_t len, Allocator<D> const &alloc) :
	    Super(len, alloc) {}
	using Super::capacity;
	using Super::size;
	template <class Iter, class OnWrite>
	int Write(Iter begin, Iter end, const int timeout_ms, const OnWrite &onWrite)
	{
		auto endtime = MSFromNow(timeout_ms);
		auto timedWritePred = [this, endtime](Guard &lock) {
			return (cond_write_.timed_wait(lock, endtime, [&]() { return !this->full(); }));
		};
		return WriteAllOnCond(begin, end, timedWritePred, onWrite);
	}

	template <class OnWrite>
	bool Write(const D &buf, const int timeout_ms, const OnWrite &onWrite) { return Write(&buf, (&buf) + 1, timeout_ms, onWrite); }
	bool Write(const D &buf, const int timeout_ms)
	{
		return Write(buf, timeout_ms, [](const D &buf) {});
	}

	template <class Iter, class OnWrite>
	int TryWrite(Iter begin, Iter end, const OnWrite &onWrite)
	{
		auto tryWritePred = [this](Guard &lock) { return !this->full(); };
		return WriteAllOnCond(begin, end, tryWritePred, onWrite);
	}

	template <class OnWrite>
	bool TryWrite(const D &buf, const OnWrite &onWrite) { return TryWrite(&buf, (&buf) + 1, onWrite); }

	bool TryWrite(const D &buf)
	{
		return TryWrite(buf, [](const D &buf) {});
	}

	template <class OnData>
	int ReadAll(const int timeout_ms, OnData const &onData) { return ReadAllOnCond(TimedReadPred(timeout_ms), onData); }
	template <class OnData>
	int TryReadAll(OnData const &onData) { return ReadAllOnCond(TryReadPred(), onData); }

	bool Read(D &buf, const int timeout_ms) { return ReadOnCond(buf, TimedReadPred(timeout_ms)); }
	bool TryRead(D &buf) { return ReadOnCond(buf, TryReadPred()); }
};

using namespace bhome_msg;

class ShmMsgQueue : private ShmObject<SharedQueue<MsgI>>
{
	typedef ShmObject<SharedQueue<MsgI>> Super;
	typedef Super::Data Queue;
	typedef std::function<void()> OnSend;
	MQId id_;

protected:
	ShmMsgQueue(const std::string &raw_name, ShmType &segment, const int len); // internal use.
public:
	ShmMsgQueue(const MQId &id, ShmType &segment, const int len);
	ShmMsgQueue(ShmType &segment, const int len);
	~ShmMsgQueue();
	static bool Remove(SharedMemory &shm, const MQId &id);
	const MQId &Id() const { return id_; }
	using Super::shm;

	bool Recv(MsgI &msg, const int timeout_ms) { return data()->Read(msg, timeout_ms); }
	bool TryRecv(MsgI &msg) { return data()->TryRead(msg); }
	template <class OnData>
	int TryRecvAll(OnData const &onData) { return data()->TryReadAll(onData); }
	static Queue *FindRemote(SharedMemory &shm, const MQId &remote_id);
	static bool Send(SharedMemory &shm, const MQId &remote_id, const MsgI &msg, const int timeout_ms, OnSend const &onsend = OnSend());
	static bool TrySend(SharedMemory &shm, const MQId &remote_id, const MsgI &msg, OnSend const &onsend = OnSend());
	template <class Iter>
	static int TrySendAll(SharedMemory &shm, const MQId &remote_id, const Iter begin, const Iter end, OnSend const &onsend = OnSend())
	{
		Queue *remote = FindRemote(shm, remote_id);
		if (remote) {
			if (onsend) {
				return remote->TryWrite(begin, end, [&onsend](const MsgI &msg) { onsend(); msg.AddRef(); });
			} else {
				return remote->TryWrite(begin, end, [](const MsgI &msg) { msg.AddRef(); });
			}
		} else {
			// SetLestError(eNotFound);
			return 0;
		}
	}

	template <class... Rest>
	bool Send(const MQId &remote_id, Rest const &...rest) { return Send(shm(), remote_id, rest...); }
	template <class... Rest>
	bool TrySend(const MQId &remote_id, Rest const &...rest) { return TrySend(shm(), remote_id, rest...); }
	template <class... Rest>
	int TrySendAll(const MQId &remote_id, Rest const &...rest) { return TrySendAll(shm(), remote_id, rest...); }

	size_t Pending() const { return data()->size(); }
};

} // namespace bhome_shm

#endif // end of include guard: SHM_QUEUE_JE0OEUP3