oak-editor/engine/codec/proxymanager.h

/*
 * Oak Video Editor - Non-Linear Video Editor
 * Copyright (C) 2026 Oak 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/>.
 */

#ifndef OAK_PROXYMANAGER_H
#define OAK_PROXYMANAGER_H

#include <QMutex>
#include <QObject>
#include <QString>
#include <QVector>

#include "task/task.h"

namespace olive
{

class ProxyTask;

class ProxyManager : public QObject {
	Q_OBJECT
public:
	static void create_instance()
	{
		if (!instance_) {
			instance_ = new ProxyManager();
		}
	}

	static void destroy_instance()
	{
		delete instance_;
		instance_ = nullptr;
	}

	static ProxyManager *instance()
	{
		return instance_;
	}

	enum ProxyState {
		k_proxy_missing,
		k_proxy_generating,
		k_proxy_ready,
		k_proxy_failed
	};

	struct ProxyParams {
		int width = 1280;
		int height = 720;
		/**
		 * @brief Source resolution divider (1 = use absolute width/height,
		 * 2/4/8 = fraction of the source resolution)
		 */
		int divider = 1;
		int version = 1;
		QString extension = QStringLiteral("mp4");
		int crf = 23;
		QString preset = QStringLiteral("veryfast");
		bool include_audio = true;
	};

	struct Proxy {
		ProxyState state = k_proxy_missing;
		QString filename;
		ProxyTask *task = nullptr;
	};

	static QString get_proxy_directory(const QString &cache_path);

	static QString get_proxy_filename(const QString &cache_path,
									const QString &source_filename,
									int stream_index,
									const ProxyParams &params);

	static QString get_working_proxy_filename(const QString &proxy_filename);

	static ProxyState get_proxy_state(const QString &proxy_filename);

	static QString proxy_state_to_string(ProxyState state);

	static ProxyState proxy_state_from_string(const QString &state);

	/**
	 * @brief Returns true if a proxy filename generated by GetProxyFilename()
	 * indicates the proxy contains audio streams
	 */
	static bool proxy_filename_has_audio(const QString &proxy_filename);

	/**
	 * @brief Builds proxy parameters from the global application config
	 */
	static ProxyParams proxy_params_from_config();

	/**
	 * @brief Locates an ffmpeg executable for proxy generation
	 *
	 * Resolution order: the explicitly configured path (if non-empty and an
	 * existing executable file), then the system PATH, then common
	 * platform-specific install locations. Returns an empty string if no
	 * executable could be found.
	 */
	static QString find_f_fmpeg_executable(const QString &configured_path);

	Proxy get_or_start_proxy(const QString &cache_path,
						  const QString &source_filename, int stream_index,
						  const ProxyParams &params);

signals:
	void proxy_ready(const QString &source_filename, int stream_index,
					const QString &proxy_filename);
	void proxy_finished(const QString &source_filename, int stream_index,
					   const QString &proxy_filename, ProxyState state);

private:
	ProxyManager() = default;

	static ProxyManager *instance_;

	struct ProxyData {
		QString source_filename;
		int stream_index = -1;
		ProxyParams params;
		ProxyTask *task = nullptr;
		QString working_filename;
		QString finished_filename;
	};

	QMutex mutex_;
	QVector<ProxyData> proxying_;

private slots:
	void proxy_task_finished(Task *task, bool succeeded);
};

}

#endif // OAK_PROXYMANAGER_H