/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Neopost - Customer Information Management
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.connection;

import java.io.File;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.List;

import org.apache.metamodel.UpdateableDataContext;
import org.apache.metamodel.excel.ExcelConfiguration;
import org.apache.metamodel.excel.ExcelDataContext;
import org.apache.metamodel.schema.naming.CustomColumnNamingStrategy;
import org.apache.metamodel.util.Resource;
import org.apache.metamodel.util.SerializableRef;
import org.datacleaner.util.ReadObjectBuilder;

/**
 * Datastore implementation for Excel spreadsheets.
 */
public final class ExcelDatastore extends UsageAwareDatastore<UpdateableDataContext>
        implements FileDatastore, ResourceDatastore, UpdateableDatastore {

    private static final long serialVersionUID = 1L;

    private final String _filename;
    private final SerializableRef<Resource> _resourceRef;
    private List<String> _customColumnNames;

    public ExcelDatastore(final String name, final Resource resource, final String filename) {
        this(name, resource, filename, null);
    }

    public ExcelDatastore(final String name, final Resource resource, final String filename,
            final List<String> customColumnNames) {
        super(name);
        _resourceRef = new SerializableRef<>(resource);
        _filename = filename;
        _customColumnNames = customColumnNames;
    }

    private void readObject(final ObjectInputStream stream) throws IOException, ClassNotFoundException {
        ReadObjectBuilder.create(this, ExcelDatastore.class).readObject(stream);
    }

    @Override
    public Resource getResource() {
        if (_resourceRef == null) {
            return null;
        }
        return _resourceRef.get();
    }

    @Override
    public String getFilename() {
        return _filename;
    }

    public List<String> getCustomColumnNames() {
        return _customColumnNames;
    }

    @Override
    protected UsageAwareDatastoreConnection<UpdateableDataContext> createDatastoreConnection() {
        final UpdateableDataContext dc;
        final Resource resource = getResource();
        final ExcelConfiguration excelConfiguration = getExcelConfiguration();

        if (resource == null) {
            dc = new ExcelDataContext(new File(_filename), excelConfiguration);
        } else {
            dc = new ExcelDataContext(resource, excelConfiguration);
        }

        return new UpdateableDatastoreConnectionImpl<>(dc, this);
    }

    private ExcelConfiguration getExcelConfiguration() {
        if (_customColumnNames != null && _customColumnNames.size() > 0) {
            return new ExcelConfiguration(ExcelConfiguration.DEFAULT_COLUMN_NAME_LINE,
                    new CustomColumnNamingStrategy(_customColumnNames), true, false);
        } else {
            return new ExcelConfiguration();
        }

    }

    @Override
    public UpdateableDatastoreConnection openConnection() {
        final DatastoreConnection connection = super.openConnection();
        return (UpdateableDatastoreConnection) connection;
    }

    @Override
    public PerformanceCharacteristics getPerformanceCharacteristics() {
        return new PerformanceCharacteristicsImpl(false, true);
    }

    @Override
    protected void decorateIdentity(final List<Object> identifiers) {
        super.decorateIdentity(identifiers);
        identifiers.add(_filename);
    }
}