/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation, Nokia and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Juerg Billeter, juergbi@ethz.ch - 47136 Search view should show match objects
 *     Ulrich Etter, etteru@ethz.ch - 47136 Search view should show match objects
 *     Roman Fuchs, fuchsro@ethz.ch - 47136 Search view should show match objects
 *******************************************************************************/
package com.nokia.carbide.search.system.internal.ui.text;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;

import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.Viewer;

import com.nokia.carbide.search.system.ui.text.AbstractTextSearchResult;

public class FileTreeContentProvider implements ITreeContentProvider, IFileSearchContentProvider {

	private final Object[] EMPTY_ARR= new Object[0];

	private AbstractTextSearchResult fResult;
	private FileSearchPage fPage;
	private AbstractTreeViewer fTreeViewer;
	private Map fChildrenMap;
	
	FileTreeContentProvider(FileSearchPage page, AbstractTreeViewer viewer) {
		fPage= page;
		fTreeViewer= viewer;
	}
	
	public Object[] getElements(Object inputElement) {
		Object[] children= getChildren(inputElement);
		int elementLimit= getElementLimit();
		if (elementLimit != -1 && elementLimit < children.length) {
			Object[] limitedChildren= new Object[elementLimit];
			System.arraycopy(children, 0, limitedChildren, 0, elementLimit);
			return limitedChildren;
		}
		return children;
	}
	
	private int getElementLimit() {
		return fPage.getElementLimit().intValue();
	}
	
	public void dispose() {
		// nothing to do
	}
	
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
		if (newInput instanceof FileSearchResult) {
			initialize((FileSearchResult) newInput);
		}
	}
	
	protected synchronized void initialize(AbstractTextSearchResult result) {
		fResult= result;
		fChildrenMap= new HashMap();
		if (result != null) {
			Object[] elements= result.getElements();
			for (int i= 0; i < elements.length; i++) {
				insert(elements[i],  false);
			}
		}
	}

	protected void insert(Object child, boolean refreshViewer) {

		Object parent= getParent(child);
		while (parent != null) {
			if (insertChild(parent, child)) {
				if (refreshViewer)
					fTreeViewer.add(parent, child);
			} else {
				if (refreshViewer)
					fTreeViewer.refresh(parent);
				return;
			}
			child= parent;
			parent= getParent(child);
		}
		if (insertChild(fResult, child)) {
			if (refreshViewer)
				fTreeViewer.add(fResult, child);
		}
	}

	/**
	 * returns true if the child already was a child of parent.
	 * 
	 * @param parent
	 * @param child
	 * @return Returns <code>trye</code> if the child was added
	 */
	private boolean insertChild(Object parent, Object child) {
		Set children= (Set) fChildrenMap.get(parent);
		if (children == null) {
			children= new HashSet();
			fChildrenMap.put(parent, children);
		}
		return children.add(child);
	}

	protected void remove(Object element, boolean refreshViewer) {
		// precondition here:  fResult.getMatchCount(child) <= 0
	
		if (hasChildren(element)) {
			if (refreshViewer)
				fTreeViewer.refresh(element);
		} else {
			if (fResult.getMatchCount(element) == 0) {
				fChildrenMap.remove(element);
				Object parent= getParent(element);
				if (parent != null) {
					removeFromSiblings(element, parent);
					remove(parent, refreshViewer);
				} else {
					removeFromSiblings(element, fResult);
					if (refreshViewer)
						fTreeViewer.refresh();
				}
			} else {
				if (refreshViewer) {
					fTreeViewer.refresh(element);
				}
			}
		}
	}

	private void removeFromSiblings(Object element, Object parent) {
		Set siblings= (Set) fChildrenMap.get(parent);
		if (siblings != null) {
			siblings.remove(element);
		}
	}

	public Object[] getChildren(Object parentElement) {
		Set children= (Set) fChildrenMap.get(parentElement);
		if (children == null)
			return EMPTY_ARR;
		return children.toArray();
	}

	public boolean hasChildren(Object element) {
		return getChildren(element).length > 0;
	}

	/*
	 * (non-Javadoc)
	 * @see com.nokia.carbide.search.system.internal.ui.text.IFileSearchContentProvider#elementsChanged(java.lang.Object[])
	 */
	public synchronized void elementsChanged(Object[] updatedElements) {
		for (int i= 0; i < updatedElements.length; i++) {
			if (fResult.getMatchCount(updatedElements[i]) > 0)
				insert(updatedElements[i], true);
			else
				remove(updatedElements[i], true);
		}
	}

	public void clear() {
		initialize(fResult);
		fTreeViewer.refresh();
	}

	public Object getParent(Object element) {
		if (element instanceof IProject)
			return null;
		if (element instanceof IResource) {
			IResource resource = (IResource) element;
			return resource.getParent();
		}
		return null;
	}
}
