package org.simantics.modeling.ui.diagramEditor;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import java.util.function.Consumer;

import org.eclipse.jface.window.Window;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IEditorPart;
import org.simantics.Simantics;
import org.simantics.databoard.util.URIStringUtils;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.NamedResource;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.variable.RVI;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.db.layer0.variable.Variables;
import org.simantics.diagram.content.ConnectionUtil;
import org.simantics.diagram.flag.FlagUtil;
import org.simantics.diagram.stubs.DiagramResource;
import org.simantics.g2d.canvas.ICanvasContext;
import org.simantics.g2d.diagram.DiagramHints;
import org.simantics.layer0.Layer0;
import org.simantics.modeling.ComponentUtils;
import org.simantics.modeling.ModelingResources;
import org.simantics.modeling.actions.NavigateToTarget;
import org.simantics.modeling.actions.NavigationTargetChooserDialog;
import org.simantics.modeling.ui.Activator;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.ui.utils.ResourceAdaptionUtils;
import org.simantics.ui.workbench.editor.AbstractResourceEditorAdapter;
import org.simantics.utils.datastructures.MapSet;
import org.simantics.utils.datastructures.Pair;
import org.simantics.utils.strings.AlphanumComparator;
import org.simantics.utils.strings.EString;
import org.simantics.utils.threads.SWTThread;
import org.simantics.utils.threads.ThreadUtils;
import org.simantics.utils.ui.AdaptionUtils;
import org.simantics.utils.ui.workbench.WorkbenchUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Tuukka Lehtonen
 */
public class OpenDiagramFromComponentAdapter extends AbstractResourceEditorAdapter {

    private static final Logger LOGGER = LoggerFactory.getLogger(OpenDiagramFromComponentAdapter.class);

    private static final String EDITOR_ID = "org.simantics.modeling.ui.diagramEditor"; //$NON-NLS-1$

    public OpenDiagramFromComponentAdapter() {
        super(Messages.OpenDiagramFromComponentAdapter_OpenDiagramContainingComponent, Activator.SYMBOL_ICON);
    }

    protected String getEditorId(ReadGraph g, Resource diagram) throws DatabaseException {
        ModelingResources MOD = ModelingResources.getInstance(g);
        String preferredEditorId = g.getPossibleRelatedValue(diagram, MOD.PreferredDiagramEditorID);
        if(preferredEditorId != null)
            return preferredEditorId;
        else
            return EDITOR_ID;
    }

    @Override
    public boolean canHandle(ReadGraph graph, Object input) throws DatabaseException {
        Pair<Resource, String> p = tryGetResource(graph, input);
        if (p == null)
            return false;
        Variable v = AdaptionUtils.adaptToSingle(input, Variable.class);
        Collection<Runnable> rs = tryFindDiagram(graph, p.first, v, p.second);
        return !rs.isEmpty();
    }

    private Pair<Resource, String> tryGetResource(ReadGraph graph, Object input) throws DatabaseException {
        Resource r = ResourceAdaptionUtils.toSingleResource(input);
        if (r != null)
            return Pair.make(r, ""); //$NON-NLS-1$
        Variable v = AdaptionUtils.adaptToSingle(input, Variable.class);
        return findResource(graph, v);
    }

    private Pair<Resource, String> findResource(ReadGraph graph, Variable v) throws DatabaseException {
        List<String> path = null;
        while (v != null) {
            Resource r = v.getPossibleRepresents(graph);
            if (r != null) {
                String rvi = ""; //$NON-NLS-1$
                if (path != null) {
                    int pathLength = path.size();
                    for (int i = 0; i < pathLength; i++)
                        path.set(i, URIStringUtils.escape(path.get(i)));
                    Collections.reverse(path);
                    rvi = EString.implode(path, "/"); //$NON-NLS-1$
                }
                return Pair.make(r, rvi);
            }
            if (path == null)
                path = new ArrayList<>(2);
            path.add( v.getName(graph) );
            v = v.browsePossible(graph, "."); //$NON-NLS-1$
        }
        return null;
    }

    @Override
    public void openEditor(final Object input) throws Exception {
        final Display d = Display.getCurrent();
        if (d == null)
            return;

        Simantics.getSession().syncRequest(new ReadRequest() {
            @Override
            public void run(ReadGraph graph) throws DatabaseException {
                Pair<Resource, String> r = tryGetResource(graph, input);
                if (r == null)
                    return;

                Variable v = AdaptionUtils.adaptToSingle(input, Variable.class);

                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug(getClass().getSimpleName() + ".openEditor: input's nearest parent resource URI: " + NameUtils.getURIOrSafeNameInternal(graph, r.first)); //$NON-NLS-1$
                    LOGGER.debug(getClass().getSimpleName() + ".openEditor: input's nearest parent RVI: " + r.second); //$NON-NLS-1$
                    LOGGER.debug(getClass().getSimpleName() + ".openEditor: input variable URI: " + (v != null ? v.getURI(graph) : "null")); //$NON-NLS-1$ //$NON-NLS-2$
                }

                final Collection<Runnable> rs = tryFindDiagram(graph, r.first, v, r.second);
                if (rs.isEmpty())
                    return;

                SWTThread.getThreadAccess(d).asyncExec(() -> rs.forEach(Runnable::run));
            }
        });
    }

    private Collection<Runnable> tryFindDiagram(ReadGraph g, Resource component, Variable variable, String rviFromComponent) throws DatabaseException {
        try {
            return findDiagram(g, component, variable, rviFromComponent);
        } catch (DatabaseException e) {
            return Collections.emptyList();
        }
    }

    private Collection<Runnable> findDiagram(ReadGraph g, Resource component, Variable variable, String rviFromComponent) throws DatabaseException {
        Layer0 l0 = Layer0.getInstance(g);
        StructuralResource2 STR = StructuralResource2.getInstance(g);
        ModelingResources MOD = ModelingResources.getInstance(g);

        if (g.isInstanceOf(component, STR.Component)) {
            Collection<Runnable> result = new ArrayList<>(1);

            Resource composite = g.getSingleObject(component, l0.PartOf);
            Resource diagram = ComponentUtils.getPossibleCompositeDiagram(g, composite);

            String editorId = getEditorId(g, composite);

            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: component: " + NameUtils.getURIOrSafeNameInternal(g, component)); //$NON-NLS-1$
                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: composite: " + NameUtils.getURIOrSafeNameInternal(g, composite)); //$NON-NLS-1$
            }

            Collection<Resource> referenceElements = diagram == null ? g.getObjects(component, MOD.HasParentComponent_Inverse) : Collections.<Resource>emptyList();
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: diagram: " + NameUtils.getURIOrSafeNameInternal(g, diagram)); //$NON-NLS-1$
                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: referenceElements: " + referenceElements.size()); //$NON-NLS-1$
                for (Object object : referenceElements)
                    LOGGER.debug("\t" + NameUtils.getURIOrSafeNameInternal(g, (Resource) object)); //$NON-NLS-1$
            }
            if (diagram == null && referenceElements.isEmpty())
                return Collections.emptyList();

            Variable compositeVariable = Variables.getPossibleVariable(g, composite);
            if (compositeVariable == null)
                return Collections.emptyList();
            final Resource indexRoot = Variables.getPossibleIndexRoot(g, compositeVariable);
            if (indexRoot == null)
                return Collections.emptyList();
            if (LOGGER.isDebugEnabled())
                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: Model: " + indexRoot); //$NON-NLS-1$

            if (diagram != null) {
                if(OpenDiagramFromConfigurationAdapter.isLocked(g, diagram))
                    return Collections.emptyList();

                RVI rvi = null;
                boolean allowNullRvi = false;
                if (variable != null) {
                    // Get proper RVI from variable if it exists.
                    Variable context = Variables.getPossibleContext(g, variable);
                    if (context != null) {
                        // We want the composite's RVI, not the component in it.
                        Variable parent = findFirstParentComposite(g, variable);
                        if (parent != null) {
                            rvi = parent.getPossibleRVI(g);
                            if (LOGGER.isDebugEnabled())
                                LOGGER.debug(getClass().getSimpleName() + ".findDiagram: resolved RVI: " + rvi); //$NON-NLS-1$
                        }
                    }
                } else {
                    allowNullRvi = true;
                    rvi = compositeVariable.getPossibleRVI(g);
                    if (LOGGER.isDebugEnabled())
                        LOGGER.debug(getClass().getSimpleName() + ".findDiagram: resolved RVI from resource path: " + rvi); //$NON-NLS-1$
                }
                if (rvi == null && !allowNullRvi)
                    return Collections.emptyList();

                Collection<Object> selectedObjects = findElementObjects(g, component, rviFromComponent);
                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug(getClass().getSimpleName() + ".findDiagram: selected objects: " + selectedObjects.size()); //$NON-NLS-1$
                    for (Object object : selectedObjects)
                        LOGGER.debug("\t" + NameUtils.getURIOrSafeNameInternal(g, (Resource) object)); //$NON-NLS-1$
                }
                // Prevent diagram from opening if there's nothing to select
                // on the diagram based on the received input.
                if (!selectedObjects.isEmpty())
                    result.add( NavigateToTarget.editorActivator(editorId, diagram, indexRoot, rvi, editorActivationCallback(selectedObjects)) );
            } else {
                final MapSet<NamedResource, Resource> referencingDiagrams = listReferenceDiagrams(g, referenceElements);
                final Set<NamedResource> diagrams = referencingDiagrams.getKeys();
                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug(getClass().getSimpleName() + ".findDiagram: selected objects: " + diagrams.size()); //$NON-NLS-1$
                    for (NamedResource d : diagrams) {
                        LOGGER.debug("\t" + NameUtils.getURIOrSafeNameInternal(g, d.getResource()) + ":"); //$NON-NLS-1$ //$NON-NLS-2$
                        for (Resource referenceElement : referencingDiagrams.getValues(d)) {
                            LOGGER.debug("\t\t" + NameUtils.getURIOrSafeNameInternal(g, referenceElement)); //$NON-NLS-1$
                        }
                    }
                }
                switch (diagrams.size()) {
                case 0:
                    // Prevent diagram from opening if there's nothing to select
                    // on the diagram based on the received input.
                    break;

                case 1:
                    // Open the one diagram straight away.
                    NamedResource singleDiagram = diagrams.iterator().next();
                    RVI rvi = getDiagramCompositeRvi(g, singleDiagram.getResource());
                    if (rvi != null) {
                        Collection<Resource> selectedObjects = referencingDiagrams.getValues(singleDiagram);
                        result.add( NavigateToTarget.editorActivator(editorId, singleDiagram.getResource(), indexRoot, rvi, editorActivationCallback(selectedObjects)) );
                    }
                    break;

                default:
                    final Map<NamedResource, RVI> diagramToRvi = new TreeMap<>(COMPARATOR);
                    for (NamedResource d : diagrams) {
                        RVI rvi2 = getDiagramCompositeRvi(g, d.getResource());
                        if (rvi2 != null)
                            diagramToRvi.put(d, rvi2);
                    }
                    result.add(() -> {
                        NamedResource selected = queryTarget(WorkbenchUtils.getActiveWorkbenchWindowShell(), diagramToRvi.keySet());
                        if (selected != null) {
                            Collection<Resource> selectedObjects = referencingDiagrams.getValues(selected);
                            RVI drvi = diagramToRvi.get(selected);
                            NavigateToTarget.editorActivator(editorId, selected.getResource(), indexRoot, drvi, editorActivationCallback(selectedObjects)).run();
                        }
                    });
                    break;
                }
            }
            return result;
        }

        // Nothing to open
        return Collections.emptyList();
    }

    private RVI getDiagramCompositeRvi(ReadGraph graph, Resource diagram) throws DatabaseException {
        ModelingResources MOD = ModelingResources.getInstance(graph);
        Resource composite = graph.getPossibleObject(diagram, MOD.DiagramToComposite);
        if (composite == null)
            return null;
        Variable v = Variables.getPossibleVariable(graph, composite);
        return v != null ? v.getPossibleRVI(graph) : null;
    }

    private Consumer<IEditorPart> editorActivationCallback(final Collection<? extends Object> selectedObjects) {
        return part -> {
            final ICanvasContext openedCanvas = (ICanvasContext) part.getAdapter(ICanvasContext.class);
            assert openedCanvas != null;
            // CanvasContext-wide denial of initial zoom-to-fit on diagram open.
            openedCanvas.getDefaultHintContext().setHint(DiagramHints.KEY_INITIAL_ZOOM_TO_FIT, Boolean.FALSE);
            ThreadUtils.asyncExec(openedCanvas.getThreadAccess(),
                    NavigateToTarget.elementSelectorZoomer(openedCanvas, selectedObjects, false));
        };
    }

    private Variable findFirstParentComposite(ReadGraph graph, Variable v) throws DatabaseException {
        Variable first = findFirstWithRepresentation(graph, v);
        if (first == null)
            return null;
        Variable parent = first.getParent(graph);
        return parent;
    }

    private Variable findFirstWithRepresentation(ReadGraph graph, Variable v) throws DatabaseException {
        while (v != null) {
            Resource represents = v.getPossibleRepresents(graph);
            if (LOGGER.isDebugEnabled())
                LOGGER.debug(v.getURI(graph) + " -> " + NameUtils.getURIOrSafeNameInternal(graph, represents)); //$NON-NLS-1$
            if (represents != null)
                return v;
            v = v.getParent(graph);
        }
        return null;
    }

    public static Collection<Object> findElementObjects(ReadGraph g, Resource component, String rviFromComponent) throws DatabaseException {
        DiagramResource DIA = DiagramResource.getInstance(g);
        ModelingResources MOD = ModelingResources.getInstance(g);
        final Collection<Object> selectedObjects = new ArrayList<>(4);
        if (rviFromComponent.isEmpty()) {
            // The selected objects are configuration objects
            for (Resource element : g.getObjects(component, MOD.ComponentToElement)) {
                if (g.isInstanceOf(element, DIA.Flag) && FlagUtil.isExternal(g, element)) {
                    // Use external flag primarily if one exists in the correspondences
                    selectedObjects.clear();
                    selectedObjects.add(element);
                    break;
                } else if (g.isInstanceOf(element, DIA.RouteGraphConnection)) {
                    selectedObjects.add(element);
                } else if (g.isInstanceOf(element, DIA.Connection)) {
                    // Okay, we need to find a part of the connection
                    ConnectionUtil cu = new ConnectionUtil(g);
                    cu.gatherConnectionParts(element, selectedObjects);
                } else {
                    selectedObjects.add(element);
                }
            }
        }
        return selectedObjects;
    }

    protected MapSet<NamedResource, Resource> listReferenceDiagrams(ReadGraph graph, Collection<Resource> referenceElements) throws DatabaseException {
        ModelingResources MOD = ModelingResources.getInstance(graph);

        // Make result diagram ordering stable and logical by using our own comparator.
        MapSet<NamedResource, Resource> diagrams = new MapSet.Tree<>(COMPARATOR);

        for (Resource referenceElement : referenceElements) {
            final Resource diagram = NavigateToTarget.getOwnerList(graph, referenceElement);
            if (diagram == null)
                continue;
            Resource composite = graph.getPossibleObject(diagram, MOD.DiagramToComposite);
            if (composite == null)
                continue;
            Variable v = Variables.getPossibleVariable(graph, composite);
            if (v == null)
                continue;

            String rvi = URIStringUtils.unescape( Variables.getRVI(graph, v) );

            diagrams.add(new NamedResource(rvi, diagram), referenceElement);
        }

        return diagrams;
    }

    private static final Comparator<? super NamedResource> COMPARATOR =
            (o1, o2) -> AlphanumComparator.CASE_INSENSITIVE_COMPARATOR.compare(o1.getName(), o2.getName());

    protected NamedResource queryTarget(final Shell parentShell, Collection<NamedResource> options) {
        NavigationTargetChooserDialog dialog = new NavigationTargetChooserDialog(
                parentShell, options.toArray(new NamedResource[options.size()]),
                Messages.OpenDiagramFromComponentAdapter_ChooseDiagramComponetReference,
                Messages.OpenDiagramFromComponentAdapter_SelectSingleDiagramfromList);
        return dialog.open() != Window.OK ? null : dialog.getSelection();
    }

}