/*
    * Copyright 2007 Kasper B. Graversen
    * 
    * 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.supercsv.encoder;
  
  import org.supercsv.prefs.CsvPreference;
  import org.supercsv.util.CsvContext;
  
  /**
   * The default CsvEncoder implementation.
   * 
   * @author James Bassett
   * @since 2.1.0
   */
  public class DefaultCsvEncoder implements CsvEncoder {
  	
  	/**
  	 * Constructs a new <tt>DefaultCsvEncoder</tt>.
  	 */
  	public DefaultCsvEncoder() {
  	}
  	
  	/**
  	 * {@inheritDoc}
  	 */
  	public String encode(final String input, final CsvContext context, final CsvPreference preference) {
  		
  		final StringBuilder currentColumn = new StringBuilder();
  		final int delimiter = preference.getDelimiterChar();
  		final char quote = (char) preference.getQuoteChar();
  		final String eolSymbols = preference.getEndOfLineSymbols();
  		final int lastCharIndex = input.length() - 1;
  		
  		boolean quotesRequiredForSpecialChar = false;
  		
  		boolean skipNewline = false;
  		
  		for( int i = 0; i <= lastCharIndex; i++ ) {
  			
  			final char c = input.charAt(i);
  			
  			if( skipNewline ) {
  				skipNewline = false;
  				if( c == '\n' ) {
  					continue; // newline following a carriage return is skipped
  				}
  			}
  			
  			if( c == delimiter ) {
  				quotesRequiredForSpecialChar = true;
  				currentColumn.append(c);
  			} else if( c == quote ) {
  				quotesRequiredForSpecialChar = true;
  				currentColumn.append(quote);
  				currentColumn.append(quote);
  			} else if( c == '\r' ) {
  				quotesRequiredForSpecialChar = true;
  				currentColumn.append(eolSymbols);
  				context.setLineNumber(context.getLineNumber() + 1);
  				skipNewline = true;
  			} else if( c == '\n' ) {
  				quotesRequiredForSpecialChar = true;
  				currentColumn.append(eolSymbols);
  				context.setLineNumber(context.getLineNumber() + 1);
  			} else {
  				currentColumn.append(c);
  			}
  		}
  		
  		final boolean quotesRequiredForMode = preference.getQuoteMode().quotesRequired(input, context, preference);
  		final boolean quotesRequiredForSurroundingSpaces = preference.isSurroundingSpacesNeedQuotes()
  			&& input.length() > 0 && (input.charAt(0) == ' ' || input.charAt(input.length() - 1) == ' ');
  		
  		if( quotesRequiredForSpecialChar || quotesRequiredForMode || quotesRequiredForSurroundingSpaces ) {
  			currentColumn.insert(0, quote).append(quote);
  		}
  		
  		return currentColumn.toString();
  	}
  	
  }