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

import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.apache.commons.lang.StringUtils;
import org.gcube.datatransfer.resolver.catalogue.ItemCatalogueURLs;
import org.gcube.datatransfer.resolver.catalogue.ResourceCatalogueCodes;
import org.gcube.datatransfer.resolver.init.UriResolverSmartGearManagerInit;
import org.gcube.datatransfer.resolver.parthenos.ParthenosRequest;
import org.gcube.datatransfer.resolver.services.error.ExceptionManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The PartheosRegistryResolver.
 * 
 * See more at
 * https://gcube.wiki.gcube-system.org/gcube/URI_Resolver#Parthenos_URL_Resolver
 *
 * @author Francesco Mangiacrapa francesco.mangiacrapa@isti.cnr.it Nov 16, 2018
 */
@Path("parthenos_registry")
public class PartheosRegistryResolver {

	private static Logger logger = LoggerFactory.getLogger(PartheosRegistryResolver.class);
	private static String helpURI = "https://wiki.gcube-system.org/gcube/URI_Resolver#Parthenos_URL_Resolver";

	/**
	 * Resolve parthenos url.
	 * 
	 * To resolve an "item" from a Parthenos URL stored in the Parthenos Catalogue
	 * at https://ckan-parthenos.d4science.org/
	 *
	 * @param req        the req
	 * @param provider   the provider
	 * @param path       the path
	 * @param remainPath the remain path
	 * @return the response
	 */
	@GET
	@Path("/{provider}/{path}{remainPath:(/[^?$]+)?}")
	public Response resolveParthenosURL(@Context HttpServletRequest req, @PathParam("provider") String provider,
			@PathParam("path") String path, @PathParam("remainPath") String remainPath) throws WebApplicationException {

		logger.info(this.getClass().getSimpleName() + " GET starts...");
		String remainPathParthenosURL = null;

		try {

			logger.debug("provider is: " + provider);
			logger.debug("path is: " + path);
			logger.debug("remainPath is: " + remainPath);

			remainPathParthenosURL = String.format("%s/%s", provider, path);

			if (remainPath != null && !remainPath.isEmpty()) {
				remainPathParthenosURL += remainPath.startsWith("/") ? remainPath : "/" + remainPath;
			}

			logger.info("Resolving parthenos URL: " + remainPathParthenosURL);
			// APPLYING URL DECODING
			remainPathParthenosURL = URLDecoder.decode(remainPathParthenosURL, "UTF-8");
			// APPLYING NAME TRANSFORMATION
			String normalizedEntityName = toNameForCatalogue(remainPathParthenosURL);
			logger.info("Trying to resolve with Catalogue EntityName: " + normalizedEntityName);
			ItemCatalogueURLs itemCatalogueURLs = CatalogueResolver.getItemCatalogueURLs(req,
					UriResolverSmartGearManagerInit.getParthenosVREName(), ResourceCatalogueCodes.CTLGD.getId(),
					normalizedEntityName);
			return Response.seeOther(new URL(itemCatalogueURLs.getPrivateVRECataloguePortletURL()).toURI()).build();

		} catch (Exception e) {

			if (!(e instanceof WebApplicationException)) {
				// UNEXPECTED EXCEPTION managing it as WebApplicationException
				String error = "Error occurred on resolving the path " + remainPathParthenosURL
						+ ". Please, contact the support!";
				if (e.getCause() != null)
					error += "\n\nCaused: " + e.getCause().getMessage();
				throw ExceptionManager.internalErrorException(req, error, this.getClass(), helpURI);
			}
			// ALREADY MANAGED AS WebApplicationException
			logger.error("Exception:", e);
			throw (WebApplicationException) e;
		}

	}

	/**
	 * To get a normalized item name from a Parthenos URL. It applies a
	 * normalization function to get from an input Parthenos URL an item name that
	 * is catalogue compliant.
	 *
	 * @param req         the req
	 * @param jsonRequest the json request
	 * @return the response
	 * @throws Exception the exception
	 */
	@POST
	@Path("")
	@Consumes(MediaType.APPLICATION_JSON)
	@Produces(MediaType.TEXT_PLAIN)
	public Response postCatalogue(@Context HttpServletRequest req, ParthenosRequest jsonRequest)
			throws WebApplicationException {
		logger.info(this.getClass().getSimpleName() + " POST starts...");

		try {
			String entityName = jsonRequest.getEntity_name();

			if (entityName == null || entityName.isEmpty()) {
				logger.error("Entity Name Parameter like 'entity_name' not found or empty");
				throw ExceptionManager.badRequestException(req,
						"Mandatory body parameter 'entity_name' not found or empty", this.getClass(), helpURI);
			}

			// REMOVING FIRST '/' IF EXISTS
			entityName = entityName.startsWith("/") ? entityName.substring(1, entityName.length()) : entityName;

			// APPLYING NAME TRANSFORMATION
			String normalizedEntityName = toNameForCatalogue(entityName);
			ItemCatalogueURLs itemCatalogueURLs = CatalogueResolver.getItemCatalogueURLs(req,
					UriResolverSmartGearManagerInit.getParthenosVREName(), ResourceCatalogueCodes.CTLGD.getId(),
					normalizedEntityName);
			logger.info("Returining Catalogue URL: " + itemCatalogueURLs.getPrivateVRECataloguePortletURL());
			return Response.ok(normalizedEntityName)
					.header("Location", itemCatalogueURLs.getPrivateVRECataloguePortletURL()).build();

		} catch (Exception e) {

			if (!(e instanceof WebApplicationException)) {
				// UNEXPECTED EXCEPTION managing it as WebApplicationException
				String error = "Error occurred on transforming the " + jsonRequest + ". Please, contact the support!";
				throw ExceptionManager.internalErrorException(req, error, this.getClass(), helpURI);
			}
			// ALREADY MANAGED AS WebApplicationException
			logger.error("Exception:", e);
			throw (WebApplicationException) e;
		}
	}

	/**
	 * To name for catalogue. this method applyes a fuction to transform a parthenos
	 * URL to acceptable catalogue name (that is URL)
	 * 
	 * @param remainPathParthenosURL the remain path parthenos url
	 * @return the string
	 * @throws UnsupportedEncodingException the unsupported encoding exception
	 */
	protected String toNameForCatalogue(final String remainPathParthenosURL) throws UnsupportedEncodingException {
		// need to double decode for URLs like:
		// http://parthenos.d4science.org/handle/Parthenos/REG/Dataset/Appellation/Isidore%2520Dataset
		String name = StringUtils.replaceChars(URLDecoder.decode(remainPathParthenosURL, "UTF-8"), "/ .:", "_")
				.toLowerCase().replaceAll("[^A-Za-z0-9]", "_");
		// TO LOWERCASE FOR CKAN SUPPORTING
		return name.toLowerCase();
	}

	// TO TEST
	// public static void main(String[] args) throws UnsupportedEncodingException {
	//
	// String remainPathParthenosURL =
	// "Culturalitalia/unknown/Dataset/oai%3Aculturaitalia.it%3Aoai%3Aculturaitalia.it%3Amuseiditalia-mus_11953";
	// System.out.println(URLDecoder.decode(remainPathParthenosURL, "UTF-8"));
	//
	// }
}