source: trunk/gsdl3/extensions/gsdl-as/src/org/greenstone/gsdlas/AlertingService.java@ 8717

/*
 * Created on Nov 22, 2004
 * Copyright (C) Andrea Schweer, 2004
 *
 * This file is part of the Greenstone Alerting Service.
 * Refer to the COPYING file in the base directory of this package
 * for licensing information.
 */
package org.greenstone.gsdlas;

import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.*;

import javax.servlet.http.*;

import org.apache.velocity.Template;
import org.apache.velocity.context.Context;
import org.apache.velocity.servlet.VelocityServlet;
import org.greenstone.gsdlas.users.UserManager;

/**
 * @author schweer
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class AlertingService extends VelocityServlet {
    
    public static final Set actions = new TreeSet();
    static {
        actions.add("createSubscription");
        actions.add("deleteSubscription");
        actions.add("editSubscription");
        actions.add("showFeed");
        actions.add("listSubscriptions");
        actions.add("login");
        actions.add("register");
    }
    
    
    protected Template handleRequest(HttpServletRequest req,
            HttpServletResponse res, Context context) {
        
        String action = req.getParameter("action");
        
        if (action == null || !actions.contains(action)) {
            String title = "Unknown action";
            String message = "I don't know how to " + action;
            String details = "The only actions I know are " + actions;
            return showError(context, message, details);
        }
        

        Map args = req.getParameterMap();
        // TODO stop this, we need multi-valued stuff
        args = normalise(args);
        
        String templateString = "";
        
        try {
            Method method = AlertingService.class.getDeclaredMethod(action, new Class[] {Map.class, Context.class});
            templateString = (String) method.invoke(this, new Object[] {args, context});
        } catch (Exception e) {
            String message = "An error has occured, I couldn't do what you told me to do.";
            String details = e.getMessage() + " (" + e.getClass().getName() + "), action is " + action;
            return showError(context, message, details);
        }
        
        Template template = null;
        try {
            template = getTemplate(templateString);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            try {
                error((HttpServletRequest)context.get(REQUEST), 
                        (HttpServletResponse)context.get(RESPONSE),
                        e);
            } catch (Exception e2) {
                // TODO Auto-generated catch block
                e2.printStackTrace();
            }
        }
        return template;
    }
    
    /**
     * @param arguments
     * @param context
     * @return the Velocity template to use
     * @throws Exception
     */
    public String createSubscription(Map arguments, Context context) throws Exception {
        HttpSession session = ((HttpServletRequest)context.get(REQUEST)).getSession(true);
        if (!UserManager.getInstance().isLoggedIn(session)) {
            session.setAttribute("next_action", "createSubscription");
            return "login.vm";
        }
        // TODO handle wizard-style stuff 
        // if "finish"
        ProfileStore.getInstance().createSubscription(arguments);
        return listSubscriptions(arguments, context);
        // else show next page
    }

    public String deleteSubscription(Map arguments, Context context) {
        HttpSession session = ((HttpServletRequest)context.get(REQUEST)).getSession(true);
        if (!UserManager.getInstance().isLoggedIn(session)) {
            session.setAttribute("next_action", "deleteSubscription");
            return "login.vm";
        }
        String subscriptionID = (String) arguments.get("subscriptionID");
        ProfileStore.getInstance().deleteSubscription(subscriptionID);
        return listSubscriptions(arguments, context);
    }
    
    public String editSubscription(Map arguments, Context context) {
        HttpSession session = ((HttpServletRequest)context.get(REQUEST)).getSession(true);
        if (!UserManager.getInstance().isLoggedIn(session)) {
            session.setAttribute("next_action", "editSubscription");
            return "login.vm";
        }
        // TODO handle wizard-style stuff
        // if "finish"
        ProfileStore.getInstance().changeSubscription(arguments, session);
        return listSubscriptions(arguments, context);
        // else show next page
    }
    
    public String showFeed(Map arguments, Context context) {
        context.put("list", ""/* TODO pass subscription list */);
        return "feed.vm";
    }

    public String listSubscriptions(Map arguments, Context context) {
        context.put("title", "List of Subscriptions");
        context.put("list", ProfileStore.getInstance().getAllSubscriptions());
        return "list.vm";
    }
    
    public String login(Map arguments, Context context) throws Exception {
        HttpSession session = ((HttpServletRequest)context.get(REQUEST)).getSession(true);
        UserManager.getInstance().loginUser(arguments, session);
        if (session.getAttribute("next_action") != null) {
            String nextAction = (String) session.getAttribute("next_action");
            Method method = AlertingService.class.getDeclaredMethod(nextAction, new Class[] {Map.class, Context.class});
            return (String) method.invoke(this, new Object[] {arguments, context});
        }
        return listSubscriptions(arguments, context);
    }
    
    public String register(Map arguments, Context context) throws Exception {
        HttpSession session = ((HttpServletRequest)context.get(REQUEST)).getSession(true);
        UserManager.getInstance().createUser(arguments, session);
        return login(arguments, context);
    }
    
    public void receiveEvent(Map event) {
        GreenstoneCommunicator gsComm = null;
        try {
            gsComm = new GreenstoneCommunicator(new URL((String) event.get("host_url")));
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Set matchedSubscriptions = ProfileStore.getInstance().filter(event, gsComm);
        // TODO do something with the matched subscriptions
    }

    /**
     * @param args
     */
    private Map normalise(Map args) {
        Map result = new TreeMap();
        for (Iterator iter = args.keySet().iterator(); iter.hasNext();) {
            String key = (String) iter.next();
            if (!key.equals("action")) {
                String firstValue = ((String[]) args.get(key))[0];
                result.put(key, firstValue);
            }
        }
        return result;
    }

    /**
     * @param context
     * @param message
     * @param details
     * @return
     */
    private Template showError(Context context, String message, String details) {
        context.put("title", "Error");
        context.put("message", message);
        context.put("details", details);
        try {
            return getTemplate("error.vm");
        } catch (Exception e) {
            try {
                super.error((HttpServletRequest)context.get("req"), 
                        (HttpServletResponse)context.get("res"), 
                        e);
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return null;
    }
}