package org.eclipse.jdt.launching.sourcelookup;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import java.io.File;
import java.io.IOException;
import java.io.StringReader;
import java.text.MessageFormat;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.xerces.dom.DocumentImpl;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.PlatformObject;
import org.eclipse.core.runtime.Status;
import org.eclipse.jdt.core.IJavaModelStatusConstants;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.internal.launching.JavaLaunchConfigurationUtils;
import org.eclipse.jdt.internal.launching.LaunchingMessages;
import org.eclipse.jdt.internal.launching.LaunchingPlugin;
import org.eclipse.jdt.launching.IJavaLaunchConfigurationConstants;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
 
/**
 * Locates source elements in a directory in the local
 * file system. Returns instances of <code>LocalFileStorage</code>.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * @see IJavaSourceLocation
 * @since 2.0
 */
public class DirectorySourceLocation extends PlatformObject implements IJavaSourceLocation {

	/**
	 * The directory associated with this source location
	 */
	private File fDirectory;
	
	/**
	 * Constructs a new empty source location to be initialized from
	 * a memento.
	 */
	public DirectorySourceLocation() {
	}
		
	/**
	 * Constructs a new source location that will retrieve source
	 * elements from the given directory.
	 * 
	 * @param directory a directory
	 */
	public DirectorySourceLocation(File directory) {
		setDirectory(directory);
	}
	
	/**
	 * @see IJavaSourceLocation#findSourceElement(String)
	 */
	public Object findSourceElement(String name) throws CoreException {
		if (getDirectory() == null) {
			return null;
		}
		
		// guess at source name if an inner type
		String pathStr= name.replace('.', '/');
		int dotIndex= pathStr.lastIndexOf('/');
		int dollarIndex= pathStr.indexOf('$', dotIndex + 1);
		if (dollarIndex >= 0) {
			pathStr = pathStr.substring(0, dollarIndex);
		}		
		pathStr += ".java"; //$NON-NLS-1$
		try {
			IPath root = new Path(getDirectory().getCanonicalPath());
			root = root.append(new Path(pathStr));
			File file = root.toFile();
			if (file.exists()) {
				return new LocalFileStorage(file);
			}
		} catch (IOException e) {
			throw new JavaModelException(e, IJavaModelStatusConstants.IO_EXCEPTION);
		}
		return null;
	}

	/**
	 * Sets the directory in which source elements will
	 * be searched for.
	 * 
	 * @param directory a directory
	 */
	private void setDirectory(File directory) {
		fDirectory = directory;
	}
	
	/**
	 * Returns the directory associated with this source
	 * location.
	 * 
	 * @return directory
	 */
	public File getDirectory() {
		return fDirectory;
	}
	
	/**
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	public boolean equals(Object object) {		
		return object instanceof DirectorySourceLocation &&
			 getDirectory().equals(((DirectorySourceLocation)object).getDirectory());
	}
	
	/**
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode() {
		return getDirectory().hashCode();
	}	
	
	/**
	 * @see IJavaSourceLocation#getMemento()
	 */
	public String getMemento() throws CoreException {
		Document doc = new DocumentImpl();
		Element node = doc.createElement("directorySourceLocation"); //$NON-NLS-1$
		doc.appendChild(node);
		node.setAttribute("path", getDirectory().getAbsolutePath()); //$NON-NLS-1$
		
		try {
			return JavaLaunchConfigurationUtils.serializeDocument(doc);
		} catch (IOException e) {
			abort(MessageFormat.format(LaunchingMessages.getString("DirectorySourceLocation.Unable_to_create_memento_for_directory_source_location_{0}_1"), new String[] {getDirectory().getAbsolutePath()}), e); //$NON-NLS-1$
		}
		// execution will not reach here
		return null;
	}

	/**
	 * @see IJavaSourceLocation#initializeFrom(String)
	 */
	public void initializeFrom(String memento) throws CoreException {
		Exception ex = null;
		try {
			Element root = null;
			DocumentBuilder parser =
				DocumentBuilderFactory.newInstance().newDocumentBuilder();
			StringReader reader = new StringReader(memento);
			InputSource source = new InputSource(reader);
			root = parser.parse(source).getDocumentElement();
												
			String path = root.getAttribute("path"); //$NON-NLS-1$
			if (isEmpty(path)) {
				abort(LaunchingMessages.getString("DirectorySourceLocation.Unable_to_initialize_source_location_-_missing_directory_path_3"), null); //$NON-NLS-1$
			} else {
				File dir = new File(path);
				if (dir.exists() && dir.isDirectory()) {
					setDirectory(dir);
				} else {
					abort(MessageFormat.format(LaunchingMessages.getString("DirectorySourceLocation.Unable_to_initialize_source_location_-_directory_does_not_exist__{0}_4"), new String[] {path}), null); //$NON-NLS-1$
				}
			}
			return;
		} catch (ParserConfigurationException e) {
			ex = e;			
		} catch (SAXException e) {
			ex = e;
		} catch (IOException e) {
			ex = e;
		}
		abort(LaunchingMessages.getString("DirectorySourceLocation.Exception_occurred_initializing_source_location._5"), ex);		 //$NON-NLS-1$
	}

	private boolean isEmpty(String string) {
		return string == null || string.length() == 0;
	}
	
	/**
	 * Throws an internal error exception
	 */
	private void abort(String message, Throwable e)	throws CoreException {
		IStatus s = new Status(IStatus.ERROR, LaunchingPlugin.getUniqueIdentifier(), IJavaLaunchConfigurationConstants.ERR_INTERNAL_ERROR, message, e);
		throw new CoreException(s);		
	}
}