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

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.util.Arrays;

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

import org.joda.time.DateTime;
import org.joda.time.Interval;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.web.context.support.ServletContextResourceLoader;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;
import org.springframework.web.util.UrlPathHelper;

import com.enonic.cms.framework.util.HttpCacheControlSettings;
import com.enonic.cms.framework.util.HttpServletUtil;
import com.enonic.cms.framework.util.MimeTypeResolver;

/**
 * This class implements a file controller that returns the actual referenced file in
 * the servlet context.
 */
public class ResourceController
    extends AbstractController
    implements InitializingBean
{
    /* js files that contain i18n strings. must be not cached. */
    private static final String[] sorted_js_files = {
        "/admin/javascript/calendar_picker.js",
        "/admin/javascript/domain.js",
        "/admin/javascript/groups.js",
        "/admin/javascript/log_filter.js",
        "/admin/javascript/resource.js",
        "/admin/javascript/section.js",
        "/admin/javascript/user.js",
        "/admin/javascript/validate.js",
        "/admin/javascript/workentry.js"
    };

    protected MimeTypeResolver mimeTypeResolver;

    private UrlPathHelper urlPathHelper;

    private ServletContextResourceLoader resourceLoader;

    public ResourceController()
    {
        urlPathHelper = new UrlPathHelper();
        urlPathHelper.setUrlDecode( true );
    }

    public void afterPropertiesSet()
    {
        this.resourceLoader = new ServletContextResourceLoader( getServletContext() );
    }

    /**
     * Handle the request.
     */
    protected ModelAndView handleRequestInternal( HttpServletRequest request, HttpServletResponse response )
        throws Exception
    {
        String path = urlPathHelper.getPathWithinApplication( request );
        Resource resource = this.resourceLoader.getResource( path );

        if ( resource.exists() )
        {
            if ( Arrays.binarySearch( sorted_js_files, request.getPathInfo() ) > 0 )
            {
                HttpServletUtil.setCacheControlNoCache( response );
            }
            else
            {
                DateTime now = new DateTime();
                DateTime expirationDate = now.plusHours( 1 );

                HttpCacheControlSettings cacheControlSettings = new HttpCacheControlSettings();
                cacheControlSettings.maxAgeSecondsToLive = new Interval( now, expirationDate ).toDurationMillis() / 1000;
                cacheControlSettings.publicAccess = true;

                HttpServletUtil.setDateHeader( response, now.toDate() );
                HttpServletUtil.setExpiresHeader( response, expirationDate.toDate() );
                HttpServletUtil.setCacheControl( response, cacheControlSettings );
            }

            serveResourceToResponse( request, response, resource );
        }
        else
        {
            response.sendError( HttpServletResponse.SC_NOT_FOUND );
        }

        return null;
    }

    /**
     * Serve resource to response.
     */
    protected void serveResourceToResponse( HttpServletRequest request, HttpServletResponse response, Resource resource )
        throws Exception
    {
        BufferedInputStream in = new BufferedInputStream( resource.getInputStream() );
        BufferedOutputStream out = new BufferedOutputStream( response.getOutputStream() );
        response.setContentType( mimeTypeResolver.getMimeType( resource.getFilename() ) );
        HttpServletUtil.copyNoCloseOut( in, out );
    }

    @Autowired
    public void setMimeTypeResolver( MimeTypeResolver mimeTypeResolver )
    {
        this.mimeTypeResolver = mimeTypeResolver;
    }
}