/* Copyright 2013-2018 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "NetJob.h"
#include "Download.h"

#include <QDebug>

void NetJob::partSucceeded(int index)
{
	// do progress. all slots are 1 in size at least
	auto &slot = parts_progress[index];
	partProgress(index, slot.total_progress, slot.total_progress);

	m_doing.remove(index);
	m_done.insert(index);
	downloads[index].get()->disconnect(this);
	startMoreParts();
}

void NetJob::partFailed(int index)
{
	m_doing.remove(index);
	auto &slot = parts_progress[index];
	if (slot.failures == 3)
	{
		m_failed.insert(index);
	}
	else
	{
		slot.failures++;
		m_todo.enqueue(index);
	}
	downloads[index].get()->disconnect(this);
	startMoreParts();
}

void NetJob::partAborted(int index)
{
	m_aborted = true;
	m_doing.remove(index);
	m_failed.insert(index);
	downloads[index].get()->disconnect(this);
	startMoreParts();
}

void NetJob::partProgress(int index, qint64 bytesReceived, qint64 bytesTotal)
{
	auto &slot = parts_progress[index];
	slot.current_progress = bytesReceived;
	slot.total_progress = bytesTotal;

	int done = m_done.size();
	int doing = m_doing.size();
	int all = parts_progress.size();

	qint64 bytesAll = 0;
	qint64 bytesTotalAll = 0;
	for(auto & partIdx: m_doing)
	{
		auto part = parts_progress[partIdx];
		// do not count parts with unknown/nonsensical total size
		if(part.total_progress <= 0)
		{
			continue;
		}
		bytesAll += part.current_progress;
		bytesTotalAll += part.total_progress;
	}

	qint64 inprogress = (bytesTotalAll == 0) ? 0 : (bytesAll * 1000) / bytesTotalAll;
	auto current = done * 1000 + doing * inprogress;
	auto current_total = all * 1000;
	// HACK: make sure it never jumps backwards.
	// FAIL: This breaks if the size is not known (or is it something else?) and jumps to 1000, so if it is 1000 reset it to inprogress
	if(m_current_progress == 1000) {
		m_current_progress = inprogress;
	}
	if(m_current_progress > current)
	{
		current = m_current_progress;
	}
	m_current_progress = current;
	setProgress(current, current_total);
}

void NetJob::executeTask()
{
	// hack that delays early failures so they can be caught easier
	QMetaObject::invokeMethod(this, "startMoreParts", Qt::QueuedConnection);
}

void NetJob::startMoreParts()
{
	if(!isRunning())
	{
		// this actually makes sense. You can put running downloads into a NetJob and then not start it until much later.
		return;
	}
	// OK. We are actively processing tasks, proceed.
	// Check for final conditions if there's nothing in the queue.
	if(!m_todo.size())
	{
		if(!m_doing.size())
		{
			if(!m_failed.size())
			{
				emitSucceeded();
			}
			else if(m_aborted)
			{
				emitAborted();
			}
			else
			{
				emitFailed(tr("Job '%1' failed to process:\n%2").arg(objectName()).arg(getFailedFiles().join("\n")));
			}
		}
		return;
	}
	// There's work to do, try to start more parts.
	while (m_doing.size() < 6)
	{
		if(!m_todo.size())
			return;
		int doThis = m_todo.dequeue();
		m_doing.insert(doThis);
		auto part = downloads[doThis];
		// connect signals :D
		connect(part.get(), SIGNAL(succeeded(int)), SLOT(partSucceeded(int)));
		connect(part.get(), SIGNAL(failed(int)), SLOT(partFailed(int)));
		connect(part.get(), SIGNAL(aborted(int)), SLOT(partAborted(int)));
		connect(part.get(), SIGNAL(netActionProgress(int, qint64, qint64)),
				SLOT(partProgress(int, qint64, qint64)));
		part->start();
	}
}


QStringList NetJob::getFailedFiles()
{
	QStringList failed;
	for (auto index: m_failed)
	{
		failed.push_back(downloads[index]->url().toString());
	}
	failed.sort();
	return failed;
}

bool NetJob::canAbort() const
{
	bool canFullyAbort = true;
	// can abort the waiting?
	for(auto index: m_todo)
	{
		auto part = downloads[index];
		canFullyAbort &= part->canAbort();
	}
	// can abort the active?
	for(auto index: m_doing)
	{
		auto part = downloads[index];
		canFullyAbort &= part->canAbort();
	}
	return canFullyAbort;
}

bool NetJob::abort()
{
	bool fullyAborted = true;
	// fail all waiting
	m_failed.unite(m_todo.toSet());
	m_todo.clear();
	// abort active
	auto toKill = m_doing.toList();
	for(auto index: toKill)
	{
		auto part = downloads[index];
		fullyAborted &= part->abort();
	}
	return fullyAborted;
}

bool NetJob::addNetAction(NetActionPtr action)
{
	action->m_index_within_job = downloads.size();
	downloads.append(action);
	part_info pi;
	parts_progress.append(pi);
	partProgress(parts_progress.count() - 1, action->currentProgress(), action->totalProgress());

	if(action->isRunning())
	{
		connect(action.get(), SIGNAL(succeeded(int)), SLOT(partSucceeded(int)));
		connect(action.get(), SIGNAL(failed(int)), SLOT(partFailed(int)));
		connect(action.get(), SIGNAL(netActionProgress(int, qint64, qint64)), SLOT(partProgress(int, qint64, qint64)));
	}
	else
	{
		m_todo.append(parts_progress.size() - 1);
	}
	return true;
}