/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * 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.argeo.util;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.UnsupportedEncodingException;
  import java.io.Writer;
  import java.util.Iterator;
  import java.util.List;
  
  /** Write in CSV format. */
  public class CsvWriter {
  	private final Writer out;
  
  	private char separator = ',';
  	private char quote = '\"';
  
  	/**
  	 * Creates a CSV writer.
  	 * 
  	 * @param out
  	 *            the stream to write to. Caller is responsible for closing it.
  	 */
  	public CsvWriter(OutputStream out) {
  		this.out = new OutputStreamWriter(out);
  	}
  
  	/**
  	 * Creates a CSV writer.
  	 * 
  	 * @param out
  	 *            the stream to write to. Caller is responsible for closing it.
  	 */
  	public CsvWriter(OutputStream out, String encoding) {
  		try {
  			this.out = new OutputStreamWriter(out, encoding);
  		} catch (UnsupportedEncodingException e) {
  			throw new UtilsException("Cannot initialize CSV writer", e);
  		}
  	}
  
  	/**
  	 * Write a CSV line. Also used to write a header if needed (this is
  	 * transparent for the CSV writer): simply call it first, before writing the
  	 * lines.
  	 */
  	public void writeLine(List<?> tokens) {
  		try {
  			Iterator<?> it = tokens.iterator();
  			while (it.hasNext()) {
  				writeToken(it.next().toString());
  				if (it.hasNext())
  					out.write(separator);
  			}
  			out.write('\n');
  			out.flush();
  		} catch (IOException e) {
  			throw new UtilsException("Could not write " + tokens, e);
  		}
  	}
  
  	/**
  	 * Write a CSV line. Also used to write a header if needed (this is
  	 * transparent for the CSV writer): simply call it first, before writing the
  	 * lines.
  	 */
  	public void writeLine(Object[] tokens) {
  		try {
  			for (int i = 0; i < tokens.length; i++) {
  				if (tokens[i] == null) {
  					// TODO configure how to deal with null
  					writeToken("");
  				} else {
  					writeToken(tokens[i].toString());
  				}
  				if (i != (tokens.length - 1))
  					out.write(separator);
  			}
  			out.write('\n');
  			out.flush();
  		} catch (IOException e) {
  			throw new UtilsException("Could not write " + tokens, e);
  		}
  	}
 
 	protected void writeToken(String token) throws IOException {
 		// +2 for possible quotes, another +2 assuming there would be an already
 		// quoted string where quotes needs to be duplicated
 		// another +2 for safety
 		// we don't want to increase buffer size while writing
 		StringBuffer buf = new StringBuffer(token.length() + 6);
 		char[] arr = token.toCharArray();
 		boolean shouldQuote = false;
 		for (char c : arr) {
 			if (!shouldQuote) {
 				if (c == separator)
 					shouldQuote = true;
 				if (c == '\n')
 					shouldQuote = true;
 			}
 
 			if (c == quote) {
 				shouldQuote = true;
 				// duplicate quote
 				buf.append(quote);
 			}
 
 			// generic case
 			buf.append(c);
 		}
 
 		if (shouldQuote == true)
 			out.write(quote);
 		out.write(buf.toString());
 		if (shouldQuote == true)
 			out.write(quote);
 	}
 
 	public void setSeparator(char separator) {
 		this.separator = separator;
 	}
 
 	public void setQuote(char quote) {
 		this.quote = quote;
 	}
 
 }