/*
 Copyright  2002-2004 MySQL AB, 2008 Sun Microsystems

 This program is free software; you can redistribute it and/or modify
 it under the terms of version 2 of the GNU General Public License as 
 published by the Free Software Foundation.

 There are special exceptions to the terms and conditions of the GPL 
 as it is applied to this software. View the full text of the 
 exception in file EXCEPTIONS-CONNECTOR-J in the directory of this 
 software distribution.

 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



 */
package com.mysql.jdbc;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.sql.SQLException;

/**
 * Simplistic implementation of java.sql.Clob for MySQL Connector/J
 * 
 * @author Mark Matthews
 * @version $Id$
 */
public class Clob implements java.sql.Clob, OutputStreamWatcher, WriterWatcher {
	private String charData;

    Clob() {
        this.charData = "";
    }
    
	Clob(String charDataInit) {
		this.charData = charDataInit;
	}

	/**
	 * @see java.sql.Clob#getAsciiStream()
	 */
	public InputStream getAsciiStream() throws SQLException {
		if (this.charData != null) {
			return new ByteArrayInputStream(this.charData.getBytes());
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#getCharacterStream()
	 */
	public Reader getCharacterStream() throws SQLException {
		if (this.charData != null) {
			return new StringReader(this.charData);
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#getSubString(long, int)
	 */
	public String getSubString(long startPos, int length) throws SQLException {
		if (startPos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.6"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		int adjustedStartPos = (int)startPos - 1;
		int adjustedEndIndex = adjustedStartPos + length;
		
		if (this.charData != null) {
			if (adjustedEndIndex > this.charData.length()) {
				throw SQLError.createSQLException(Messages.getString("Clob.7"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
			}

			return this.charData.substring(adjustedStartPos, 
					adjustedEndIndex);
		}

		return null;
	}

	/**
	 * @see java.sql.Clob#length()
	 */
	public long length() throws SQLException {
		if (this.charData != null) {
			return this.charData.length();
		}

		return 0;
	}

	/**
	 * @see java.sql.Clob#position(Clob, long)
	 */
	public long position(java.sql.Clob arg0, long arg1) throws SQLException {
		return position(arg0.getSubString(0L, (int) arg0.length()), arg1);
	}

	/**
	 * @see java.sql.Clob#position(String, long)
	 */
	public long position(String stringToFind, long startPos)
			throws SQLException {
		if (startPos < 1) {
			throw SQLError.createSQLException(
					Messages.getString("Clob.8") //$NON-NLS-1$
							+ startPos + Messages.getString("Clob.9"), SQLError.SQL_STATE_ILLEGAL_ARGUMENT); //$NON-NLS-1$
		}

		if (this.charData != null) {
			if ((startPos - 1) > this.charData.length()) {
				throw SQLError.createSQLException(Messages.getString("Clob.10"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
			}

			int pos = this.charData.indexOf(stringToFind, (int) (startPos - 1));

			return (pos == -1) ? (-1) : (pos + 1);
		}

		return -1;
	}

	/**
	 * @see java.sql.Clob#setAsciiStream(long)
	 */
	public OutputStream setAsciiStream(long indexToWriteAt) throws SQLException {
		if (indexToWriteAt < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.0"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		WatchableOutputStream bytesOut = new WatchableOutputStream();
		bytesOut.setWatcher(this);

		if (indexToWriteAt > 0) {
			bytesOut.write(this.charData.getBytes(), 0,
					(int) (indexToWriteAt - 1));
		}

		return bytesOut;
	}

	/**
	 * @see java.sql.Clob#setCharacterStream(long)
	 */
	public Writer setCharacterStream(long indexToWriteAt) throws SQLException {
		if (indexToWriteAt < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.1"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		WatchableWriter writer = new WatchableWriter();
		writer.setWatcher(this);

		//
		// Don't call write() if nothing to write...
		//
		if (indexToWriteAt > 1) {
			writer.write(this.charData, 0, (int) (indexToWriteAt - 1));
		}

		return writer;
	}

	/**
	 * @see java.sql.Clob#setString(long, String)
	 */
	public int setString(long pos, String str) throws SQLException {
		if (pos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.2"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		if (str == null) {
			throw SQLError.createSQLException(Messages.getString("Clob.3"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		StringBuffer charBuf = new StringBuffer(this.charData);

		pos--;

		int strLength = str.length();

		charBuf.replace((int) pos, (int) (pos + strLength), str);

		this.charData = charBuf.toString();

		return strLength;
	}

	/**
	 * @see java.sql.Clob#setString(long, String, int, int)
	 */
	public int setString(long pos, String str, int offset, int len)
			throws SQLException {
		if (pos < 1) {
			throw SQLError.createSQLException(Messages.getString("Clob.4"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		if (str == null) {
			throw SQLError.createSQLException(Messages.getString("Clob.5"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}

		StringBuffer charBuf = new StringBuffer(this.charData);

		pos--;

		String replaceString = str.substring(offset, len);

		charBuf.replace((int) pos, (int) (pos + replaceString.length()),
				replaceString);

		this.charData = charBuf.toString();

		return len;
	}

	/**
	 * @see com.mysql.jdbc.OutputStreamWatcher#streamClosed(byte[])
	 */
	public void streamClosed(WatchableOutputStream out) {
		int streamSize = out.size();

		if (streamSize < this.charData.length()) {
			try {
				out.write(StringUtils
						.getBytes(this.charData, null, null, false, null),
						streamSize, this.charData.length() - streamSize);
			} catch (SQLException ex) {
				//
			}
		}

		this.charData = StringUtils.toAsciiString(out.toByteArray());
	}

	/**
	 * @see java.sql.Clob#truncate(long)
	 */
	public void truncate(long length) throws SQLException {
		if (length > this.charData.length()) {
			throw SQLError.createSQLException(
					Messages.getString("Clob.11") //$NON-NLS-1$
							+ this.charData.length()
							+ Messages.getString("Clob.12") + length + Messages.getString("Clob.13")); //$NON-NLS-1$ //$NON-NLS-2$
		}

		this.charData = this.charData.substring(0, (int) length);
	}

	/**
	 * @see com.mysql.jdbc.WriterWatcher#writerClosed(char[])
	 */
	public void writerClosed(char[] charDataBeingWritten) {
		this.charData = new String(charDataBeingWritten);
	}

	/**
	 * @see com.mysql.jdbc.WriterWatcher#writerClosed(char[])
	 */
	public void writerClosed(WatchableWriter out) {
		int dataLength = out.size();

		if (dataLength < this.charData.length()) {
			out.write(this.charData, dataLength, this.charData.length()
					- dataLength);
		}

		this.charData = out.toString();
	}

	public void free() throws SQLException {
		this.charData = null;
	}

	public Reader getCharacterStream(long pos, long length) throws SQLException {
		return new StringReader(getSubString(pos, (int)length));
	}
}
