package dk.thoerup.traininfo.provider;

import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;

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

public class XmlDepartureProvider extends DefaultHandler implements DepartureProvider {

	final static long CACHE_TIMEOUT = 60*1000;
	
	class CacheEntry {
		public long timestamp;
		public List<DepartureBean> departures;
	}
	
	HashMap<Integer, CacheEntry> departureCache = new HashMap<Integer,CacheEntry>();	
	ArrayList<DepartureBean> departures;
		
	
	DepartureBean tempDeparture;
	StringBuilder builder = new StringBuilder(512);
	
	@Override
	public boolean lookupDepartures(int stationID) {
		CacheEntry entry = departureCache.get(stationID);
		boolean success;
	
		long now = android.os.SystemClock.elapsedRealtime();
		if (entry == null || (entry.timestamp+CACHE_TIMEOUT) < now) {
			
			success = lookupDeparturesWorker(stationID);
			
			if (success) {
				entry = new CacheEntry();
				entry.timestamp = android.os.SystemClock.elapsedRealtime();
				entry.departures = departures;
			
				departureCache.put(stationID, entry);
			}
		} else {
			Log.i("XmlDepartureProvider", "cache hit !!!");
			success = true;
		}		
		
		return success;
	}
	
	private boolean lookupDeparturesWorker(int stationID) {
		boolean success = false;
		departures = new ArrayList<DepartureBean>();
		try
		{	

			String url = XmlUtil.SERVICE_BASE + "/DepartureServlet?format=xml&station=" + stationID;
			Log.i("xmlurl",url);
			String doc =  DownloadUtil.getContentString(url, 45000, "ISO-8859-1");
			
			InputSource source = new InputSource( new StringReader(doc));
			
			SAXParserFactory spf = SAXParserFactory.newInstance();
            SAXParser sp = spf.newSAXParser();
            XMLReader xr = sp.getXMLReader();

			xr.setContentHandler(this);
			xr.setErrorHandler(this);
			xr.parse(source);
			success = true;
			
		} catch (Exception e) {
			Log.e("XmlDepartureProvider", "looupFunction", e);
		}
		return success;
	}
	
	@Override
	public List<DepartureBean> getDepartures(int station) {
		CacheEntry entry = departureCache.get(station);
		
		if (entry != null) {			
			return entry.departures;
		} else {
			return new ArrayList<DepartureBean>();
		}
		
	}
	
	// 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) 
	{		
		for (int i= start; i<start+length; i++)
			builder.append(ch[i]);	
	}
	
	@Override
	public void startElement (String uri, String name, String qName, Attributes atts)throws SAXException
	{
		if (name.equalsIgnoreCase("train"))
			tempDeparture = new DepartureBean();
		
		builder.setLength(0); //reset StringBuilder
	}
	
	@Override
	public void endElement (String uri, String name, String qName) throws SAXException
	{
		if (name.equals("train")) {
			departures.add( tempDeparture );
		} else if (name.equals("time")) {
			tempDeparture.setTime(builder.toString().trim());
		} else if (name.equals("updated")) {
			tempDeparture.setLastUpdate(builder.toString().trim());
		} else if (name.equals("trainnumber")) {
			tempDeparture.setTrainNumber(builder.toString().trim());
		} else if (name.equals("destination")) {
			tempDeparture.setDestination(builder.toString().trim());
		} else if (name.equals("origin")) {
			tempDeparture.setOrigin(builder.toString().trim());
		} else if (name.equals("location")) {
			tempDeparture.setLocation(builder.toString().trim());
		} else if (name.equals("status")) {
			tempDeparture.setStatus(builder.toString().trim());
		} else if (name.equals("note")) {
			tempDeparture.setNote(builder.toString().trim());
		} 
	}
}