/***

  Olive - Non-Linear Video Editor
  Copyright (C) 2022 Olive Team
  Modifications Copyright (C) 2025 mikesolar

  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 VIEWERSIZER_H
#define VIEWERSIZER_H

#include <olive/core/core.h>
#include <QScrollBar>
#include <QWidget>

namespace olive
{

using namespace core;

/**
 * @brief A container widget that enforces the aspect ratio of a child widget
 *
 * Using a provided width and height, this widget calculates the aspect ratio and forces the child widget to stay
 * confined to that aspect ratio and centered within the widget.
 *
 * The aspect ratio is calculated width divided by height. If the aspect ratio is zero (either width or height == 0),
 * the widget is hidden until a valid size is provided.
 */
class ViewerSizer : public QWidget {
	Q_OBJECT
public:
	ViewerSizer(QWidget *parent = nullptr);

	/**
   * @brief Set the widget to be adjusted by this widget
   *
   * ViewerSizer takes ownership of this widget. If a widget was previously set, it is destroyed.
   */
	void SetWidget(QWidget *widget);

	QSize GetContainerSize() const;

	static constexpr int kZoomLevelCount = 10;
	static constexpr double kZoomLevels[kZoomLevelCount] = {
		0.05, 0.1, 0.25, 0.5, 0.75, 1.0, 1.5, 2.0, 4.0, 8.0
	};

public slots:
	/**
   * @brief Set resolution to use
   *
   * This is not the actual resolution of the viewer, it's used to calculate the aspect ratio
   */
	void SetChildSize(int width, int height);

	/**
   * @brief Set pixel aspect ratio
   */
	void SetPixelAspectRatio(const rational &pixel_aspect);

	/**
   * @brief Set the zoom value of the child widget
   *
   * The number is an integer percentage (100 = 100%). Set to 0 to auto-fit.
   */
	void SetZoom(double percent);
	void SetZoomAnchored(double percent, double cursor_x, double cursor_y);

	void HandDragMove(int x, int y);

	virtual bool eventFilter(QObject *watched, QEvent *event) override;

signals:
	void RequestScale(const QMatrix4x4 &matrix);

	void RequestTranslate(const QMatrix4x4 &matrix);

protected:
	/**
   * @brief Listen for resize events to ensure the child widget remains correctly sized
   */
	virtual void resizeEvent(QResizeEvent *event) override;

private:
	/**
   * @brief Main sizing function, resizes widget_ to fit aspect_ratio_ (or hides if aspect ratio is 0)
   */
	void UpdateSize();

	int GetZoomedValue(int value);

	double GetRealCurrentZoom() const;

	/**
   * @brief Reference to widget
   *
   * If this is nullptr, all sizing operations are no-ops
   */
	QWidget *widget_;

	/**
   * @brief Internal resolution values
   */
	int width_;
	int height_;

	rational pixel_aspect_;

	/**
   * @brief Internal zoom value
   */
	double zoom_;
	double current_widget_scale_;

	QScrollBar *horiz_scrollbar_;
	QScrollBar *vert_scrollbar_;

private slots:
	void ScrollBarMoved();
};

}

#endif // VIEWERSIZER_H