/*
 * =====================================================================================
 *
 *       Filename:  shm_msg_queue.cpp
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  2021年04月26日 16时25分05秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Li Chao (), lichao@aiotlink.com
 *   Organization:  
 *
 * =====================================================================================
 */
#include "shm_msg_queue.h"

using namespace bhome_msg;
using namespace boost::interprocess;

namespace
{
std::string MsgQIdToName(const ShmMsgQueue::MQId id)
{
	char buf[40] = "mqOx";
	int n = sprintf(buf + 4, "%lx", id);
	return std::string(buf, n + 4);
}

} // namespace

ShmMsgQueue::MQId ShmMsgQueue::NewId()
{
	static auto &id = GetData();
	return (++id) * 10;
}

ShmMsgQueue::ShmMsgQueue(const MQId id, ShmType &segment, const int len) :
    id_(id),
    queue_(segment, MsgQIdToName(id_), len, segment.get_segment_manager())
{
}

ShmMsgQueue::ShmMsgQueue(const MQId id, const bool create_or_else_find, ShmType &segment, const int len) :
    id_(id),
    queue_(segment, create_or_else_find, MsgQIdToName(id_), len, segment.get_segment_manager())
{
	if (!queue_.IsOk()) {
		throw("error create/find msgq " + std::to_string(id_));
	}
}
ShmMsgQueue::ShmMsgQueue(ShmType &segment, const int len) :
    ShmMsgQueue(NewId(), true, segment, len) {}

ShmMsgQueue::~ShmMsgQueue() {}

#ifndef BH_USE_ATOMIC_Q
ShmMsgQueue::Mutex &ShmMsgQueue::GetMutex(const MQId id)
{
	static std::unordered_map<MQId, std::shared_ptr<Mutex>> imm;

	static std::mutex mtx;
	std::lock_guard<std::mutex> lock(mtx);
	auto pos = imm.find(id);
	if (pos == imm.end()) {
		pos = imm.emplace(id, new Mutex(id)).first;
		// pos = imm.emplace(id, new Mutex()).first;
	}
	return *pos->second;
}
#endif

bool ShmMsgQueue::Remove(SharedMemory &shm, const MQId id)
{
	Queue *q = Find(shm, id);
	if (q) {
		RawData val = 0;
		while (q->TryRead(val)) {
			if (IsCmd(val)) {
				LOG_DEBUG() << "clsing queue " << id << ", has a cmd" << DecodeCmd(val);
			} else {
				MsgI(val).Release();
			}
		}
	}
	return Shmq::Remove(shm, MsgQIdToName(id));
}

ShmMsgQueue::Queue *ShmMsgQueue::Find(SharedMemory &shm, const MQId remote_id)
{
	return Shmq::Find(shm, MsgQIdToName(remote_id));
}

bool ShmMsgQueue::TrySend(SharedMemory &shm, const MQId remote_id, int64_t val)
{
	try {
		ShmMsgQueue dest(remote_id, false, shm, 1);
#ifndef BH_USE_ATOMIC_Q
		Guard lock(GetMutex(remote_id));
#endif
		return dest.queue().TryWrite(val);
	} catch (...) {
		// SetLastError(eNotFound, "remote not found");
		return false;
	}
}

// Test shows that in the 2 cases:
// 1) build msg first, then find remote queue;
// 2) find remote queue first, then build msg;
// 1 is about 50% faster than 2, maybe cache related.