/*
 Copyright (C) 2002-2004 MySQL AB

 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 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.UnsupportedEncodingException;
import java.io.Writer;
import java.sql.SQLException;


/**
 * Simplistic implementation of java.sql.Clob for MySQL Connector/J
 *
 * @version $Id: Clob.java,v 1.5.2.7 2004/08/09 22:15:12 mmatthew Exp $
 * @author Mark Matthews
 */
public class Clob implements java.sql.Clob, OutputStreamWatcher, WriterWatcher {
    private String charData;

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

    /**
     * @see java.sql.Clob#setAsciiStream(long)
     */
    public OutputStream setAsciiStream(long indexToWriteAt)
        throws SQLException {
        if (indexToWriteAt < 1) {
            throw new SQLException("indexToWriteAt must be >= 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#getAsciiStream()
     */
    public InputStream getAsciiStream() throws SQLException {
        if (this.charData != null) {
            return new ByteArrayInputStream(this.charData.getBytes());
        } else {
            return null;
        }
    }

    /**
     * @see java.sql.Clob#setCharacterStream(long)
     */
    public Writer setCharacterStream(long indexToWriteAt)
        throws SQLException {
        if (indexToWriteAt < 1) {
            throw new SQLException("indexToWriteAt must be >= 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#getCharacterStream()
     */
    public Reader getCharacterStream() throws SQLException {
        if (this.charData != null) {
            return new StringReader(this.charData);
        } else {
            return null;
        }
    }

    /**
     * @see java.sql.Clob#setString(long, String)
     */
    public int setString(long pos, String str) throws SQLException {
        if (pos < 1) {
            throw new SQLException("Starting position can not be < 1", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
        }

        if (str == null) {
            throw new SQLException("String to set can not be NULL", 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 new SQLException("Starting position can not be < 1", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
        }

        if (str == null) {
            throw new SQLException("String to set can not be NULL", 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 java.sql.Clob#getSubString(long, int)
     */
    public String getSubString(long startPos, int length)
        throws SQLException {
        if (startPos < 1) {
            throw new SQLException("CLOB start position can not be < 1", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
        }

        if (this.charData != null) {
            if (((startPos - 1) + length) > charData.length()) {
                throw new SQLException("CLOB start position + length can not be > length of CLOB",
                    SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
            }

            return this.charData.substring((int) (startPos - 1), length);
        } else {
            return null;
        }
    }

    /**
     * @see java.sql.Clob#length()
     */
    public long length() throws SQLException {
        if (this.charData != null) {
            return this.charData.length();
        } else {
            return 0;
        }
    }

    /**
     * @see java.sql.Clob#position(String, long)
     */
    public long position(String stringToFind, long startPos)
        throws SQLException {
        if (startPos < 1) {
            throw new SQLException("Illegal starting position for search, '"
                + startPos + "'", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
        }

        if (this.charData != null) {
            if ((startPos - 1) > this.charData.length()) {
                throw new SQLException("Starting position for search is past end of CLOB",
                    SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
            }

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

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

    /**
     * @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 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), streamSize, this.charData.length() - streamSize);
    		} catch (UnsupportedEncodingException 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 new SQLException("Cannot truncate CLOB of length " 
    		+ this.charData.length() 
			+ " to length of " 
			+ length 
			+ ".");
    	}
    	
        this.charData = this.charData.substring(0, (int) length);
    }

    /**
     * @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();
    }
}
