/*
 * Copyright 2000-2013 Enonic AS
 * http://www.enonic.com/license
 */
package com.enonic.cms.server.service.dwr;

import java.io.IOException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;
import org.directwebremoting.servlet.DwrServlet;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.enonic.cms.core.config.ConfigProperties;
import com.enonic.cms.core.servlet.ServletRequestAccessor;
import com.enonic.cms.core.vhost.VirtualHostHelper;
import com.enonic.cms.server.service.admin.ajax.AdminAjaxServiceImpl;
import com.enonic.cms.server.service.admin.ajax.dto.PreferenceDto;
import com.enonic.cms.server.service.admin.ajax.dto.RegionDto;
import com.enonic.cms.server.service.admin.ajax.dto.SynchronizeStatusDto;
import com.enonic.cms.server.service.admin.ajax.dto.UserDto;
import com.enonic.cms.store.dao.PreferenceDao;

/**
 * This class implements a servlet that wraps around dwr. It fixes a path problem that is seen when certain virtual hosts are used.
 */
public final class DwrServletWrapper
    extends DwrServlet
{

    private final StringBuilder classes;

    /**
     * Construct the wrapper.
     */
    public DwrServletWrapper()
    {
        this.classes = new StringBuilder();

        addClass( AdminAjaxServiceImpl.class );
        addClass( PreferenceDao.class );
        addClass( SynchronizeStatusDto.class );
        addClass( RegionDto.class );
        addClass( UserDto.class );
        addClass( PreferenceDto.class );
    }

    private void addClass( final Class type )
    {
        if ( this.classes.length() > 0 )
        {
            this.classes.append( "," );
        }

        this.classes.append( type.getName() );
    }

    @Override
    protected void service( final HttpServletRequest req, final HttpServletResponse res )
        throws ServletException, IOException
    {
        if ( VirtualHostHelper.hasBasePath( req ) )
        {
            String basePath = VirtualHostHelper.getBasePath( req );
            final String servletPath = req.getServletPath().replace( "/admin", basePath );

            HttpServletRequest newReq = new HttpServletRequestWrapper( req )
            {
                public String getServletPath()
                {
                    return servletPath;
                }
            };

            doService( res, newReq );
        }
        else
        {
            doService( res, req );
        }
    }

    private void doService( HttpServletResponse res, HttpServletRequest req )
        throws ServletException, IOException
    {
        ServletRequestAccessor.setRequest( req );
        super.service( req, res );
        setContentType( req, res );
    }

    private void setContentType( HttpServletRequest req, HttpServletResponse res )
    {
        String url = req.getRequestURL().toString();

        if ( StringUtils.endsWith( url, ".js" ) )
        {
            res.setContentType( "text/javascript" );
        }
    }

    @Override
    public void init( final ServletConfig config )
        throws ServletException
    {
        final ConfigProperties configProperties = getConfigProperties( config.getServletContext() );

        final Map<String, String> params = new HashMap<String, String>();
        params.put( "debug", configProperties.getProperty( "cms.admin.dwr.debug", "false" ) );
        params.put( "crossDomainSessionSecurity", configProperties.getProperty( "cms.admin.dwr.crossDomainSessionSecurity", "false" ) );
        params.put( "classes", this.classes.toString() );

        final ServletConfig wrapper = new ServletConfig()
        {
            public String getServletName()
            {
                return config.getServletName();
            }

            public ServletContext getServletContext()
            {
                return config.getServletContext();
            }

            public String getInitParameter( final String name )
            {
                return params.get( name );
            }

            public Enumeration getInitParameterNames()
            {
                return Collections.enumeration( params.keySet() );
            }
        };

        super.init( wrapper );
    }

    private ConfigProperties getConfigProperties( final ServletContext servletContext )
    {
        final WebApplicationContext context = WebApplicationContextUtils.getRequiredWebApplicationContext( servletContext );
        return context.getBean( ConfigProperties.class );
    }
}