package html;

import java.io.*;
import org.jsoup.*;
import org.jsoup.nodes.*;
import org.jsoup.select.*;
import org.jsoup.parser.*;
import org.jsoup.helper.*;

public class HtmlParser {
	
	public static class TextVisitor implements NodeVisitor {
		
		//单线程一般用StringBuilder，多线程一般用StringBuffer
		private StringBuilder text = new StringBuilder();
		private boolean showBlock;
		
		public TextVisitor(boolean showBlock) {
			this.showBlock = showBlock;
		}
		
		public String getText() {
			return text.toString().trim();
		}
		
		public static boolean preserveWhitespace(Node node) {
	        if (node != null && node instanceof Element) {
	            Element element = (Element)node;
	            return element.tag().preserveWhitespace() ||
	                element.parent() != null && element.parent().tag().preserveWhitespace();
	        }
	        return false;
	    }
		
		public static boolean lastCharIsSpace(StringBuilder sb) {
	        return sb.length() != 0 && sb.charAt(sb.length() - 1) == ' ';
	    }
		
		public static boolean lastCharIsLineBreak(StringBuilder sb) {
	        return sb.length() != 0 && sb.charAt(sb.length() - 1) == '\n';
	    }
		
		private static void appendNormalisedText(StringBuilder accum, TextNode textNode) {
	        String text = textNode.getWholeText();
	        text = text.trim();
	        if (preserveWhitespace(textNode.parent()))
	            accum.append(text);
	        else
	            StringUtil.appendNormalisedWhitespace(accum, text, lastCharIsSpace(accum));
	    }
		
		public void head(Node node, int depth) {
			if (node instanceof TextNode) {
                TextNode textNode = (TextNode)node;
                appendNormalisedText(text, textNode);
            } else if (node instanceof Element) {
                Element element = (Element)node;
                Tag tag = element.tag();
                String tagName = tag.getName();
                boolean isBlock = tag.isBlock();
                if (showBlock)
                	System.out.println(tagName + " block state is " + isBlock);
                
                if (text.length() > 0
                		&& (isBlock || tagName.equals("br"))
                		&& !lastCharIsLineBreak(text))
                    text.append("\n");
            }
		}
		
		public void tail(Node node, int depth) {
		}
	}
	
	public static void parseSimpleHtml() throws Exception {
		InputStream input =
				HtmlParser.class.getResourceAsStream("/index.html");
		Document doc = Jsoup.parse(input, "utf-8", "http://www.3scard.com");
		
		TextVisitor visitor = new TextVisitor(true);
		NodeTraversor traversor = new NodeTraversor(visitor);
		traversor.traverse(doc);
		System.out.println(visitor.getText());
	}
	
	public static void parseComplexHtml() throws Exception {
		String url = "http://www.3scard.com/index.php?m=blog&f=index";
		Document doc = Jsoup.connect(url).get();
		System.out.println(doc.text());
		
		TextVisitor visitor = new TextVisitor(false);
		NodeTraversor traversor = new NodeTraversor(visitor);
		traversor.traverse(doc);
		System.out.println(visitor.getText());
	}
	
	public static void main(String[] args) throws Exception {
		parseSimpleHtml();
		parseComplexHtml();
	}
}