package org.greenstone.gatherer.file;

import java.io.File;
import java.util.*;
import java.util.regex.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import org.greenstone.gatherer.Dictionary;
import org.greenstone.gatherer.Gatherer;
import org.greenstone.gatherer.file.FileFilter;
import org.greenstone.gatherer.file.FileNode;
import org.greenstone.gatherer.file.FileOpenActionListener;
import org.greenstone.gatherer.gui.tree.DragTree;
import org.greenstone.gatherer.util.SynchronizedTreeModelTools;

public class FileSystemModel
    extends DefaultTreeModel 
    implements TreeExpansionListener, TreeWillExpandListener {

    private int counter = 0;
    private DragTree tree;
    private FileFilter current_filter;
    private FileFilter[] filters;
    /** The filters in place for any file system model. */
    private FileFilter[] default_filters = { new FileFilter("\\..*", true), new FileFilter("metadata\\.xml", true) };

    public FileSystemModel(FileNode root) {
	super(root);
	current_filter = null;
	filters = null;
	tree = null;
	root.setModel(this);
	root.map();
    }

    public int getChildCount(Object parent) {
	return ((TreeNode)parent).getChildCount();
    }

    public FileFilter[] getFilters() {
	if(filters == null) {
	    if(current_filter != null) {
		filters = new FileFilter[default_filters.length + 1];
		filters[default_filters.length] = current_filter;
	    }
	    else {
		filters = new FileFilter[default_filters.length];
	    }
	    System.arraycopy(default_filters, 0, filters, 0, default_filters.length);
	}
	return filters;
    }
	 
    /** Retrieve the node denoted by the given tree path. Note that this isn't equivelent to saying path.lastPathComponent, as the references within the path may be stale. */
    public FileNode getNode(TreePath path) {
	///atherer.println("**** getNode(" + path + ") ****");
	FileNode current = (FileNode)root;
	// Special case for the root node. Check the first path component is the root node.
	FileNode first_node = (FileNode)path.getPathComponent(0);
	if(current.equals(first_node)) {
	    Gatherer.println("First path component matches root node.");
	    // For each path with this tree path
	    for(int i = 1; current != null && i < path.getPathCount(); i++) {
		// Retrieve the stale path
		Object stale_object = path.getPathComponent(i);
		FileNode stale_node = null;
		if(stale_object instanceof FileNode) {
		    stale_node = (FileNode) stale_object;
		}
		Gatherer.print("Searching for '" + stale_object + "': ");
		// Locate the fresh node by searching current's children. Remember to ensure that current is mapped.
		//current.unmap();
		boolean found = false;

		// First we search through the mapped children
		for(int j = 0; !found && j < current.getChildCount(); j++) {
		    FileNode child_node = (FileNode) current.getChildAt(j);
		    Gatherer.print(child_node + " ");
		    if((stale_node != null && stale_node.equals(child_node)) || stale_object.toString().equals(child_node.toString())) {
			found = true;
			current = child_node;
			Gatherer.println("Found!");
		    }
		    child_node = null;
		}
		// Failing that we search through all the children, including filtered files
		for(int j = 0; !found && j < current.size(); j++) {
		    FileNode child_node = (FileNode) current.get(j);
		    Gatherer.print(child_node + " ");
		    if((stale_node != null && stale_node.equals(child_node)) || stale_object.toString().equals(child_node.toString())) {
			found = true;
			current = child_node;
			Gatherer.println("Found!");
		    }
		    child_node = null;
		}
		// If no match is found, then set current to null and exit.
		if(!found) {
		    current = null;
		    Gatherer.println("Not Found!");
		}
		else {
		    Gatherer.println("Returning node: " + new TreePath(current.getPath()));
		}
		// Repeat as necessary
	    }
	}
	return current;
    }

    public void insertNodeInto(MutableTreeNode newChild, MutableTreeNode parent, int index) {
	///ystem.err.println("insertNodeInto(" + newChild + ", " + parent + ", " + index + ")");
	super.insertNodeInto(newChild, parent, index);
    }

    public void mapDirectory(File directory, String title) {
	FileNode node = new FileNode(directory, this, title, true);
	SynchronizedTreeModelTools.insertNodeInto(this, (FileNode)root, node);
    }


    public void refresh(TreePath path)
    {
	// Can only refresh if the model is currently being displayed in a tree
	if (tree == null) {
	    return;
	}

	// If no path is set, take the path to the root node (ie. update the whole tree)
	if (path == null) {
	    // System.err.println("\nFileSystemModel.refresh(entire tree).");
	    path = new TreePath(((FileNode) root).getPath());

	    // Make sure the root node is expanded
	    tree.expandPath(path);
	}
	// else {
	//     System.err.println("\nFileSystemModel.refresh(" + path + ").");
	// }

	// Record all the expanded paths under this node
	Enumeration old_expanded_paths_enumeration = tree.getExpandedDescendants(path);
	if (old_expanded_paths_enumeration == null) {
	    return;
	}

	// Map and unmap the node to refresh its contents
	FileNode node = (FileNode) path.getLastPathComponent();
	node.refresh();

	// Fire the appropriate event
	nodeStructureChanged(node);

	// Sort the old expanded paths by length, smallest first
	ArrayList old_expanded_paths_list = Collections.list(old_expanded_paths_enumeration);
	Collections.sort(old_expanded_paths_list, new TreePathComparator());

	// Restore each of the expanded paths
	for (int i = 0; i < old_expanded_paths_list.size(); i++) {
  	    TreePath old_expanded_path = (TreePath) old_expanded_paths_list.get(i);
	    // System.err.println("Expanded path: " + old_expanded_path);

	    // Build up the new path in the tree
	    TreePath current_path = new TreePath(path.getPath());
  	    FileNode current_node = node;

	    // Traverse the tree to find the node to expand (or find it no longer exists)
	    while (!current_path.toString().equals(old_expanded_path.toString())) {
		// System.err.println("Current path: " + current_path);

		FileNode old_expanded_node =
		    (FileNode) old_expanded_path.getPathComponent(current_path.getPathCount());
		// System.err.println("Looking for: " + old_expanded_node);

		// Find the child node that matches the next element in the path
		boolean found = false;
		for (int j = 0; j < current_node.getChildCount(); j++) {
		    FileNode child_node = (FileNode) current_node.getChildAt(j);
		    // System.err.println("Child node: " + child_node);
		    if (child_node.equals(old_expanded_node)) {
			// System.err.println("Found!");
			current_path = current_path.pathByAddingChild(child_node);
			current_node = child_node;
			found = true;
			break;
		    }
		}

		// The node was not found, so we cannot expand this path
		if (!found) {
		    // System.err.println("Not found...");
		    break;
		}
	    }

	    // If we have built up the correct path, expand it
	    if (current_path.toString().equals(old_expanded_path.toString())) {
		tree.expandPath(current_path);
	    }
	}
    }


    private class TreePathComparator
	implements Comparator {

	public int compare(Object o1, Object o2)
	{
	    return (((TreePath) o1).getPathCount() - ((TreePath) o2).getPathCount());
	}
    }


    public void setFilter(String pattern) {
  	if(pattern != null) {
  	    current_filter = new FileFilter(pattern, false);
  	}
  	else {
  	    current_filter = null;
  	}
  	filters = null;
    }

    public void setTree(DragTree tree) {
	this.tree = tree;
    }

    public String toString() {
	if(tree != null) {
	    return tree.toString();
	}
	return "FileSystemModel";
    }

    /** Called whenever an item in the tree has been collapsed. */
    public void treeCollapsed(TreeExpansionEvent event) {
	// Deallocate the affected nodes children. Don't need to do this in a swing worker, as the nodes children are currently not visable.
	TreePath path = event.getPath();
	FileNode node = (FileNode) path.getLastPathComponent();
	///ystem.err.println("Unmap: " + node);
	node.unmap();
	// Fire the appropriate event.
	nodeStructureChanged(node);
    }

    /** Called whenever an item in the tree has been expanded. */
    public void treeExpanded(TreeExpansionEvent event) {
    }

    /** Invoked whenever a node in the tree is about to be collapsed. */
    public void treeWillCollapse(TreeExpansionEvent event) 
	throws ExpandVetoException {
	// Veto the event if the user is attempting to collapse the root node (regardless of whether it is visible).
	TreePath path = event.getPath();
	if(path.getPathCount() == 1) {
	    throw new ExpandVetoException(event, "Cannot collapse root node!");
	}
    }
	 
    /** Invoked whenever a node in the tree is about to be expanded. */
    public void treeWillExpand(TreeExpansionEvent event) 
	throws ExpandVetoException {
	// Set the wait cursor.
	Gatherer.g_man.wait(true);
	// Allocate the children. Don't need to do this in a swing worker, as the nodes children are currently not visable.
	TreePath path = event.getPath();
	FileNode node = (FileNode) path.getLastPathComponent();
	///ystem.err.println("Mapping: " + node);
	node.map();
	///ystem.err.println(" -> node has " + node.getChildCount() + " children");
	nodeStructureChanged(node);
	// Restore the cursor.
	Gatherer.g_man.wait(false);
    }
}