/**
 *
 */
package org.gcube.datatransfer.resolver;

import java.io.IOException;
import java.util.HashSet;
import java.util.Set;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

import org.gcube.datatransfer.resolver.catalogue.CatalogueRequestParameter;
import org.gcube.datatransfer.resolver.catalogue.UrlEncoderUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;



/**
 * The Class UriResolverRewriteFilter.
 *
 * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it
 * Dec 5, 2016
 */
public class UriResolverRewriteFilter implements Filter{

	/**
	 *
	 */
	public static final String SERVLET_URI_RESOLVER = "/uri-resolver";

	private static final String PATH_SEPARATOR = "/";
	public static final String SERVLET_GEONETWORK = "/geonetwork";
	public static final String PARAMETER_FILTER_PUBLIC_IDS = "filterpublicids";
	public static final String PARAMETER_NO_AUTHENTICATION = "noauthentication";
	public static final String REQUEST_PARAMETER_SEPARATOR = "#";

	public static final String PARAMETER_SMP_ID = "smp-id";
	public static final String SERVLET_STORAGE_ID = "id";

	public static final String PARAMETER_ENC_CATALOGUE_LINK = "cl";
	public static final String PARAMETER_DIRECT_CATALOGUE_LINK = "dl";
	public static final String SERVLET_CATALOGUE = "/catalogue";

	protected static final Logger logger = LoggerFactory.getLogger(UriResolverRewriteFilter.class);
	private FilterConfig config;

	private static final Set<String> resourceCataloguesCodes = new HashSet<String>(ResourceCatalogueCodes.codes());

	//private ApplicationProfileReaderForCatalogueResolver appPrfCatResolver = new ApplicationProfileReaderForCatalogueResolver(scope, useRootScope)

	/**
	 * Gets the config.
	 *
	 * @return the config
	 */
	public FilterConfig getConfig() {

		return config;
	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#destroy()
	 */
	@Override
	public void destroy() {
		  logger.trace("run destroy");
	}


	/* (non-Javadoc)
	 * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
	 */
	@Override
	public void doFilter(ServletRequest req, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		/* wrap the request in order to read the inputstream multiple times */
	    MultiReadHttpServletRequest multiReadRequest = new MultiReadHttpServletRequest((HttpServletRequest) req);
		String requestURI = multiReadRequest.getRequestURI();
		String queryString = multiReadRequest.getQueryString();
		String servletPath = multiReadRequest.getServletPath();
		logger.debug("Request URI: " + requestURI + ", QueryString: " +queryString+ ", Servlet path: "+servletPath);

		//IS A REQUEST FOR GEONETWORK AUTHENTICATION? (CKAN HARVESTING?)
		if(servletPath.startsWith(SERVLET_GEONETWORK) || servletPath.startsWith(SERVLET_URI_RESOLVER+SERVLET_GEONETWORK)){
			logger.debug("It is a request to geonetwork");
			GeonetworkRequestDecoder grd = new GeonetworkRequestDecoder(servletPath, queryString);
			logger.debug("forward to: "+grd.getNewURI());
			multiReadRequest.getRequestDispatcher(grd.getNewURI()).forward(multiReadRequest, response);

		}else{
				logger.debug("checking if it is a request to catologue...");
				boolean isCatalogueServletReference = servletPath.startsWith(SERVLET_CATALOGUE);

				String idCodeCatalogue = null;
				boolean isIdCodeCatalogue = false;
				String splittedServletPath[] = servletPath.split(PATH_SEPARATOR);
				if(!isCatalogueServletReference){
					idCodeCatalogue = splittedServletPath[1];
					logger.trace("checking if the code: "+idCodeCatalogue+" belongs to a catalogue code");
					isIdCodeCatalogue = resourceCataloguesCodes.contains(idCodeCatalogue);
					logger.debug("\tIs it a catalogue code? "+isIdCodeCatalogue);
				}

				if(isCatalogueServletReference || isIdCodeCatalogue){

					//int startIndex = requestURI.indexOf(SERVLET_CATALOGUE))+SERVLET_CATALOGUE.length();
					//String vreName = requestURI.substring(beginIndex)
					HttpServletRequest request = (HttpServletRequest) req;
					logger.trace("method is: "+request.getMethod());

					if(request.getMethod().compareToIgnoreCase("POST")==0){
						logger.debug("Managing as Catalogue POST request..");
						logger.debug("forward to: " + SERVLET_CATALOGUE);
						multiReadRequest.getRequestDispatcher(SERVLET_CATALOGUE).forward(multiReadRequest, response);
					}else{
						logger.debug("Managing as Catalogue GET request..");
						String newURI = SERVLET_CATALOGUE;
						//String[] pathSplit = newServletPath.split(PATH_SEPARATOR);
						if(isIdCodeCatalogue){
							//TO BUILD A COMPLETE URL
//							logger.debug("is a catalogue code, rebuilding complete url...");
//							ResourceCatalogueCodes rcc = ResourceCatalogueCodes.valueOfId(idCodeCatalogue);
//							newServletPath = SERVLET_CATALOGUE+splittedServletPath[2]+PATH_SEPARATOR+rcc.getValue()+PATH_SEPARATOR+splittedServletPath[3];
//							logger.debug("rebuilded complete url: "+newServletPath);
							logger.debug("is a catalogue code, resolving a short url in clear ...");
							ResourceCatalogueCodes rcc = ResourceCatalogueCodes.valueOfCodeId(idCodeCatalogue);
							logger.debug("found VRE name: "+splittedServletPath[2]);
							String gcubeScope = CatalogueRequestParameter.GCUBE_SCOPE.getKey() +"="+splittedServletPath[2];
							String eC = CatalogueRequestParameter.ENTITY_CONTEXT.getKey() +"="+rcc.getValue();
							logger.debug("found id code: "+idCodeCatalogue+", resolving it with context name: "+eC);
							String eN = CatalogueRequestParameter.ENTITY_NAME.getKey() +"="+splittedServletPath[3];
							logger.debug("found entity name: "+eN);
							String encodedQuery = UrlEncoderUtil.encodeQuery(gcubeScope,eC,eN);
							newURI+=  "?" + PARAMETER_DIRECT_CATALOGUE_LINK + "=" + encodedQuery;
						}else
							if(splittedServletPath.length==5){
								logger.info("resolving a complete URL in clear...");
								logger.debug("found VRE name: "+splittedServletPath[2]);
								String gcubeScope = CatalogueRequestParameter.GCUBE_SCOPE.getKey() +"="+splittedServletPath[2];
								String eC = CatalogueRequestParameter.ENTITY_CONTEXT.getKey() +"="+splittedServletPath[3];
								logger.debug("found context name: "+eC);
								String eN = CatalogueRequestParameter.ENTITY_NAME.getKey() +"="+splittedServletPath[4];
								logger.debug("found entity name: "+eN);
								String encodedQuery = UrlEncoderUtil.encodeQuery(gcubeScope,eC,eN);
								newURI+=  "?" + PARAMETER_DIRECT_CATALOGUE_LINK + "=" + encodedQuery;
						}else{

							logger.info("Resolving an encrypted URL to catalogue...");
							int lastSlash = requestURI.lastIndexOf(PATH_SEPARATOR);
							String toCatalogueLink = requestURI.substring(lastSlash + 1, requestURI.length());
							newURI+=  "?" + PARAMETER_ENC_CATALOGUE_LINK + "=" + toCatalogueLink;
						}

						logger.debug("forward to: " + newURI);
						multiReadRequest.getRequestDispatcher(newURI).forward(multiReadRequest, response);
					}

				//chain.doFilter(multiReadRequest, response);
			}else{
				logger.debug("It is a request to workspace/storage");
				//LAST CASE, IS WORKSPACE REQUEST?
				if (queryString == null) { // IS A /XXXXX
					logger.debug("QueryString is null, is It a new SMP public uri by ID?");
					int lastSlash = requestURI.lastIndexOf(PATH_SEPARATOR);
					if (lastSlash + 1 == requestURI.length()) {
						logger.debug("'/' is last index, doFilter Request");
						// req.getRequestDispatcher("/").forward(req, res);
						chain.doFilter(multiReadRequest, response);
					}
					else {
						String toStorageID = requestURI.substring(lastSlash + 1, requestURI.length());
						// String newURI = requestURI.replace(toReplace,
						// SERVLET_RESOLVER_BY_ID+"?"+SMP_ID+"="+toReplace);
						String newURI = SERVLET_STORAGE_ID + "?" + PARAMETER_SMP_ID + "=" + toStorageID;
						logger.debug("forward to: " + newURI);
						multiReadRequest.getRequestDispatcher(newURI).forward(multiReadRequest, response);
					}
				}
				else {
					logger.debug("is NOT a SMP public uri by ID, doFilter Request");
					chain.doFilter(multiReadRequest, response);
				}
			}

		}
	}


	/**
	 * Gets the scope.
	 *
	 * @param scope the scope
	 * @return the scope
	 */
	private static String getScope(String scope){
		logger.debug("Read scope path: "+scope);
//		String scope = servletPath.substring(servletPath.indexOf("/"), servletPath.length());
		return PATH_SEPARATOR+scope.replaceAll("_", PATH_SEPARATOR);
	}

	/* (non-Javadoc)
	 * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
	 */
	@Override
	public void init(FilterConfig config) throws ServletException {
		 logger.trace("run init");
		 this.config = config;
	}

	/*public static void main(String[] args) {

		String split = "/catalogue/NextNext/dataset/sarda-sarda";

		String[] array = split.split("/");

		System.out.println(array.length);

		for (int i = 0; i < array.length; i++) {
			System.out.println(i+" "+array[i]);
		}

		System.out.println(array[2]);

	}*/
}