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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.template;

import org.drools.template.parser.DataListener;
import org.drools.template.parser.DefaultTemplateContainer;
import org.drools.template.parser.TemplateDataListener;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * An object of this class acts as a template compiler, inserting spreadsheet
 * data into templates. Template data may come from a resource or an
 * InputStream, or you may provide a TemplateDataListener.
 */
public class DataProviderCompiler {

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider the data provider for the spreadsheet data
     * @param template     the string containing the template resource name
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final String template) {
        final InputStream templateStream = this.getClass().getResourceAsStream(template);
        return compile(dataProvider,
                       templateStream);
    }

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider   the data provider for the spreadsheet data
     * @param templateStream the InputStream for reading the templates
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final InputStream templateStream) {
        return compile(dataProvider,templateStream, true );
    }

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider the data provider for the spreadsheet data
     * @param listener     a template data listener
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final TemplateDataListener listener) {
        return compile(dataProvider, listener, true);
    }

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider the data provider for the spreadsheet data
     * @param template     the string containing the template resource name
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final String template,
                          boolean replaceOptionals) {
        final InputStream templateStream = this.getClass().getResourceAsStream(template);
        return compile(dataProvider,
                       templateStream);
    }

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider   the data provider for the spreadsheet data
     * @param templateStream the InputStream for reading the templates
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final InputStream templateStream,
                          boolean replaceOptionals) {
        DefaultTemplateContainer tc = new DefaultTemplateContainer(templateStream, replaceOptionals);
        closeStream(templateStream);
        return compile(dataProvider,
                       new TemplateDataListener(tc));
    }

    /**
     * Generates DRL from a data provider for the spreadsheet data and templates.
     *
     * @param dataProvider the data provider for the spreadsheet data
     * @param listener     a template data listener
     * @return the generated DRL text as a String
     */
    public String compile(final DataProvider dataProvider,
                          final TemplateDataListener listener,
                          boolean replaceOptionals) {
        List listeners = new ArrayList<>();
        listeners.add(listener);
        processData(dataProvider,
                    listeners);
        return listener.renderDRL();
    }

    private void processData(final DataProvider dataProvider,
                             List listeners) {
        for (int i = 0; dataProvider.hasNext(); i++) {
            String[] row = dataProvider.next();
            newRow(listeners,
                   i,
                   row.length);
            for (int cellNum = 0; cellNum < row.length; cellNum++) {
                String cell = row[cellNum];

                newCell(listeners,
                        i,
                        cellNum,
                        cell,
                        DataListener.NON_MERGED);
            }
        }
        finishData(listeners);
    }

    private void finishData(List listeners) {
        for (DataListener listener : listeners) {
            listener.finishSheet();
        }
    }

    private void newRow(List listeners,
                        int row,
                        int cols) {
        for (DataListener listener : listeners) {
            listener.newRow(row,
                            cols);
        }
    }

    public void newCell(List listeners,
                        int row,
                        int column,
                        String value,
                        int mergedColStart) {
        for (DataListener listener : listeners) {
            listener.newCell(row,
                             column,
                             value,
                             mergedColStart);
        }
    }

    protected void closeStream(final InputStream stream) {
        try {
            stream.close();
        } catch (final Exception e) {
            System.err.print("WARNING: Wasn't able to correctly close stream for rule template. " + e.getMessage());
        }
    }

}