/*
  GRANITE DATA SERVICES
  Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.

  This file is part of Granite Data Services.

  Granite Data Services is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 3 of the License, or (at your
  option) any later version.

  Granite Data Services is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

package org.granite.scan;

import java.io.File;
import java.io.IOException;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.List;

import org.jboss.vfs.VFS;
import org.jboss.vfs.VirtualFile;

/**
 * @author Franck WOLFF
 */
public class VFS3Scanner implements Scanner {

    ///////////////////////////////////////////////////////////////////////////
    // Fields.

    private final List<ScannedItemHandler> handlers = new ArrayList<ScannedItemHandler>();
    private final String marker;
    private final ClassLoader loader;

    ///////////////////////////////////////////////////////////////////////////
    // Constructors.

    public VFS3Scanner(ScannedItemHandler handler) {
        this(handler, null, Thread.currentThread().getContextClassLoader());
    }

    public VFS3Scanner(ScannedItemHandler handler, String marker) {
        this(handler, marker, Thread.currentThread().getContextClassLoader());
    }

    public VFS3Scanner(ScannedItemHandler handler, ClassLoader loader) {
        this(handler, null, loader);
    }

    public VFS3Scanner(ScannedItemHandler handler, String marker, ClassLoader loader) {
        this.marker = marker;
        this.handlers.add(handler);
        this.loader = loader;
    }

    ///////////////////////////////////////////////////////////////////////////
    // Properties.

    public String getMarker() {
        return marker;
    }

    public void addHandler(ScannedItemHandler handler) {
        if (!handlers.contains(handler))
                handlers.add(handler);
    }

    public void addHandlers(Collection<ScannedItemHandler> handlers) {
        for (ScannedItemHandler handler : handlers)
                addHandler(handler);
    }
    
    public ClassLoader getLoader() {
        return loader;
    }

    ///////////////////////////////////////////////////////////////////////////
    // Scan methods.

    public void scan() throws IOException {
        if (marker == null) {
                if (!(loader instanceof URLClassLoader))
                        throw new RuntimeException("ClassLoader used with no marker should be a URLClassLoader: " + loader);
                
            for (URL url : ((URLClassLoader)loader).getURLs()) {
                VirtualFile root = getRoot(url, 1);
                if (root != null)
                        handleRoot(null, root);
            }
        }
        else {
            for (Enumeration<URL> urlEnum = loader.getResources(marker); urlEnum.hasMoreElements(); ) {
                URL url = urlEnum.nextElement();
                VirtualFile root = getRoot(url, marker.lastIndexOf('/') > 0 ? 2 : 1);
                if (root != null)
                        handleRoot(url, root);
            }
        }
    }

    
    protected void handleRoot(URL markerUrl, VirtualFile root) throws IOException {
        VFS3FileScannedItem markerItem = null;
        
        if (markerUrl != null) {
                try {
                        VirtualFile markerFile = VFS.getChild(markerUrl);
                        markerItem = new VFS3FileScannedItem(this, null, markerFile, markerFile);
                    for (ScannedItemHandler handler : handlers) {
                        boolean skip = handler.handleMarkerItem(markerItem);
                        if (skip)
                                return;
                    }
                }
                catch (URISyntaxException e) {
                        IOException ex = new IOException("Invalid URI " + markerUrl);
                        ex.initCause(e);
                        throw ex;
                }
        }
        
        if (root.isFile()) {
            for (ScannedItemHandler handler : handlers)
                handler.handleScannedItem(new VFS3FileScannedItem(this, markerItem, root, root));
        }
        else {
                String rootPathName = root.getPathName();
                int rootPathNameLength = rootPathName.length();
                List<VirtualFile> children = root.getChildrenRecursively();
                for (VirtualFile child : children) {
                        if (child.isFile()) {
                                String name = child.getPathName();
                                // move past '/'
                                int length = rootPathNameLength;
                                if (name.charAt(length) == '/')
                                        length++;
                    for (ScannedItemHandler handler : handlers)
                        handler.handleScannedItem(new VFS3FileScannedItem(this, markerItem, root, child));
                        }
                }
        }
    }
    

    protected static VirtualFile getRoot(URL url, int parentDepth) throws IOException {
        String urlString = url.toString();
        // TODO - this should go away once we figure out why -exp.war is part of CL resources
        if (urlString.startsWith("vfs") == false)
                return null;

        int p = urlString.indexOf(":");
        String file = urlString.substring(p + 1);
        URL vfsurl = null;
        String relative;
        File fp = new File(file);

        if (fp.exists()) {
                vfsurl = fp.getParentFile().toURI().toURL();
                relative = fp.getName();
        }
        else {
                File curr = fp;
                relative = fp.getName();
                while ((curr = curr.getParentFile()) != null) {
                        if (curr.exists()) {
                                vfsurl = curr.toURI().toURL();
                                break;
                        }
                        
                        relative = curr.getName() + "/" + relative;
                }
        }

        try {
                VirtualFile top = VFS.getChild(vfsurl);
                top = top.getChild(relative);
                while (parentDepth > 0) {
                        if (top == null)
                                throw new IllegalArgumentException("Null parent: " + vfsurl + ", relative: " + relative);
                        top = top.getParent();
                        parentDepth--;
                }
        
                return top;
        }
        catch (URISyntaxException e) {
                IOException ex = new IOException("Invalid URI " + url);
                ex.initCause(e);
                throw ex;
        }
    }
}