/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * 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:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.views.swt;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.eclipse.jface.action.IMenuManager;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.resource.LocalResourceManager;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceListener;
import org.eclipse.swt.dnd.FileTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.ui.IMemento;
import org.eclipse.ui.ISelectionListener;
import org.eclipse.ui.IViewSite;
import org.eclipse.ui.IWorkbenchSite;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.contexts.IContextService;
import org.eclipse.ui.part.ViewPart;
import org.simantics.browsing.ui.BuiltinKeys;
import org.simantics.browsing.ui.Column;
import org.simantics.browsing.ui.GraphExplorer;
import org.simantics.browsing.ui.NodeContext;
import org.simantics.browsing.ui.common.ColumnKeys;
import org.simantics.browsing.ui.common.node.IDropTargetNode;
import org.simantics.browsing.ui.graph.impl.GraphInputSources;
import org.simantics.browsing.ui.graph.impl.SessionContextInputSource;
import org.simantics.browsing.ui.swt.ContextMenuInitializer;
import org.simantics.browsing.ui.swt.DefaultKeyListener;
import org.simantics.browsing.ui.swt.DefaultMouseListener;
import org.simantics.browsing.ui.swt.DefaultSelectionDataResolver;
import org.simantics.browsing.ui.swt.GraphExplorerFactory;
import org.simantics.browsing.ui.swt.IContextMenuInitializer;
import org.simantics.browsing.ui.swt.ViewArgumentUtils;
import org.simantics.browsing.ui.swt.widgets.GraphExplorerComposite;
import org.simantics.browsing.ui.swt.widgets.impl.WidgetSupport;
import org.simantics.browsing.ui.swt.widgets.impl.WidgetSupportImpl;
import org.simantics.db.Disposable;
import org.simantics.db.management.ISessionContext;
import org.simantics.db.management.ISessionContextChangedListener;
import org.simantics.db.management.ISessionContextProvider;
import org.simantics.db.management.SessionContextChangedEvent;
import org.simantics.project.ProjectKeys;
import org.simantics.ui.SimanticsUI;
import org.simantics.ui.dnd.LocalObjectTransfer;
import org.simantics.ui.dnd.LocalSelectionDragSourceListener;
import org.simantics.ui.dnd.NoImageDragSourceEffect;
import org.simantics.ui.workbench.IPropertyPage;
import org.simantics.utils.ObjectUtils;
import org.simantics.utils.datastructures.Function;
import org.simantics.utils.datastructures.disposable.DisposeState;
import org.simantics.utils.datastructures.hints.HintContext;
import org.simantics.utils.datastructures.hints.HintListenerAdapter;
import org.simantics.utils.datastructures.hints.HintTracker;
import org.simantics.utils.datastructures.hints.IHintContext;
import org.simantics.utils.datastructures.hints.IHintContext.Key;
import org.simantics.utils.datastructures.hints.IHintListener;
import org.simantics.utils.datastructures.hints.IHintObservable;
import org.simantics.utils.datastructures.hints.IHintTracker;
import org.simantics.utils.ui.LayoutUtils;

/**
 * @author Antti Villberg
 * @deprecated in favor of org.simantics.views.swt.ModelledView
 */
public abstract class SimanticsView extends ViewPart {

    private final WidgetSupportImpl          widgetSupport = createSupport();

    protected IHintContext                   factoryHints = new HintContext();

    protected LocalResourceManager           resourceManager;

    protected ISelectionListener             workbenchSelectionListener;

    protected Composite                      parent;

    private Map<String, String>              args;

    private ISessionContextProvider          contextProvider;

    private ISessionContext                  sessionContext;

    protected IMemento                       memento;

    private IHintTracker                     sessionContextTracker = new SessionContextProjectTracker();

    private SessionContextInputSource        inputSource           = GraphInputSources.projectSource();

    private DisposeState                     disposeState          = DisposeState.Alive;

    protected ISessionContextChangedListener contextChangeListener = new ISessionContextChangedListener() {
        @Override
        public void sessionContextChanged(SessionContextChangedEvent event) {
            sessionContext = event.getNewValue();
            sessionContextTracker.track(sessionContext);
        }
    };

    protected Set<String> getBrowseContexts() {
        return Collections.emptySet();
    }

    protected WidgetSupportImpl createSupport() {
        return new WidgetSupportImpl();
    }
    
    abstract protected void createControls(Composite body, IWorkbenchSite site, ISessionContext context, WidgetSupport support);

    protected void activateUiContexts() {
        Collection<String> contexts = getUiContexts();
        if (!contexts.isEmpty()) {
            IContextService cs = (IContextService) getSite().getService(IContextService.class);
            for (String context : contexts)
                cs.activateContext(context);
        }
    }

    protected Transfer[] getAcceptedDataTypes() {
        return new Transfer[] {  LocalObjectTransfer.getTransfer(), FileTransfer.getInstance() };
    }

    protected void handleDrop(Object data, NodeContext target) {
        if (target != null) {
            Object input = target.getConstant(BuiltinKeys.INPUT);
            //System.out.println("DROPPED " + data + " ON " + target);
            if (input instanceof IDropTargetNode)
                ((IDropTargetNode) input).drop(data);
        }
    }

    protected Object createDragSource(GraphExplorer explorer) {
        ISelectionProvider selectionProvider = (ISelectionProvider) explorer.getAdapter(ISelectionProvider.class);

        DragSourceListener listener = new LocalSelectionDragSourceListener(selectionProvider);

        Control control = explorer.getControl();
        DragSource source = new DragSource(control, DND.DROP_LINK | DND.DROP_MOVE | DND.DROP_COPY | DND.DROP_DEFAULT);
        source.setTransfer(new Transfer[] {LocalObjectTransfer.getTransfer()});
        source.addDragListener(listener);
        source.setDragSourceEffect(new NoImageDragSourceEffect(control));

        return listener;
    }

    /**
     * @return the set of <code>org.eclipse.ui.context</code> contexts to
     *         activate for this view site
     */
    protected Set<String> getUiContexts() {
        return Collections.emptySet();
    }

    /**
     * The default hint tracker that will be active if
     * {@link SimanticsViewBase#setSessionContextTracker(IHintTracker) is
     * not called.
     */
    public class SessionContextProjectTracker extends HintTracker {
        public SessionContextProjectTracker() {
            IHintListener activeProjectListener = new HintListenerAdapter() {
                @Override
                public void hintChanged(IHintObservable sender, Key key, Object oldValue, Object newValue) {
                    applySessionContext(getSessionContext());
                }
            };
            addKeyHintListener(ProjectKeys.KEY_PROJECT, activeProjectListener);
        }
    }

    protected void setSessionContextTracker(IHintTracker tracker) {
        this.sessionContextTracker = tracker;
    }

    public void setInputSource(SessionContextInputSource source) {
        this.inputSource = source;
    }

    protected final SessionContextInputSource getInputSource() {
        return inputSource;
    }

    protected Map<String, String> getViewArguments() {
        return args;
    }

    protected DisposeState getDisposeState() {
        return disposeState;
    }

    public ISessionContext getSessionContext() {
        return sessionContext;
    }

    public ISessionContextProvider getSessionContextProvider() {
        return contextProvider;
    }

    @Override
    public void createPartControl(Composite parent) {
        this.parent = parent;
        this.resourceManager = new LocalResourceManager(JFaceResources.getResources(parent.getDisplay()));

        contextProvider = SimanticsUI.getSessionContextProvider(getViewSite().getWorkbenchWindow());

        parent.setLayout(LayoutUtils.createNoBorderGridLayout(1, false));

        setWorkbenchListeners();
        activateUiContexts();

        createControls(parent, getSite(), getSessionContext(), widgetSupport);

        attachToSession();

    }

    /**
     * Invoked when this viewpart is disposed. Unhooks the view from its
     * ISessionContextProvider. Overriding is allowed but super.dispose() must
     * be called.
     * 
     * @see org.eclipse.ui.part.WorkbenchPart#dispose()
     */
    @Override
    public void dispose() {
        removeWorkbenchListeners();
        disposeState = DisposeState.Disposing;
        try {
            if (inputSource instanceof Disposable) {
                ((Disposable) inputSource).dispose();
            }
            //System.out.println(this + ".GraphExplorerViewBase.dispose()");
            if (contextProvider != null) {
                contextProvider.removeContextChangedListener(contextChangeListener);
                contextProvider = null;
            }
            sessionContextTracker.untrack();
            resourceManager.dispose();
            if (widgetSupport instanceof Disposable)
                ((Disposable) widgetSupport).dispose();
            resourceManager = null;
            args = null;
            sessionContext = null;
            parent = null;
            super.dispose();
        } finally {
            disposeState = DisposeState.Disposed;
        }
    }

    @Override
    public void setFocus() {
    }

    @Override
    public void init(IViewSite site) throws PartInitException {
        super.init(site);
        this.args = ViewArgumentUtils.parseViewArguments(this);
    }

    @Override
    public void init(IViewSite site, IMemento memento) throws PartInitException {
        super.init(site, memento);
        this.args = ViewArgumentUtils.parseViewArguments(this);
        this.memento = memento;
    }

    @Override
    public void saveState(IMemento memento) {
        if (this.memento != null) {
            memento.putMemento(this.memento);
        }
//        if (explorer != null)
//            explorer.saveState(memento);
    }

    protected void setWorkbenchListeners() {
        if (workbenchSelectionListener == null) {

//            ISelectionProvider selectionProvider = (ISelectionProvider)explorer.getAdapter(ISelectionProvider.class);
//            getSite().setSelectionProvider(selectionProvider);

            // Listen to the workbench selection also to propagate it to
            // the explorer also.
//            workbenchSelectionListener = new DefaultExplorerSelectionListener(this, explorer);
//            getSite().getWorkbenchWindow().getSelectionService().addPostSelectionListener(workbenchSelectionListener);
        }
    }

    protected void removeWorkbenchListeners() {
        // Remember to remove the installed workbench selection listener
        if (workbenchSelectionListener != null) {
            getSite().getWorkbenchWindow().getSelectionService().removePostSelectionListener(workbenchSelectionListener);
            workbenchSelectionListener = null;

            getSite().setSelectionProvider(null);
        }
    }

    protected final void attachToSession() {
        // Track active ISessionContext changes
        //contextProvider = SimanticsUI.getSessionContextProvider(getViewSite().getWorkbenchWindow());
        contextProvider.addContextChangedListener(contextChangeListener);

        // Start tracking the current session context for input changes.
        // This will/must cause applySessionContext to get called.
        // Doing the applySessionContext initialization this way
        // instead of directly calling it will also make sure that
        // applySessionContext is only called once when first initialized,
        // and not twice like with the direct invocation.
        this.sessionContext = contextProvider.getSessionContext();
        sessionContextTracker.track(sessionContext);
    }

    // /////////////////////////////////////////////////////////////////////////
    // Override / implement these:

    protected Column[] getColumns() {
        return null;
    }

    /**
     * Override this method to add controls to the view part. This is invoked
     * before attaching the view part to a database session.
     * 
     * @param parent
     */
    protected void createControls(Composite parent) {

        parent.setLayout(LayoutUtils.createNoBorderGridLayout(1, false));

    }

    /**
     * Override this method and provide a proper context menu initializer if you
     * want to have this base class initialize one for you.
     * 
     * @return the initializer to be used by {@link #createControls(Composite)}
     */
    protected IContextMenuInitializer getContextMenuInitializer() {
        String contextMenuId = getContextMenuId();
        if(contextMenuId != null) {
            return new ContextMenuInitializer(contextMenuId);
        } else {
            return null;
        }
    }

    protected String getContextMenuId() {
        return null;
    }

    protected int getStyle() {
        return SWT.MULTI;
    }

    /**
     * @param parent
     * @return
     */
    protected GraphExplorer createExplorerControl(Composite parent) {
        return GraphExplorerFactory.getInstance()
        .selectionDataResolver(new DefaultSelectionDataResolver())
        .create(parent, getStyle());
    }

    /**
     * Override to customize the addition of listeners a newly created
     * GraphExplorer.
     * 
     * @param explorer
     */
    protected void addListeners(GraphExplorer explorer, IMenuManager menuManager) {
        addSelectionInputListeners(explorer, menuManager);
    }

    protected void addSelectionInputListeners(GraphExplorer explorer, IMenuManager menuManager) {
        // Consider ENTER presses to simulate mouse left button double clicks
        explorer.addListener(new DefaultKeyListener(contextProvider, explorer, new Function<String[]>() {
            @Override
            public String[] execute(Object... obj) {
                return new String[] { getEditingColumn((NodeContext) obj[0]) };
            }
        }));
        // Default double click handling
        explorer.addListener(new DefaultMouseListener(explorer));
    }

    protected String getEditingColumn(NodeContext context) {
        return ColumnKeys.SINGLE;
    }

    // Needed for preventing unnecessary re-initialization of the explorer with the same input.
    private Object currentInput;

    protected boolean isImportantInput(Object previousInput, Object input) {
        return !ObjectUtils.objectEquals(previousInput, input);
    }

    /**
     * Invoke this to reinitialize the explorer and reset its input. The input
     * will be resolved from the specified ISessionContext based on the
     * {@link SessionContextInputSource} that is currently in use. If the input
     * is identical to the previous input, nothing will be done.
     * 
     * @param context
     */
    protected final boolean applySessionContext(ISessionContext context) {
        // If control is not alive anymore, do nothing.
        //System.out.println(this + "(SimanticsView).applySessionContext(context=" + context + ")");
        if (disposeState != DisposeState.Alive)
            return false;
        
        if(this.sessionContext == null && context == null)
            return false;

        this.sessionContext = context;
        Object input = getInputSource().get(context);
        //System.out.println(this + "(SimanticsView).applySessionContext(input=" + input + ")");
        if (!isImportantInput(currentInput, input))
            return false;

//        System.out.println(this + ": initializeExplorer(" + explorer + ", " + context + ")");
//        initializeExplorer(explorer, context);
//        System.out.println(this + ": setRoot(" + input + ")");
//        explorer.setRoot(input);

        currentInput = input;
        //System.out.println(this + "(SimanticsView).applySessionContext(new input=" + currentInput + ")");

        widgetSupport.fireInput(context, input);

        // Start tracking the session context.
        //
        // If this is not the same session that is currently tracked, it will
        // cause IHintListeners of the sessionContextTracker to fire.
        // For this we need the above input equality (identity) checking.
        // This is here just to make sure that we are tracking the correct
        // session context.
        sessionContextTracker.track(sessionContext);

        return true;
    }
    
    @SuppressWarnings("unchecked")
    <T extends Control> void searchControl(Control control, Class<T> c, Set<T> result) {
    	if(c.isInstance(control))
    		result.add((T)control);
    	if(control instanceof Composite) {
    		for(Control child : ((Composite)control).getChildren()) {
    			searchControl(child, c, result);
    		}
    	}
    }

    @SuppressWarnings("unchecked")
    @Override
    public <T> T getAdapter(Class<T> adapter) {

        if(ISessionContextProvider.class == adapter)
            return (T) getSessionContextProvider();
        else if(IPropertyPage.class == adapter)
            return (T) getPropertyPage();
        else if(GraphExplorer.class == adapter) {
        	Set<GraphExplorerComposite> composites = new HashSet<>();
        	searchControl(parent, GraphExplorerComposite.class, composites);
        	if(composites.size() == 1) {
        		GraphExplorerComposite gec = composites.iterator().next(); 
        		return (T) gec.getExplorer();
        	}
        	return null;
        }

        return super.getAdapter(adapter);

    }

    abstract protected IPropertyPage getPropertyPage();
    
//    protected IPropertyPage getPropertyPage() {
//        return new StandardPropertyPage(getSite(), getBrowseContexts());
//    }

}