/* 
 
Copyright 2006 Rene Grothmann, modified by Eric Hakenholz

This file is part of C.a.R. software.

    C.a.R. is a 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, version 3 of the License.

    C.a.R. 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, see <http://www.gnu.org/licenses/>.
 
 */
 
 
 package rene.util.xml;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import rene.util.SimpleByteBuffer;
import rene.util.SimpleStringBuffer;
import rene.util.list.ListElement;

public class XmlReader {
	BufferedReader In;
	SimpleStringBuffer buf = new SimpleStringBuffer(10000);

	public XmlReader() {
		In = null;
	}

	public XmlReader(final BufferedReader in) {
		In = in;
	}

	public XmlReader(final InputStream in) throws XmlReaderException {
		try { // read the file into a buffer
			final BufferedInputStream rin = new BufferedInputStream(in);
			final SimpleByteBuffer bb = new SimpleByteBuffer(10000);
			while (true) {
				final int k = rin.read();
				if (k < 0)
					break;
				bb.append((byte) k);
			}
			rin.close();
			final byte b[] = bb.getByteArray();

			// Try to open an ASCII stream, or a default stream
			ByteArrayInputStream bin = new ByteArrayInputStream(b);
			XmlReader R = null;
			try {
				R = new XmlReader(new BufferedReader(new InputStreamReader(bin,
				"ASCII")));
			} catch (final UnsupportedEncodingException ex) {
				R = new XmlReader(
						new BufferedReader(new InputStreamReader(bin)));
			}

			// Determine the encoding
			String Encoding = null;
			while (true) {
				while (true) {
					final int c = R.read();
					if (c == -1)
						throw new Exception("<?xml> tag not found");
					if (c == '<')
						break;
				}
				if (R.found("?xml")) {
					String s = R.scanFor("?>");
					if (s == null)
						throw new Exception("<?xml> tag error");
					int n = s.indexOf("encoding=\"");
					if (n >= 0) {
						n += "encoding=\"".length();
						s = s.substring(n);
						final int m = s.indexOf('\"');
						if (m < 0)
							throw new Exception("Closing bracket missing");
						Encoding = s.substring(0, m).toUpperCase();
						if (Encoding.equals("UTF-8"))
							Encoding = "UTF8";
						// for IE5 !
						break;
					}
					break;
				}
			}

			// Open a stream with this encoding
			bin = new ByteArrayInputStream(b);
			if (Encoding == null)
				In = new BufferedReader(new InputStreamReader(bin));
			else
				try {
					In = new BufferedReader(
							new InputStreamReader(bin, Encoding));
				} catch (final UnsupportedEncodingException e) {
					try {
						In = new BufferedReader(new InputStreamReader(bin,
						"ASCII"));
					} catch (final UnsupportedEncodingException ex) {
						In = new BufferedReader(new InputStreamReader(bin));
					}
				}
		} catch (final Exception e) {
			throw new XmlReaderException(e.toString());
		}
	}

	public void init(final InputStream in) throws XmlReaderException {
		try { // read the file into a buffer

			final BufferedInputStream rin = new BufferedInputStream(in);
			final SimpleByteBuffer bb = new SimpleByteBuffer(10000);
			while (true) {
				final int k = rin.read();
				if (k < 0)
					break;
				bb.append((byte) k);
			}
			rin.close();
			final byte b[] = bb.getByteArray();

			// Try to open an ASCII stream, or a default stream
			ByteArrayInputStream bin = new ByteArrayInputStream(b);
			XmlReader R = null;
			try {
				R = new XmlReader(new BufferedReader(new InputStreamReader(bin,
				"ASCII")));
			} catch (final UnsupportedEncodingException ex) {
				R = new XmlReader(
						new BufferedReader(new InputStreamReader(bin)));
			}

			// Determine the encoding
			String Encoding = null;
			while (true) {
				while (true) {
					final int c = R.read();
					if (c == -1)
						throw new Exception("<?xml> tag not found");
					if (c == '<')
						break;
				}
				if (R.found("?xml")) {
					String s = R.scanFor("?>");
					if (s == null)
						throw new Exception("<?xml> tag error");
					int n = s.indexOf("encoding=\"");
					if (n >= 0) {
						n += "encoding=\"".length();
						s = s.substring(n);
						final int m = s.indexOf('\"');
						if (m < 0)
							throw new Exception("Closing bracket missing");
						Encoding = s.substring(0, m).toUpperCase();
						if (Encoding.equals("UTF-8"))
							Encoding = "UTF8";
						// for IE5 !
						break;
					}
					break;
				}
			}

			// Open a stream with this encoding
			bin = new ByteArrayInputStream(b);
			if (Encoding == null)
				In = new BufferedReader(new InputStreamReader(bin));
			else
				try {
					In = new BufferedReader(
							new InputStreamReader(bin, Encoding));
				} catch (final UnsupportedEncodingException e) {
					try {
						In = new BufferedReader(new InputStreamReader(bin,
						"ASCII"));
					} catch (final UnsupportedEncodingException ex) {
						In = new BufferedReader(new InputStreamReader(bin));
					}
				}
		} catch (final Exception e) {
			throw new XmlReaderException(e.toString());
		}
	}

	/**
	 * Scan an xml file. This function reads, until <?xml is found. then it
	 * skips this declaration and scans the rest of the items.
	 */
	public XmlTree scan() throws XmlReaderException {
		while (true) {
			while (true) {
				final int c = read();
				if (c == -1)
					return null;
				if (c == '<')
					break;
			}
			if (found("?xml")) {
				final String s = scanFor("?>");
				if (s == null)
					return null;
				final XmlTree t = new XmlTree(new XmlTagRoot());
				t.addchild(new XmlTree(new XmlTagPI(s)));
				scanContent(t);
				return t;
			}
		}
	}

	public void scanContent(final XmlTree t) throws XmlReaderException { // System.out.println("Sanning for "+t.getTag().name()+" ("+
		// t.getTag().countParams()+")");
		while (true) {
			String s = scanFor('<');
			if (s == null) {
				if (t.getTag() instanceof XmlTagRoot)
					return;
				exception("File ended surprisingly");
			}
			if (!empty(s)) {
				t
				.addchild(new XmlTree(new XmlTagText(XmlTranslator
						.toText(s))));
			}
			if (found("!--")) {
				s = scanFor("-->");
				continue;
			}
			if (found("!")) {
				s = scanTagFor('>');
				continue;
			}
			if (found("?")) {
				s = scanTagFor("?>");
				t.addchild(new XmlTree(new XmlTagPI(s)));
				continue;
			}
			s = scanTagFor('>');
			if (s == null)
				exception("> missing");
			if (s.startsWith("/")) {
				if (s.substring(1).equals(t.getTag().name()))
					return;
				else
					exception("End tag without start tag");
			}
			if (s.endsWith("/")) {
				t.addchild(new XmlTree(new XmlTag(s
						.substring(0, s.length() - 1))));
			} else {
				final XmlTree t0 = new XmlTree(new XmlTag(s));
				scanContent(t0);
				t.addchild(t0);
			}
		}
	}

	public boolean empty(final String s) {
		final int n = s.length();
		for (int i = 0; i < n; i++) {
			final char c = s.charAt(i);
			if (c != ' ' && c != '\n' && c != '\t')
				return false;
		}
		return true;
	}

	/**
	 * Skip Blanks.
	 * 
	 * @return Non-blank character or -1 for EOF.
	 */
	public int skipBlanks() throws XmlReaderException {
		while (true) {
			final int c = read();
			if (c == ' ' || c == '\t' || c == '\n')
				continue;
			else
				return c;
		}
	}

	/**
	 * Scan for an end character.
	 * 
	 * @return String between the current position and the end character, or
	 *         null.
	 */
	public String scanFor(final char end) throws XmlReaderException {
		buf.clear();
		int c = read();
		while (c != end) {
			buf.append((char) c);
			c = read();
			if (c < 0)
				return null;
		}
		return buf.toString();
	}

	/**
	 * Scan for a specific string.
	 * 
	 * @return String between the current position and the string.
	 */
	public String scanFor(final String s) throws XmlReaderException {
		buf.clear();
		while (!found(s)) {
			final int c = read();
			if (c < 0)
				return null;
			buf.append((char) c);
		}
		for (int i = 0; i < s.length(); i++)
			read();
		return buf.toString();
	}

	/**
	 * Scan tag for an end character (interpreting " and ')
	 * 
	 * @return String between the current position and the end character, or
	 *         null.
	 */
	public String scanTagFor(final char end) throws XmlReaderException {
		buf.clear();
		int c = read();
		while (c != end) {
			if (c == '\"') {
				buf.append((char) c);
				while (true) {
					c = read();
					if (c < 0)
						return null;
					if (c == '\"')
						break;
					buf.append((char) c);
				}
				buf.append((char) c);
			} else if (c == '\'') {
				buf.append((char) c);
				while (true) {
					c = read();
					if (c < 0)
						return null;
					if (c == '\'')
						break;
					buf.append((char) c);
				}
				buf.append((char) c);
			} else
				buf.append((char) c);
			c = read();
			if (c < 0)
				return null;
		}
		return buf.toString();
	}

	/**
	 * Scan tag for a specific string (interpreting " and ')
	 * 
	 * @return String between the current position and the string.
	 */
	public String scanTagFor(final String s) throws XmlReaderException {
		buf.clear();
		while (!found(s)) {
			int c = read();
			if (c < 0)
				return null;
			if (c == '\"') {
				buf.append((char) c);
				while (true) {
					c = read();
					if (c < 0)
						return null;
					if (c == '\"')
						break;
					buf.append((char) c);
				}
				buf.append((char) c);
			} else if (c == '\'') {
				buf.append((char) c);
				while (true) {
					c = read();
					if (c < 0)
						return null;
					if (c == '\'')
						break;
					buf.append((char) c);
				}
				buf.append((char) c);
			} else
				buf.append((char) c);
		}
		for (int i = 0; i < s.length(); i++)
			read();
		return buf.toString();
	}

	String Line = null;
	int LinePos;

	public int read() throws XmlReaderException {
		try {
			if (Line == null) {
				Line = In.readLine();
				LinePos = 0;
				// System.out.println("Read --> "+Line);
			}
			if (Line == null)
				return -1;
			if (LinePos >= Line.length()) {
				Line = null;
				return '\n';
			}
			return Line.charAt(LinePos++);
		} catch (final Exception e) {
			return -1;
		}
	}

	/**
	 * @return If the string is at the current line position.
	 */
	public boolean found(final String s) {
		final int n = s.length();
		if (LinePos + n > Line.length())
			return false;
		for (int i = 0; i < n; i++)
			if (s.charAt(i) != Line.charAt(LinePos + i))
				return false;
		return true;
	}

	public void exception(final String s) throws XmlReaderException {
		throw new XmlReaderException(s, Line, LinePos);
	}

	/**
	 * A test program.
	 */
	public static void main(final String args[]) {
		try {
			final BufferedReader in = new BufferedReader(new InputStreamReader(
					new FileInputStream("rene\\util\\xml\\test.xml"), "UTF8"));
			final XmlReader reader = new XmlReader(in);
			final XmlTree tree = reader.scan();
			in.close();
			print(tree);
		} catch (final XmlReaderException e) {
			System.out.println(e.toString() + "\n" + e.getLine() + "\n"
					+ "Position : " + e.getPos());
		} catch (final IOException e) {
			System.out.println(e);
		}
	}

	public static void print(final XmlTree t) {
		final XmlTag tag = t.getTag();
		System.out.print("<" + tag.name());
		for (int i = 0; i < tag.countParams(); i++) {
			System.out.print(" " + tag.getParam(i) + "=\"" + tag.getValue(i)
					+ "\"");
		}
		System.out.println(">");
		ListElement el = t.children().first();
		while (el != null) {
			print((XmlTree) (el.content()));
			el = el.next();
		}
		System.out.println("</" + tag.name() + ">");
	}

	public static boolean testXml(final String s) {
		int i = 0;
		while (i < s.length()) {
			final char c = s.charAt(i);
			if (c == '<')
				break;
			i++;
		}
		if (i >= s.length())
			return false;
		if (s.substring(i).startsWith("<?xml"))
			return true;
		return false;
	}
}