/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.dltk.internal.ui.scriptview;

import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.MultiStatus;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.IProjectFragment;
import org.eclipse.dltk.internal.corext.util.Resources;
import org.eclipse.dltk.ui.DLTKUIPlugin;
import org.eclipse.dltk.ui.util.ExceptionHandler;
import org.eclipse.jface.dialogs.ProgressMonitorDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;
import org.eclipse.jface.util.TransferDragSourceListener;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSourceAdapter;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.FileTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.actions.WorkspaceModifyOperation;

/**
 * Drag support class to allow dragging of files and folder from the packages
 * view to another application.
 */
public class FileTransferDragAdapter extends DragSourceAdapter implements
		TransferDragSourceListener {

	private ISelectionProvider fProvider;

	public FileTransferDragAdapter(ISelectionProvider provider) {
		fProvider = provider;
		Assert.isNotNull(fProvider);
	}

	@Override
	public Transfer getTransfer() {
		return FileTransfer.getInstance();
	}

	@Override
	public void dragStart(DragSourceEvent event) {
		event.doit = isDragable(fProvider.getSelection());
	}

	private boolean isDragable(ISelection s) {
		if (!(s instanceof IStructuredSelection)) {
			return false;
		}
		IStructuredSelection selection = (IStructuredSelection) s;
		for (Iterator iter = selection.iterator(); iter.hasNext();) {
			Object element = iter.next();
			if (element instanceof IModelElement) {
				IModelElement jElement = (IModelElement) element;
				int type = jElement.getElementType();
				// valid elements are: roots, units and types. Don't allow
				// dragging
				// projects outside of eclipse
				if (type != IModelElement.PROJECT_FRAGMENT
						&& type != IModelElement.SOURCE_MODULE
						&& type != IModelElement.TYPE) {
					return false;
				}
				IProjectFragment root = (IProjectFragment) jElement
						.getAncestor(IModelElement.PROJECT_FRAGMENT);
				if (root != null && root.isArchive()) {
					return false;
				}
			} else if (element instanceof IProject) {
				return false;
			}
		}
		List resources = convertIntoResources(selection);
		return resources.size() == selection.size();
	}

	@Override
	public void dragSetData(DragSourceEvent event) {
		List elements = getResources();
		if (elements == null || elements.size() == 0) {
			event.data = null;
			return;
		}

		event.data = FileTransferDragAdapter.getResourceLocations(elements);
	}

	private static String[] getResourceLocations(List resources) {
		return Resources.getLocationOSStrings((IResource[]) resources
				.toArray(new IResource[resources.size()]));
	}

	@Override
	public void dragFinished(DragSourceEvent event) {
		if (!event.doit) {
			return;
		}

		if (event.detail == DND.DROP_MOVE) {
			// http://bugs.eclipse.org/bugs/show_bug.cgi?id=30543
			// handleDropMove(event);
		} else if (event.detail == DND.DROP_TARGET_MOVE) {
			handleRefresh();
		}
	}

	/* package */void handleDropMove() {
		final List elements = getResources();
		if (elements == null || elements.size() == 0) {
			return;
		}

		WorkspaceModifyOperation op = new WorkspaceModifyOperation() {
			@Override
			public void execute(IProgressMonitor monitor) throws CoreException {
				try {
					monitor.beginTask(ScriptMessages.DragAdapter_deleting,
							elements.size());
					MultiStatus status = createMultiStatus();
					Iterator iter = elements.iterator();
					while (iter.hasNext()) {
						IResource resource = (IResource) iter.next();
						try {
							monitor
									.subTask(resource.getFullPath()
											.toOSString());
							resource.delete(true, null);

						} catch (CoreException e) {
							status.add(e.getStatus());
						} finally {
							monitor.worked(1);
						}
					}
					if (!status.isOK()) {
						throw new CoreException(status);
					}
				} finally {
					monitor.done();
				}
			}
		};
		runOperation(op, true, false);
	}

	private void handleRefresh() {
		final Set roots = collectRoots(getResources());

		WorkspaceModifyOperation op = new WorkspaceModifyOperation() {
			@Override
			public void execute(IProgressMonitor monitor) throws CoreException {
				try {
					monitor.beginTask(ScriptMessages.DragAdapter_refreshing,
							roots.size());
					MultiStatus status = createMultiStatus();
					Iterator iter = roots.iterator();
					while (iter.hasNext()) {
						IResource r = (IResource) iter.next();
						try {
							r.refreshLocal(IResource.DEPTH_ONE,
									new SubProgressMonitor(monitor, 1));
						} catch (CoreException e) {
							status.add(e.getStatus());
						}
					}
					if (!status.isOK()) {
						throw new CoreException(status);
					}
				} finally {
					monitor.done();
				}
			}
		};

		runOperation(op, true, false);
	}

	protected Set collectRoots(final List elements) {
		final Set roots = new HashSet(10);

		Iterator iter = elements.iterator();
		while (iter.hasNext()) {
			IResource resource = (IResource) iter.next();
			IResource parent = resource.getParent();
			if (parent == null) {
				roots.add(resource);
			} else {
				roots.add(parent);
			}
		}
		return roots;
	}

	private List getResources() {
		ISelection s = fProvider.getSelection();
		if (!(s instanceof IStructuredSelection)) {
			return null;
		}

		return convertIntoResources((IStructuredSelection) s);
	}

	private List convertIntoResources(IStructuredSelection selection) {
		List result = new ArrayList(selection.size());
		for (Iterator iter = selection.iterator(); iter.hasNext();) {
			Object o = iter.next();
			IResource r = null;
			if (o instanceof IResource) {
				r = (IResource) o;
			} else if (o instanceof IAdaptable) {
				r = ((IAdaptable) o).getAdapter(IResource.class);
			}
			// Only add resource for which we have a location
			// in the local file system.
			if (r != null && r.getLocation() != null) {
				result.add(r);
			}
		}
		return result;
	}

	private MultiStatus createMultiStatus() {
		return new MultiStatus(DLTKUIPlugin.getPluginId(), IStatus.OK,
				ScriptMessages.DragAdapter_problem, null);
	}

	private void runOperation(IRunnableWithProgress op, boolean fork,
			boolean cancelable) {
		try {
			Shell parent = DLTKUIPlugin.getActiveWorkbenchShell();
			new ProgressMonitorDialog(parent).run(fork, cancelable, op);
		} catch (InvocationTargetException e) {
			String message = ScriptMessages.DragAdapter_problem;
			String title = ScriptMessages.DragAdapter_problemTitle;
			ExceptionHandler.handle(e, title, message);
		} catch (InterruptedException e) {
			// Do nothing. Operation has been canceled by user.
		}
	}
}