/*
 * =====================================================================================
 *
 *       Filename:  pubsub_center.cpp
 *
 *    Description:  pub/sub center/manager
 *
 *        Version:  1.0
 *        Created:  2021年04月01日 09时29分04秒
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Li Chao (), 
 *   Organization:  
 *
 * =====================================================================================
 */
#include "pubsub_center.h"
#include "bh_util.h"
using namespace bhome_shm;

bool PubSubCenter::Start(const int nworker)
{
	auto onRecv = [&](MsgI &imsg) {
#ifndef NDEBUG
		static std::atomic<time_t> last(0);
		time_t now = 0;
		time(&now);
		if (last.exchange(now) < now) {
			printf("bus queue size: %ld\n", socket_.Pending());
		}
#endif

		BHMsg msg;
		if (!imsg.Unpack(msg)) {
			return;
		}

		auto OnSubChange = [&](auto &&update) {
			DataSub sub;
			if (!msg.route().empty() && sub.ParseFromString(msg.body()) && !sub.topics().empty()) {
				assert(sizeof(MQId) == msg.route(0).mq_id().size());
				MQId client;
				memcpy(&client, msg.route(0).mq_id().data(), sizeof(client));

				std::lock_guard<std::mutex> guard(mutex_);
				auto &topics = sub.topics();
				for (auto &topic : topics) {
					try {
						update(topic, client);
					} catch (...) {
						//TODO log error
					}
				}
			}
		};

		auto Sub1 = [this](const std::string &topic, const MQId &id) {
			records_[topic].insert(id);
		};

		auto Unsub1 = [this](const std::string &topic, const MQId &id) {
			auto pos = records_.find(topic);
			if (pos != records_.end()) {
				if (pos->second.erase(id) && pos->second.empty()) {
					records_.erase(pos);
				}
			}
		};

		auto OnPublish = [&]() {
			DataPub pub;
			if (!pub.ParseFromString(msg.body())) {
				return;
			}
			auto FindClients = [&](const std::string &topic) {
				Clients dests;
				std::lock_guard<std::mutex> guard(mutex_);
				auto Find1 = [&](const std::string &t) {
					auto pos = records_.find(topic);
					if (pos != records_.end() && !pos->second.empty()) {
						auto &clients = pos->second;
						for (auto &cli : clients) {
							dests.insert(cli);
						}
					}
				};
				Find1(topic);

				//TODO check and adjust topic on client side sub/pub.
				size_t pos = 0;
				while (true) {
					pos = topic.find(kTopicSep, pos);
					if (pos == topic.npos || ++pos == topic.size()) {
						// Find1(std::string()); // sub all.
						break;
					} else {
						Find1(topic.substr(0, pos));
					}
				}
				return dests;
			};

			auto Dispatch = [&](auto &&send1) {
				const Clients &clients(FindClients(pub.topic()));
				for (auto &cli : clients) {
					send1(cli);
				}
			};

			if (imsg.IsCounted()) {
				Dispatch([&](const MQId &cli) { ShmMsgQueue::Send(shm(), cli, imsg, 100); });
			} else {
				MsgI pubmsg;
				if (!pubmsg.MakeRC(shm(), msg)) { return; }
				DEFER1(pubmsg.Release(shm()));

				Dispatch([&](const MQId &cli) { ShmMsgQueue::Send(shm(), cli, pubmsg, 100); });
			}
		};

		switch (msg.type()) {
		case kMsgTypeSubscribe: OnSubChange(Sub1); break;
		case kMsgTypeUnsubscribe: OnSubChange(Unsub1); break;
		case kMsgTypePublish: OnPublish(); break;
		default: break;
		}
	};

	const int kMaxWorker = 16;
	return socket_.StartRaw(onRecv, std::min((nworker > 0 ? nworker : 2), kMaxWorker));
}