oak-editor/app/timeline/timelineundopointer.h

/*
 * 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/>.
 */

#ifndef TIMELINEUNDOPOINTER_H
#define TIMELINEUNDOPOINTER_H

#include "node/block/gap/gap.h"
#include "node/output/track/track.h"
#include "node/output/track/tracklist.h"
#include "node/project/sequence/sequence.h"
#include "timelineundogeneral.h"
#include "timelineundoripple.h"

namespace olive
{

/**
 * @brief Performs a trim in the timeline that only affects the block and the block adjacent
 *
 * Changes the length of one block while also changing the length of the block directly adjacent
 * to compensate so that the rest of the track is unaffected.
 *
 * By default, this will only affect the length of gaps. If the adjacent needs to increase its
 * length and is not a gap, a gap will be created and inserted to fill that time. This command can
 * be set to always trim even if the adjacent clip isn't a gap with SetTrimIsARollEdit()
 */
class BlockTrimCommand : public UndoCommand {
public:
	BlockTrimCommand(Track *track, Block *block, rational new_length,
					 Timeline::MovementMode mode)
		: track_(track)
		, block_(block)
		, new_length_(new_length)
		, mode_(mode)
		, deleted_adjacent_command_(nullptr)
		, trim_is_a_roll_edit_(false)
	{
	}

	virtual ~BlockTrimCommand() override
	{
		delete deleted_adjacent_command_;
	}

	virtual Project *GetRelevantProject() const override
	{
		return track_->project();
	}

	/**
   * @brief Set this if the trim should always affect the adjacent clip and not create a gap
   */
	void SetTrimIsARollEdit(bool e)
	{
		trim_is_a_roll_edit_ = e;
	}

	/**
   * @brief Set whether adjacent blocks set to zero length should be removed from the whole graph
   *
   * If an adjacent block's length is set to 0, it's automatically removed from the track. By
   * default it also gets removed from the whole graph. Set this to FALSE to disable that
   * functionality.
   */
	void SetRemoveZeroLengthFromGraph(bool e)
	{
		remove_block_from_graph_ = e;
	}

protected:
	virtual void prepare() override;
	virtual void redo() override;
	virtual void undo() override;

private:
	bool doing_nothing_;
	rational trim_diff_;

	Track *track_;
	Block *block_;
	rational old_length_;
	rational new_length_;
	Timeline::MovementMode mode_;

	Block *adjacent_;
	bool needs_adjacent_;
	bool we_created_adjacent_;
	bool we_removed_adjacent_;
	UndoCommand *deleted_adjacent_command_;

	bool trim_is_a_roll_edit_;
	bool remove_block_from_graph_;

	QObject memory_manager_;
};

class TrackSlideCommand : public UndoCommand {
public:
	TrackSlideCommand(Track *track, const QList<Block *> &moving_blocks,
					  Block *in_adjacent, Block *out_adjacent,
					  const rational &movement)
		: track_(track)
		, blocks_(moving_blocks)
		, movement_(movement)
		, we_removed_in_adjacent_(false)
		, in_adjacent_(in_adjacent)
		, in_adjacent_remove_command_(nullptr)
		, we_removed_out_adjacent_(false)
		, out_adjacent_(out_adjacent)
		, out_adjacent_remove_command_(nullptr)
	{
		Q_ASSERT(!movement_.isNull());
	}

	virtual ~TrackSlideCommand() override
	{
		delete in_adjacent_remove_command_;
		delete out_adjacent_remove_command_;
	}

	virtual Project *GetRelevantProject() const override
	{
		return track_->project();
	}

protected:
	virtual void prepare() override;

	virtual void redo() override;

	virtual void undo() override;

private:
	Track *track_;
	QList<Block *> blocks_;
	rational movement_;

	bool we_created_in_adjacent_;
	bool we_removed_in_adjacent_;
	Block *in_adjacent_;
	UndoCommand *in_adjacent_remove_command_;
	bool we_created_out_adjacent_;
	bool we_removed_out_adjacent_;
	Block *out_adjacent_;
	UndoCommand *out_adjacent_remove_command_;

	QObject memory_manager_;
};

/**
 * @brief Destructively places `block` at the in point `start`
 *
 * The Block is guaranteed to be placed at the starting point specified. If there are Blocks in this area, they are
 * either trimmed or removed to make space for this Block. Additionally, if the Block is placed beyond the end of
 * the Sequence, a GapBlock is inserted to compensate.
 */
class TrackPlaceBlockCommand : public UndoCommand {
public:
	TrackPlaceBlockCommand(TrackList *timeline, int track, Block *block,
						   rational in)
		: timeline_(timeline)
		, track_index_(track)
		, in_(in)
		, gap_(nullptr)
		, insert_(block)
		, ripple_remove_command_(nullptr)
	{
	}

	virtual ~TrackPlaceBlockCommand() override;

	virtual Project *GetRelevantProject() const override
	{
		return timeline_->parent()->project();
	}

protected:
	virtual void redo() override;

	virtual void undo() override;

private:
	TrackList *timeline_;
	int track_index_;
	rational in_;
	GapBlock *gap_;
	Block *insert_;
	QVector<TimelineAddTrackCommand *> add_track_commands_;
	QObject memory_manager_;
	TrackRippleRemoveAreaCommand *ripple_remove_command_;
};

}

#endif // TIMELINEUNDOPOINTER_H