package wiki;

import java.util.Stack;

import org.stringtree.factory.AbstractStringFetcher;
import org.stringtree.juicer.string.SplitLinesStringFilter;
import org.stringtree.juicer.string.StringFilter;
import org.stringtree.juicer.string.StringStringSource;
import org.stringtree.regex.Matcher;
import org.stringtree.regex.Pattern;
import org.stringtree.util.StringUtils;

class LineTransformContext 
	extends Stack
{
	public String getType()
	{
		return (isEmpty())
			? null
			: StringUtils.stringValue(peek());
	}

	public void endList(StringBuffer buf)
	{
		if (!isEmpty())
		{
			String type = StringUtils.stringValue(pop());
			buf.append("</");
			buf.append(type);
			buf.append(">\n");
		}
	}

	public void startList(String type, StringBuffer buf)
	{
		push(type);
		buf.append("<");
		buf.append(type);
		buf.append(">\n");
	}

	public void endAll(StringBuffer buf)
	{
		while (!isEmpty())
		{
			endList(buf);
		}
	}

	public void ensureType(StringBuffer buf, String type, int indent)
	{
		while (!isEmpty() && size() > indent)
		{
			endList(buf);
		}
		while (size() < indent)
		{
			startList(type, buf);
		}

		if (!type.equals(getType()))
		{
			endList(buf);
			startList(type, buf);
		}
	}
}

public class ListRow
	extends AbstractStringFetcher
{
	private static Pattern pattern = Pattern.compile("^(\t+)(\\*|[1234567890]+)\\.?\\s*(.+)$");
	 
	public Object getObject(String content)
	{
		LineTransformContext context = new LineTransformContext();
		StringBuffer buf = new StringBuffer();

		StringFilter rows = new SplitLinesStringFilter();
		rows.connectSource(new StringStringSource(content));
		
		for (String row = rows.nextString(); row != null; row = rows.nextString())
		{
			Matcher matcher = pattern.matcher(row);

			if (matcher.find() && matcher.groupCount() >= 3)
			{
				int indent = matcher.group(1).length();
				String type = ("*".equals(matcher.group(2))) ? "ul" : "ol";
				String text = matcher.group(3);

				context.ensureType(buf, type, indent);
				buf.append("<li>");
				buf.append(text);
				buf.append("</li>\n");
			}
			else
			{
				buf.append(row);
				buf.append("\n");
			}
		}
		context.endAll(buf);

		String ret = buf.toString();
		return ret;
	}
}