//  Job: Jay's Own Browser, a web browser written in Java by Jay Skeer
//  Copyright (C) 1996 Jay Skeer, Jay Prime Positive
//
//  This program is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  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., 675 Mass Ave, Cambridge, MA 02139, USA.
//

/** 
Subclass of PushbackInputStream which returns HTML tokens
*/
import Jdb;
import java.io.*;
import HtmlToken;

public class HtmlTokenStream extends PushbackInputStream {
    int angle_level= 0;
    HtmlToken unread_token= null;
    boolean eof= true;

    public HtmlTokenStream (String file_path) throws IOException {
	super(new FileInputStream(file_path));
	eof= false;
    }

    public HtmlTokenStream (File file_path) throws IOException {
	super(new FileInputStream(file_path));
	eof= false;
    }

    public void close() throws IOException {
	eof= true;
	super.close();
    }

    public boolean eof() {
	return ((null == unread_token) && eof);
    }

    static final String IDOKSTR=
	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    boolean isIdChar(int c) {
	return (0 <= (IDOKSTR.indexOf(c)));
    }

    public void skipEmptySpace() throws IOException {
	int bytes_left= this.available();
	if (0 < bytes_left) {
	    int read_byte= this.read();
	    bytes_left= this.available();
	    while ((0 < bytes_left)
	       &&  (Character.isSpace((char)read_byte)))
	    {
		read_byte= this.read();
		bytes_left= this.available();
	    }
	    if (! Character.isSpace((char)read_byte)) {
		this.unread(read_byte); /* put back non-space */
	    }
	}
    }

    /** Parse the folowing bytes in this stream, along with the 
	first_char, as an Id token.
    */
    public HtmlToken readIdToken(int first_char) throws IOException {
        String value= String.valueOf((char)first_char);
	int bytes_left= this.available();
	int read_byte;
	boolean working= (0 < bytes_left);
	while (working) {
	    read_byte= this.read();
	    if (isIdChar(read_byte)) {
		value= value + String.valueOf((char)read_byte);
		bytes_left= this.available();
		working= (0 < bytes_left);
	    } else {
		this.unread(read_byte);
		working= false;
	    }
	}
	HtmlToken rv= new HtmlToken(value);
	rv.value= value;
	if (HtmlToken.OTHER == rv.id) {
	    rv.id= HtmlToken.ID;
	}
	return rv;
    }

    /** Parse the folowing bytes in this stream, along with the 
	first_char, as a "..." type token.
    */
    public HtmlToken readStringToken(int first_char) throws IOException {
        String value= new String();
	int read_byte;
	int bytes_left= this.available();
	boolean working= (0 < bytes_left);
	while (working) {
	    read_byte= this.read();
	    if ('"' == read_byte) {
		HtmlToken rv= new HtmlToken(HtmlToken.STRING);
		rv.value= value;
		/* check for reserved words? */
		return rv;
	    } else {
		value= value + String.valueOf((char)read_byte);
		bytes_left= this.available();
		working= (0 < bytes_left);
	    }
	}
	/* ran out of characters -- an error! */
	HtmlToken rv= new HtmlToken(HtmlToken.STRING);
	rv.value= value;
	/* check for reserved words? */
	return rv;
    }

    /** Parse the folowing bytes in this stream, along with the 
	first_char, as a TEXT type token.
    */
    public HtmlToken readTextToken(int first_char) {
	//Jdb.enter("HTS.readTextToken()");
        StringBuffer value= new StringBuffer();
	value.append((char)first_char);
	HtmlToken rv;
	try {
	    int bytes_left= this.available();
	    int read_byte;
	    boolean working= (0 < bytes_left);
	    while (working) {
		read_byte= this.read();
		if ((0 < angle_level)
		    ?('>' == read_byte)
	            :('<' == read_byte))
		{
		    this.unread(read_byte);
		    working= false;
		} else {
		    value.append((char)read_byte);
		    bytes_left= this.available();
		    working= (0 < bytes_left);
		}
	    }
	    rv= new HtmlToken(HtmlToken.TEXT);
	    rv.value= value.toString();
	} catch (IOException x) {
	    // file io problem???
	    rv= new HtmlToken(HtmlToken.OTHER, "ioerror");
        }
	//Jdb.exit("HTS.readTextToken()");
	return rv;
    }

    /** Parse the bytes in a file into (and return) a HtmlComponent which
	captures the essence of the html file.
    */
    public HtmlToken readToken() {
//	Jdb.enter("HTS.readToken()");
	HtmlToken rv;
	if (null != unread_token) {
	    rv= unread_token;
	    unread_token= null;
//	    Jdb.trace("HTS.readToken() ... rereads old token");
	} else {
	    try {
		int bytes_left= this.available();
		if (bytes_left <= 0) {
		    //Jdb.trace("see EOF condition");
		    rv= new HtmlToken(HtmlToken.EOF, "");
		    eof= true;
		} else {
		    int read_byte;
		    read_byte= this.read();
		    if ('<' == read_byte) {
			angle_level++;
			//Jdb.trace("see OPEN");
			rv= new HtmlToken(HtmlToken.OPEN, "<");
		    } else if ('>' == read_byte) {
			angle_level--;
			//Jdb.trace("see CLOSE");
			rv= new HtmlToken(HtmlToken.CLOSE, ">");
		    } else if (-1 == read_byte) {
			//Jdb.trace("see EOF char");
			rv= new HtmlToken(HtmlToken.EOF, "");
			eof= true;
		    } else if (0 < angle_level) {
			if ('/' == read_byte) {
			    //Jdb.trace("see END");
			    rv= new HtmlToken(HtmlToken.END, "/");
			} else if ('=' == read_byte) {
			    rv= new HtmlToken(HtmlToken.EQUAL, "=");
			    //Jdb.trace("see EQUAL");
			} else if ('"' == read_byte) {
			    //Jdb.trace("see DblQt");
			    rv= this.readStringToken(read_byte);
			} else {
			    Jdb.trace("try id");
			    unread(read_byte);
			    skipEmptySpace();
			    read_byte= read();
			    rv= this.readIdToken(read_byte);
			}
		    } else {
			Jdb.trace("try text");
			rv= this.readTextToken(read_byte);
		    }
		}
	    } catch (IOException x) {
		// file io problem???;
		rv= new HtmlToken(HtmlToken.OTHER, "ioerror");
	    }
	}
//	Jdb.exit(
	Jdb.trace(
	    "HTS.readToken() " +
	    Integer.toString(angle_level) +
	    " => "+rv.toString());
	return rv;
    }

    public HtmlToken readCdata() {
	HtmlToken rv;
	try {
	    int read_byte= this.read();
	    if ('"' == read_byte) {
		rv= readStringToken(read_byte);
	    } else {
		rv= readTextToken(read_byte);
	    }
	} catch (IOException x) {
	    // file io problem???
	    rv= new HtmlToken(HtmlToken.OTHER, "ioerror");
	}
	return rv;
    }

    public HtmlToken readNdata() {
	HtmlToken rv;
	try {
	    int read_byte= this.read();
	    rv= readIdToken(read_byte);
	} catch (IOException x) {
	    // file io problem???
	    rv= new HtmlToken(HtmlToken.OTHER, "ioerror");
	}
	return rv;
    }

    /** read the token which folows foo= in a <bar ... foo=...> tag */
    public HtmlToken readArgValueToken(String tag, String name) {
	//Jdb.enter("HTS.readArgValueToken()");
	HtmlToken rv;
	if ((tag.equalsIgnoreCase("img"))
	||  (tag.equalsIgnoreCase("applet")))
	{
	    if ((name.equalsIgnoreCase("width"))
	    ||  (name.equalsIgnoreCase("height")))
            {
		rv= readNdata();
	    } else {
		rv= readCdata();
	    }
	} else {
	    rv= readCdata();
	}
	//Jdb.exit("HTS.readArgValueToken()");
	return rv;
    }

    /** Put the given token (back) as the next token to be read */
    public void unreadToken(HtmlToken t) {
//	Jdb.enter("HTS.unreadToken("+t.toString()+")");
	unread_token= t;
//	Jdb.exit("HTS.unreadToken("+t.toString()+")");
    }

    /** Look at the next token with out removing it from the stream */
    public HtmlToken peekToken() {
	HtmlToken t= readToken();
	unreadToken(t);
	return t;
    }


}