/*
 * Copyright (c) 2012, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.dart.tools.search2.internal.ui.text;

import com.google.dart.tools.search.internal.ui.SearchPlugin;
import com.google.dart.tools.search.ui.text.Match;
import com.google.dart.tools.search2.internal.ui.InternalSearchUI;
import com.google.dart.tools.search2.internal.ui.SearchMessages;

import org.eclipse.core.filebuffers.IFileBuffer;
import org.eclipse.core.filebuffers.ITextFileBuffer;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.Position;
import org.eclipse.jface.text.source.Annotation;
import org.eclipse.jface.text.source.IAnnotationModel;
import org.eclipse.jface.text.source.IAnnotationModelExtension;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class AnnotationHighlighter extends Highlighter {
  private IAnnotationModel fModel;
  private IDocument fDocument;
  private Map<Match, Annotation> fMatchesToAnnotations;

  public AnnotationHighlighter(IAnnotationModel model, IDocument document) {
    fModel = model;
    fDocument = document;
    fMatchesToAnnotations = new HashMap<Match, Annotation>();
  }

  public void addHighlights(Match[] matches) {
    HashMap<Annotation, Position> map = new HashMap<Annotation, Position>(matches.length);
    for (int i = 0; i < matches.length; i++) {
      int offset = matches[i].getOffset();
      int length = matches[i].getLength();
      if (offset >= 0 && length >= 0) {
        Position position = createPosition(matches[i]);
        if (position != null) {
          Annotation annotation = matches[i].isFiltered() ? new Annotation(
              SearchPlugin.FILTERED_SEARCH_ANNOTATION_TYPE,
              true,
              null) : new Annotation(SearchPlugin.SEARCH_ANNOTATION_TYPE, true, null);
          fMatchesToAnnotations.put(matches[i], annotation);
          map.put(annotation, position);
        }
      }
    }
    addAnnotations(map);

  }

  private Position createPosition(Match match) {
    Position position = InternalSearchUI.getInstance().getPositionTracker().getCurrentPosition(
        match);
    if (position == null)
      position = new Position(match.getOffset(), match.getLength());
    else
      // need to clone position, can't have it twice in a document.
      position = new Position(position.getOffset(), position.getLength());
    if (match.getBaseUnit() == Match.UNIT_LINE) {
      if (fDocument != null) {
        try {
          position = PositionTracker.convertToCharacterPosition(position, fDocument);
        } catch (BadLocationException e) {
          // ignore, match must be outdated
          return null;
        }
      } else {
        SearchPlugin.log(new Status(
            IStatus.ERROR,
            SearchPlugin.getID(),
            0,
            SearchMessages.AnnotationHighlighter_error_noDocument,
            null));
        return null;
      }
    }
    return position;
  }

  public void removeHighlights(Match[] matches) {
    HashSet<Annotation> annotations = new HashSet<Annotation>(matches.length);
    for (int i = 0; i < matches.length; i++) {
      Annotation annotation = fMatchesToAnnotations.remove(matches[i]);
      if (annotation != null) {
        annotations.add(annotation);
      }
    }
    removeAnnotations(annotations);
  }

  public void removeAll() {
    Collection<Annotation> matchSet = fMatchesToAnnotations.values();
    removeAnnotations(matchSet);
    fMatchesToAnnotations.clear();
  }

  private void addAnnotations(Map<Annotation, Position> annotationToPositionMap) {
    if (fModel instanceof IAnnotationModelExtension) {
      IAnnotationModelExtension ame = (IAnnotationModelExtension) fModel;
      ame.replaceAnnotations(new Annotation[0], annotationToPositionMap);
    } else {
      for (Iterator<Annotation> elements = annotationToPositionMap.keySet().iterator(); elements.hasNext();) {
        Annotation element = elements.next();
        Position p = annotationToPositionMap.get(element);
        fModel.addAnnotation(element, p);
      }
    }
  }

  /**
   * Removes annotations from the given annotation model. The default implementation works for
   * editors that implement <code>ITextEditor</code>. Subclasses may override this method.
   * 
   * @param annotations A set containing the annotations to be removed.
   * @see Annotation
   */
  private void removeAnnotations(Collection<Annotation> annotations) {
    if (fModel instanceof IAnnotationModelExtension) {
      IAnnotationModelExtension ame = (IAnnotationModelExtension) fModel;
      Annotation[] annotationArray = new Annotation[annotations.size()];
      ame.replaceAnnotations(annotations.toArray(annotationArray), Collections.EMPTY_MAP);
    } else {
      for (Iterator<Annotation> iter = annotations.iterator(); iter.hasNext();) {
        Annotation element = iter.next();
        fModel.removeAnnotation(element);
      }
    }
  }

  protected void handleContentReplaced(IFileBuffer buffer) {
    if (!(buffer instanceof ITextFileBuffer))
      return;

    ITextFileBuffer textBuffer = (ITextFileBuffer) buffer;
    if (fDocument != null && fDocument.equals(textBuffer.getDocument())) {
      Set<Match> allMatches = fMatchesToAnnotations.keySet();
      Match[] matchesCopy = allMatches.toArray(new Match[allMatches.size()]);
      removeAll();
      addHighlights(matchesCopy);
    }
  }
}