/*
 * =====================================================================================
 *
 *       Filename:  socket.h
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  2021年03月30日 15时49分19秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Li Chao (), 
 *   Organization:  
 *
 * =====================================================================================
 */

#ifndef SOCKET_GWTJHBPO
#define SOCKET_GWTJHBPO

#include "bh_util.h"
#include "defs.h"
#include "sendq.h"
#include "shm_msg_queue.h"
#include <atomic>
#include <boost/noncopyable.hpp>
#include <condition_variable>
#include <functional>
#include <memory>
#include <mutex>
#include <thread>
#include <vector>

using namespace bhome_msg;
class ShmSocket : private boost::noncopyable
{

protected:
	typedef ShmMsgQueue Queue;

public:
	typedef ShmMsgQueue::MQId MQId;
	typedef bhome_shm::SharedMemory Shm;
	typedef std::function<void(ShmSocket &sock, MsgI &imsg)> RawRecvCB;
	typedef std::function<void(ShmSocket &sock, MsgI &imsg, BHMsgHead &head)> RecvCB;
	typedef std::function<bool(ShmSocket &sock, MsgI &imsg, BHMsgHead &head)> PartialRecvCB;
	typedef std::function<void(ShmSocket &sock)> IdleCB;

	ShmSocket(Shm &shm, const MQId id, const int len);
	ShmSocket(Shm &shm, const bool create_or_else_find, const MQId id, const int len);
	ShmSocket(Shm &shm, const int len = 12);
	~ShmSocket();
	static bool Remove(SharedMemory &shm, const MQId id) { return Queue::Remove(shm, id); }
	bool Remove() { return Remove(shm(), id()); }
	MQId id() const { return mq().Id(); }
	// start recv.
	bool Start(const RawRecvCB &onData, const IdleCB &onIdle, int nworker = 1);
	bool Start(int nworker = 1, const RecvCB &onData = RecvCB(), const IdleCB &onIdle = IdleCB());
	bool Start(const RecvCB &onData, const IdleCB &onIdle, int nworker = 1) { return Start(nworker, onData, onIdle); }
	bool Start(const RecvCB &onData, int nworker = 1) { return Start(nworker, onData); }
	bool Stop();

	template <class Body>
	bool Send(const MQId remote, BHMsgHead &head, Body &body, RecvCB &&cb = RecvCB())
	{
		try {
			if (!cb) {
				return SendImpl(remote, MsgI::Serialize(head, body));
			} else {
				std::string msg_id(head.msg_id());
				per_msg_cbs_->Store(msg_id, std::move(cb));
				auto onExpireRemoveCB = [this, msg_id](SendQ::Data const &msg) {
					RecvCB cb_no_use;
					per_msg_cbs_->Pick(msg_id, cb_no_use);
				};
				return SendImpl(remote, MsgI::Serialize(head, body), onExpireRemoveCB);
			}
		} catch (...) {
			SetLastError(eError, "Send internal error.");
			return false;
		}
	}

	bool Send(const MQId remote, const MsgI &imsg)
	{
		return SendImpl(remote, imsg);
	}

	bool SyncRecv(MsgI &msg, bhome_msg::BHMsgHead &head, const int timeout_ms);

	template <class Body>
	bool SendAndRecv(const MQId remote, BHMsgHead &head, Body &body, MsgI &reply, BHMsgHead &reply_head, const int timeout_ms)
	{
		struct State {
			std::mutex mutex;
			std::condition_variable cv;
			bool canceled = false;
		};

		try {
			std::shared_ptr<State> st(new State);
			auto endtime = std::chrono::steady_clock::now() + std::chrono::milliseconds(timeout_ms);

			auto OnRecv = [st, &reply, &reply_head](ShmSocket &sock, MsgI &msg, BHMsgHead &head) {
				std::unique_lock<std::mutex> lk(st->mutex);
				if (!st->canceled) {
					reply.swap(msg);
					reply_head.Swap(&head);
					st->cv.notify_one();
				} else { // ignore
				}
			};

			std::unique_lock<std::mutex> lk(st->mutex);
			bool sendok = Send(remote, head, body, std::move(OnRecv));
			if (!sendok) {
				LOG_DEBUG() << "send timeout";
			}
			if (sendok && st->cv.wait_until(lk, endtime) == std::cv_status::no_timeout) {
				return true;
			} else {
				st->canceled = true;
				SetLastError(ETIMEDOUT, "timeout");
				return false;
			}
		} catch (...) {
			return false;
		}
	}

	Shm &shm() const { return mq().shm(); }

protected:
	Queue &mq() { return mq_; } // programmer should make sure that mq_ is valid.
	const Queue &mq() const { return mq_; }
	std::mutex &mutex() { return mutex_; }

private:
	bool StopNoLock();
	bool RunningNoLock() { return !workers_.empty(); }

	template <class... Rest>
	bool SendImpl(const MQId remote, Rest &&...rest)
	{
		// TODO send alloc request, and pack later, higher bit means alloc?
		send_buffer_.Append(remote, std::forward<decltype(rest)>(rest)...);
		return true;
	}

	std::vector<std::thread> workers_;
	std::mutex mutex_;
	std::atomic<bool> run_;

	Queue mq_;
	template <class Key>
	class CallbackRecords
	{
		std::unordered_map<Key, RecvCB> store_;

	public:
		bool empty() const { return store_.empty(); }
		bool Store(const Key &id, RecvCB &&cb) { return store_.emplace(id, std::move(cb)).second; }
		bool Pick(const Key &id, RecvCB &cb)
		{
			auto pos = store_.find(id);
			if (pos != store_.end()) {
				cb.swap(pos->second);
				store_.erase(pos);
				return true;
			} else {
				return false;
			}
		}
	};

	Synced<CallbackRecords<std::string>> per_msg_cbs_;

	SendQ send_buffer_;
};

#endif // end of include guard: SOCKET_GWTJHBPO