#include <iostream>
#include <componentThread.h>
#include <boost/asio.hpp>

namespace smo {

thread_local std::shared_ptr<ComponentThread> thisComponentThread;

const std::string ComponentThread::threadNames[N_ITEMS] =
{
	"mrntt",
	"director",
	"simulator",
	"subconscious",
	"body",
	"world"
};

namespace mrntt {
std::shared_ptr<ComponentThread> mrntt =
	std::make_shared<ComponentThread>(ComponentThread::MRNTT);
}
namespace director {
/* The director is the seat of volition in Salmanoff. It receives sensor
* events from the body and world, and uses them to direct its implexors
* to implex new menties. It then loads the menties into canvas for simulation
* and correlation with intrins, in order to form new attrimotions and
* menties.
*/
std::shared_ptr<ComponentThread> director =
	std::make_shared<ComponentThread>(ComponentThread::DIRECTOR);
}
namespace simulator {
/* The canvas is the simulation engine in Salmanoff. It receives menties and
 * simulates them in accordance with the instructions from director. It then
 * re-renders them into perception for director to get feedback.
 */
std::shared_ptr<ComponentThread> canvas =
	std::make_shared<ComponentThread>(ComponentThread::SIMULATOR);
}
namespace subconscious {
/* The subconscious is the seat of memory in Salmanoff. It receives menties
 * from director and stores them in memory for later recall.
 */
std::shared_ptr<ComponentThread> subconscious =
	std::make_shared<ComponentThread>(ComponentThread::SUBCONSCIOUS);
}
namespace body {
/* The body is a thread that polls, processes, and sends interoceptive sensor
 * events to director. It enables these events to occur asynchronously,
 * indepdendent any actions that the other threads are taking.
 */
std::shared_ptr<ComponentThread> body =
	std::make_shared<ComponentThread>(ComponentThread::BODY);
}
namespace world {
/* The world performs the same functions as the body, but for extrospective
 * sensor events.
 */
std::shared_ptr<ComponentThread> world =
	std::make_shared<ComponentThread>(ComponentThread::WORLD);
}

std::array<std::shared_ptr<ComponentThread>, ComponentThread::N_ITEMS>
	ComponentThread::componentThreads =
{
	mrntt::mrntt,
	director::director,
	simulator::canvas,
	subconscious::subconscious,
	body::body,
	world::world
};

void ComponentThread::initializeTls(void)
{
	thisComponentThread = shared_from_this();
}

const std::shared_ptr<ComponentThread> ComponentThread::getSelf(void)
{
	if (!thisComponentThread)
	{
		throw std::runtime_error(std::string(__func__)
			+ ": TLS not initialized");
	}

	return thisComponentThread;
}

void ComponentThread::main(ComponentThread& self)
{
	std::cout << self.name << ":" << __func__ << ": Waiting for JOLT" <<"\n";
	self.getIoService().run();
	self.initializeTls();

	std::cout << self.name << ":" << __func__ << ": Entering event loop" <<"\n";

	/* We loop here because when an exception is caught, we need to first catch
	 * it in the catch blocks. We bubble the exception to mrntt in the catch
	 * blocks, and then we loop here to await control messages from mrntt.
	 *
	 * We can't just exit on our own. Rather, we must wait for mrntt to tell us
	 * to exit. When we wish to finally exit, we set keepLooping to false.
	 */
	for (self.keepLooping = true; self.keepLooping;)
	{
		try {
			self.getIoService().reset();
			self.getIoService().run();
		}
		catch (const std::exception& e)
		{
			std::cerr << self.name << ":" << __func__
				<< ": Exception occurred: " << e.what() << "\n";

			mrntt::mrntt->exceptionInd(self);
		}
		catch (...)
		{
			std::cerr << self.name << ":" << __func__
				<< ": Unknown exception occurred" << "\n";

			mrntt::mrntt->exceptionInd(self);
		}
	}

	std::cout << self.name << ":" << __func__ << ": Exited event loop" << "\n";
}

// Thread management method implementations
void ComponentThread::startThreadReq(std::function<void()> callback)
{
	this->getIoService().post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling startThread." << "\n";

		// Execute private setup sequence here
		// This is where each thread would implement its specific initialization

		if (callback) {
			caller->getIoService().post(callback);
		}
	});
}

void ComponentThread::cleanup(void)
{
	this->keepLooping = false;
}

void ComponentThread::exitThreadReq(std::function<void()> callback)
{
	// Post to the main io_service
	this->getIoService().post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling exitThread "
			"(main queue)." << std::endl;

		cleanup();

		// Stop the main io_service to exit the thread
		io_service.stop();
		if (callback) { caller->getIoService().post(callback); }
	});

	// Also post to the pause io_service
	this->pause_io_service.post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling exitThread "
			"(pause queue)." << std::endl;

		cleanup();

		// Stop both io_services to exit the thread
		pause_io_service.stop();
		io_service.stop();
		if (callback) { caller->getIoService().post(callback); }
	});
}

void ComponentThread::pauseThreadReq(std::function<void()> callback)
{
	this->getIoService().post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling pauseThread."
			<< std::endl;

		if (callback) {
			caller->getIoService().post(callback);
		}

		// Reset the pause io_service before running to ensure it can run again
		pause_io_service.reset();
		// Run the pause io_service to block this thread
		pause_io_service.run();
	});
}

void ComponentThread::resumeThreadReq(std::function<void()> callback)
{
	// Post to the pause_io_service to unblock the paused thread
	pause_io_service.post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling resumeThread."
			<< std::endl;

		if (callback) {
			caller->getIoService().post(callback);
		}

		// Stop the pause_io_service to unblock the thread
		pause_io_service.stop();
	});
}

void ComponentThread::joltThreadReq(std::function<void()> callback)
{
	this->getIoService().post([this, caller = getSelf(), callback]()
	{
		std::cout << "Thread '" << name << "': handling JOLT request." << "\n";

		// Stop the main io_service to jolt the thread
		io_service.stop();

		if (callback) {
			caller->getIoService().post(callback);
		}
	});
}

struct AllMindThreadsOpReqContext {
	AllMindThreadsOpReqContext() : nThreadsProcessed(0) {}

	int nThreadsProcessed;
};

static const std::string getOpName(ComponentThread::ThreadOp op)
{
	if (op < (ComponentThread::ThreadOp)0
		|| op > ComponentThread::ThreadOp::JOLT)
	{
		throw std::runtime_error(std::string(__func__)
			+ ": Invalid operation");
	}

	switch (op)
	{
		case ComponentThread::ThreadOp::START: return "starting";
		case ComponentThread::ThreadOp::PAUSE: return "pausing";
		case ComponentThread::ThreadOp::RESUME: return "resuming";
		case ComponentThread::ThreadOp::EXIT: return "exiting";
		case ComponentThread::ThreadOp::JOLT: return "jolting";
		default: return "unknown";
	}
}

void ComponentThread::execOpOnAllMindThreadsReq(
	ThreadOp op, std::function<void()> callback
	)
{
	std::shared_ptr<ComponentThread> self = getSelf();
	// Check that we're being called from the marionette thread
	if (self->id != MRNTT)
	{
		throw std::runtime_error(std::string(__func__)
			+ ": invoked on non-mrntt thread " + self->name);
	}

	std::cout << "Mrntt: " << getOpName(op) << " all mind threads." << "\n";

	auto context = std::make_shared<AllMindThreadsOpReqContext>();
	const int N_THREADS_EXCEPT_MRNTT = ComponentThread::N_ITEMS - 1;

	for (auto &currThread : ComponentThread::componentThreads)
	{
		if (currThread->id == ComponentThread::MRNTT)
			{ continue; }

		auto threadCallback = [context, callback, N_THREADS_EXCEPT_MRNTT, op]()
		{
			++context->nThreadsProcessed;
			if (context->nThreadsProcessed < N_THREADS_EXCEPT_MRNTT)
				{ return; }

			if (op == ThreadOp::EXIT)
			{
				// Special cleanup for exit operations
				for (auto &currThreadJ : ComponentThread::componentThreads)
				{
					if (currThreadJ->id == ComponentThread::MRNTT)
						{ continue; }

					currThreadJ->thread.join();
				}
			}

			std::cout << "Mrntt: all mind threads done " << getOpName(op) << "."
				<< "\n";

			if (callback) { callback(); }
		};

		switch (op) {
			case ThreadOp::START:
				currThread->startThreadReq(threadCallback);
				break;
			case ThreadOp::PAUSE:
				currThread->pauseThreadReq(threadCallback);
				break;
			case ThreadOp::RESUME:
				currThread->resumeThreadReq(threadCallback);
				break;
			case ThreadOp::EXIT:
				currThread->exitThreadReq(threadCallback);
				break;
			case ThreadOp::JOLT:
				currThread->joltThreadReq(threadCallback);
				break;
			default:
				throw std::runtime_error("Invalid operation");
		}
	}
}

void ComponentThread::startAllMindThreadsReq(std::function<void()> callback)
{
	execOpOnAllMindThreadsReq(ThreadOp::START, callback);
}

void ComponentThread::pauseAllMindThreadsReq(std::function<void()> callback)
{
	execOpOnAllMindThreadsReq(ThreadOp::PAUSE, callback);
}

void ComponentThread::resumeAllMindThreadsReq(std::function<void()> callback)
{
	execOpOnAllMindThreadsReq(ThreadOp::RESUME, callback);
}

void ComponentThread::exitAllMindThreadsReq(std::function<void()> callback)
{
	execOpOnAllMindThreadsReq(ThreadOp::EXIT, callback);
}

void ComponentThread::joltAllMindThreadsReq(std::function<void()> callback)
{
	execOpOnAllMindThreadsReq(ThreadOp::JOLT, callback);
}

/* This shouldn't take a callback because the caller shouldn't expect to
 * Mrntt to send a reply signal to it. Sending this Indication means that
 * Mrntt will send the calling thread an exitThreadReq. When the caller
 * processes that exitThreadReq(), the caller will exit its event loop and then
 * terminate.
 *
 * Even if Mrntt sent a RDY response, the caller shouldn't actually be executing
 * any longer to receive it anyway.
 */
void ComponentThread::exceptionInd(ComponentThread& thread)
{
	if (this->id != ComponentThread::MRNTT)
	{
		throw std::runtime_error(std::string(__func__)
			+ ": invoked on non-mrntt thread " + thread.name);
	}

	// Post the exception to the mrntt thread.
	this->getIoService().post(
	[&thread]()
	{
		std::cerr << "Mrntt: Exception occurred: in thread "
			<< thread.name << ". Killing Salmanoff." << "\n";

		ComponentThread::exitAllMindThreadsReq(
		[]()
		{
			mrntt::mrntt->keepLooping = false;
			mrntt::mrntt->getIoService().stop();
			std::cout << "Mrntt: Signaled main loop to exit." << "\n";
		});
	});
}

} // namespace smo