/*
 * Olive Community Edition - Non-Linear Video Editor
 * Copyright (C) 2025 Olive CE Team
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include "playbackcache.h"

#include "node/output/viewer/viewer.h"
#include "node/project.h"
#include "node/project/sequence/sequence.h"
#include "render/diskmanager.h"

namespace olive
{

void PlaybackCache::Invalidate(const TimeRange &r)
{
	if (r.in() == r.out()) {
		qWarning() << "Tried to invalidate zero-length range";
		return;
	}

	validated_.remove(r);

	if (!passthroughs_.empty()) {
		TimeRangeList::util_remove(&passthroughs_, r);
	}

	InvalidateEvent(r);

	emit Invalidated(r);

	if (saving_enabled_) {
		SaveState();
	}
}

Node *PlaybackCache::parent() const
{
	return dynamic_cast<Node *>(QObject::parent());
}

QDir PlaybackCache::GetThisCacheDirectory() const
{
	return GetThisCacheDirectory(GetCacheDirectory(), GetUuid());
}

QDir PlaybackCache::GetThisCacheDirectory(const QString &cache_path,
										  const QUuid &cache_id)
{
	return QDir(cache_path).filePath(cache_id.toString());
}

void PlaybackCache::LoadState()
{
	QDir cache_dir = GetThisCacheDirectory();
	QFile f(cache_dir.filePath(QStringLiteral("state")));

	if (!f.exists()) {
		// No state exists, assume nothing valid
		validated_.clear();
		passthroughs_.clear();
		return;
	}

	qint64 file_time =
		f.fileTime(QFileDevice::FileModificationTime).toMSecsSinceEpoch();
	if (file_time > last_loaded_state_ && f.open(QFile::ReadOnly)) {
		QDataStream s(&f);

		uint32_t version;
		s >> version;

		LoadStateEvent(s);

		switch (version) {
		case 1: {
			int valid_count, pass_count;

			s >> valid_count;
			for (int i = 0; i < valid_count; i++) {
				int in_num, in_den, out_num, out_den;

				s >> in_num;
				s >> in_den;
				s >> out_num;
				s >> out_den;

				validated_.insert(TimeRange(rational(in_num, in_den),
											rational(out_num, out_den)));
			}

			s >> pass_count;
			for (int i = 0; i < pass_count; i++) {
				QUuid id;
				int in_num, in_den, out_num, out_den;

				s >> in_num;
				s >> in_den;
				s >> out_num;
				s >> out_den;
				s >> id;

				Passthrough p = TimeRange(rational(in_num, in_den),
										  rational(out_num, out_den));
				p.cache = id;
				passthroughs_.push_back(p);
			}

			break;
		}
		}

		f.close();

		last_loaded_state_ = file_time;
	}
}

void PlaybackCache::SaveState()
{
	if (!DiskManager::instance()) {
		return;
	}

	QDir cache_dir = GetThisCacheDirectory();
	QFile f(cache_dir.filePath(QStringLiteral("state")));
	if (validated_.isEmpty() && passthroughs_.empty()) {
		if (f.exists()) {
			f.remove();
		}
	} else {
		if (FileFunctions::DirectoryIsValid(cache_dir)) {
			if (f.open(QFile::WriteOnly)) {
				QDataStream s(&f);

				uint32_t version = 1;
				s << version;

				SaveStateEvent(s);

				// Using "int" for backwards compatibility with when we used QVector, could potentially overflow
				s << int(validated_.size());

				for (const TimeRange &r : validated_) {
					s << r.in().numerator();
					s << r.in().denominator();
					s << r.out().numerator();
					s << r.out().denominator();
				}

				// Using "int" for backwards compatibility with when we used QVector, could potentially overflow
				s << int(passthroughs_.size());

				for (const Passthrough &p : passthroughs_) {
					s << p.in().numerator();
					s << p.in().denominator();
					s << p.out().numerator();
					s << p.out().denominator();
					s << p.cache;
				}

				f.close();

				last_loaded_state_ =
					f.fileTime(QFileDevice::FileModificationTime)
						.toMSecsSinceEpoch();
			}
		}
	}
}

void PlaybackCache::Draw(QPainter *p, const rational &start, double scale,
						 const QRect &rect) const
{
	p->fillRect(rect, Qt::red);

	foreach (const TimeRange &range, GetValidatedRanges()) {
		int range_left = rect.left() + (range.in() - start).toDouble() * scale;
		if (range_left >= rect.right()) {
			continue;
		}

		int range_right =
			rect.left() + (range.out() - start).toDouble() * scale;
		if (range_right < rect.left()) {
			continue;
		}

		int adjusted_left = std::max(range_left, rect.left());
		int adjusted_right = std::min(range_right, rect.right());

		p->fillRect(adjusted_left, rect.top(), adjusted_right - adjusted_left,
					rect.height(), Qt::green);
	}
}

void PlaybackCache::SetPassthrough(PlaybackCache *cache)
{
	for (const TimeRange &r : cache->GetValidatedRanges()) {
		Passthrough p = r;
		p.cache = cache->GetUuid();
		passthroughs_.push_back(p);
	}

	passthroughs_.insert(passthroughs_.end(), cache->GetPassthroughs().begin(),
						 cache->GetPassthroughs().end());

	if (saving_enabled_) {
		SaveState();
	}
}

void PlaybackCache::InvalidateAll()
{
	Invalidate(TimeRange(0, RATIONAL_MAX));
}

void PlaybackCache::Request(ViewerOutput *context, const TimeRange &r)
{
	request_context_ = context;
	requested_.insert(r);

	emit Requested(request_context_, r);
}

void PlaybackCache::Validate(const TimeRange &r, bool signal)
{
	validated_.insert(r);

	if (signal) {
		emit Validated(r);
	}

	if (saving_enabled_) {
		SaveState();
	}
}

void PlaybackCache::InvalidateEvent(const TimeRange &)
{
}

Project *PlaybackCache::GetProject() const
{
	return Project::GetProjectFromObject(this);
}

PlaybackCache::PlaybackCache(QObject *parent)
	: QObject(parent)
	, saving_enabled_(true)
	, last_loaded_state_(0)
{
	uuid_ = QUuid::createUuid();
}

void PlaybackCache::SetUuid(const QUuid &u)
{
	uuid_ = u;

	LoadState();
}

TimeRangeList PlaybackCache::GetInvalidatedRanges(TimeRange intersecting) const
{
	TimeRangeList invalidated;

	// Prevent TimeRange from being below 0, some other behavior in Olive relies on this behavior
	// and it seemed reasonable to have safety code in here
	intersecting.set_out(qMax(rational(0), intersecting.out()));
	intersecting.set_in(qMax(rational(0), intersecting.in()));

	invalidated.insert(intersecting);

	foreach (const TimeRange &range, validated_) {
		invalidated.remove(range);
	}

	foreach (const TimeRange &range, passthroughs_) {
		invalidated.remove(range);
	}

	return invalidated;
}

bool PlaybackCache::HasInvalidatedRanges(const TimeRange &intersecting) const
{
	return !validated_.contains(intersecting);
}

QString PlaybackCache::GetCacheDirectory() const
{
	Project *project = GetProject();

	if (project) {
		return project->cache_path();
	} else {
		return DiskManager::instance()->GetDefaultCachePath();
	}
}

}