/*
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.drools.eclipse.menu;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.drools.eclipse.wizard.decisiontable.NewDTFileWizard;
import org.drools.eclipse.wizard.dsl.NewDSLFileWizard;
import org.drools.eclipse.wizard.project.NewDroolsProjectWizard;
import org.drools.eclipse.wizard.rule.NewRulePackageWizard;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.wizard.WizardDialog;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.INewWizard;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.IWorkbenchWindowPulldownDelegate;
import org.kie.eclipse.wizard.project.AbstractKieProjectWizard;

/**
 * Menu driver for launching wizards etc from the top level toolbar.
 * 
 * More can be added to this as needed.
 */
public class RuleHelperActionDelegate
    implements
    IWorkbenchWindowPulldownDelegate {

    private IWorkbench workbench;
    private Menu menu;

    /** Return a menu which launches the various wizards */
    public Menu getMenu(Control parent) {

        setMenu( new Menu( parent ) );
        
        final Shell shell = parent.getShell();
        addProjectWizard( menu,
                shell );

        addRuleWizard( menu,
                       shell );

        addDSLWizard( menu,
                      shell );
        
        addDTWizard( menu,
                      shell );
        
        return menu;
    }
    
    private void setMenu(Menu menu) {
        if (this.menu != null) {
            this.menu.dispose();
        }
        this.menu = menu;
    }

    private void addDTWizard(Menu menu,
                             final Shell shell) {
        MenuItem dsl = new MenuItem( menu,
                                     SWT.NONE );
        dsl.setText( "New Decision Table" );
        dsl.addSelectionListener( new SelectionListener() {

            public void widgetSelected(SelectionEvent e) {
                NewDTFileWizard wizard = new NewDTFileWizard();
                launchWizard( shell, wizard );
            }
            public void widgetDefaultSelected(SelectionEvent e) {}
        });
        
    }

    private void addProjectWizard(Menu menu, final Shell shell) {
        MenuItem rule = new MenuItem(menu, SWT.NONE);
        rule.setText("New Drools Project");

        rule.addSelectionListener(new SelectionListener() {
            public void widgetSelected(SelectionEvent e) {
                AbstractKieProjectWizard wizard = new NewDroolsProjectWizard();
                launchWizard(shell, wizard);
            }

            public void widgetDefaultSelected(SelectionEvent e) {
            }
        });
    }

    private void addRuleWizard(Menu menu,
                               final Shell shell) {
        MenuItem rule = new MenuItem( menu,
                                      SWT.NONE );
        rule.setText( "New Rule" );

        rule.addSelectionListener( new SelectionListener() {
            public void widgetSelected(SelectionEvent e) {
                NewRulePackageWizard wizard = new NewRulePackageWizard();
                launchWizard( shell,
                              wizard );
            }
            public void widgetDefaultSelected(SelectionEvent e) {}
        });
    }

    private void addDSLWizard(Menu menu,
                              final Shell shell) {
        MenuItem dsl = new MenuItem( menu,
                                     SWT.NONE );
        dsl.setText( "New Domain Specific Language" );
        dsl.addSelectionListener( new SelectionListener() {

            public void widgetSelected(SelectionEvent e) {
                NewDSLFileWizard wizard = new NewDSLFileWizard();
                launchWizard( shell, wizard );
            }
            public void widgetDefaultSelected(SelectionEvent e) {}
        });
    }
    
    private void launchWizard(Shell shell,
                              INewWizard wizard) {
        wizard.init( workbench,
                     new DummySelection() );
        WizardDialog dialog = new WizardDialog( shell,
                                                wizard );
        dialog.open();
    }

    public void dispose() {
    }

    public void init(IWorkbenchWindow window) {
        workbench = window.getWorkbench();
    }

    public void run(IAction action) {
    }

    public void selectionChanged(IAction action,
                                 ISelection selection) {
    }
    
    /** Stub structured selection listener, as is required to launch the wizard */
    static class DummySelection implements IStructuredSelection {
        public Object getFirstElement() {
            return null;
        }

        public Iterator<?> iterator() {
            return (new ArrayList<Object>()).iterator();
        }

        public int size() {
            return 0;
        }

        public Object[] toArray() {
            return null;
        }

        public List<?> toList() {
            return null;
        }

        public boolean isEmpty() {
            return true;
        }
    }

}
