/*-
 *******************************************************************************
 * Copyright (c) 2011, 2015 Diamond Light Source Ltd.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Matthew Gerring - initial API and implementation and/or initial documentation
 *******************************************************************************/
package org.eclipse.dawnsci.remotedataset.server.info;

import java.io.IOException;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.dawnsci.analysis.api.io.IDataHolder;
import org.eclipse.dawnsci.analysis.api.persistence.IMarshallerService;
import org.eclipse.dawnsci.analysis.api.tree.Tree;
import org.eclipse.dawnsci.analysis.tree.TreeToMapUtils;
import org.eclipse.dawnsci.remotedataset.XMLMarshallerService;
import org.eclipse.dawnsci.remotedataset.server.utils.DataServerUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The handler for incoming requests. No work should be done here
 * the request should be delegated down to the backing LoaderFactory instance
 * using the current session.
 * 
 * In this way if someone does a slice which is time consuming, another request coming
 * in will not be blocked while it is done.
 * 
 * Gives info about a given ILazyDataset, specifically:
 * name
 * shape
 * dType
 * elements per item
 * 
 * For example: http://localhost:8080/info/?path=c%3A/Work/results/TomographyDataSet.hdf5
 * Gives:
 * 
dark_data
[37, 1024, 1024]
2
1
  
 * Or: http://localhost:8080/info/?path=c%3A/Work/results/TomographyDataSet.hdf5&dataset=/entry/exchange/data
 * Gives:
data
[720, 1024, 1024]
2
1
 * 
 * @author Matthew Gerring
 *
 */
public class TreeServlet extends HttpServlet {
			
 
	/**
	 * 
	 */
	private static final long serialVersionUID = 9159927667493661200L;
	
	private static Logger logger = LoggerFactory.getLogger(TreeServlet.class);

	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    	doHandle(req, resp);
    }
    
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    	doHandle(req, resp);
    }
    
	/**
	 * Remember with servlets each of these is done on a thread from the
	 * pool. Therefore it should filter down giving each session its
	 * own object with which to slice. In this way if a user decides to
	 * do a long running slice, they only block themselves.
	 * 
	 * TODO User should be able to cancel slice...
	 * 
	 */
	private void doHandle(HttpServletRequest  request,
						  HttpServletResponse response)  throws IOException, ServletException {
				
		final String path    = request.getParameter("path");
		
		try {
			
			final IDataHolder holder = DataServerUtils.getDataHolderWithLogging(path);
			final Tree tree = holder.getTree();
			
			
			Map<String,Object> map = TreeToMapUtils.treeToMap(tree);
			IMarshallerService mservice = new XMLMarshallerService();
			final String xml = mservice.marshal(map);
			response.setContentType("text/xml;charset=utf-8");
			response.getWriter().println(xml);
		   
		} catch (Exception e) {
			logger.info("Read of tree from {} failed due to {}", path, e.getMessage());
			response.setContentType("text/html;charset=utf-8");
			response.setStatus(HttpServletResponse.SC_FORBIDDEN);
			response.getWriter().println("<h1>"+e.getMessage()+"</h1>");
		}
		
		 
	}

 }