/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.search.ui.text;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.eclipse.search.ui.ISearchResult;
import org.eclipse.search.ui.ISearchResultListener;
import org.eclipse.search.ui.SearchResultEvent;

/**
 * An abstract base implementation for text-match based search results. This search
 * result implementation consists of a list of {@link org.eclipse.search.ui.text.Match matches}. 
 * No assumptions are made about the kind of elements these matches are reported against.
 * 
 * @since 3.0 
 */
public abstract class AbstractTextSearchResult implements ISearchResult {
	private Map fElementsToMatches;
	private List fListeners;
	private static final Match[] EMPTY_ARRAY= new Match[0];
	private MatchEvent fMatchEvent;

	/**
	 * Constructs a new <code>AbstractTextSearchResult</code>
	 */
	protected AbstractTextSearchResult() {
		fElementsToMatches= new HashMap();
		fListeners= new ArrayList();
		fMatchEvent= new MatchEvent(this);
	}

	/**
	 * Returns an array with all matches reported against the given element.
	 * 
	 * @param element the element to report matches for
	 * @return all matches reported for this element
	 * @see Match#getElement()
	 */
	public Match[] getMatches(Object element) {
		synchronized (fElementsToMatches) {
			return doGetMatches(element);
		}
	}
	
	private Match[] doGetMatches(Object element) {
		List matches= (List) fElementsToMatches.get(element);
		if (matches != null)
			return (Match[]) matches.toArray(new Match[matches.size()]);
		return EMPTY_ARRAY;
	}
	
	/**
	 * Adds a <code>Match</code> to this search result. This method does nothing if the
	 * match is already present.
	 * <p>
	 * Subclasses may extend this method.
	 * </p>
	 * 
	 * @param match the match to add
	 */
	public void addMatch(Match match) {
		boolean hasAdded= false;
		synchronized (fElementsToMatches) {
			hasAdded= doAddMatch(match);
		}
		if (hasAdded)
			fireChange(getSearchResultEvent(match, MatchEvent.ADDED));
	}
	
	/**
	 * Adds a number of Matches to this search result. This method does nothing for 
	 * matches that are already present.
	 * <p>
	 * Subclasses may extend this method.
	 * </p>
	 * @param matches the matches to add
	 */
	public void addMatches(Match[] matches) {

		Set reallyAdded= new HashSet();
		synchronized (fElementsToMatches) {
			for (int i = 0; i < matches.length; i++) {
				if (doAddMatch(matches[i]))
					reallyAdded.add(matches[i]);
			}
		}
		if (reallyAdded.size() > 0)
			fireChange(getSearchResultEvent(reallyAdded, MatchEvent.ADDED));
	}
	
	private MatchEvent getSearchResultEvent(Match match, int eventKind) {
		fMatchEvent.setKind(eventKind);
		fMatchEvent.setMatch(match);
		return fMatchEvent;
	}

	private MatchEvent getSearchResultEvent(Set matches, int eventKind) {
		fMatchEvent.setKind(eventKind);
		Match[] matchArray= new Match[matches.size()];
		matches.toArray(matchArray);
		fMatchEvent.setMatches(matchArray);
		return fMatchEvent;
	}

	private boolean doAddMatch(Match match) {
		List matches= (List) fElementsToMatches.get(match.getElement());
		if (matches == null) {
			matches= new ArrayList();
			fElementsToMatches.put(match.getElement(), matches);
		}
		if (!matches.contains(match)) {
			insertSorted(matches, match);
			return true;
		}
		return false;
	}
	
	private static void insertSorted(List matches, Match match) {
		if (matches.size() == 0) {
			matches.add(match);
			return;
		}
		int insertIndex= getInsertIndex(matches, match, 0, matches.size());
		matches.add(insertIndex, match);
	}
	
	private static int getInsertIndex(List matches, Match match, int min, int max) {
		if (min == max)
			return min;
		int middle= (min+max)/2;
		int compareResult= compare(match, (Match) matches.get(middle));
		if (compareResult == 0)
			return middle+1;
		if (compareResult > 0)
			return getInsertIndex(matches, match, min, middle);
		return getInsertIndex(matches, match, middle+1, max);
	}

	private static int compare(Match match1, Match match2) {
		int diff= match2.getOffset()-match1.getOffset();
		if (diff != 0)
			return diff;
		return match2.getLength()-match1.getLength();
	}

	/**
	 * Removes all matches from this search result.
	 * <p>
	 * Subclasses may extend this method.
	 * </p>
	 */
	public void removeAll() {
		synchronized (fElementsToMatches) {
			doRemoveAll();
		}
		fireChange(new RemoveAllEvent(this));
	}
	private void doRemoveAll() {
		fElementsToMatches.clear();
	}
	
	/**
	 * Removes the given match from this search result. This method has no
	 * effect if the match is not found.
	 * <p>
	 * Subclasses may extend this method.
	 * </p>
	 * @param match the match to remove
	 */
	public void removeMatch(Match match) {
		boolean existed= false;
		synchronized (fElementsToMatches) {
			existed= doRemoveMatch(match);
		}
		if (existed)
			fireChange(getSearchResultEvent(match, MatchEvent.REMOVED));
	}
	
	/**
	 * Removes the given matches from this search result. This method has no
	 * effect for matches that are not found
	 * <p>
	 * Subclasses may extend this method.
	 * </p>
	 * 
	 * @param matches the matches to remove
	 */
	public void removeMatches(Match[] matches) {
		Set existing= new HashSet();
		synchronized (fElementsToMatches) {
			for (int i = 0; i < matches.length; i++) {
				if (doRemoveMatch(matches[i]))
					existing.add(matches[i]);
			}
		}
		if (existing.size() > 0)
			fireChange(getSearchResultEvent(existing, MatchEvent.REMOVED));
	}

	
	private boolean doRemoveMatch(Match match) {
		boolean existed= false;
		List matches= (List) fElementsToMatches.get(match.getElement());
		if (matches != null) {
			existed= matches.remove(match);
			if (matches.isEmpty())
				fElementsToMatches.remove(match.getElement());
		}
		return existed;
	}
	/**
	 * {@inheritDoc}
	 */
	public void addListener(ISearchResultListener l) {
		synchronized (fListeners) {
			fListeners.add(l);
		}
	}
	
	/**
	 * {@inheritDoc}
	 */
	public void removeListener(ISearchResultListener l) {
		synchronized (fListeners) {
			fListeners.remove(l);
		}
	}
	
	/**
	 * Send the given <code>SearchResultEvent</code> to all registered search
	 * result listeners.
	 * 
	 * @param e the event to be sent
	 * 
	 * @see ISearchResultListener
	 */
	protected void fireChange(SearchResultEvent e) {
		HashSet copiedListeners= new HashSet();
		synchronized (fListeners) {
			copiedListeners.addAll(fListeners);
		}
		Iterator listeners= copiedListeners.iterator();
		while (listeners.hasNext()) {
			((ISearchResultListener) listeners.next()).searchResultChanged(e);
		}
	}
	/**
	 * Returns the total number of matches contained in this search result.
	 * 
	 * @return total number of matches
	 */
	public int getMatchCount() {
		int count= 0;
		synchronized (fElementsToMatches) {
			for (Iterator elements= fElementsToMatches.values().iterator(); elements.hasNext();) {
				List element= (List) elements.next();
				if (element != null)
					count+= element.size();
			}
		}
		return count;
	}
	/**
	 * Returns the number of matches reported against a given element. This is
	 * equivalent to calling <code>getMatches(element).length</code>
	 * 
	 * @param element the element to get the match count for
	 * @return the number of matches reported against the element
	 */
	public int getMatchCount(Object element) {
		List matches= (List) fElementsToMatches.get(element);
		if (matches != null)
			return matches.size();
		return 0;
	}
	/**
	 * Returns an array containing the set of all elements that matches are
	 * reported against in this search result.
	 * 
	 * @return the set of elements in this search result
	 */
	public Object[] getElements() {
		synchronized (fElementsToMatches) {
			return fElementsToMatches.keySet().toArray();
		}
	}

	/**
	 * Returns an implementation of <code>IEditorMatchAdapter</code> appropriate
	 * for this search result.
	 *  
	 * @return an appropriate adapter or <code>null</code> if none has been implemented
	 * 
	 * @see IEditorMatchAdapter
	 */
	public abstract IEditorMatchAdapter getEditorMatchAdapter();
	

	/**
	 * Returns an implementation of <code>IFileMatchAdapter</code> appropriate
	 * for this search result. 
	 * 
	 * @return an appropriate adapter or <code>null</code> if none has been implemented
	 * 
	 * @see IFileMatchAdapter
	 */
	public abstract IFileMatchAdapter getFileMatchAdapter();
}