/******************************************************************************
 * Icinga 2                                                                   *
 * Copyright (C) 2012 Icinga Development Team (http://www.icinga.org/)        *
 *                                                                            *
 * This program is free software; you can redistribute it and/or              *
 * modify it under the terms of the GNU General Public License                *
 * as published by the Free Software Foundation; either version 2             *
 * of the License, or (at your option) any later version.                     *
 *                                                                            *
 * This program is distributed in the hope that it will be useful,            *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
 * GNU General Public License for more details.                               *
 *                                                                            *
 * You should have received a copy of the GNU General Public License          *
 * along with this program; if not, write to the Free Software Foundation     *
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
 ******************************************************************************/

#include "i2-checker.h"

using namespace icinga;

string CheckerComponent::GetName(void) const
{
	return "checker";
}

void CheckerComponent::Start(void)
{
	m_Endpoint = boost::make_shared<VirtualEndpoint>();
	m_Endpoint->RegisterTopicHandler("checker::AssignService",
		boost::bind(&CheckerComponent::AssignServiceRequestHandler, this, _2, _3));
	m_Endpoint->RegisterTopicHandler("checker::ClearServices",
		boost::bind(&CheckerComponent::ClearServicesRequestHandler, this, _2, _3));
	m_Endpoint->RegisterPublication("checker::CheckResult");
	EndpointManager::GetInstance()->RegisterEndpoint(m_Endpoint);

	m_CheckTimer = boost::make_shared<Timer>();
	m_CheckTimer->SetInterval(1);
	m_CheckTimer->OnTimerExpired.connect(boost::bind(&CheckerComponent::CheckTimerHandler, this));
	m_CheckTimer->Start();

	NagiosCheckTask::Register();
	NullCheckTask::Register();

	m_ResultTimer = boost::make_shared<Timer>();
	m_ResultTimer->SetInterval(5);
	m_ResultTimer->OnTimerExpired.connect(boost::bind(&CheckerComponent::ResultTimerHandler, this));
	m_ResultTimer->Start();
}

void CheckerComponent::Stop(void)
{
	EndpointManager::Ptr mgr = EndpointManager::GetInstance();

	if (mgr)
		mgr->UnregisterEndpoint(m_Endpoint);
}

void CheckerComponent::CheckTimerHandler(void)
{
	Logger::Write(LogDebug, "checker", "CheckTimerHandler entered.");

	double now = Utility::GetTime();
	long tasks = 0;

	while (!m_Services.empty()) {
		Service service = m_Services.top();

		if (service.GetNextCheck() > now)
			break;

		m_Services.pop();

		Logger::Write(LogDebug, "checker", "Executing service check for '" + service.GetName() + "'");

		m_PendingServices.insert(service.GetConfigObject());

		vector<Variant> arguments;
		arguments.push_back(service.GetConfigObject());
		ScriptTask::Ptr task;
		task = service.InvokeMethod("check", arguments, boost::bind(&CheckerComponent::CheckCompletedHandler, this, service, _1));
		assert(task); /* TODO: gracefully handle missing hooks */

		service.SetTag("current_task", task);

		tasks++;
	}

	Logger::Write(LogDebug, "checker", "CheckTimerHandler: past loop.");

	stringstream msgbuf;
	msgbuf << "CheckTimerHandler: created " << tasks << " tasks";
	Logger::Write(LogInformation, "checker", msgbuf.str());
}

void CheckerComponent::CheckCompletedHandler(Service service, const ScriptTask::Ptr& task)
{
	service.RemoveTag("current_task");

	try {
		Variant vresult = task->GetResult();

		if (vresult.IsObjectType<Dictionary>()) {
			CheckResult result = CheckResult(static_cast<Dictionary::Ptr>(vresult));

			RequestMessage rm;
			rm.SetMethod("checker::CheckResult");

			CheckResultMessage params;
			params.SetService(service.GetName());
			params.SetCheckResult(result);

			rm.SetParams(params);

			EndpointManager::GetInstance()->SendMulticastMessage(m_Endpoint, rm);
		}
	} catch (const exception& ex) {
		stringstream msgbuf;
		msgbuf << "Exception occured during check for service '"
		       << service.GetName() << "': " << ex.what();
		Logger::Write(LogWarning, "checker", msgbuf.str());
	}

	/* figure out when the next check is for this service; the local
	 * cibsync component should've already done this as part of processing
	 * the CheckResult message, but lets do it again to be sure */
	service.UpdateNextCheck();

	/* remove the service from the list of pending services; if it's not in the
	 * list this was a manual (i.e. forced) check and we must not re-add the
	 * service to the services list because it's already there. */
	set<ConfigObject::Ptr>::iterator it;
	it = m_PendingServices.find(service.GetConfigObject());
	if (it != m_PendingServices.end()) {
		m_PendingServices.erase(it);
		m_Services.push(service);
	}

	Logger::Write(LogDebug, "checker", "Check finished for service '" + service.GetName() + "'");
}

void CheckerComponent::ResultTimerHandler(void)
{
	Logger::Write(LogDebug, "checker", "ResultTimerHandler entered.");

	stringstream msgbuf;
	msgbuf << "Pending services: " << m_PendingServices.size() << "; Idle services: " << m_Services.size();
	Logger::Write(LogInformation, "checker", msgbuf.str());
}

void CheckerComponent::AssignServiceRequestHandler(const Endpoint::Ptr& sender, const RequestMessage& request)
{
	MessagePart params;
	if (!request.GetParams(&params))
		return;

	string service;
	if (!params.Get("service", &service))
		return;

	ConfigObject::Ptr object = ConfigObject::GetObject("service", service);

	if (!object) {
		Logger::Write(LogWarning, "checker", "Ignoring delegation request for unknown service '" + service + "'.");
		return;
	}

	m_Services.push(object);

	Logger::Write(LogDebug, "checker", "Accepted delegation for service '" + service + "'");
}

void CheckerComponent::ClearServicesRequestHandler(const Endpoint::Ptr& sender, const RequestMessage& request)
{
	Logger::Write(LogInformation, "checker", "Clearing service delegations.");

	/* clear the services lists */
	m_Services = ServiceQueue();
	m_PendingServices.clear();
}

EXPORT_COMPONENT(checker, CheckerComponent);