/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#define FORBIDDEN_SYMBOL_ALLOW_ALL

#include "backends/networking/curl/connectionmanager.h"
#include "backends/networking/curl/networkreadstream.h"
#include "common/debug.h"
#include "common/system.h"
#include "common/timer.h"
#include <curl/curl.h>

namespace Common {

DECLARE_SINGLETON(Networking::ConnectionManager);

}

namespace Networking {

ConnectionManager::ConnectionManager(): _multi(0), _timerStarted(false), _frame(0) {
	curl_global_init(CURL_GLOBAL_ALL);
	_multi = curl_multi_init();
}

ConnectionManager::~ConnectionManager() {
	stopTimer();

	//terminate all requests
	_handleMutex.lock();
	for (Common::Array<RequestWithCallback>::iterator i = _requests.begin(); i != _requests.end(); ++i) {
		Request *request = i->request;
		RequestCallback callback = i->onDeleteCallback;
		if (request)
			request->finish();
		delete request;
		if (callback)
			(*callback)(request);
	}
	_requests.clear();

	//cleanup
	curl_multi_cleanup(_multi);
	curl_global_cleanup();
	_multi = nullptr;
	_handleMutex.unlock();
}

void ConnectionManager::registerEasyHandle(CURL *easy) const {
	curl_multi_add_handle(_multi, easy);
}

Request *ConnectionManager::addRequest(Request *request, RequestCallback callback) {
	_addedRequestsMutex.lock();
	_addedRequests.push_back(RequestWithCallback(request, callback));
	if (!_timerStarted)
		startTimer();
	_addedRequestsMutex.unlock();
	return request;
}

Common::String ConnectionManager::urlEncode(Common::String s) const {
	if (!_multi)
		return "";
#if LIBCURL_VERSION_NUM >= 0x070F04
	char *output = curl_easy_escape(_multi, s.c_str(), s.size());
#else
	char *output = curl_escape(s.c_str(), s.size());
#endif
	if (output) {
		Common::String result = output;
		curl_free(output);
		return result;
	}
	return "";
}

uint32 ConnectionManager::getCloudRequestsPeriodInMicroseconds() {
	return TIMER_INTERVAL * CLOUD_PERIOD;
}

//private goes here:

void connectionsThread(void *ignored) {
	ConnMan.handle();
}

void ConnectionManager::startTimer(int interval) {
	Common::TimerManager *manager = g_system->getTimerManager();
	if (manager->installTimerProc(connectionsThread, interval, 0, "Networking::ConnectionManager's Timer")) {
		_timerStarted = true;
	} else {
		warning("Failed to install Networking::ConnectionManager's timer");
	}
}

void ConnectionManager::stopTimer() {
	debug(9, "timer stopped");
	Common::TimerManager *manager = g_system->getTimerManager();
	manager->removeTimerProc(connectionsThread);
	_timerStarted = false;
}

bool ConnectionManager::hasAddedRequests() {
	_addedRequestsMutex.lock();
	bool hasNewRequests = !_addedRequests.empty();
	_addedRequestsMutex.unlock();
	return hasNewRequests;
}

void ConnectionManager::handle() {
	//lock mutex here (in case another handle() would be called before this one ends)
	_handleMutex.lock();
	++_frame;
	if (_frame % CLOUD_PERIOD == 0)
		interateRequests();
	if (_frame % CURL_PERIOD == 0)
		processTransfers();

	if (_requests.empty() && !hasAddedRequests())
		stopTimer();
	_handleMutex.unlock();
}

void ConnectionManager::interateRequests() {
	//add new requests
	_addedRequestsMutex.lock();
	for (Common::Array<RequestWithCallback>::iterator i = _addedRequests.begin(); i != _addedRequests.end(); ++i) {
		_requests.push_back(*i);
	}
	_addedRequests.clear();
	_addedRequestsMutex.unlock();

	//call handle() of all running requests (so they can do their work)
	debug(9, "handling %d request(s)", _requests.size());
	for (Common::Array<RequestWithCallback>::iterator i = _requests.begin(); i != _requests.end();) {
		Request *request = i->request;
		if (request) {
			if (request->state() == PROCESSING)
				request->handle();
			else if (request->state() == RETRY)
				request->handleRetry();
		}

		if (!request || request->state() == FINISHED) {
			delete (i->request);
			if (i->onDeleteCallback)
				(*i->onDeleteCallback)(i->request); //that's not a mistake (we're passing an address and that method knows there is no object anymore)
			_requests.erase(i);
			continue;
		}

		++i;
	}
}

void ConnectionManager::processTransfers() {
	if (!_multi) return;

	//check libcurl's transfers and notify requests of messages from queue (transfer completion or failure)
	int transfersRunning;
	curl_multi_perform(_multi, &transfersRunning);

	int messagesInQueue;
	CURLMsg *curlMsg;
	while ((curlMsg = curl_multi_info_read(_multi, &messagesInQueue))) {
		CURL *easyHandle = curlMsg->easy_handle;

		NetworkReadStream *stream;
		curl_easy_getinfo(easyHandle, CURLINFO_PRIVATE, &stream);
		if (stream)
			stream->finished();

		if (curlMsg->msg == CURLMSG_DONE) {
			debug(9, "ConnectionManager: SUCCESS (%d - %s)", curlMsg->data.result, curl_easy_strerror(curlMsg->data.result));
		} else {
			warning("ConnectionManager: FAILURE (CURLMsg (%d))", curlMsg->msg);
		}

		curl_multi_remove_handle(_multi, easyHandle);
	}
}

} // End of namespace Cloud
