package net.quies.tech.csv;

/*
Copyright (c) 2006, 2007 Pascal S. de Kloe. All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived
   from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
OF SUCH DAMAGE.
*/

import java.io.*;


/**
 * Formats CSV to to a stream.
 @author Pascal S. de Kloe
 @since 1.0
 */
public final class CSVWriter {

/**
 @param target the CSV stream. The use of {@link java.io.BufferedWriter} is recommended.
 @since 1.0
 */
public
CSVWriter(Writer target) {
	if (target == null)
		throw new IllegalArgumentException();
	out = target;
}


/**
 * Flushes the stream.
 @throws IOException if the {@code Writer} caused any troubles.
 @since 1.0
 @see java.io.Writer#flush()
 */
public void
flush()
throws IOException {
	out.flush();
}


/**
 @deprecated As of version 1.1, replaced by {@link #getRecordIndex()}.
 @since 1.0
 */
public long
getRecordNumber() {
        return getRecordIndex();
}


/**
 * Gets the zero-based record index which is equal to the number of written records.
 @since 1.1
 */
public long
getRecordIndex() {
	return record;
}


/**
 * This method is equal to {@link #writeRecord(String[])}.
 @since 1.0
 */
public void
writeHeader(String[] name)
throws IOException, RFC4180Violation {
	writeRecord(name);
}


/**
 @throws NullPointerException if {@code field} is {@code null} or if {@code field} has any {@code null} elements.
 @throws IOException if the {@code Writer} caused any troubles.
 @throws RFC4180Violation if {@code field} has no elements or if one or more fields contain characters that can't be written.
 * These characters are in ASCII sexadecimal: 00-09, 0B-0C, 0E-1F.
 @since 1.0
 */
public void
writeRecord(String[] field)
throws IOException, RFC4180Violation {
	int fields = field.length;	// throws NullPointerException if field is null
	if (fields == 0)
		throw new RFC4180Violation("A record must contain at least one field.");

	writeField(field[0]);
	for (int i = 1; i < fields; ++i) {
		out.write((int) ',');
		writeField(field[i]);
	}
	out.write("\r\n");
	++record;
}


private void
writeField(String field)
throws IOException, RFC4180Violation {
	char[] data = field.toCharArray();	// throws NullPointerException if field is null
	if (needEscape(data))
		writeEscaped(data);
	else
		out.write(data);
}


/**
 * Verifies the characters.
 @return {@code true} if {@code data} containes characters that need to be escaped.
 @throws RFC4180Violation if {@code data} containes characters that can't be written.
 */
private static boolean
needEscape(char[] data)
throws RFC4180Violation {
	boolean need = false;
	for (int i = data.length; --i >= 0;) {
		char c = data[i];
		if (c < ' ') {
			if (c == '\r' || c == '\n')
				need = true;
			else
				throw new RFC4180Violation("illegal character 0x" + Integer.toHexString((int) c).toUpperCase());
		} else if (c == ',' || c == '"')
			need = true;
	}
	return need;
}


private void
writeEscaped(char[] data)
throws IOException {
	out.write((int) '"');
	for (int i = 0; i < data.length; ++i) {
		char c = data[i];
		if (c == '"')
			out.write("\"\"");
		else
			out.write((int) c);
	}
	out.write((int) '"');
}


private final Writer out;
private long record = 0L;

}