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

import java.net.URI;
import java.net.URLEncoder;
import java.util.Random;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;

import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.datatransfer.resolver.caches.LoadingGeoExplorerApplicationURLCache;
import org.gcube.datatransfer.resolver.caches.LoadingGeonetworkInstanceCache;
import org.gcube.datatransfer.resolver.caches.LoadingGisViewerApplicationURLCache;
import org.gcube.datatransfer.resolver.gis.GeonetworkInstance;
import org.gcube.datatransfer.resolver.gis.MetadataConverter;
import org.gcube.datatransfer.resolver.gis.entity.GisLayerItem;
import org.gcube.datatransfer.resolver.gis.exception.GeonetworkInstanceException;
import org.gcube.datatransfer.resolver.gis.exception.IllegalArgumentException;
import org.gcube.datatransfer.resolver.services.error.ExceptionManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * The Class GisResolver.
 *
 * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it
 * Nov 2, 2018
 */
@Path("gis")
public class GisResolver {

	private static Logger logger = LoggerFactory.getLogger(GisResolver.class);

	public static String help = "https://wiki.gcube-system.org/gcube/URI_Resolver#GIS_Resolver";

	public static final String UTF_8 = "UTF-8";

	public static final String GIS_UUID = "gis-UUID";
	public static final String SCOPE = "scope";
	public static final String GEO_EXPLORER_LAYER_UUID = "geo-exp";

	/**
	 * Submit get.
	 *
	 * @param req the req
	 * @param scope the scope
	 * @param gisUUID the gis uuid
	 * @param geoExplorerUUID the geo explorer uuid
	 * @return the response
	 */
	@GET
	@Path("")
	public Response submitGet(@Context HttpServletRequest req, @QueryParam(SCOPE) String scope, @QueryParam(GIS_UUID) String gisUUID,  @QueryParam(GEO_EXPLORER_LAYER_UUID) String geoExplorerUUID){

		logger.info(this.getClass().getSimpleName()+" GET starts...");

		boolean isGisLink = false;
		boolean isGeoExplorerLink = false;

		if(scope==null || scope.isEmpty()){
			logger.error("Query Parameter 'scope' not found");
			ExceptionManager.throwBadRequestException(req, "Missing mandatory query parameter 'scope'", this.getClass(), help);
		}

		if(gisUUID==null || gisUUID.isEmpty()){
			logger.error("Path Parameter 'gis-UUID' not found");
			ExceptionManager.throwBadRequestException(req, "Missing mandatory query parameter 'gis-UUID'", this.getClass(), help);
		}else
			isGisLink = true;

		logger.info(SCOPE +" is: " + scope);
		logger.info(GIS_UUID +" is: " + gisUUID);

		if (geoExplorerUUID == null || geoExplorerUUID.isEmpty()) {
			logger.debug(GEO_EXPLORER_LAYER_UUID+ " not found");
		}else
			isGeoExplorerLink = true;

		logger.info(GEO_EXPLORER_LAYER_UUID +" is: " + geoExplorerUUID);

		if(!isGisLink && !isGeoExplorerLink){
			String err = GIS_UUID+" or "+GEO_EXPLORER_LAYER_UUID+" not found or empty in the query string";
			logger.error(err);
			ExceptionManager.throwBadRequestException(req, err, this.getClass(), help);
		}

		try {

			if(isGisLink){
				ScopeProvider.instance.set(scope);
				//ServerParameters geonetworkParams = getCachedServerParameters(scope);

				GisLayerItem gisLayerItem = getGisLayerForLayerUUID(scope, gisUUID);
				logger.info("wms url is: " + gisLayerItem.getFullWmsUrlRequest());
				String wmsRequest = URLEncoder.encode(gisLayerItem.getFullWmsUrlRequest(), UTF_8);
				logger.info("encoded WMS url is: " + wmsRequest);

				String layerTitle = null;
					if(gisLayerItem.getCitationTitle()!=null && !gisLayerItem.getCitationTitle().isEmpty())
						layerTitle = URLEncoder.encode(gisLayerItem.getCitationTitle(), UTF_8);

				logger.info("layer Title encoded is: " + layerTitle);

				String gisViewerPortletUrl = getGisViewerApplicationURL(scope);
				logger.info("Gis Viewer Application url is: " + gisViewerPortletUrl);
				gisViewerPortletUrl+="?rid="+new Random().nextLong()
								+"&wmsrequest="+wmsRequest
								+"&uuid="+URLEncoder.encode(gisUUID, UTF_8);

				if(layerTitle!=null)
					gisViewerPortletUrl+="&layertitle="+layerTitle;

				logger.info("Redirecting to: "+gisViewerPortletUrl);
				return Response.seeOther(new URI(gisViewerPortletUrl)).build();
			}

			if(isGeoExplorerLink){
				ScopeProvider.instance.set(scope);
				String geoExplorerPortletUrl  = getGeoExplorerApplicationURL(scope);
				logger.info("GeoExplorer Application url is: " + geoExplorerPortletUrl);
				geoExplorerPortletUrl+="?rid="+new Random().nextLong()
								+"&luuid="+URLEncoder.encode(geoExplorerUUID, UTF_8);
				//urlRedirect(req, resp, geoExplorerPortletUrl);
				return Response.seeOther(new URI(geoExplorerPortletUrl)).build();
			}

			ExceptionManager.throwBadRequestException(req, GIS_UUID+" or "+GEO_EXPLORER_LAYER_UUID+" not found or empty in the query string", this.getClass(), help);
			return null;

		} catch (Exception e) {
			logger.error("Exception:", e);
			String error = "Sorry, an error occurred on resolving request with UUID "+gisUUID+" and scope "+scope+". Please, contact support!";
			ExceptionManager.throwInternalErrorException(req, error, this.getClass(), help);
			return null;
		}

	}


	/**
	 * Gets the gis viewer application url.
	 *
	 * @param scope the scope
	 * @return the gis viewer application url
	 * @throws Exception the exception
	 */
	protected String getGisViewerApplicationURL(String scope) throws Exception{

		logger.info("Tentative of recovering gis viewer application hostname from cache for scope: "+scope);
		String gisViewerAppHostname = LoadingGisViewerApplicationURLCache.getCache().get(scope);
		if(gisViewerAppHostname==null){
//			logger.info("Gis viewer application hostname is null, reading from application profile..");
//			String url = LoadingGisViewerApplicationURLCache.loadGisViewerApplicationURL(scope);
//			LoadingGisViewerApplicationURLCache.getCache().put(scope, url);
//			logger.info("Updated GisViewerApplication cache! Scope "+scope+" linking "+url);
//			return url;
			throw new Exception("GisViewer Application not found in the scope: "+scope);
		}else
			logger.info("Cache for GisViewerApplication end point is not null using it");

		return gisViewerAppHostname;
	}


	/**
	 * Gets the gis layer for layer uuid.
	 *
	 * @param scope the scope
	 * @param gisUUID the gis uuid
	 * @return the gis layer for layer uuid
	 * @throws Exception the exception
	 */
	protected GisLayerItem getGisLayerForLayerUUID(String scope, String gisUUID) throws Exception{

		try {
			GeonetworkInstance gi = getCachedGeonetworkInstance(scope);
			GisLayerItem gisLayerItem = MetadataConverter.getWMSOnLineResource(gi, gisUUID);
			return gisLayerItem;
			//TODO CREATE A BEAN ADDING WMS REQUEST AND LAYER TITLE MetadataConverter.
		}catch (GeonetworkInstanceException e){
			logger.error("An error occurred when instancing geonetowrk gis layer with UUID "+gisUUID, e);
			throw new IllegalArgumentException("Sorry, An error occurred when instancing geonetwork with UUID: "+gisUUID);
		} catch (Exception e) {
			logger.error("An error occurred when retrieving gis layer with UUID "+gisUUID, e);
			throw new IllegalArgumentException("Sorry, An error occurred when retrieving gis layer with UUID "+gisUUID);
		}
	}

	/**
	 * Gets the cached geonetwork instance.
	 *
	 * @param scope the scope
	 * @return the cached geonetwork instance
	 * @throws Exception the exception
	 */
	protected GeonetworkInstance getCachedGeonetworkInstance(String scope) throws Exception{

		logger.info("Attempt to get the GeonetworkInstance from cache by scope: "+scope);
		GeonetworkInstance geonInstance = LoadingGeonetworkInstanceCache.getCache().get(scope);

		if(geonInstance==null){
			logger.info("GeonetworkInstance is null in cache, reading from library...");
			try {
				geonInstance = LoadingGeonetworkInstanceCache.loadGeonetworkInstance(scope);
				LoadingGeonetworkInstanceCache.getCache().put(scope, geonInstance);
				logger.info("Updated GeonetworkInstance cache! Scope "+scope+" linking "+geonInstance);
			} catch (Exception e) {
				logger.error("An error occurred on getting GeonetworkInstance for scope: "+scope, e);
				throw new Exception("Sorry, An error occurred on getting GeonetworkInstance for scope: "+scope);
			}
		}else
			logger.info("GeonetworkInstance is not null using it");

		logger.info("returning GeonetworkInstance: "+geonInstance);

		return geonInstance;
	}


	/**
	 * Gets the geo explorer application url.
	 *
	 * @param scope the scope
	 * @return the geo explorer application url
	 * @throws Exception the exception
	 */
	protected String getGeoExplorerApplicationURL(String scope) throws Exception{

		logger.info("Tentative of recovering geo explorer application hostname from cache for scope: "+scope);
		String geoExplorerApplicationHostname = LoadingGeoExplorerApplicationURLCache.getCache().get(scope);
		if(geoExplorerApplicationHostname==null){
			logger.info("GeoExplorer application hostname is null, reading from application profile..");
			String url = LoadingGeoExplorerApplicationURLCache.loadGeoExplorerApplicationURL(scope);
			LoadingGeoExplorerApplicationURLCache.getCache().put(scope, url);
			logger.info("Updated GeoExplorerApplication cache! Scope "+scope+" linking "+url);
			return url;
		}else
			logger.info("Cache for GeoExplorerApplication end point is not null using it");

		return geoExplorerApplicationHostname;

	}


}