/*
 * DBeaver - Universal Database Manager
 * Copyright (C) 2010-2017 Serge Rider (serge@jkiss.org)
 *
 * 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.jkiss.dbeaver.tools.transfer.handlers;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.handlers.HandlerUtil;
import org.jkiss.dbeaver.tools.transfer.IDataTransferConsumer;
import org.jkiss.dbeaver.tools.transfer.IDataTransferNode;
import org.jkiss.dbeaver.tools.transfer.IDataTransferProducer;
import org.jkiss.dbeaver.tools.transfer.wizard.DataTransferWizard;
import org.jkiss.dbeaver.ui.dialogs.ActiveWizardDialog;

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

public abstract class DataTransferHandler extends AbstractHandler {

    @Override
    public Object execute(ExecutionEvent event) throws ExecutionException {
        final IWorkbenchWindow workbenchWindow = HandlerUtil.getActiveWorkbenchWindow(event);
        final ISelection selection = HandlerUtil.getCurrentSelection(event);
        if (!(selection instanceof IStructuredSelection)) {
            return null;
        }
        IStructuredSelection ss = (IStructuredSelection)selection;
        final List<IDataTransferProducer> producers = new ArrayList<>();
        final List<IDataTransferConsumer> consumers = new ArrayList<>();
        for (Iterator<?> iter = ss.iterator(); iter.hasNext(); ) {
            Object object = iter.next();

            IDataTransferNode node = adaptTransferNode(object);
            if (node instanceof IDataTransferProducer) {
                producers.add((IDataTransferProducer) node);
            } else if (node instanceof IDataTransferConsumer) {
                consumers.add((IDataTransferConsumer) node);
            }
        }

        if (!consumers.isEmpty()) {
            // We need to choose producer for consumers
            for (IDataTransferConsumer consumer : consumers) {
                IDataTransferProducer producer = chooseProducer(event, consumer);
                if (producer == null) {
                    return null;
                }
                producers.add(producer);
            }
        }

        // Run transfer wizard
        if (!producers.isEmpty() || !consumers.isEmpty()) {
            ActiveWizardDialog dialog = new ActiveWizardDialog(
                workbenchWindow,
                new DataTransferWizard(
                    producers.toArray(new IDataTransferProducer[producers.size()]),
                    consumers.toArray(new IDataTransferConsumer[consumers.size()])));
            dialog.open();
        }

        return null;
    }

    protected IDataTransferProducer chooseProducer(ExecutionEvent event, IDataTransferConsumer consumer)
    {
        return null;
    }

    protected abstract IDataTransferNode adaptTransferNode(Object object);
}