/*******************************************************************************
 * Copyright (c) 2000, 2006 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.dialogs;

import java.util.ArrayList;
import java.util.Iterator;

import org.eclipse.core.resources.IContainer;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.jface.viewers.CheckStateChangedEvent;
import org.eclipse.jface.viewers.ICheckStateListener;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ControlEvent;
import org.eclipse.swt.events.ControlListener;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
import org.eclipse.ui.internal.ide.IIDEHelpContextIds;
import org.eclipse.ui.internal.ide.misc.CheckboxTreeAndListGroup;
import org.eclipse.ui.model.WorkbenchContentProvider;
import org.eclipse.ui.model.WorkbenchLabelProvider;

/**
 * A standard resource selection dialog which solicits a list of resources from
 * the user. The <code>getResult</code> method returns the selected resources.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 * <p>
 * Example:
 * <pre>
 * 	ResourceSelectionDialog dialog =
 *		new ResourceSelectionDialog(getShell(), rootResource, msg);
 *	dialog.setInitialSelections(selectedResources));
 *	dialog.open();
 *	return dialog.getResult();
 * </pre>
 * </p>
 */
public class ResourceSelectionDialog extends SelectionDialog {
    // the root element to populate the viewer with
    private IAdaptable root;

    // the visual selection widget group
    private CheckboxTreeAndListGroup selectionGroup;

    // constants
    private final static int SIZING_SELECTION_WIDGET_WIDTH = 400;

    private final static int SIZING_SELECTION_WIDGET_HEIGHT = 300;

    /**
     * Creates a resource selection dialog rooted at the given element.
     *
     * @param parentShell the parent shell
     * @param rootElement the root element to populate this dialog with
     * @param message the message to be displayed at the top of this dialog, or
     *    <code>null</code> to display a default message
     */
    public ResourceSelectionDialog(Shell parentShell, IAdaptable rootElement,
            String message) {
        super(parentShell);
        setTitle(IDEWorkbenchMessages.ResourceSelectionDialog_title);
        root = rootElement;
        if (message != null) {
			setMessage(message);
		} else {
			setMessage(IDEWorkbenchMessages.ResourceSelectionDialog_message);
		}
        setShellStyle(getShellStyle() | SWT.RESIZE);
    }

    /**
     * Visually checks the previously-specified elements in the container (left)
     * portion of this dialog's resource selection viewer.
     */
    private void checkInitialSelections() {
        Iterator itemsToCheck = getInitialElementSelections().iterator();

        while (itemsToCheck.hasNext()) {
            IResource currentElement = (IResource) itemsToCheck.next();

            if (currentElement.getType() == IResource.FILE) {
				selectionGroup.initialCheckListItem(currentElement);
			} else {
				selectionGroup.initialCheckTreeItem(currentElement);
			}
        }
    }


    /**
     * @param event the event
     */
    public void checkStateChanged(CheckStateChangedEvent event) {
        getOkButton().setEnabled(selectionGroup.getCheckedElementCount() > 0);
    }

    /* (non-Javadoc)
     * Method declared in Window.
     */
    protected void configureShell(Shell shell) {
        super.configureShell(shell);
        PlatformUI.getWorkbench().getHelpSystem().setHelp(shell,
				IIDEHelpContextIds.RESOURCE_SELECTION_DIALOG);
    }

    public void create() {
        super.create();
        initializeDialog();
    }

    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected Control createDialogArea(Composite parent) {
        // page group
        Composite composite = (Composite) super.createDialogArea(parent);

        //create the input element, which has the root resource
        //as its only child
        ArrayList input = new ArrayList();
        input.add(root);

        createMessageArea(composite);
        selectionGroup = new CheckboxTreeAndListGroup(composite, input,
                getResourceProvider(IResource.FOLDER | IResource.PROJECT
                        | IResource.ROOT), WorkbenchLabelProvider
                        .getDecoratingWorkbenchLabelProvider(),
                getResourceProvider(IResource.FILE), WorkbenchLabelProvider
                        .getDecoratingWorkbenchLabelProvider(), SWT.NONE,
                // since this page has no other significantly-sized
                // widgets we need to hardcode the combined widget's
                // size, otherwise it will open too small
                SIZING_SELECTION_WIDGET_WIDTH, SIZING_SELECTION_WIDGET_HEIGHT);

        composite.addControlListener(new ControlListener() {
            public void controlMoved(ControlEvent e) {
            }

            public void controlResized(ControlEvent e) {
                //Also try and reset the size of the columns as appropriate
                TableColumn[] columns = selectionGroup.getListTable()
                        .getColumns();
                for (int i = 0; i < columns.length; i++) {
                    columns[i].pack();
                }
            }
        });

        return composite;
    }

    /**
     * Returns a content provider for <code>IResource</code>s that returns 
     * only children of the given resource type.
     */
    private ITreeContentProvider getResourceProvider(final int resourceType) {
        return new WorkbenchContentProvider() {
            public Object[] getChildren(Object o) {
                if (o instanceof IContainer) {
                    IResource[] members = null;
                    try {
                        members = ((IContainer) o).members();
                    } catch (CoreException e) {
                        //just return an empty set of children
                        return new Object[0];
                    }

                    //filter out the desired resource types
                    ArrayList results = new ArrayList();
                    for (int i = 0; i < members.length; i++) {
                        //And the test bits with the resource types to see if they are what we want
                        if ((members[i].getType() & resourceType) > 0) {
                            results.add(members[i]);
                        }
                    }
                    return results.toArray();
                }
                //input element case
                if (o instanceof ArrayList) {
                    return ((ArrayList) o).toArray();
                } 
                return new Object[0];
            }
        };
    }

    /**
     * Initializes this dialog's controls.
     */
    private void initializeDialog() {
        selectionGroup.addCheckStateListener(new ICheckStateListener() {
            public void checkStateChanged(CheckStateChangedEvent event) {
                getOkButton().setEnabled(
                        selectionGroup.getCheckedElementCount() > 0);
            }
        });

        if (getInitialElementSelections().isEmpty()) {
			getOkButton().setEnabled(false);
		} else {
			checkInitialSelections();
		}
    }

    /**
     * The <code>ResourceSelectionDialog</code> implementation of this 
     * <code>Dialog</code> method builds a list of the selected resources for later 
     * retrieval by the client and closes this dialog.
     */
    protected void okPressed() {
        Iterator resultEnum = selectionGroup.getAllCheckedListItems();
        ArrayList list = new ArrayList();
        while (resultEnum.hasNext()) {
			list.add(resultEnum.next());
		}
        setResult(list);
        super.okPressed();
    }
}
