package dk.thoerup.traininfo.provider;

import java.io.StringReader;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

import android.util.Log;

import dk.thoerup.traininfo.util.AndroidTimeoutCache;
import dk.thoerup.traininfo.util.DownloadUtil;
import dk.thoerup.traininfo.util.XmlUtil;

public class XmlMetroProvider implements MetroProvider {
	
	final int CACHE_TIMEOUT = 60000;

	AndroidTimeoutCache<Integer,MetroBean> metroCache = new AndroidTimeoutCache<Integer,MetroBean>(CACHE_TIMEOUT);
	

	@Override
	public MetroBean lookupMetroInfo(int stationID) {
		
		MetroBean metro = metroCache.get(stationID);
	
		if (metro == null) {			
			metro = lookupMetroWorker(stationID);
			
			if (metro != null) {			
				metroCache.put(stationID, metro);
			}
			
		} else {
			Log.i("XmlDepartureProvider", "cache hit !!!");
		}		
		
		return metro;
	}
	
	
	private MetroBean lookupMetroWorker(int stationID) {

		try
		{	
			String url = XmlUtil.SERVICE_BASE + "/MetroServlet?station=" + stationID;
			Log.i("xmlurl",url);
			String doc =  DownloadUtil.getContentString(url, 15000, "ISO-8859-1");
			
			InputSource source = new InputSource( new StringReader(doc));
			
			SAXParserFactory spf = SAXParserFactory.newInstance();
            SAXParser sp = spf.newSAXParser();
            XMLReader xr = sp.getXMLReader();

            MetroParser metroParser = new MetroParser();
			xr.setContentHandler(metroParser);
			xr.setErrorHandler(metroParser);
			xr.parse(source);
			
			return metroParser.getMetroDepartures();
			
		} catch (Exception e) {
			Log.e("XmlMetroProvider", "lookupFunction", e);
			return null;
		}		
	}
	
	
	class MetroParser extends DefaultHandler { 
		
		StringBuilder builder = new StringBuilder(256);
		private MetroBean metro = new MetroBean();
		
		MetroEntry tempEntry = new MetroEntry();

		public MetroBean getMetroDepartures() {
			return metro;
		}
				
	
		// this can be called several times fore the same text-node if there are many chardata / lines
		@Override
		public void characters (char ch[], int start, int length) 
		{		
			builder.append(ch, start, length);
		}
		
		@Override
		public void startElement (String uri, String name, String qName, Attributes atts)throws SAXException
		{
			if (name.equalsIgnoreCase("entry"))
				tempEntry = new MetroEntry();
			
			builder.setLength(0); //reset StringBuilder
		}
		
		@Override
		public void endElement (String uri, String name, String qName) throws SAXException
		{
			String str = builder.toString().trim();
			
			if (name.equals("entry")) {			
				metro.entries.add( tempEntry );				
			} else if (name.equals("head")) {
				metro.head = str; 				
			} else if (name.equals("operations")) {
				metro.operationInfo = str;				
			} else if (name.equals("metro")) {
				tempEntry.metro = str;
			} else if (name.equals("destination")) {
				tempEntry.destination = str;
			} else if (name.equals("minutes")) {
				tempEntry.minutes = str;
			} else if (name.equals("plan")) {
				metro.plan = str;
			} 
		}
	}
	
}