package org.simantics.district.network.ui.contributions;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.inject.Named;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.e4.core.di.annotations.CanExecute;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.layout.GridDataFactory;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.dialogs.SelectionStatusDialog;
import org.simantics.DatabaseJob;
import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.SelectionHints;
import org.simantics.db.request.Read;
import org.simantics.district.network.ontology.DistrictNetworkResource;
import org.simantics.district.network.ui.function.Functions;
import org.simantics.district.network.ui.internal.Activator;
import org.simantics.layer0.Layer0;
import org.simantics.utils.ui.ISelectionUtils;

public class ChangeMappingTypeHandler {

    
    @CanExecute
    public boolean canExecute(@Named(IServiceConstants.ACTIVE_SELECTION) ISelection selection) {
        List<Resource> elements = ISelectionUtils.getPossibleKeys(selection, SelectionHints.KEY_MAIN, Resource.class);
        if (elements.size() < 1)
            return false;
        try {
            return Simantics.getSession().syncRequest(new Read<Boolean>() {

                @Override
                public Boolean perform(ReadGraph graph) throws DatabaseException {
                    Layer0 L0 = Layer0.getInstance(graph);
                    Resource instanceOf = null;
                    for (Resource element : elements) {
                        if (instanceOf == null) {
                            instanceOf = graph.getSingleObject(element, L0.InstanceOf);
                        } else {
                            Resource currentInstanceOf = graph.getSingleObject(element, L0.InstanceOf);
                            if (!currentInstanceOf.equals(instanceOf)) {
                                return false;
                            }
                        }
                    }
                    return true;
                }
            });
        } catch (DatabaseException e) {
            e.printStackTrace();
            return false;
        }
    }
    
    @Execute
    public void execute(@Named(IServiceConstants.ACTIVE_SELECTION) Object selection) {
        final List<Resource> elements = ISelectionUtils.getPossibleKeys(selection, SelectionHints.KEY_MAIN, Resource.class);
        if (elements.size() < 1)
            return;
        
        SelectMappingDialog dialog = new SelectMappingDialog(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), elements);
        if (dialog.open() != Dialog.OK)
            return;
        
        Resource mapping = dialog.getDefaultVertexMapping();
        Job job = new DatabaseJob("Join selected vertices") {
            
            @Override
            protected IStatus run(IProgressMonitor monitor) {
                try {
                    Simantics.getSession().syncRequest(new WriteRequest() {
                        
                        @Override
                        public void perform(WriteGraph graph) throws DatabaseException {
                            DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
                            for (Resource element : elements) {
                                graph.deny(element, DN.HasMapping);
                                graph.claim(element, DN.HasMapping, mapping);
                            }
                        }
                    });
                } catch (DatabaseException e) {
                    return new Status(IStatus.ERROR, Activator.PLUGIN_ID, getName() + " failed.", e);
                }
                return Status.OK_STATUS;
            }
        };
        job.setUser(true);
        job.schedule();
    }
    
    private static class SelectMappingDialog extends SelectionStatusDialog {

        private Combo vertexMappingCombo;
        
        private Composite composite;
        
        private List<Resource> elements;
        private Map<String, Resource> vertexMappings = new HashMap<>();
        
        private Resource defaultVertexMapping;

        protected SelectMappingDialog(Shell parentShell, List<Resource> elements) {
            super(parentShell);
            this.elements = elements;
            setTitle("Select mappings for new DN diagram");
        }

        public Resource getDefaultVertexMapping() {
            return defaultVertexMapping;
        }

        @Override
        protected Control createDialogArea(Composite parent) {
            composite = (Composite) super.createDialogArea(parent);
            
            createMappingsGroup(composite);
            
            // compute default values
            Simantics.getSession().asyncRequest(new ReadRequest() {

                @Override
                public void run(ReadGraph graph) throws DatabaseException {
                    DistrictNetworkResource DN = DistrictNetworkResource.getInstance(graph);
                    Resource element = elements.get(0);
                    if (graph.isInstanceOf(element, DN.Vertex)) {
                        vertexMappings = Functions.getVertexMappings(graph, element);
                    } else if (graph.isInstanceOf(element, DN.Edge)) {
                        vertexMappings = Functions.getEdgeMappings(graph, element);
                    }
                    composite.getDisplay().asyncExec(() -> {
                        vertexMappingCombo.setItems(vertexMappings.keySet().toArray(new String[vertexMappings.size()]));
                        vertexMappingCombo.select(0);
                    }); 
                    
                }
            });
            return composite;
        }

        @Override
        protected void computeResult() {
            defaultVertexMapping = vertexMappings.get(vertexMappingCombo.getItem(vertexMappingCombo.getSelectionIndex()));
        }
        
        private void createMappingsGroup(Composite parent) {
            Group group= new Group(parent, SWT.NONE);
            group.setFont(parent.getFont());
            group.setText("Default mappings");
            GridDataFactory.fillDefaults().grab(true, false).applyTo(group);
            group.setLayout(new GridLayout(1, false));
            
            Composite cmposite = new Composite(group, SWT.NONE);
            cmposite.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true, false));
            cmposite.setLayout(new GridLayout(2, false));
            
            Label vertexMappingLabel = new Label(cmposite, SWT.NONE);
            vertexMappingLabel.setText("Default vertex mapping");

            vertexMappingCombo = new Combo(cmposite, SWT.READ_ONLY | SWT.BORDER);
            GridDataFactory.fillDefaults().grab(true, false).applyTo(vertexMappingCombo);
            
        }
    }
}