/*******************************************************************************
 *  Copyright (c) 2000, 2013 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
 *     Wind River Systems - refactored on top of VirtualTreeModelViewer
 *******************************************************************************/
package org.eclipse.debug.internal.ui.viewers.model;


import java.lang.reflect.InvocationTargetException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.debug.internal.core.IInternalDebugCoreConstants;
import org.eclipse.debug.internal.ui.DebugUIPlugin;
import org.eclipse.debug.internal.ui.actions.AbstractDebugActionDelegate;
import org.eclipse.debug.internal.ui.actions.ActionMessages;
import org.eclipse.debug.internal.ui.viewers.model.provisional.ILabelUpdate;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IModelDelta;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IVirtualItemListener;
import org.eclipse.debug.internal.ui.viewers.model.provisional.IVirtualItemValidator;
import org.eclipse.debug.internal.ui.viewers.model.provisional.ModelDelta;
import org.eclipse.debug.internal.ui.viewers.model.provisional.TreeModelViewer;
import org.eclipse.debug.internal.ui.viewers.model.provisional.VirtualItem;
import org.eclipse.debug.internal.ui.viewers.model.provisional.VirtualItem.Index;
import org.eclipse.debug.internal.ui.viewers.model.provisional.VirtualTreeModelViewer;
import org.eclipse.debug.ui.IDebugView;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.dialogs.ProgressMonitorDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTError;
import org.eclipse.swt.dnd.Clipboard;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class VirtualCopyToClipboardActionDelegate extends AbstractDebugActionDelegate {

	private TreeModelViewer fClientViewer;
	private static final String TAB = "\t"; //$NON-NLS-1$

	/**
	 * Virtual viewer listener.  It tracks progress of copy and increments
	 * the progress monitor.
	 */
	private class VirtualViewerListener implements ILabelUpdateListener, IVirtualItemListener {

		VirtualTreeModelViewer fVirtualViewer;
		IProgressMonitor fProgressMonitor;
		int fSelectionRootDepth;
		Set<VirtualItem> fItemsToUpdate;

		@Override
		public void labelUpdateStarted(ILabelUpdate update) {}
		@Override
		public void labelUpdateComplete(ILabelUpdate update) {
			VirtualItem updatedItem = fVirtualViewer.findItem(update.getElementPath());
			if (fItemsToUpdate.remove(updatedItem)) {
				incrementProgress(1);
			}
		}
		@Override
		public void labelUpdatesBegin() {
		}
		@Override
		public void labelUpdatesComplete() {
		}

		@Override
		public void revealed(VirtualItem item) {
		}

		@Override
		public void disposed(VirtualItem item) {
			if (fItemsToUpdate.remove(item)) {
				incrementProgress(1);
			}
		}

		private void incrementProgress(int count) {
			IProgressMonitor pm;
			synchronized (VirtualCopyToClipboardActionDelegate.this) {
				pm = fProgressMonitor;
			}
			if (pm != null) {
				pm.worked(count);
				if (fItemsToUpdate.isEmpty()) {
					pm.done();
				}
			}
		}
	}

	/**
	 * @see AbstractDebugActionDelegate#initialize(IAction, ISelection)
	 */
	@Override
	protected boolean initialize(IAction action, ISelection selection) {
		if (!isInitialized()) {
			IDebugView adapter= getView().getAdapter(IDebugView.class);
			if (adapter != null) {
				if (adapter.getViewer() instanceof TreeModelViewer) {
					setViewer((TreeModelViewer) adapter.getViewer());
				}
				adapter.setAction(getActionId(), action);
			}
			return super.initialize(action, selection);
		}
		return false;
	}

	protected String getActionId() {
		return IDebugView.COPY_ACTION;
	}

	/**
	 * Appends the representation of the specified element (using the label provider and indent)
	 * to the buffer.  For elements down to stack frames, children representations
	 * are append to the buffer as well.
	 * @param item Item to append to string
	 * @param buffer String buffer for copy text.
	 * @param indent Current indentation in tree text.
	 */
	protected void append(VirtualItem item, StringBuilder buffer, int indent) {
		for (int i= 0; i < indent; i++) {
			buffer.append(TAB);
		}
		String[] labels = (String[]) item.getData(VirtualItem.LABEL_KEY);
		if(labels != null && labels.length > 0) {
			for (String label : labels) {
				String text = trimLabel(label);
				if (text != null && !text.equals(IInternalDebugCoreConstants.EMPTY_STRING)) {
					buffer.append(text);
				}
				buffer.append(TAB);
			}
			buffer.append(System.lineSeparator());
		}
	}

	/**
	 * Trims the given String. Subclasses might want to cut off additional
	 * things from the given label retrieved by the label provider by overriding
	 * this method.
	 *
	 * @param label the label that should be trimmed (might be null)
	 * @return the trimmed label or null if label is null
	 */
	protected String trimLabel(String label) {
		if (label == null) {
			return null;
		}
		return label.trim();
	}

	private static class ItemsToCopyVirtualItemValidator implements IVirtualItemValidator {

		Set<VirtualItem> fItemsToCopy = Collections.EMPTY_SET;
		Set<VirtualItem> fItemsToValidate = Collections.EMPTY_SET;

		@Override
		public boolean isItemVisible(VirtualItem item) {
			return fItemsToValidate.contains(item);
		}

		@Override
		public void showItem(VirtualItem item) {
		}

		void setItemsToCopy(Set<VirtualItem> itemsToCopy) {
			fItemsToCopy = itemsToCopy;
			fItemsToValidate = new HashSet<>();
			for (VirtualItem itemToCopy : itemsToCopy) {
				while (itemToCopy != null) {
					fItemsToValidate.add(itemToCopy);
					itemToCopy = itemToCopy.getParent();
				}
			}
		}
	}

	private VirtualTreeModelViewer initVirtualViewer(TreeModelViewer clientViewer, VirtualViewerListener listener, ItemsToCopyVirtualItemValidator validator) {
		Object input = clientViewer.getInput();
		ModelDelta stateDelta = new ModelDelta(input, IModelDelta.NO_CHANGE);
		clientViewer.saveElementState(TreePath.EMPTY, stateDelta, IModelDelta.EXPAND);
		VirtualTreeModelViewer virtualViewer = new VirtualTreeModelViewer(
			clientViewer.getDisplay(),
			SWT.VIRTUAL,
			clientViewer.getPresentationContext(),
			validator);
		virtualViewer.setFilters(clientViewer.getFilters());
		virtualViewer.addLabelUpdateListener(listener);
		virtualViewer.getTree().addItemListener(listener);
		String[] columns = clientViewer.getPresentationContext().getColumns();
		virtualViewer.setInput(input);
		if (virtualViewer.canToggleColumns()) {
			virtualViewer.setShowColumns(clientViewer.isShowColumns());
			virtualViewer.setVisibleColumns(columns);
		}
		virtualViewer.updateViewer(stateDelta);

		// Parse selected items from client viewer and add them to the virtual viewer selection.
		listener.fSelectionRootDepth = Integer.MAX_VALUE;
		TreeItem[] selection = getSelectedItems(clientViewer);
		Set<VirtualItem> vSelection = new HashSet<>(selection.length * 4 / 3);
		for (TreeItem element : selection) {
			TreePath parentPath = fClientViewer.getTreePathFromItem(element.getParentItem());
			listener.fSelectionRootDepth = Math.min(parentPath.getSegmentCount() + 1, listener.fSelectionRootDepth);
			VirtualItem parentVItem = virtualViewer.findItem(parentPath);
			if (parentVItem != null) {
				int index = -1;
				TreeItem parentItem = element.getParentItem();
				if (parentItem != null) {
					index = parentItem.indexOf(element);
				} else {
					Tree parentTree = element.getParent();
					index = parentTree.indexOf(element);
				}
				index = ((ITreeModelContentProvider)clientViewer.getContentProvider()).viewToModelIndex(parentPath, index);
				vSelection.add( parentVItem.getItem(new Index(index)) );
			}
		}
		validator.setItemsToCopy(vSelection);
		listener.fItemsToUpdate = new HashSet<>(vSelection);
		virtualViewer.getTree().validate();
		return virtualViewer;
	}

	protected TreeItem[] getSelectedItems(TreeModelViewer clientViewer) {
		return clientViewer.getTree().getSelection();
	}

	/**
	 * Do the specific action using the current selection.
	 * @param action Action that is running.
	 */
	@Override
	public void run(final IAction action) {
		if (fClientViewer.getSelection().isEmpty()) {
			return;
		}

		final VirtualViewerListener listener = new VirtualViewerListener();
		ItemsToCopyVirtualItemValidator validator = new ItemsToCopyVirtualItemValidator();
		VirtualTreeModelViewer virtualViewer = initVirtualViewer(fClientViewer, listener, validator);
		listener.fVirtualViewer = virtualViewer;

		ProgressMonitorDialog dialog = new TimeTriggeredProgressMonitorDialog(fClientViewer.getControl().getShell(), 500);
		final IProgressMonitor monitor = dialog.getProgressMonitor();
		dialog.setCancelable(true);

		IRunnableWithProgress runnable = m -> {
			synchronized(listener) {
				listener.fProgressMonitor = m;
				listener.fProgressMonitor.beginTask(DebugUIPlugin.removeAccelerators(getAction().getText()), listener.fItemsToUpdate.size());
			}

			while (!listener.fItemsToUpdate.isEmpty() && !listener.fProgressMonitor.isCanceled()) {
				Thread.sleep(1);
			}
			synchronized(listener) {
				listener.fProgressMonitor = null;
			}
		};
		try {
			dialog.run(true, true, runnable);
		} catch (InvocationTargetException e) {
			DebugUIPlugin.log(e);
			return;
		} catch (InterruptedException e) {
			return;
		}

		if (!monitor.isCanceled()) {
			copySelectionToClipboard(virtualViewer, validator.fItemsToCopy, listener.fSelectionRootDepth);
		}

		virtualViewer.removeLabelUpdateListener(listener);
		virtualViewer.getTree().removeItemListener(listener);
		virtualViewer.dispose();
	}

	private void copySelectionToClipboard(VirtualTreeModelViewer virtualViewer, Set<VirtualItem> itemsToCopy, int selectionRootDepth) {
		StringBuilder buffer = new StringBuilder();
		writeItemToBuffer (virtualViewer.getTree(), itemsToCopy, buffer, -selectionRootDepth);
		writeBufferToClipboard(buffer);
	}

	protected void writeItemToBuffer(VirtualItem item, Set<VirtualItem> itemsToCopy, StringBuilder buffer, int indent) {
		if (itemsToCopy.contains(item)) {
			append(item, buffer, indent);
		}
		VirtualItem[] children = item.getItems();
		if (children != null) {
			for (VirtualItem element : children) {
				writeItemToBuffer(element, itemsToCopy, buffer, indent + 1);
			}
		}
	}

	protected void writeBufferToClipboard(StringBuilder buffer) {
		if (buffer.length() == 0) {
			return;
		}

		TextTransfer plainTextTransfer = TextTransfer.getInstance();
		Clipboard clipboard= new Clipboard(fClientViewer.getControl().getDisplay());
		try {
			clipboard.setContents(
					new String[]{buffer.toString()},
					new Transfer[]{plainTextTransfer});
		} catch (SWTError e){
			if (e.code != DND.ERROR_CANNOT_SET_CLIPBOARD) {
				throw e;
			}
			if (MessageDialog.openQuestion(fClientViewer.getControl().getShell(), ActionMessages.CopyToClipboardActionDelegate_Problem_Copying_to_Clipboard_1, ActionMessages.CopyToClipboardActionDelegate_There_was_a_problem_when_accessing_the_system_clipboard__Retry__2)) { //
				writeBufferToClipboard(buffer);
			}
		} finally {
			clipboard.dispose();
		}
	}

	protected TreeModelViewer getViewer() {
		return fClientViewer;
	}

	protected void setViewer(TreeModelViewer viewer) {
		fClientViewer = viewer;
	}
	/**
	 * @see AbstractDebugActionDelegate#doAction(Object)
	 */
	@Override
	protected void doAction(Object element) {
		//not used
	}

	@Override
	protected boolean getEnableStateForSelection(IStructuredSelection selection) {
		if (selection.isEmpty()) {
			return true;
		} else {
			return super.getEnableStateForSelection(selection);
		}
	}

	@Override
	public void runWithEvent(IAction action, Event event) {
		run(action);
	}
}