package net.sourceforge.phpeclipse.phpeditor;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.BadPositionCategoryException;
import org.eclipse.jface.text.DefaultPositionUpdater;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IPositionUpdater;
import org.eclipse.jface.text.ITextInputListener;
import org.eclipse.jface.text.ITextListener;
import org.eclipse.jface.text.Position;
import org.eclipse.jface.text.TextEvent;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseListener;
import org.eclipse.swt.widgets.Control;

public final class PaintManager implements KeyListener, MouseListener,
		ISelectionChangedListener, ITextListener, ITextInputListener {

	static class PaintPositionUpdater extends DefaultPositionUpdater {

		/**
		 * Creates the position updater.
		 */
		protected PaintPositionUpdater(String category) {
			super(category);
		}

		/**
		 * If an insertion happens at a position's offset, the position is
		 * extended rather than shifted. Also, if something is added right
		 * behind the end of the position, the position is extended rather than
		 * kept stable.
		 */
		protected void adaptToInsert() {

			int myStart = fPosition.offset;
			int myEnd = fPosition.offset + fPosition.length;
			myEnd = Math.max(myStart, myEnd);

			int yoursStart = fOffset;
			int yoursEnd = fOffset + fReplaceLength;// - 1;
			yoursEnd = Math.max(yoursStart, yoursEnd);

			if (myEnd < yoursStart)
				return;

			if (myStart <= yoursStart)
				fPosition.length += fReplaceLength;
			else
				fPosition.offset += fReplaceLength;
		}
	};

	static class PositionManager implements IPositionManager {

		private IDocument fDocument;

		private IPositionUpdater fPositionUpdater;

		private String fCategory;

		public PositionManager() {
			fCategory = getClass().getName() + hashCode();
			fPositionUpdater = new PaintPositionUpdater(fCategory);
		}

		public void install(IDocument document) {
			fDocument = document;
			fDocument.addPositionCategory(fCategory);
			fDocument.addPositionUpdater(fPositionUpdater);
		}

		public void dispose() {
			uninstall(fDocument);
		}

		public void uninstall(IDocument document) {
			if (document == fDocument && document != null) {
				try {
					fDocument.removePositionUpdater(fPositionUpdater);
					fDocument.removePositionCategory(fCategory);
				} catch (BadPositionCategoryException x) {
					// should not happen
				}
				fDocument = null;
			}
		}

		/*
		 * @see IPositionManager#addManagedPosition(Position)
		 */
		public void addManagedPosition(Position position) {
			try {
				fDocument.addPosition(fCategory, position);
			} catch (BadPositionCategoryException x) {
				// should not happen
			} catch (BadLocationException x) {
				// should not happen
			}
		}

		/*
		 * @see IPositionManager#removeManagedPosition(Position)
		 */
		public void removeManagedPosition(Position position) {
			try {
				fDocument.removePosition(fCategory, position);
			} catch (BadPositionCategoryException x) {
				// should not happen
			}
		}
	};

	private List fPainters = new ArrayList(2);

	private PositionManager fManager;

	private ISourceViewer fSourceViewer;

	private boolean fTextChanged = false;

	private boolean fAutoRepeat = false;

	public PaintManager(ISourceViewer sourceViewer) {
		fSourceViewer = sourceViewer;
	}

	public void addPainter(IPainter painter) {
		if (!fPainters.contains(painter)) {
			fPainters.add(painter);
			if (fPainters.size() == 1)
				install();
			painter.setPositionManager(fManager);
			painter.paint(IPainter.INTERNAL);
		}
	}

	public void removePainter(IPainter painter) {
		if (fPainters.remove(painter))
			painter.setPositionManager(null);
		if (fPainters.size() == 0)
			dispose();
	}

	private void install() {

		fManager = new PositionManager();
		fManager.install(fSourceViewer.getDocument());

		fSourceViewer.addTextInputListener(this);

		ISelectionProvider provider = fSourceViewer.getSelectionProvider();
		provider.addSelectionChangedListener(this);

		fSourceViewer.addTextListener(this);

		StyledText text = fSourceViewer.getTextWidget();
		text.addKeyListener(this);
		text.addMouseListener(this);
	}

	public void dispose() {

		if (fManager != null) {
			fManager.dispose();
			fManager = null;
		}

		for (Iterator e = fPainters.iterator(); e.hasNext();)
			((IPainter) e.next()).dispose();
		fPainters.clear();

		fSourceViewer.removeTextInputListener(this);

		ISelectionProvider provider = fSourceViewer.getSelectionProvider();
		if (provider != null)
			provider.removeSelectionChangedListener(this);

		fSourceViewer.removeTextListener(this);

		StyledText text = fSourceViewer.getTextWidget();
		if (text != null && !text.isDisposed()) {
			text.removeKeyListener(this);
			text.removeMouseListener(this);
		}
	}

	private void paint(int reason) {
		for (Iterator e = fPainters.iterator(); e.hasNext();)
			((IPainter) e.next()).paint(reason);
	}

	/*
	 * @see KeyListener#keyPressed(KeyEvent)
	 */
	public void keyPressed(KeyEvent e) {
		paint(IPainter.KEY_STROKE);
	}

	/*
	 * @see KeyListener#keyReleased(KeyEvent)
	 */
	public void keyReleased(KeyEvent e) {
	}

	/*
	 * @see MouseListener#mouseDoubleClick(MouseEvent)
	 */
	public void mouseDoubleClick(MouseEvent e) {
	}

	/*
	 * @see MouseListener#mouseDown(MouseEvent)
	 */
	public void mouseDown(MouseEvent e) {
		paint(IPainter.MOUSE_BUTTON);
	}

	/*
	 * @see MouseListener#mouseUp(MouseEvent)
	 */
	public void mouseUp(MouseEvent e) {
	}

	/*
	 * @see ISelectionChangedListener#selectionChanged(SelectionChangedEvent)
	 */
	public void selectionChanged(SelectionChangedEvent event) {
		paint(IPainter.SELECTION);
	}

	/*
	 * @see ITextListener#textChanged(TextEvent)
	 */
	public void textChanged(TextEvent event) {

		if (!event.getViewerRedrawState())
			return;

		fTextChanged = true;
		Control control = fSourceViewer.getTextWidget();
		if (control != null) {
			control.getDisplay().asyncExec(new Runnable() {
				public void run() {
					if (fTextChanged && fSourceViewer != null)
						paint(IPainter.TEXT_CHANGE);
				}
			});
		}
	}

	/*
	 * @see ITextInputListener#inputDocumentAboutToBeChanged(IDocument,
	 *      IDocument)
	 */
	public void inputDocumentAboutToBeChanged(IDocument oldInput,
			IDocument newInput) {
		if (oldInput != null) {
			for (Iterator e = fPainters.iterator(); e.hasNext();)
				((IPainter) e.next()).deactivate(false);
			fManager.uninstall(oldInput);
		}
	}

	/*
	 * @see ITextInputListener#inputDocumentChanged(IDocument, IDocument)
	 */
	public void inputDocumentChanged(IDocument oldInput, IDocument newInput) {
		if (newInput != null) {
			fManager.install(newInput);
			paint(IPainter.TEXT_CHANGE);
		}
	}
}