/*
 *(c) Copyright QNX Software Systems Ltd. 2002.
 * All Rights Reserved.
 * 
 */

package org.eclipse.cdt.debug.internal.core.sourcelookup;

import java.io.IOException;
import java.io.StringReader;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.xerces.dom.DocumentImpl;
import org.eclipse.cdt.debug.core.CDebugCorePlugin;
import org.eclipse.cdt.debug.core.CDebugUtils;
import org.eclipse.cdt.debug.core.model.IStackFrameInfo;
import org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocation;
import org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator;
import org.eclipse.cdt.debug.core.sourcelookup.IProjectSourceLocation;
import org.eclipse.cdt.debug.core.sourcelookup.SourceLookupFactory;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceChangeEvent;
import org.eclipse.core.resources.IResourceChangeListener;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.debug.core.ILaunchConfiguration;
import org.eclipse.debug.core.model.IPersistableSourceLocator;
import org.eclipse.debug.core.model.IStackFrame;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
 * 
 * Default source locator.
 * 
 * @since Aug 19, 2002
 */

public class CSourceLocator implements ICSourceLocator, IPersistableSourceLocator, IResourceChangeListener
{
	private static final String SOURCE_LOCATOR_NAME = "cSourceLocator";
	private static final String DISABLED_GENERIC_PROJECT_NAME = "disabledGenericProject";
	private static final String ADDITIONAL_SOURCE_LOCATION_NAME = "additionalSourceLocation";
	private static final String SOURCE_LOCATION_NAME = "cSourceLocation";
	private static final String ATTR_CLASS = "class";
	private static final String ATTR_MEMENTO = "memento";
	private static final String ATTR_PROJECT_NAME = "projectName";
	private static final String ATTR_DUPLICATE_FILES = "duplicateFiles";

	/**
	 * The project associated with this locator.
	 */
	private IProject fProject = null;

	/**
	 * The array of source locations associated with this locator.
	 */
	private ICSourceLocation[] fSourceLocations;

	/**
	 * The array of projects referenced by main project.
	 */
	private List fReferencedProjects = new ArrayList( 10 );

	/**
	 * The flag specifies whether to search for all source elements, 
	 * or just the first match.
	 */
	private boolean fDuplicateFiles = false;

	/**
	 * Constructor for CSourceLocator.
	 */
	public CSourceLocator( IProject project )
	{
		setProject( project );
		setReferencedProjects();
		setSourceLocations( getDefaultSourceLocations() );
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.ISourceLocator#getSourceElement(IStackFrame)
	 */
	public Object getSourceElement( IStackFrame stackFrame )
	{
		if ( stackFrame != null && stackFrame.getAdapter( IStackFrameInfo.class ) != null )
		{
			return getInput( (IStackFrameInfo)stackFrame.getAdapter( IStackFrameInfo.class ) );
		}
		return null;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.ICSourceLocator#getLineNumber(IStackFrameInfo)
	 */
	public int getLineNumber( IStackFrame frame )
	{
		IStackFrameInfo info = (IStackFrameInfo)frame.getAdapter( IStackFrameInfo.class );
		return ( info != null ) ? info.getFrameLineNumber() : 0;
	}

	protected Object getInput( IStackFrameInfo info )
	{
		LinkedList list = new LinkedList();
		if ( info != null )
		{
			Object result = null;
			String fileName = info.getFile();
			if ( fileName != null && fileName.length() > 0 )
			{
				ICSourceLocation[] locations = getSourceLocations();
				for ( int i = 0; i < locations.length; ++i )
				{
					try
					{
						result = locations[i].findSourceElement( fileName );
					}
					catch( CoreException e )
					{
						// do nothing
					}
					if ( result != null )
					{
						if ( result instanceof List )
							list.addAll( (List)result );
						else
							list.add( result );
						if ( !searchForDuplicateFiles() )
							break;
					}
				}
			}
		}		
		return ( list.size() > 0 ) ? ( ( list.size() == 1 ) ? list.getFirst() : list ) : null;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.ICSourceLocator#contains(IResource)
	 */
	public boolean contains( IResource resource )
	{
		ICSourceLocation[] locations = getSourceLocations();
		for ( int i = 0; i < locations.length; ++i )
		{
			if ( resource instanceof IProject )
			{
				if ( locations[i] instanceof CProjectSourceLocation && 
					 ((CProjectSourceLocation)locations[i]).getProject().equals( resource ) )
				{
					return true;
				}
			}
			if ( resource instanceof IFile )
			{
				try
				{
					Object result = locations[i].findSourceElement( resource.getLocation().toOSString() );
					if ( result instanceof IFile && ((IFile)result).equals( resource ) )
						return true;
					if ( result instanceof List && ((List)result).contains( resource ) )
						return true;
				}
				catch( CoreException e )
				{
				}
			}
		}
		return false;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator#getSourceLocations()
	 */
	public ICSourceLocation[] getSourceLocations()
	{
		return fSourceLocations;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator#setSourceLocations(ICSourceLocation[])
	 */
	public void setSourceLocations( ICSourceLocation[] locations )
	{
		fSourceLocations = locations;
	}

	/**
	 * Returns a default collection of source locations for
	 * the given project. Default source locations consist
	 * of the given project and all of its referenced projects.
	 * 
	 * @param project a project
	 * @return a collection of source locations for all required
	 *  projects
	 * @exception CoreException 
	 */
	public static ICSourceLocation[] getDefaultSourceLocations( IProject project )
	{
		ArrayList list = new ArrayList();
		if ( project != null && project.exists() )
		{
			list.add( SourceLookupFactory.createProjectSourceLocation( project ) );
			addReferencedSourceLocations( list, project );
		}
		return (ICSourceLocation[])list.toArray( new ICSourceLocation[list.size()] );
	}

	private static void addReferencedSourceLocations( List list, IProject project )
	{
		if ( project != null )
		{
			try
			{
				IProject[] projects = project.getReferencedProjects();
				for ( int i = 0; i < projects.length; i++ )
				{
					if (  projects[i].exists() && !containsProject( list, projects[i] ) )
					{
						list.add( SourceLookupFactory.createProjectSourceLocation( projects[i] ) );
						addReferencedSourceLocations( list, projects[i] );
					}
				}
			}
			catch( CoreException e )
			{
				// do nothing
			}
		}
	}
 	
 	private static boolean containsProject( List list, IProject project )
 	{
		Iterator it = list.iterator();
		while( it.hasNext() )
		{
			CProjectSourceLocation location = (CProjectSourceLocation)it.next();
			if ( project.equals( location.getProject() ) )
				return true;
		}
		return false;
 	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator#findSourceElement(String)
	 */
	public Object findSourceElement( String fileName )
	{
		Object result = null;
		if ( fileName != null && fileName.length() > 0 )
		{
			ICSourceLocation[] locations = getSourceLocations();
			for ( int i = 0; i < locations.length; ++i )
			{
				try
				{
					result = locations[i].findSourceElement( fileName );
				}
				catch( CoreException e )
				{
					// do nothing
				}
				if ( result != null )
					break;
			}
		}
		return result;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.IPersistableSourceLocator#getMemento()
	 */
	public String getMemento() throws CoreException
	{
		Document doc = new DocumentImpl();
		Element node = doc.createElement( SOURCE_LOCATOR_NAME );
		doc.appendChild( node );

		ICSourceLocation[] locations = getSourceLocations();
		saveDisabledGenericSourceLocations( locations, doc, node );
		saveAdditionalSourceLocations( locations, doc, node );
		node.setAttribute( ATTR_DUPLICATE_FILES, new Boolean( searchForDuplicateFiles() ).toString() );
		try
		{
			return CDebugUtils.serializeDocument( doc, " " );
		}
		catch( IOException e )
		{
			abort( "Unable to create memento for C/C++ source locator.", e );
		}
		// execution will not reach here
		return null;
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.IPersistableSourceLocator#initializeDefaults(org.eclipse.debug.core.ILaunchConfiguration)
	 */
	public void initializeDefaults( ILaunchConfiguration configuration ) throws CoreException
	{
		setSourceLocations( getDefaultSourceLocations() );
	}

	/* (non-Javadoc)
	 * @see org.eclipse.debug.core.model.IPersistableSourceLocator#initializeFromMemento(java.lang.String)
	 */
	public void initializeFromMemento( 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();

			if ( !root.getNodeName().equalsIgnoreCase( SOURCE_LOCATOR_NAME ) )
			{
				abort( "Unable to restore C/C++ source locator - invalid format.", null );
			}

			List sourceLocations = new ArrayList();
			
			// Add locations based on referenced projects
			IProject project = getProject();
			if ( project != null && project.exists() && project.isOpen() )
				sourceLocations.addAll( Arrays.asList( getDefaultSourceLocations() ) );

			removeDisabledLocations( root, sourceLocations );
			addAdditionalLocations( root, sourceLocations );
			// To support old launch configuration
			addOldLocations( root, sourceLocations );
			setSourceLocations( (ICSourceLocation[])sourceLocations.toArray( new ICSourceLocation[sourceLocations.size()] ) );
			
			setSearchForDuplicateFiles( Boolean.valueOf( root.getAttribute( ATTR_DUPLICATE_FILES ) ).booleanValue() );

			return;
		}
		catch( ParserConfigurationException e )
		{
			ex = e;
		}
		catch( SAXException e )
		{
			ex = e;
		}
		catch( IOException e )
		{
			ex = e;
		}
		abort( "Exception occurred initializing source locator.", ex );
	}

	private void removeDisabledLocations( Element root, List sourceLocations ) throws CoreException
	{
		NodeList list = root.getChildNodes();
		int length = list.getLength();
		HashSet disabledProjects = new HashSet( length );
		for ( int i = 0; i < length; ++i )
		{
			Node node = list.item( i );
			short type = node.getNodeType();
			if ( type == Node.ELEMENT_NODE )
			{
				Element entry = (Element)node;
				if ( entry.getNodeName().equalsIgnoreCase( DISABLED_GENERIC_PROJECT_NAME ) )
				{
					String projectName = entry.getAttribute( ATTR_PROJECT_NAME );
					if ( isEmpty( projectName ) )
					{
						CDebugCorePlugin.log( "Unable to restore C/C++ source locator - invalid format." );
					}
					disabledProjects.add( projectName.trim() );
				}
			}
		}
		Iterator it = sourceLocations.iterator();
		while( it.hasNext() )
		{
			ICSourceLocation location = (ICSourceLocation)it.next();
			if ( location instanceof IProjectSourceLocation && 
				 disabledProjects.contains( ((IProjectSourceLocation)location).getProject().getName() ) )
				 it.remove();
		}
	}

	private void addAdditionalLocations( Element root, List sourceLocations ) throws CoreException
	{
		ClassLoader classLoader = CDebugCorePlugin.getDefault() .getDescriptor().getPluginClassLoader();

		MultiStatus status = new MultiStatus( CDebugCorePlugin.getUniqueIdentifier(), 
											  CDebugCorePlugin.INTERNAL_ERROR, 
											  "Error initializing directory source location.", 
											  null );
		NodeList list = root.getChildNodes();
		int length = list.getLength();
		for ( int i = 0; i < length; ++i )
		{
			Node node = list.item( i );
			short type = node.getNodeType();
			if ( type == Node.ELEMENT_NODE )
			{
				Element entry = (Element)node;
				if ( entry.getNodeName().equalsIgnoreCase( ADDITIONAL_SOURCE_LOCATION_NAME ) )
				{
					String className = entry.getAttribute( ATTR_CLASS );
					String data = entry.getAttribute( ATTR_MEMENTO );
					if ( isEmpty( className ) )
					{
						CDebugCorePlugin.log( "Unable to restore C/C++ source locator - invalid format." );
						continue;
					}
					Class clazz = null;
					try
					{
						clazz = classLoader.loadClass( className );
					}
					catch( ClassNotFoundException e )
					{
						CDebugCorePlugin.log( MessageFormat.format( "Unable to restore source location - class not found {0}", new String[] { className } ) );
						continue;
					}

					ICSourceLocation location = null;
					try
					{
						location = (ICSourceLocation)clazz.newInstance();
					}
					catch( IllegalAccessException e )
					{
						CDebugCorePlugin.log( "Unable to restore source location." );
						continue;
					}
					catch( InstantiationException e )
					{
						CDebugCorePlugin.log( "Unable to restore source location." );
						continue;
					}
					try
					{
						location.initializeFrom( data );
						sourceLocations.add( location );
					}
					catch( CoreException e )
					{
						status.addAll( e.getStatus() );
					}
				}
			}
		}
		if ( status.getSeverity() > IStatus.OK )
			throw new CoreException( status );
	}

	private void addOldLocations( Element root, List sourceLocations ) throws CoreException
	{
		ClassLoader classLoader = CDebugCorePlugin.getDefault() .getDescriptor().getPluginClassLoader();

		NodeList list = root.getChildNodes();
		int length = list.getLength();
		for ( int i = 0; i < length; ++i )
		{
			Node node = list.item( i );
			short type = node.getNodeType();
			if ( type == Node.ELEMENT_NODE )
			{
				Element entry = (Element)node;
				if ( entry.getNodeName().equalsIgnoreCase( SOURCE_LOCATION_NAME ) )
				{
					String className = entry.getAttribute( ATTR_CLASS );
					String data = entry.getAttribute( ATTR_MEMENTO );
					if ( isEmpty( className ) )
					{
						CDebugCorePlugin.log( "Unable to restore C/C++ source locator - invalid format." );
						continue;
					}
					Class clazz = null;
					try
					{
						clazz = classLoader.loadClass( className );
					}
					catch( ClassNotFoundException e )
					{
						CDebugCorePlugin.log( MessageFormat.format( "Unable to restore source location - class not found {0}", new String[] { className } ) );
						continue;
					}

					ICSourceLocation location = null;
					try
					{
						location = (ICSourceLocation)clazz.newInstance();
					}
					catch( IllegalAccessException e )
					{
						CDebugCorePlugin.log( "Unable to restore source location." );
						continue;
					}
					catch( InstantiationException e )
					{
						CDebugCorePlugin.log( "Unable to restore source location." );
						continue;
					}
					location.initializeFrom( data );
					if ( !sourceLocations.contains( location ) )
					{
						if ( location instanceof CProjectSourceLocation )
							((CProjectSourceLocation)location).setGenerated( isReferencedProject( ((CProjectSourceLocation)location).getProject() ) );
						sourceLocations.add( location );
					}
				}
			}
		}
	}

	/**
	 * Throws an internal error exception
	 */
	private void abort( String message, Throwable e ) throws CoreException
	{
		IStatus s = new Status( IStatus.ERROR,
								CDebugCorePlugin.getUniqueIdentifier(),
								CDebugCorePlugin.INTERNAL_ERROR,
								message,
								e );
		throw new CoreException( s );
	}


	private boolean isEmpty( String string )
	{
		return string == null || string.trim().length() == 0;
	}
	
	public void resourceChanged( IResourceChangeEvent event )
	{
		if ( event.getSource() instanceof IWorkspace && event.getDelta() != null )
		{
			IResourceDelta[] deltas = event.getDelta().getAffectedChildren();
			if ( deltas != null )
			{
				ArrayList list = new ArrayList( deltas.length );
				for ( int i = 0; i < deltas.length; ++i )
					if ( deltas[i].getResource() instanceof IProject )
						list.add( deltas[i].getResource() );
				resetSourceLocations( list );
			}
		}
	}

	private void saveDisabledGenericSourceLocations( ICSourceLocation[] locations, Document doc, Element node )
	{
		IProject project = getProject();
		if ( project != null && project.exists() && project.isOpen() )
		{
			List list = CDebugUtils.getReferencedProjects( project );
			HashSet names = new HashSet( list.size() + 1 );
			names.add( project.getName() );
			Iterator it = list.iterator();
			while( it.hasNext() )
			{
				names.add( ((IProject)it.next()).getName() );
			}
			for ( int i = 0; i < locations.length; ++i )
				if ( locations[i] instanceof IProjectSourceLocation && 
					 ((IProjectSourceLocation)locations[i]).isGeneric() )
					 names.remove( ((IProjectSourceLocation)locations[i]).getProject().getName() );
			
			it = names.iterator();
			while ( it.hasNext() )
			{
				Element child = doc.createElement( DISABLED_GENERIC_PROJECT_NAME );
				child.setAttribute( ATTR_PROJECT_NAME, (String)it.next() );
				node.appendChild( child );
			}
		}
	}

	private void saveAdditionalSourceLocations( ICSourceLocation[] locations, Document doc, Element node )
	{
		for ( int i = 0; i < locations.length; i++ )
		{
			if ( locations[i] instanceof IProjectSourceLocation && 
				 ((IProjectSourceLocation)locations[i]).isGeneric() )
				continue;
			Element child = doc.createElement( ADDITIONAL_SOURCE_LOCATION_NAME );
			child.setAttribute( ATTR_CLASS, locations[i].getClass().getName() );
			try
			{
				child.setAttribute( ATTR_MEMENTO, locations[i].getMemento() );
			}
			catch( CoreException e )
			{
				CDebugCorePlugin.log( e );
				continue;
			}
			node.appendChild( child );
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator#getProject()
	 */
	public IProject getProject()
	{
		return fProject;
	}

	protected void setProject( IProject project )
	{
		fProject = project;
	}

	private boolean isReferencedProject( IProject ref )
	{
		if ( getProject() != null )
		{
			try
			{
				return Arrays.asList( getProject().getReferencedProjects() ).contains( ref );
			}
			catch( CoreException e )
			{
				CDebugCorePlugin.log( e );
			}
		}
		return false;
	}

	private void setReferencedProjects()
	{
		fReferencedProjects.clear(); 
		fReferencedProjects = CDebugUtils.getReferencedProjects( getProject() );
	}

	protected ICSourceLocation[] getDefaultSourceLocations()
	{
		Iterator it = fReferencedProjects.iterator();
		ArrayList list = new ArrayList( fReferencedProjects.size() );
		if ( getProject() != null && getProject().exists() && getProject().isOpen() )
			list.add( SourceLookupFactory.createProjectSourceLocation( getProject() ) );
		while( it.hasNext() )
		{
			IProject project = (IProject)it.next();
			if ( project != null && project.exists() && project.isOpen() )
				list.add( SourceLookupFactory.createProjectSourceLocation( project ) );
		}
		return (ICSourceLocation[])list.toArray( new ICSourceLocation[list.size()] );
	}

	private void resetSourceLocations( List affectedProjects )
	{
		if ( affectedProjects.size() != 0 && getProject() != null )
		{
			if ( !getProject().exists() || !getProject().isOpen() )
			{
				removeGenericSourceLocations();
			}
			else
			{
				updateGenericSourceLocations( affectedProjects );
			}
		}
	}

	private void removeGenericSourceLocations()
	{
		fReferencedProjects.clear();
		ICSourceLocation[] locations = getSourceLocations();
		ArrayList newLocations = new ArrayList( locations.length ); 
		for ( int i = 0; i < locations.length; ++i )
			if ( !(locations[i] instanceof IProjectSourceLocation) || !((IProjectSourceLocation)locations[i]).isGeneric() )
				newLocations.add( locations[i] );
		setSourceLocations( (ICSourceLocation[])newLocations.toArray( new ICSourceLocation[newLocations.size()] ) );
	}

	private void updateGenericSourceLocations( List affectedProjects )
	{
		List newRefs = CDebugUtils.getReferencedProjects( getProject() );
		ICSourceLocation[] locations = getSourceLocations();
		ArrayList newLocations = new ArrayList( locations.length ); 
		for ( int i = 0; i < locations.length; ++i )
		{
			if ( !(locations[i] instanceof IProjectSourceLocation) || !((IProjectSourceLocation)locations[i]).isGeneric() )
			{
				newLocations.add( locations[i] );
			}
			else
			{
				IProject project = ((IProjectSourceLocation)locations[i]).getProject();
				if ( project.exists() && project.isOpen() )
				{
					if ( newRefs.contains( project ) || project.equals( getProject() ) )
					{
						newLocations.add( locations[i] );
						newRefs.remove( project );
					}
				}
			}
		}
		Iterator it = newRefs.iterator();
		while( it.hasNext() )
		{
			IProject project = (IProject)it.next();
			if ( !fReferencedProjects.contains( project ) )
				newLocations.add( SourceLookupFactory.createProjectSourceLocation( project ) );
		}
		fReferencedProjects = newRefs;
		setSourceLocations( (ICSourceLocation[])newLocations.toArray( new ICSourceLocation[newLocations.size()] ) );
	}

	/* (non-Javadoc)
	 * @see org.eclipse.cdt.debug.core.sourcelookup.ICSourceLocator#searchForDuplicateFiles()
	 */
	public boolean searchForDuplicateFiles()
	{
		return fDuplicateFiles;
	}

	public void setSearchForDuplicateFiles( boolean search )
	{
		fDuplicateFiles = search;
		ICSourceLocation[] locations = getSourceLocations();
		for ( int i = 0; i < locations.length; ++i )
			locations[i].setSearchForDuplicateFiles( search );
	}
}