package eu.clarin.cmdi.mdservice.action;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.xml.sax.SAXException;

public class Helpers {

	private static PrintStream log;
	
	public static Document readFSLS(String infile)
	{
		Document document = null;
		try {
		    DocumentBuilderFactory factory = 
		    DocumentBuilderFactory.newInstance();
		    DocumentBuilder builder = factory.newDocumentBuilder();
		    document = builder.parse(infile);		    
		}
		catch (FactoryConfigurationError e) {
		    // unable to get a document builder factory
			notifyUser(e.getClass() + ": " + e.getLocalizedMessage());
		} 
		catch (ParserConfigurationException e) {
		    // parser was unable to be configured
			notifyUser(e.getClass() + ": " + e.getLocalizedMessage());			
		}
		catch (IOException e) {
		    // i/o error
			notifyUser(e.getClass() + ": io-error " + e.getLocalizedMessage());			
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return document;
	}
	
	public static void notifyUser (String msg) {
		if (log== null) { log = System.err; }
		log.println(msg);
		
	}

	public static void copy (InputStream in, OutputStream out) throws IOException, InterruptedException {		
		
		byte[] buffer = new byte[1024];
		int len = in.read(buffer);
		while (len != -1) {
		    out.write(buffer, 0, len);
		    len = in.read(buffer);
		    if (Thread.interrupted()) {
		        throw new InterruptedException();
		    }
		}
	}
	

	public static Document getDocument(InputStream is){
		Document doc = null;
		DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
     	DocumentBuilder docBuilder;
		try {
			docBuilder = docFactory.newDocumentBuilder();
			doc = docBuilder.parse(is);
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}	
		return doc;
	}
	
	public static String getDocumentData(InputStream is, String expression){
		String data = "";
	
		XPathFactory factory = XPathFactory.newInstance(); 
	    XPath xpath = factory.newXPath(); 
	    XPathExpression expr;
		try {
			expr = xpath.compile(expression);
			data = (String) expr.evaluate(getDocument(is), XPathConstants.STRING);
		} catch (XPathExpressionException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		        
		return data;
		
	}
	/*
	 * TODO: this should go to Utilities!
	 */
	public  static String convertStreamToString(InputStream is) {  
		
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));  
		StringBuilder sb = new StringBuilder();  
		String line = null;  
		
		try {
			while ((line = reader.readLine()) != null) {  
			                 sb.append(line + "\n");  
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}  finally {
			try {
				is.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				is.reset();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		  
		
		return sb.toString();  
	}


}