/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.externaltools.internal.ui;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

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.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.viewers.IStructuredSelection;
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.externaltools.internal.model.IExternalToolsHelpContextIds;
import org.eclipse.ui.model.WorkbenchContentProvider;
import org.eclipse.ui.model.WorkbenchLabelProvider;

/**
 * Dialog for selecting a file in the workspace. Derived from
 * org.eclipse.ui.dialogs.ResourceSelectionDialog
 */
public class FileSelectionDialog extends MessageDialog {
	// the root element to populate the viewer with
	private IAdaptable root;

	// the visual selection widget group
	private TreeAndListGroup selectionGroup;
	// constants
	private final static int SIZING_SELECTION_WIDGET_WIDTH = 400;
	private final static int SIZING_SELECTION_WIDGET_HEIGHT = 300;
	/**
	 * The file(s) selected by the user.
	 */
	private IStructuredSelection result = null;

	private boolean allowMultiselection= false;

	private Pattern fPattern;
	/**
	 * 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 FileSelectionDialog(Shell parentShell, IAdaptable rootElement, String message) {
		super(parentShell, ExternalToolsUIMessages.FileSelectionDialog_Choose_Location_1, null, message, MessageDialog.NONE, new String[] { ExternalToolsUIMessages.FileSelectionDialog_Ok_2, ExternalToolsUIMessages.FileSelectionDialog_Cancel_3}, 0);
		root = rootElement;
		setShellStyle(getShellStyle() | SWT.RESIZE);
	}

	/**
	 * Limits the files displayed in this dialog to files matching the given
	 * pattern. The string can be a filename or a regular expression containing
	 * '*' for any series of characters or '?' for any single character.
	 *
	 * @param pattern
	 *            a pattern used to filter the displayed files or <code>null</code>
	 *            to display all files. If a pattern is supplied, only files
	 *            whose names match the given pattern will be available for
	 *            selection.
	 * @param ignoreCase
	 *            if true, case is ignored. If the pattern argument is <code>null</code>,
	 *            this argument is ignored.
	 */
	public void setFileFilter(String pattern, boolean ignoreCase) {
		if (pattern != null) {
			if (ignoreCase) {
				fPattern = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);
			} else {
				fPattern = Pattern.compile(pattern);
			}
		} else {
			fPattern = null;
		}
	}

	@Override
	protected void configureShell(Shell shell) {
		super.configureShell(shell);
		PlatformUI.getWorkbench().getHelpSystem().setHelp(shell, IExternalToolsHelpContextIds.FILE_SELECTION_DIALOG);
	}

	@Override
	protected void createButtonsForButtonBar(Composite parent) {
		super.createButtonsForButtonBar(parent);
		initializeDialog();
	}

	@Override
	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
		selectionGroup =
			new TreeAndListGroup(
				composite,
				root,
				getResourceProvider(
					IResource.FOLDER | IResource.PROJECT | IResource.ROOT),
				new WorkbenchLabelProvider(),
				getResourceProvider(IResource.FILE),
				new WorkbenchLabelProvider(),
				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,
				allowMultiselection);

		composite.addControlListener(new ControlListener() {
			@Override
			public void controlMoved(ControlEvent e) {
			}
			@Override
			public void controlResized(ControlEvent e) {
				//Also try and reset the size of the columns as appropriate
				TableColumn[] columns =
					selectionGroup.getListTable().getColumns();
				for (TableColumn column : columns) {
					column.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() {
			@Override
			public Object[] getChildren(Object o) {
				if (o instanceof IContainer) {
					IResource[] members = null;
					try {
						members = ((IContainer) o).members();
						List<IResource> accessibleMembers = new ArrayList<>(members.length);
						for (IResource resource : members) {
							if (resource.isAccessible()) {
								accessibleMembers.add(resource);
							}
						}
						members = accessibleMembers.toArray(new IResource[accessibleMembers.size()]);
					} catch (CoreException e) {
						//just return an empty set of children
						return new Object[0];
					}

					//filter out the desired resource types
					ArrayList<IResource> results = new ArrayList<>();
					for (IResource member : members) {
						//And the test bits with the resource types to see if
						// they are what we want
						if ((member.getType() & resourceType) > 0) {
							if (member.getType() == IResource.FILE && fPattern != null && !fPattern.matcher(member.getName()).find()) {
								continue;
							}
							results.add(member);
						}
					}
					return results.toArray();
				}

				return new Object[0];
			}
		};
	}
	/**
	 * Initializes this dialog's controls.
	 */
	private void initializeDialog() {
		selectionGroup
			.addSelectionChangedListener(event -> getButton(IDialogConstants.OK_ID).setEnabled(
				!selectionGroup.getListTableSelection().isEmpty()));
		selectionGroup.addDoubleClickListener(event -> buttonPressed(IDialogConstants.OK_ID));

		getButton(IDialogConstants.OK_ID).setEnabled(false);
	}

	/**
	 * Returns the file the user chose or <code>null</code> if none.
	 */
	public IStructuredSelection getResult() {
		return result;
	}

	@Override
	protected void buttonPressed(int buttonId) {
		if (buttonId == IDialogConstants.OK_ID) {
			result= selectionGroup.getListTableSelection();
		}
		super.buttonPressed(buttonId);
	}
	/**
	 * Sets whether this dialog will allow multi-selection.
	 * Must be called before <code>open</code>
	 * @param allowMultiselection whether to allow multi-selection in the dialog
	 */
	public void setAllowMultiselection(boolean allowMultiselection) {
		this.allowMultiselection= allowMultiselection;
	}
}