/*******************************************************************************
 * Copyright (c) 2006 Tom Schindl 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:
 *     Tom Schindl - initial API and implementation
 * Port to the D programming language:
 *     yidabu at gmail dot com  ( D China http://www.d-programming-language-china.org/ ) 
 *******************************************************************************/

module jface.snippets.Snippet047VirtualLazyTreeViewer;

import dwtx.jface.viewers.ILazyTreeContentProvider;
import dwtx.jface.viewers.LabelProvider;
import dwtx.jface.viewers.TreeViewer;
import dwtx.jface.viewers.Viewer;
import dwt.DWT;
import dwt.layout.FillLayout;
import dwt.widgets.Display;
import dwt.widgets.Shell;

import dwt.dwthelper.utils;

import tango.util.Convert;
import tango.util.container.LinkedList;


/**
 * @param args
 */
void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new FillLayout());
    new Snippet047VirtualLazyTreeViewer(shell);
    shell.open();

    while (!shell.isDisposed()) {
        if (!display.readAndDispatch())
            display.sleep();
    }

    display.dispose();

}

/**
 * A simple TreeViewer to demonstrate usage of an ILazyContentProvider.
 * 
 */
public class Snippet047VirtualLazyTreeViewer {
    alias ArrayWrapperT!(IntermediateNode)  ArrayWrapperIntermediateNode;    
    alias ArrayWrapperT!(LeafNode)  ArrayWrapperLeafNode;  
    
	private class MyContentProvider : ILazyTreeContentProvider {
		private TreeViewer viewer;
		private IntermediateNode[] elements;

		public this(TreeViewer viewer) {
			this.viewer = viewer;
		}

		public void dispose() {

		}

		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
            if(cast(ArrayWrapperIntermediateNode) newInput)
                this.elements = (cast(ArrayWrapperIntermediateNode) newInput).array;
		}

		/*
		 * (non-Javadoc)
		 * 
		 * @see dwtx.jface.viewers.ILazyTreeContentProvider#getParent(java.lang.Object)
		 */
		public Object getParent(Object element) {
			if (cast(LeafNode)element)
				return (cast(LeafNode) element).parent;
			return new ArrayWrapperIntermediateNode(elements);
		}

		/*
		 * (non-Javadoc)
		 * 
		 * @see dwtx.jface.viewers.ILazyTreeContentProvider#updateChildCount(java.lang.Object,
		 *      int)
		 */
		public void updateChildCount(Object element, int currentChildCount) {
			
			int length = 0;
			if (cast(IntermediateNode)element) {
				IntermediateNode node = cast(IntermediateNode) element;
				length =  node.children.length;
			} 
            /// TODO: fix me  access violation here
			if(element !is null && elements !is null && (cast(ArrayWrapperIntermediateNode)element) && (cast(ArrayWrapperIntermediateNode)element).array is elements)
				length = elements.length;
			viewer.setChildCount(element, length);    
		}

		/*
		 * (non-Javadoc)
		 * 
		 * @see dwtx.jface.viewers.ILazyTreeContentProvider#updateElement(java.lang.Object,
		 *      int)
		 */
		public void updateElement(Object parent, int index) {
			
			Object element;
			if (cast(IntermediateNode)parent) 
				element = (cast(IntermediateNode) parent).children[index];
			
			else
				element =  elements[index];
			viewer.replace(parent, index, element);
			updateChildCount(element, -1);
			
		}

	}

	public class LeafNode {
		public int counter;
		public IntermediateNode parent;

		public this(int counter, IntermediateNode parent) {
			this.counter = counter;
			this.parent = parent;
		}

		public String toString() {
			return "Leaf " ~ to!(String)(this.counter);
		}
	}

	public class IntermediateNode {
		public int counter;
		public LeafNode[] children;

		public this(int counter) {
			this.counter = counter;
            children = new LeafNode[0];
		}

		public String toString() {
			return "Node " ~ to!(String)(this.counter);
		}

		public void generateChildren(int i) {
			children = new LeafNode[i];
			for (int j = 0; j < i; j++) {
				children[j] = new LeafNode(j, this);
			}

		}
	}

	public this(Shell shell) {
		final TreeViewer v = new TreeViewer(shell, DWT.VIRTUAL | DWT.BORDER);
		v.setLabelProvider(new LabelProvider());
		v.setContentProvider(new MyContentProvider(v));
		v.setUseHashlookup(true);
		IntermediateNode[] model = createModel();
		v.setInput(new ArrayWrapperIntermediateNode(model));
		v.getTree().setItemCount(model.length);

	}

	private IntermediateNode[] createModel() {
		IntermediateNode[] elements = new IntermediateNode[10];

		for (int i = 0; i < 10; i++) {
			elements[i] = new IntermediateNode(i);
			elements[i].generateChildren(1000);
		}

		return elements;
	}

}