content: /*******************************************************************************
   * Copyright (c) 2000, 2008 IBM Corporation 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
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.ui.util;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.Reader;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.eclipse.core.runtime.Assert;
  import org.eclipse.core.runtime.CoreException;
  import org.eclipse.help.HelpSystem;
  import org.eclipse.help.IContext;
  import org.eclipse.help.IContext2;
  import org.eclipse.help.IHelpResource;
  import org.eclipse.wst.jsdt.internal.ui.text.html.HTML2TextReader;
  import org.eclipse.ui.PlatformUI;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.IMember;
  import org.eclipse.wst.jsdt.core.IPackageFragmentRoot;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.internal.corext.util.JavaModelUtil;
  import org.eclipse.wst.jsdt.internal.corext.util.Messages;
  import org.eclipse.wst.jsdt.internal.ui.JavaUIMessages;
  import org.eclipse.wst.jsdt.internal.ui.actions.ActionUtil;
  import org.eclipse.wst.jsdt.ui.JavaScriptElementLabels;
  import org.eclipse.wst.jsdt.ui.JavaScriptUI;
  import org.eclipse.wst.jsdt.ui.JSdocContentAccess;
  
  import com.ibm.icu.text.BreakIterator;
  
  public class JavadocHelpContext implements IContext2 {
  	
  	
  	public static void displayHelp(String contextId, Object[] selected) throws CoreException {
  		IContext context= HelpSystem.getContext(contextId);
  		if (context != null) {
  			if (selected != null && selected.length > 0) {
  				context= new JavadocHelpContext(context, selected);
  			}
  			PlatformUI.getWorkbench().getHelpSystem().displayHelp(context);
  		}
  	}
  	
  	
  	private static class JavaUIHelpResource implements IHelpResource {
  
  		private IJavaScriptElement fElement;
  		private String fUrl;
  
  		public JavaUIHelpResource(IJavaScriptElement element, String url) {
  			fElement= element;
  			fUrl= url;
  		}
  
  		public String getHref() {
  			return fUrl;
  		}
  
  		public String getLabel() {
  			String label= JavaScriptElementLabels.getTextLabel(fElement, JavaScriptElementLabels.ALL_DEFAULT | JavaScriptElementLabels.ALL_FULLY_QUALIFIED);
  			return Messages.format(JavaUIMessages.JavaUIHelp_link_label, label); 
  		}
  	}	
  	
  
  	private IHelpResource[] fHelpResources;
  	private String fText;
  	private String fTitle;
  	
  	
  	// see: https://bugs.eclipse.org/bugs/show_bug.cgi?id=85719
  	private static final boolean BUG_85719_FIXED= false; 
  
  	public JavadocHelpContext(IContext context, Object[] elements) throws JavaScriptModelException {
  		Assert.isNotNull(elements);
  		if (context instanceof IContext2)
  			fTitle= ((IContext2)context).getTitle();
  
  		List helpResources= new ArrayList();
  
  		String javadocSummary= null;
  		for (int i= 0; i < elements.length; i++) {
  			if (elements[i] instanceof IJavaScriptElement) {
  				IJavaScriptElement element= (IJavaScriptElement) elements[i];
  				// if element isn't on the build path skip it
  				if (!ActionUtil.isOnBuildPath(element))
  					continue;
  				
  				// Create Javadoc summary
  				if (BUG_85719_FIXED) {
  					if (javadocSummary == null) {
  						javadocSummary= retrieveText(element);
  						if (javadocSummary != null) {
  							String elementLabel= JavaScriptElementLabels.getTextLabel(element, JavaScriptElementLabels.ALL_DEFAULT);
  							
  							// FIXME: needs to be NLSed once the code becomes active
  							javadocSummary= "<b>Javadoc for " + elementLabel + ":</b><br>" + javadocSummary;   //$NON-NLS-1$//$NON-NLS-2$
  						}
  					} else {
  						javadocSummary= ""; // no Javadoc summary for multiple selection //$NON-NLS-1$
  					}	
  				}
  				
  				URL url= JavaScriptUI.getJSdocLocation(element, true);
  				if (url == null || doesNotExist(url)) {
  					IPackageFragmentRoot root= JavaModelUtil.getPackageFragmentRoot(element);
  					if (root != null) {
  						url= JavaScriptUI.getJSdocBaseLocation(element);
  						if (root.getKind() == IPackageFragmentRoot.K_SOURCE) {
  							element= element.getJavaScriptProject();
  						} else {
  							element= root;
  						}
  						url= JavaScriptUI.getJSdocLocation(element, false);
  					}
  				}
  				if (url != null) {
  					IHelpResource javaResource= new JavaUIHelpResource(element, getURLString(url)); 
  					helpResources.add(javaResource);
  				}
  			}
  		}
  
  		// Add static help topics
  		if (context != null) {
  			IHelpResource[] resources= context.getRelatedTopics();
  			if (resources != null) {
  				for (int j= 0; j < resources.length; j++) {
  					helpResources.add(resources[j]);
  				}
  			}
  		}
  		
  		fHelpResources= (IHelpResource[]) helpResources.toArray(new IHelpResource[helpResources.size()]);
  
  		if (context != null)
  			fText= context.getText();
  		
  		if (BUG_85719_FIXED) {
  			if (javadocSummary != null && javadocSummary.length() > 0) {
  				if (fText != null)
  					fText= context.getText() + "<br><br>" + javadocSummary; //$NON-NLS-1$
  				else
  					fText= javadocSummary;
  			}
  		}
  		
  		if (fText == null)
  			fText= "";  //$NON-NLS-1$
  		
  	}
  	
  	private String getURLString(URL url) {
  		String location= url.toExternalForm();
  		if (url.getRef() != null) {
  			int anchorIdx= location.lastIndexOf('#');
  			if (anchorIdx != -1) {
  				return location.substring(0, anchorIdx) + "?noframes=true" + location.substring(anchorIdx); //$NON-NLS-1$
  			}
  		}
  		return location + "?noframes=true"; //$NON-NLS-1$
  	}
  
  	private boolean doesNotExist(URL url) {
  		if (url.getProtocol().equals("file")) { //$NON-NLS-1$
  			File file= new File(url.getFile());
  			return !file.exists();
  		}
  		return false;
  	}
  
  	private String retrieveText(IJavaScriptElement elem) throws JavaScriptModelException {
  		if (elem instanceof IMember) {
  			Reader reader= JSdocContentAccess.getHTMLContentReader((IMember)elem, true, true);
  			if (reader != null)
  				reader= new HTML2TextReader(reader, null);
  			if (reader != null) {
  				String str= getString(reader);
  				BreakIterator breakIterator= BreakIterator.getSentenceInstance();
  				breakIterator.setText(str);
  				return str.substring(0, breakIterator.next());
  			}
  		}
  		return ""; //$NON-NLS-1$
  	}
  	
  	/**
  	 * Gets the reader content as a String
  	 */
  	private static String getString(Reader reader) {
  		StringBuffer buf= new StringBuffer();
  		char[] buffer= new char[1024];
  		int count;
  		try {
  			while ((count= reader.read(buffer)) != -1)
  				buf.append(buffer, 0, count);
  		} catch (IOException e) {
  			return null;
  		}
  		return buf.toString();
  	}
  
  	public IHelpResource[] getRelatedTopics() {
  		return fHelpResources;
  	}
  
  	public String getText() {
  		return fText;
  	}
  
  	public String getStyledText() {
  		return fText;
  	}
  
  	public String getCategory(IHelpResource topic) {
  		if (topic instanceof JavaUIHelpResource)
  			return JavaUIMessages.JavaUIHelpContext_javaHelpCategory_label; 
  
  		return null;
  	}
  	
  	/*
  	 * @see org.eclipse.help.IContext2#getTitle()
  	 * 
  	 */
  	public String getTitle() {
  		return fTitle;
  	}
  
  }
  
  