// SPDX-FileCopyrightText: 2020 Roberto Posenato <roberto.posenato@univr.it>
//
// SPDX-License-Identifier: LGPL-3.0-or-later
package it.univr.di.cstnu.visualization;

import com.google.common.base.Supplier;
import edu.uci.ics.jung.algorithms.layout.GraphElementAccessor;
import edu.uci.ics.jung.algorithms.layout.Layout;
import edu.uci.ics.jung.graph.util.EdgeType;
import edu.uci.ics.jung.visualization.VisualizationViewer;
import edu.uci.ics.jung.visualization.control.EdgeSupport;
import edu.uci.ics.jung.visualization.control.SimpleEdgeSupport;
import edu.uci.ics.jung.visualization.control.SimpleVertexSupport;
import edu.uci.ics.jung.visualization.control.VertexSupport;

import javax.swing.*;
import java.awt.*;
import java.awt.event.InputEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Point2D;

/**
 * A plugin that can create vertices, undirected edges, and directed edges using mouse gestures. vertexSupport and edgeSupport member classes are responsible for actually creating the new graph elements and for repainting the view when changes are made.
 *
 * @param <V> generic type extending Node
 * @param <E> generic type extending Edge
 *
 * @author Tom Nelson, Roberto Posenato
 * @version $Rev$
 */
public class EditingGraphMousePlugin<V, E> extends edu.uci.ics.jung.visualization.control.AbstractGraphMousePlugin implements MouseListener, MouseMotionListener {

	private enum Creating {
		EDGE, VERTEX, UNDETERMINED
	}
	/*
	 * logger
	 */
//	static Logger LOG = Logger.getLogger(EditingGraphMousePlugin.class.getName());
	/**
	 * Mask for button
	 */
	static int shiftButtonDownMask = InputEvent.BUTTON1_DOWN_MASK | InputEvent.SHIFT_DOWN_MASK;
	/**
	 * Helper for creating a node
	 */
	protected VertexSupport<V, E> vertexSupport;
	/**
	 * Helper for creating an edge
	 */
	protected EdgeSupport<V, E> edgeSupport;
	private Creating createMode = Creating.UNDETERMINED;

	/**
	 * Creates an instance and prepares shapes for visual effects, using the default modifiers of the designed button
	 * (button 1).
	 *
	 * @param vertexFactory for creating vertices
	 * @param edgeFactory   for creating edges
	 */
	public EditingGraphMousePlugin(Supplier<V> vertexFactory, Supplier<E> edgeFactory) {
		this(shiftButtonDownMask, vertexFactory, edgeFactory);
	}

	/**
	 * Creates an instance and prepares shapes for visual effects.
	 *
	 * @param modifiers1    the mouse event modifiers to use
	 * @param vertexFactory for creating vertices
	 * @param edgeFactory   for creating edges
	 */
	private EditingGraphMousePlugin(int modifiers1, Supplier<V> vertexFactory, Supplier<E> edgeFactory) {
		super(modifiers1);
		cursor = Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
		vertexSupport = new SimpleVertexSupport<>(vertexFactory);
		edgeSupport = new SimpleEdgeSupport<>(edgeFactory);
	}

	/**
	 * {@inheritDoc} Overridden to be more flexible, and pass events with key combinations. The default responds to both ButtonOne and ButtonOne+Shift
	 */
	@Override
	public boolean checkModifiers(MouseEvent e) {
		// LOG.severe("checkModifiers: " + e.getModifiersEx() + " this.modifiers: " + this.modifiers);
		return (e.getModifiersEx() & modifiers) == modifiers;
	}

	/**
	 * @return a {@link edu.uci.ics.jung.visualization.control.EdgeSupport} object.
	 */
	public EdgeSupport<V, E> getEdgeSupport() {
		return edgeSupport;
	}

	/**
	 * {@inheritDoc} If startVertex is non-null, stretch an edge shape between startVertex and the mouse pointer to simulate edge creation
	 */
	@Override
	@SuppressWarnings("unchecked")
	public void mouseDragged(MouseEvent e) {
		if (checkModifiers(e)) {
			final VisualizationViewer<V, E> vv = (VisualizationViewer<V, E>) e.getSource();
			if (createMode == Creating.EDGE) {
				edgeSupport.midEdgeCreate(vv, e.getPoint());
			} else if (createMode == Creating.VERTEX) {
				vertexSupport.midVertexCreate(vv, e.getPoint());
			}
		}
	}

	/**
	 * @return a {@link edu.uci.ics.jung.visualization.control.VertexSupport} object.
	 */
	public VertexSupport<V, E> getVertexSupport() {
		return vertexSupport;
	}

	@Override
	public void mouseMoved(MouseEvent e) {
		// empty block
	}

	@Override
	public void mouseClicked(MouseEvent e) {
		// empty block
	}

	/**
	 * {@inheritDoc}
	 * <p>
	 * If the mouse is pressed in an empty area, create a new vertex there. If the mouse is pressed on an existing vertex, prepare to create an edge from that vertex to another.
	 */
	@Override
	public void mousePressed(MouseEvent e) {
		// LOG.severe("mousePressed: " + e);
		if (checkModifiers(e)) {
			@SuppressWarnings("unchecked")
			final VisualizationViewer<V, E> vv = (VisualizationViewer<V, E>) e.getSource();
			final Point2D p = e.getPoint();
			final GraphElementAccessor<V, E> pickSupport = vv.getPickSupport();
			if (pickSupport != null) {
				final V vertex = pickSupport.getVertex(vv.getModel().getGraphLayout(), p.getX(), p.getY());
				if (vertex != null) { // get ready to make an edge
					createMode = Creating.EDGE;
					// Graph<V,E> graph = vv.getModel().getGraphLayout().getGraph();
					// set default edge type
					final EdgeType edgeType = EdgeType.DIRECTED;// (graph instanceof DirectedGraph) ? EdgeType.DIRECTED : EdgeType.UNDIRECTED;
					// if ((e.getModifiers() & InputEvent.SHIFT_MASK) != 0) {// && graph instanceof UndirectedGraph == false) {
					// edgeType = EdgeType.DIRECTED;
					// }
					edgeSupport.startEdgeCreate(vv, vertex, e.getPoint(), edgeType);
				}
			}
		}
	}

	@Override
	public void mouseEntered(MouseEvent e) {
		final JComponent c = (JComponent) e.getSource();
		c.setCursor(cursor);
	}

	@Override
	public void mouseExited(MouseEvent e) {
		final JComponent c = (JComponent) e.getSource();
		c.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
	}

	/**
	 * {@inheritDoc}
	 * <p>
	 * If 'startVertex' is non-null, and the mouse is released over an existing vertex, create an undirected edge from startVertex to the vertex under the mouse pointer. If the shift was also pressed, create a directed edge.
	 */
	@Override
	@SuppressWarnings("unchecked")
	public void mouseReleased(MouseEvent e) {
		// LOG.severe("mouseReleased: " + e);
		// if(checkModifiers(e)) {
		final VisualizationViewer<V, E> vv = (VisualizationViewer<V, E>) e.getSource();
		final Point2D p = e.getPoint();
		final Layout<V, E> layout = vv.getGraphLayout();
		if (createMode == Creating.EDGE) {
			final GraphElementAccessor<V, E> pickSupport = vv.getPickSupport();
			V vertex = null;
			if (pickSupport != null) {
				vertex = pickSupport.getVertex(layout, p.getX(), p.getY());
			}
			edgeSupport.endEdgeCreate(vv, vertex);
		} else if (createMode == Creating.VERTEX) {
			vertexSupport.endVertexCreate(vv, e.getPoint());
		}
		// }
		createMode = Creating.UNDETERMINED;
	}

	/**
	 * Setter for the field {@code edgeSupport}.
	 *
	 * @param edgeSupport1 a {@link edu.uci.ics.jung.visualization.control.EdgeSupport} object.
	 */
	public void setEdgeSupport(EdgeSupport<V, E> edgeSupport1) {
		edgeSupport = edgeSupport1;
	}

	/**
	 * Setter for the field {@code vertexSupport}.
	 *
	 * @param vertexSupport1 a {@link edu.uci.ics.jung.visualization.control.VertexSupport} object.
	 */
	public void setVertexSupport(VertexSupport<V, E> vertexSupport1) {
		vertexSupport = vertexSupport1;
	}

	/**
	 * setEdgeFactory.
	 *
	 * @param edgeFactory1 a {@link com.google.common.base.Supplier} object.
	 */
	public void setEdgeFactory(Supplier<E> edgeFactory1) {
		edgeSupport = new SimpleEdgeSupport<>(edgeFactory1);
	}

}