package net.sourceforge.fenixedu.presentationTier.servlets.ajax;

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

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

import net.sourceforge.fenixedu.applicationTier.IUserView;
import net.sourceforge.fenixedu.presentationTier.Action.resourceAllocationManager.utils.ServiceUtils;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.lang.StringUtils;

import pt.ist.fenixWebFramework.renderers.utils.RenderUtils;
import pt.ist.fenixWebFramework.security.UserView;

public class AutoCompleteServlet extends HttpServlet {

    private static final String JAVASCRIPT_LIBRARY_ENCODING = "UTF-8";
    private static final int DEFAULT_MAX_COUNT = 20;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	process(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	process(request, response);
    }

    private void process(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

	request.setCharacterEncoding(JAVASCRIPT_LIBRARY_ENCODING);

	String service = request.getParameter("serviceName");
	Class type = getConcreteType(request.getParameter("class"));
	String value = request.getParameter("value");

	Map<String, String> serviceArgsMap = getServiceArgsMap(request.getParameter("serviceArgs"));
	int maxCount = getNumber(request.getParameter("maxCount"), DEFAULT_MAX_COUNT);

	IUserView userView = getUserView(request);
	Collection result = executeService(userView, service, type, value, maxCount, serviceArgsMap);

	String labelField = request.getParameter("labelField");
	String format = request.getParameter("format");
	String valueField = request.getParameter("valueField");
	String styleClass = request.getParameter("styleClass");

	response.setContentType("text/html");
	response.getWriter().write(getResponseHtml(result, labelField, format, valueField, styleClass, maxCount));
    }

    private Class getConcreteType(String className) throws ServletException {
	try {
	    return Class.forName(className);
	} catch (ClassNotFoundException e) {
	    throw new ServletException("could not find type " + className, e);
	}
    }

    private int getNumber(String parameter, int defaultValue) {
	if (parameter == null) {
	    return defaultValue;
	}

	try {
	    return Integer.parseInt(parameter);
	} catch (NumberFormatException e) {
	    return defaultValue;
	}
    }

    private Collection executeService(IUserView userView, String serviceName, Class type, String value, int maxCount,
	    Map<String, String> arguments) throws ServletException {
	try {
	    return (Collection) ServiceUtils.executeService(serviceName, new Object[] { type, value, maxCount, arguments });
	} catch (Exception e) {
	    throw new ServletException("Error executing service", e);
	}
    }

    private Map<String, String> getServiceArgsMap(String encodedServiceArgs) {
	String[] serviceArgsArray = StringUtils.split(encodedServiceArgs, ',');
	Map<String, String> serviceArgsMap = new HashMap<String, String>();

	for (String serviceArg : serviceArgsArray) {
	    String[] argNameArgValue = StringUtils.split(serviceArg, '=');
	    serviceArgsMap.put(argNameArgValue[0], argNameArgValue[1]);
	}

	return serviceArgsMap;
    }

    private IUserView getUserView(HttpServletRequest request) {
	return UserView.getUser();
    }

    private String getResponseHtml(Collection result, String labelField, String format, String valueField, String styleClass,
	    int maxCount) {
	StringBuilder responseHtml = new StringBuilder();
	responseHtml.append("<ul ").append("class=\"").append(styleClass).append("\">");

	try {

	    int count = 0;
	    for (final Object element : result) {
		if (count++ >= maxCount) {
		    break;
		}
		final String labelProperty = BeanUtils.getProperty(element, labelField);
		responseHtml.append("<li id=\"").append(BeanUtils.getProperty(element, valueField)).append("\" name=\"").append(
			labelProperty).append("\">");

		if (format == null) {
		    responseHtml.append(labelProperty);
		} else {
		    responseHtml.append(RenderUtils.getFormattedProperties(format, element));
		}

		responseHtml.append("</li>");
	    }
	} catch (Exception ex) {
	    throw new RuntimeException("Error getting field property (see label and value fields)", ex);

	}

	responseHtml.append("</ul>");

	return responseHtml.toString();
    }
}