/*******************************************************************************
 * Copyright (c) 2009, 2015 Wind River Systems 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:
 *     Wind River Systems - initial API and implementation
 *     IBM Corporation = bug fixing
 *******************************************************************************/
package org.eclipse.debug.internal.ui.views.launch;

import java.util.ArrayList;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.debug.internal.ui.viewers.breadcrumb.AbstractBreadcrumb;
import org.eclipse.debug.internal.ui.viewers.breadcrumb.BreadcrumbViewer;
import org.eclipse.debug.internal.ui.viewers.breadcrumb.IBreadcrumbDropDownSite;
import org.eclipse.debug.internal.ui.viewers.breadcrumb.TreeViewerDropDown;
import org.eclipse.debug.internal.ui.viewers.model.ILabelUpdateListener;
import org.eclipse.debug.internal.ui.viewers.model.SubTreeModelViewer;
import org.eclipse.debug.internal.ui.viewers.model.TreeModelContentProvider;
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.IModelDeltaVisitor;
import org.eclipse.debug.internal.ui.viewers.model.provisional.ModelDelta;
import org.eclipse.debug.internal.ui.viewers.model.provisional.TreeModelViewer;
import org.eclipse.debug.ui.contexts.AbstractDebugContextProvider;
import org.eclipse.debug.ui.contexts.DebugContextEvent;
import org.eclipse.debug.ui.contexts.IDebugContextListener;
import org.eclipse.debug.ui.contexts.IDebugContextProvider;
import org.eclipse.jface.action.IMenuListener;
import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.action.MenuManager;
import org.eclipse.jface.viewers.AbstractTreeViewer;
import org.eclipse.jface.viewers.BaseLabelProvider;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionChangedListener;
import org.eclipse.jface.viewers.ITreePathContentProvider;
import org.eclipse.jface.viewers.ITreePathLabelProvider;
import org.eclipse.jface.viewers.ITreeSelection;
import org.eclipse.jface.viewers.SelectionChangedEvent;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreePath;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.jface.viewers.ViewerLabel;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MenuDetectEvent;
import org.eclipse.swt.events.MenuDetectListener;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.progress.UIJob;

/**
 * @since 3.5
 */
public class LaunchViewBreadcrumb extends AbstractBreadcrumb implements IDebugContextListener, ILabelUpdateListener  {

    private static class Input {
        final TreePath fPath;

        Input(TreePath path) {
            fPath = path;
        }

        @Override
		public boolean equals(Object obj) {
            return obj instanceof Input &&
                ((fPath == null && ((Input)obj).fPath == null) ||
                 (fPath != null && fPath.equals( ((Input)obj).fPath )));
        }

        @Override
		public int hashCode() {
            return fPath == null ? 0 : fPath.hashCode();
        }
    }

    private static class ContentProvider implements ITreePathContentProvider {

        private static final Object[] EMPTY_ELEMENTS_ARRAY = new Object[0];

        public Input fInput;

        @Override
		public Object[] getChildren(TreePath parentPath) {
            if (hasChildren(parentPath)) {
                return new Object[] { fInput.fPath.getSegment(parentPath.getSegmentCount()) };
            }
            return EMPTY_ELEMENTS_ARRAY;
        }

        @Override
		public TreePath[] getParents(Object element) {
            // Not supported
            return new TreePath[] { TreePath.EMPTY };
        }

        @Override
		public boolean hasChildren(TreePath parentPath) {
            if ( parentPath.getSegmentCount() == 0) {
                return fInput != null;
            } else if (fInput != null &&
                       fInput.fPath != null &&
                       fInput.fPath.getSegmentCount() > parentPath.getSegmentCount())
            {
                for (int i = 0; i < parentPath.getSegmentCount(); i++) {
                    if (i >= fInput.fPath.getSegmentCount()) {
                        return false;
                    } else {
                        Object parentElement = parentPath.getSegment(i);
                        Object contextElement = fInput.fPath.getSegment(i);
                        if (!parentElement.equals(contextElement)) {
                            return false;
                        }
                    }
                }
                return true;
            }
            return false;
        }

        @Override
		public Object[] getElements(Object inputElement) {
            if (fInput != null &&
                fInput.fPath != null)
            {
                return getChildren(TreePath.EMPTY);
            } else {
                return new Object[] { fgEmptyDebugContextElement };
            }
        }

        @Override
		public void dispose() {
            fInput = null;
        }

        @Override
		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
            if (newInput instanceof Input) {
                fInput = ((Input)newInput);
            } else {
                fInput = null;
            }
        }
    }

    private class LabelProvider extends BaseLabelProvider implements ITreePathLabelProvider {
        @Override
		public void updateLabel(ViewerLabel label, TreePath elementPath) {
            if (fgEmptyDebugContextElement.equals(elementPath.getLastSegment())) {
                label.setText(LaunchViewMessages.Breadcrumb_NoActiveContext);
                label.setImage(null);
            } else {
                ViewerLabel treeViewerLabel = fTreeViewer.getElementLabel(elementPath, null);
                if (treeViewerLabel == null) {
                    label.setText(LaunchViewMessages.Breadcrumb_NoActiveContext);
                    label.setImage(null);
                } else {
                    label.setText(treeViewerLabel.getText());
                    label.setTooltipText(treeViewerLabel.getText());
                    label.setImage(treeViewerLabel.getImage());
                    label.setFont(treeViewerLabel.getFont());
                    label.setForeground(treeViewerLabel.getForeground());
                    label.setBackground(treeViewerLabel.getBackground());

                }
            }
        }
    }

    private final LaunchView fView;
    private final TreeModelViewer fTreeViewer;
    private final IDebugContextProvider fTreeViewerContextProvider;
    private Input fBreadcrumbInput;
    static final private Object fgEmptyDebugContextElement = new Object();
    private BreadcrumbViewer fViewer;
    private boolean fRefreshBreadcrumb = false;

    private class BreadcrumbContextProvider extends AbstractDebugContextProvider implements IDebugContextListener, ISelectionChangedListener {

        private ISelection fBreadcrumbSelection = null;

        BreadcrumbContextProvider() {
            super(fView);
            fViewer.addSelectionChangedListener(this);
            fBreadcrumbSelection = fViewer.getSelection();
            fTreeViewerContextProvider.addDebugContextListener(this);
        }

        @Override
		public ISelection getActiveContext() {
            if (fBreadcrumbSelection != null && !fBreadcrumbSelection.isEmpty()) {
                return fBreadcrumbSelection;
            } else {
                ISelection treeViewerSelection = fTreeViewerContextProvider.getActiveContext();
                return treeViewerSelection != null ? treeViewerSelection : StructuredSelection.EMPTY;
            }
        }

        void dispose() {
            fViewer.removeSelectionChangedListener(this);
            fTreeViewerContextProvider.removeDebugContextListener(this);
        }

        @Override
		public void debugContextChanged(DebugContextEvent event) {
            fire(new DebugContextEvent(this, getActiveContext(), event.getFlags()));
        }

        @Override
		public void selectionChanged(SelectionChangedEvent event) {
            ISelection oldContext = getActiveContext();
            fBreadcrumbSelection = event.getSelection();
            if (!getActiveContext().equals(oldContext)) {
                fire(new DebugContextEvent(this, getActiveContext(), DebugContextEvent.ACTIVATED));
            }
        }
    }

    private BreadcrumbContextProvider fBreadcrumbContextProvider;

    public LaunchViewBreadcrumb(LaunchView view, TreeModelViewer treeViewer, IDebugContextProvider contextProvider) {
        fView = view;
        fTreeViewer = treeViewer;
        fTreeViewer.addLabelUpdateListener(this);
        fTreeViewerContextProvider = contextProvider;
        fBreadcrumbInput = new Input( getPathForSelection(fTreeViewerContextProvider.getActiveContext()) );
        fTreeViewerContextProvider.addDebugContextListener(this);
    }

    @Override
	protected void activateBreadcrumb() {
    }

    @Override
	protected void deactivateBreadcrumb() {
        if (fViewer.isDropDownOpen()) {
            Shell shell = fViewer.getDropDownShell();
            if (shell != null && !shell.isDisposed()) {
                shell.close();
            }
        }
    }

    @Override
	protected BreadcrumbViewer createViewer(Composite parent) {
        fViewer = new BreadcrumbViewer(parent, SWT.NONE) {
            @Override
			protected Control createDropDown(Composite dropDownParent, IBreadcrumbDropDownSite site, TreePath path) {
                return createDropDownControl(dropDownParent, site, path);
            }
        };

        // Force the layout of the breadcrumb viewer so that we may calcualte
        // its proper size.
        parent.pack(true);

        fViewer.setContentProvider(new ContentProvider());
        fViewer.setLabelProvider(new LabelProvider());

        createMenuManager();

        fViewer.setInput(getCurrentInput());

        fBreadcrumbContextProvider = new BreadcrumbContextProvider();

        return fViewer;
    }

    protected void createMenuManager() {
        MenuManager menuMgr = new MenuManager("#PopUp"); //$NON-NLS-1$
        menuMgr.setRemoveAllWhenShown(true);
        menuMgr.addMenuListener(new IMenuListener() {
            @Override
			public void menuAboutToShow(IMenuManager mgr) {
                fView.fillContextMenu(mgr);
            }
        });
        final Menu menu= menuMgr.createContextMenu(fViewer.getControl());

        // register the context menu such that other plug-ins may contribute to it
        if (fView.getSite() != null) {
            fView.getSite().registerContextMenu(menuMgr, fViewer);
        }
        fView.addContextMenuManager(menuMgr);

        fViewer.addMenuDetectListener(new MenuDetectListener() {
            @Override
			public void menuDetected(MenuDetectEvent event) {
                menu.setLocation(event.x + 10, event.y + 10);
                menu.setVisible(true);
                while (!menu.isDisposed() && menu.isVisible()) {
                    if (!menu.getDisplay().readAndDispatch()) {
						menu.getDisplay().sleep();
					}
                }
            }
        });
    }

    @Override
	protected Object getCurrentInput() {
        return fBreadcrumbInput;
    }

    @Override
	protected boolean open(ISelection selection) {
        // Let the drop-down control implementation itself handle activating a new context.
        return false;
    }

    @Override
	public void dispose() {
        fTreeViewerContextProvider.removeDebugContextListener(this);
        fTreeViewer.removeLabelUpdateListener(this);
        if (fBreadcrumbContextProvider != null) {
            fBreadcrumbContextProvider.dispose();
            fBreadcrumbContextProvider = null;
        }
        fViewer = null;
        super.dispose();
    }

    @Override
	public void debugContextChanged(DebugContextEvent event) {
        if (fView.isBreadcrumbVisible()) {
            fBreadcrumbInput = new Input(getPathForSelection(event.getContext()));
            if ((event.getFlags() & DebugContextEvent.ACTIVATED) != 0) {
                setInput(getCurrentInput());

                // If the context was activated, then clear the selection in breadcrumb
                // so that the activated context will become the active context for the
                // window.
                fViewer.setSelection(StructuredSelection.EMPTY);
            } else {
                refresh();
            }
        }
    }

    @Override
	public void labelUpdateStarted(ILabelUpdate update) {
    }

    @Override
	public void labelUpdateComplete(ILabelUpdate update) {
        if (fBreadcrumbInput != null && fBreadcrumbInput.fPath != null) {
            if (fBreadcrumbInput.fPath.startsWith(update.getElementPath(), null)) {
                synchronized (this) {
                    fRefreshBreadcrumb = true;
                }
            }
        }
    }

    @Override
	public void labelUpdatesBegin() {
    }

    @Override
	public void labelUpdatesComplete() {
        boolean refresh = false;
        synchronized(this) {
            refresh = fRefreshBreadcrumb;
            fRefreshBreadcrumb = false;
        }
        if (fView.isBreadcrumbVisible() && refresh) {
            new UIJob(fViewer.getControl().getDisplay(), "refresh breadcrumb") { //$NON-NLS-1$
                { setSystem(true); }
                @Override
				public IStatus runInUIThread(IProgressMonitor monitor) {
                    refresh();
                    return Status.OK_STATUS;
                }
            }.schedule();
        }
    }

    IDebugContextProvider getContextProvider() {
        return fBreadcrumbContextProvider;
    }

    int getHeight() {
        return fViewer.getControl().getSize().y;
    }

    void clearSelection() {
        fViewer.setSelection(StructuredSelection.EMPTY);
    }

    private TreePath getPathForSelection(ISelection selection) {
        if (selection instanceof ITreeSelection && !selection.isEmpty()) {
            return ((ITreeSelection)selection).getPaths()[0];
        }
        return null;
    }

    public Control createDropDownControl(Composite parent, final IBreadcrumbDropDownSite site, TreePath paramPath) {

        TreeViewerDropDown dropDownTreeViewer = new TreeViewerDropDown() {

            SubTreeModelViewer fDropDownViewer;

            @Override
			protected TreeViewer createTreeViewer(Composite composite, int style, final TreePath path) {
                fDropDownViewer = new SubTreeModelViewer(
                    composite, SWT.SINGLE | SWT.H_SCROLL | SWT.V_SCROLL | SWT.VIRTUAL | SWT.POP_UP,
                    fTreeViewer.getPresentationContext());

                Object launchViewInput = fTreeViewer.getInput();
                fDropDownViewer.setInput(launchViewInput, path.getParentPath());

                ViewerFilter[] filters = fTreeViewer.getFilters();
                fDropDownViewer.setFilters(filters);

                ModelDelta stateDelta = new ModelDelta(launchViewInput, IModelDelta.NO_CHANGE);
                fTreeViewer.saveElementState(TreePath.EMPTY, stateDelta, IModelDelta.EXPAND | IModelDelta.SELECT);

                // If we do not want to expand the elements in the drop-down.
                // Prune the delta to only select the element in the
                // top-most list.
                if (!fView.getBreadcrumbDropDownAutoExpand()) {
                    final ModelDelta prunedDelta = new ModelDelta(launchViewInput, IModelDelta.NO_CHANGE);
                    stateDelta.accept(new IModelDeltaVisitor() {
                        ModelDelta copy = prunedDelta;
                        @Override
						public boolean visit(IModelDelta delta, int depth) {
                            TreePath deltaPath = getViewerTreePath(delta);
                            if (deltaPath.getSegmentCount() == 0) {
                                // skip copying the root element, only copy it's child count
                                copy.setChildCount(delta.getChildCount());
                            } else if (deltaPath.getSegmentCount() != 0 && path.startsWith(deltaPath, null) ) {
                                // Build up the delta copy along the path of the drop-down element.
                                copy = copy.addNode(
                                    delta.getElement(), delta.getIndex(), delta.getFlags(), delta.getChildCount());
                            }

                            // If the delta is for the drop-down element, set its select flag and stop traversing
                            // the delta..
                            if (deltaPath.equals(path)) {
                                copy.setFlags(IModelDelta.SELECT | IModelDelta.REVEAL);
                                return false;
                            }

                            // Continue traversing the delta.
                            return true;
                        }

                        private TreePath getViewerTreePath(IModelDelta node) {
							ArrayList<Object> list = new ArrayList<>();
                            IModelDelta parentDelta = node.getParentDelta();
                            while (parentDelta != null) {
                                list.add(0, node.getElement());
                                node = parentDelta;
                                parentDelta = node.getParentDelta();
                            }
                            return new TreePath(list.toArray());
                        }
                    });
                    stateDelta = prunedDelta;
                }

                fDropDownViewer.updateViewer(stateDelta);

                fDropDownViewer.addLabelUpdateListener(new ILabelUpdateListener() {
                    @Override
					public void labelUpdateComplete(ILabelUpdate update) {}
                    @Override
					public void labelUpdatesBegin() {}
                    @Override
					public void labelUpdateStarted(ILabelUpdate update) {}
                    @Override
					public void labelUpdatesComplete() {
                        new UIJob(fViewer.getControl().getDisplay(), "resize breadcrub dropdown") { //$NON-NLS-1$
                            { setSystem(true); }
                            @Override
							public IStatus runInUIThread(IProgressMonitor monitor) {
                                site.updateSize();
                                return Status.OK_STATUS;
                            }
                        }.schedule();
                    }
                });

                return fDropDownViewer;
            }

            @Override
			protected void openElement(ISelection selection) {
                if (fTreeViewer.getControl().isDisposed()) {
                    return;
                }

                if (selection != null && (selection instanceof ITreeSelection) && !selection.isEmpty()) {
                    // Create the path to the root element of the drop-down viewer.  Need to calcualte
                    // indexes and counts for the delta in order for the selection from the drop-down
                    // viewer to work properly.
                    TreeModelContentProvider contentProvider = (TreeModelContentProvider)fTreeViewer.getContentProvider();
                    TreePath path = TreePath.EMPTY;
                    int count = fTreeViewer.getChildCount(path);
                    count = contentProvider.viewToModelCount(path, count);
                    ModelDelta rootDelta =
                        new ModelDelta(fTreeViewer.getInput(), -1, IModelDelta.NO_CHANGE, count);
                    TreePath rootPath = fDropDownViewer.getRootPath();
                    ModelDelta delta = rootDelta;
                    for (int i = 0; i < rootPath.getSegmentCount(); i++) {
                        Object element = rootPath.getSegment(i);
                        int index = fTreeViewer.findElementIndex(path, element);
                        index = contentProvider.viewToModelIndex(path, index);
                        path = path.createChildPath(element);
                        count = fTreeViewer.getChildCount(path);
                        count = contentProvider.viewToModelCount(path, count);
                        delta = delta.addNode(rootPath.getSegment(i), index, IModelDelta.NO_CHANGE, count);
                    }

                    // Create the delta and save the drop-down viewer's state to it.
                    fDropDownViewer.saveElementState(TreePath.EMPTY, delta, IModelDelta.EXPAND | IModelDelta.SELECT);

                    // Add the IModelDelta.FORCE flag to override the current selection in view.
                    rootDelta.accept(new IModelDeltaVisitor(){
                        @Override
						public boolean visit(IModelDelta paramDelta, int depth) {
                            if ((paramDelta.getFlags() & IModelDelta.SELECT) != 0) {
                                ((ModelDelta)paramDelta).setFlags(paramDelta.getFlags() | IModelDelta.FORCE);
                            }
                            return true;
                        }
                    });

                    // If elements in the drop-down were auto-expanded, then collapse the drop-down's sub tree in the
                    // full viewer.  After the drop-down's full expansion state is saved out to the tree viewer, the
                    // tree viewer will accurately reflect the state changes made by the user.
                    if (fView.getBreadcrumbDropDownAutoExpand()) {
                        fTreeViewer.collapseToLevel(rootPath, AbstractTreeViewer.ALL_LEVELS);
                    }

                    // Save the state of the drop-down out into the tree viewer.
                    fTreeViewer.updateViewer(rootDelta);
                    fViewer.setSelection(StructuredSelection.EMPTY);
                    site.close();
                }

                super.openElement(selection);
            }
        };


        return dropDownTreeViewer.createDropDown(parent, site, paramPath);
    }
}