/*
 * @(#)AlignCommand.java
 *
 * Project:		JHotdraw - a GUI framework for technical drawings
 *				http://www.jhotdraw.org
 *				http://jhotdraw.sourceforge.net
 * Copyright:	© by the original author(s) and all contributors
 * License:		Lesser GNU Public License (LGPL)
 *				http://www.opensource.org/licenses/lgpl-license.html
 */

package CH.ifa.draw.standard;

import CH.ifa.draw.framework.*;
import CH.ifa.draw.util.UndoableAdapter;
import CH.ifa.draw.util.Undoable;
import java.util.*;
import java.awt.*;

/**
 * Align a selection of figures relative to each other.
 *
 * @version <$CURRENT_VERSION$>
 */
public class AlignCommand extends AbstractCommand {

	public static abstract class Alignment {
		/**
		 * align left sides
		 */
		public final static Alignment LEFTS = new Alignment("Lefts") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy(anchor.x-rr.x, 0);
			}
		};
	
		/**
		 * align centers (horizontally)
		 */
		public final static Alignment CENTERS = new Alignment("Centers") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy((anchor.x+anchor.width/2) - (rr.x+rr.width/2), 0);
			}
		};
	
		/**
		 * align right sides
		 */
		public final static Alignment RIGHTS = new Alignment("Rights") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy((anchor.x+anchor.width) - (rr.x+rr.width), 0);
			}
		};
	
		/**
		 * align tops
		 */
		public final static Alignment TOPS = new Alignment("Tops") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy(0, anchor.y-rr.y);
			}
		};
	
		/**
		 * align middles (vertically)
		 */
		public final static Alignment MIDDLES = new Alignment("Middles") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy(0, (anchor.y+anchor.height/2) - (rr.y+rr.height/2));
			}
		};
	
		/**
		 * align bottoms
		 */
		public final static Alignment BOTTOMS = new Alignment("Bottoms") {
			public void moveBy(Figure f, Rectangle anchor) {
				Rectangle rr = f.displayBox();
				f.moveBy(0, (anchor.y+anchor.height) - (rr.y+rr.height));
			}
		};
		
		private String myDescription;
		
		private Alignment(String newDescription) {
			setDescription(newDescription);
		}

		public String toString() {
			return getDescription();
		}
		
		public String getDescription() {
			return myDescription;
		}
	
		private void setDescription(String newDescription) {
			myDescription = newDescription;
		}
		
		public abstract void moveBy(Figure f, Rectangle anchor);
	}

	private Alignment myAlignment;

	/**
	 * Constructs an alignment command.
	 * @param newAlignment the alignment operation (LEFTS, CENTERS, RIGHTS, etc.)
	 * @param newDrawingEditor the DrawingEditor which manages the views
	 */
	public AlignCommand(Alignment newAlignment, DrawingEditor newDrawingEditor) {
		super(newAlignment.getDescription(), newDrawingEditor);
		setAlignment(newAlignment);
	}

	protected boolean isExecutableWithView() {
		return view().selectionCount() > 1;
	}

	public void execute() {
		super.execute();
		setUndoActivity(createUndoActivity());
		// get selected figures in the order the figures have been selected
		getUndoActivity().setAffectedFigures(new FigureEnumerator(view().selection()));
		((AlignCommand.UndoActivity)getUndoActivity()).alignAffectedFigures(getAlignment());
		view().checkDamage();
	}
	
	protected void setAlignment(Alignment newAlignment) {
		myAlignment = newAlignment;
	}
	
	public Alignment getAlignment() {
		return myAlignment;
	}

	/**
	 * Factory method for undo activity
	 */
	protected Undoable createUndoActivity() {
		return new AlignCommand.UndoActivity(view(), getAlignment());
	}

	public static class UndoActivity extends UndoableAdapter {
		private Hashtable myOriginalPoints;
		private Alignment myAppliedAlignment;
		
		public UndoActivity(DrawingView newView, Alignment newAlignment) {
			super(newView);
			myOriginalPoints = new Hashtable();
			setAppliedAlignment(newAlignment);
			setUndoable(true);
			setRedoable(true);
		}

		public boolean undo() {
			if (!super.undo()) {
				return false;
			}

			FigureEnumeration k = getAffectedFigures();
			while (k.hasMoreElements()) {
				Figure f = k.nextFigure();
				Point originalPoint = getOriginalPoint(f);
				Point currentPoint = f.displayBox().getLocation();
				// substract current lcoation to get to 0,0 and then move to original location
				f.moveBy(-currentPoint.x + originalPoint.x, 
						 -currentPoint.y + originalPoint.y);
			}
			
			return true;
		}

		public boolean redo() {
			if (!isRedoable()) {
				return false;
			}
			alignAffectedFigures(getAppliedAlignment());
			return true;
		}		

		protected void setAppliedAlignment(Alignment newAlignment) {
			myAppliedAlignment = newAlignment;
		}
		
		public Alignment getAppliedAlignment() {
			return myAppliedAlignment;
		}

		protected void addOriginalPoint(Figure f) {
			myOriginalPoints.put(f, f.displayBox().getLocation());
		}
		
		public Point getOriginalPoint(Figure f) {
			return (Point)myOriginalPoints.get(f);
		}
		
		public void alignAffectedFigures(Alignment applyAlignment) {
			FigureEnumeration fe = getAffectedFigures();
			Figure anchorFigure = fe.nextFigure();
			Rectangle r = anchorFigure.displayBox();
	
			while (fe.hasMoreElements()) {
				Figure f = fe.nextFigure();
				applyAlignment.moveBy(f, r);
			}
		}

		public void setAffectedFigures(FigureEnumeration fe) {
			// first make copy of FigureEnumeration in superclass
			super.setAffectedFigures(fe);
			// then get new FigureEnumeration of copy to save aligment
			FigureEnumeration copyFe = getAffectedFigures();
			while (copyFe.hasMoreElements()) {
				addOriginalPoint(copyFe.nextFigure());
			}
		}
	}
}