/*
    * dpkg - Debian Package library and the Debian Package Maven plugin
    * (c) Copyright 2016 Gerrit Hohl
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU General Public License
    * as published by the Free Software Foundation; either version 2
    * of the License, or (at your option) any later version.
    *
   * 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  package net.sourceforge.javadpkg.field.impl;
  
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.io.OutputStreamWriter;
  import java.util.List;
  
  import net.sourceforge.javadpkg.BuildException;
  import net.sourceforge.javadpkg.Context;
  import net.sourceforge.javadpkg.GlobalConstants;
  import net.sourceforge.javadpkg.field.Field;
  import net.sourceforge.javadpkg.field.FieldBuilder;
  import net.sourceforge.javadpkg.io.DataTarget;
  
  
  /**
   * <p>
   * A {@link FieldBuilder} implementation.
   * </p>
   *
   * @author Gerrit Hohl (gerrit-hohl@users.sourceforge.net)
   * @version <b>1.0</b>, 29.04.2016 by Gerrit Hohl
   */
  public class FieldBuilderImpl implements FieldBuilder, GlobalConstants {
  	
  	
  	/**
  	 * <p>
  	 * Creates a builder.
  	 * </p>
  	 */
  	public FieldBuilderImpl() {
  		super();
  	}
  
  
  	@Override
  	public void buildFields(List<Field> fields, DataTarget target, Context context) throws IOException, BuildException {
  		StringBuilder sb;
  		String value;
  		
  		
  		if (fields == null)
  			throw new IllegalArgumentException("Argument fields is null.");
  		if (target == null)
  			throw new IllegalArgumentException("Argument target is null.");
  		if (context == null)
  			throw new IllegalArgumentException("Argument context is null.");
  		
  		sb = new StringBuilder();
  		for (Field field : fields) {
  			if (sb.length() > 0) {
  				sb.append('\n');
  			}
  			
  			if (field.isEmpty()) {
  				continue;
  			}
  			
  			if (!field.isNameless()) {
  				sb.append(field.getName());
  				sb.append(": ");
  			}
  			value = this.getFormattedValue(field.getValue());
  			sb.append(value);
  		}
  		if (sb.length() > 0) {
  			sb.append('\n');
  		}
  
  		try (BufferedWriter out = new BufferedWriter(new OutputStreamWriter(target.getOutputStream(), UTF_8_CHARSET))) {
  			out.write(sb.toString());
  		}
  	}
  	
  	
  	/**
  	 * <p>
  	 * Returns the formatted value.
  	 * </p>
  	 *
 	 * @param value
 	 *            The value.
 	 * @return The formatted value.
 	 */
 	private String getFormattedValue(String value) {
 		String[] values;
 		StringBuilder sb;
 		
 		
 		if (value.indexOf('\n') == -1)
 			return value;
 		
 		// ROADMAP Throw a BuildException if a line is empty.
 		values = value.split("\n", -1);
 		sb = new StringBuilder();
 		for (String v : values) {
 			if (sb.length() > 0) {
 				sb.append("\n ");
 			}
 			sb.append(v);
 		}
 		return sb.toString();
 	}
 	
 	
 }