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

import static org.gcube.common.authorization.client.Constants.authorizationService;
import static org.gcube.resources.discovery.icclient.ICFactory.clientFor;
import static org.gcube.resources.discovery.icclient.ICFactory.queryFor;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.file.Files;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
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 javax.xml.bind.JAXBException;

import org.apache.commons.io.IOUtils;
import org.gcube.common.authorization.library.AuthorizationEntry;
import org.gcube.common.authorization.library.provider.ClientInfo;
import org.gcube.common.authorization.library.provider.SecurityTokenProvider;
import org.gcube.common.encryption.StringEncrypter;
import org.gcube.common.resources.gcore.ServiceEndpoint;
import org.gcube.common.resources.gcore.ServiceEndpoint.AccessPoint;
import org.gcube.common.resources.gcore.ServiceEndpoint.Property;
import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.common.scope.impl.ScopeBean.Type;
import org.gcube.common.storagehub.model.Metadata;
import org.gcube.data.analysis.dminvocation.ActionType;
import org.gcube.data.analysis.dminvocation.DataMinerInvocationManager;
import org.gcube.data.analysis.dminvocation.model.DataMinerInvocation;
import org.gcube.datatransfer.resolver.requesthandler.RequestHandler;
import org.gcube.datatransfer.resolver.services.error.ExceptionManager;
import org.gcube.datatransfer.resolver.services.exceptions.InternalServerException;
import org.gcube.datatransfer.resolver.util.ScopeUtil;
import org.gcube.datatransfer.resolver.util.Util;
import org.gcube.resources.discovery.client.api.DiscoveryClient;
import org.gcube.resources.discovery.client.queries.api.SimpleQuery;
import org.gcube.storagehub.ApplicationMode;
import org.gcube.storagehub.StorageHubManagement;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.SAXException;

/**
 * The AnalyticsCreateResolver provides a method to get the Analytics URLs by
 * which is possible to invoke through the DataMiner Executor the run of an
 * algorithm stored in a certain VRE.
 * 
 * See more at
 * https://gcube.wiki.gcube-system.org/gcube/URI_Resolver#Analytics_Resolver
 * 
 * @author Francesco Mangiacrapa at ISTI-CNR (francesco.mangiacrapa@isti.cnr.it)
 *         Dec 12, 2018
 */
@Path("analytics")
public class AnalyticsCreateResolver {

	/**
	 *
	 */
	protected static final String GCUBE_TOKEN = "gcube-token";
	/**
	 *
	 */
	private static final String ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME = "Analytics-Resolver";
	private static final String DATAMINER_INVOCATION_MODEL = "dim";
	private static Logger logger = LoggerFactory.getLogger(AnalyticsCreateResolver.class);
	private static String helpURI = "https://gcube.wiki.gcube-system.org/gcube/URI_Resolver#Analytics_Resolver";

	/**
	 * Creates the analytics url.
	 * 
	 * Request format: [URI_RESOLVER_SERVICE_ENDPOINT]/analytics/create
	 * 
	 * See more at
	 * https://gcube.wiki.gcube-system.org/gcube/URI_Resolver#HTTP_POST:_Create_an_Analytics_URL
	 * 
	 * @param req  the req
	 * @param body the body
	 * @return the response
	 * @throws WebApplicationException the web application exception
	 */
	@POST
	@Path("/create")
	@Consumes(MediaType.TEXT_PLAIN)
	@Produces(MediaType.TEXT_PLAIN)
	public Response createAnalyticsURL(@Context HttpServletRequest req, String body) throws WebApplicationException {
		logger.info(this.getClass().getSimpleName() + " POST starts...");

		try {
			logger.info("body is: " + body);

			DataMinerInvocation jsonRequest = null;
			try {

				jsonRequest = DataMinerInvocationManager.getInstance().unmarshalingJSON(IOUtils.toInputStream(body),
						true);
			} catch (IOException | JAXBException | SAXException e1) {
				logger.error("The body is not a valid DataMinerInvocation JSON request", e1);
				throw ExceptionManager.badRequestException(req,
						"Bad 'dataminer-invocation' JSON request: \n" + e1.getCause().getMessage(), this.getClass(),
						helpURI);
			}

			logger.debug("The body contains the request: " + jsonRequest.toString());

			String contextToken = SecurityTokenProvider.instance.get();
			String scope = ScopeProvider.instance.get();
			// logger.info("SecurityTokenProvider contextToken: "+contextToken);
			logger.info("ScopeProvider has scope: " + scope);

			String appToken = req.getServletContext().getInitParameter(RequestHandler.ROOT_APP_TOKEN);

			if (contextToken.compareTo(appToken) == 0) {
				logger.error("Token not passed, SecurityTokenProvider contains the root app token: "
						+ appToken.substring(0, 10) + "...");
				throw ExceptionManager.unauthorizedException(req,
						"You are not authorized. You must pass a token of VRE", this.getClass(), helpURI);
			}

			String operatorID = jsonRequest.getOperatorId();

			if (scope == null || scope.isEmpty()) {
				logger.error("The parameter 'scope' not found or empty in the JSON object");
				throw ExceptionManager.badRequestException(req,
						"Mandatory body parameter 'scope' not found or empty in the JSON object", this.getClass(),
						helpURI);
			}

			if (operatorID == null || operatorID.isEmpty()) {
				logger.error("The parameter 'operatorId' not found or empty in the JSON object");
				throw ExceptionManager.badRequestException(req,
						"Mandatory body parameter 'operatorId' not found or empty in the JSON object", this.getClass(),
						helpURI);
			}

			ScopeBean scopeBean = new ScopeBean(scope);
			String publicLinkToDMInvFile = "";

			if (scopeBean.is(Type.VRE)) {
				String vreName = scopeBean.name();

				String analyticsGetResolverURL = String.format("%s/%s", Util.getServerURL(req), "analytics/get");
				// Creating DM invocation file
				if (jsonRequest.getActionType() == null)
					jsonRequest.setActionType(ActionType.RUN);

				File tempInvocationFile = null;
				try {

					String xmlRequest = DataMinerInvocationManager.getInstance().marshalingXML(jsonRequest, true, true);
					String uniqueName = createDMInvocationFileName(jsonRequest.getOperatorId());
					tempInvocationFile = createTempFile(uniqueName, ".xml", xmlRequest.getBytes());
					logger.info("Created StorageHubClient Instance, uploading file: " + tempInvocationFile.getName());

					AuthorizationEntry entry = authorizationService().get(contextToken);
					// retrieve the info of the token owner
					ClientInfo clientInfo = entry.getClientInfo();
					String owner = clientInfo.getId(); // IS THIS THE USERNAME?

					String infra = ScopeUtil.getInfrastructureNameFromScope(ScopeProvider.instance.get());
					String theAppToken = readApplicationTokenFromSE(req, infra);

					logger.info("By using infra scope: " + infra + " and the Application Token: "
							+ theAppToken.substring(0, theAppToken.length() / 2) + "... of "
							+ ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + " to instance the "
							+ StorageHubManagement.class.getSimpleName());
					ScopeProvider.instance.set(infra);
					ApplicationMode applicationMode = new ApplicationMode(theAppToken);
					applicationMode.start();

					StorageHubManagement storageHubManagement = new StorageHubManagement();
					Metadata metadata = new Metadata();
					Map<String, String> theMap = new HashMap<String, String>();
					theMap.put("owner", owner);
					URL thePublicLink = null;
					try {

						logger.info("Saving dataminer-invocation file for the user: " + owner);
						thePublicLink = storageHubManagement.persistFile(new FileInputStream(tempInvocationFile),
								tempInvocationFile.getName(), "application/xml", metadata);
						logger.info("Saved dataminer-invocation file at: " + thePublicLink);
					} catch (Exception e) {
						logger.error("Error when storing your 'dataminer-invocation':", e);
						throw ExceptionManager
								.internalErrorException(
										req, "Error when storing your 'dataminer-invocation' request with "
												+ jsonRequest + ". \nPlease contact the support",
										this.getClass(), helpURI);
					}

//					FileContainer fileContainer = shc.getWSRoot().uploadFile(new FileInputStream(tempInvocationFile), tempInvocationFile.getName(), "DataMinerInvocation Request created by "+this.getClass().getSimpleName());
//					logger.info("UPLOADED FILE at: "+fileContainer.getPublicLink());
//					URL thePublicLink = fileContainer.getPublicLink();
					publicLinkToDMInvFile = thePublicLink != null ? thePublicLink.toString() : null;
				} catch (Exception e) {

					if (e instanceof InternalServerException) {
						// error during storing the file via StorageHubManagent
						throw e;
					}
					logger.error("Error on creating 'dataminer-invocation:", e);
					throw ExceptionManager.badRequestException(req,
							"Error on creating your 'dataminer-invocation' request with " + jsonRequest
									+ ". \nPlease contact the support",
							this.getClass(), helpURI);
				} finally {
					// No needed to reset the scope, it is provided by TokenSetter
					try {
						// DELETING THE TEMP FILE
						if (tempInvocationFile != null && tempInvocationFile.exists())
							tempInvocationFile.delete();
					} catch (Exception e) {
						// silent
					}
				}

				if (publicLinkToDMInvFile == null) {
					logger.error("Error on creating the public link to file");
					throw ExceptionManager.badRequestException(req,
							"Error on getting link to your 'dataminer-invocation' request. Plese contact the support "
									+ jsonRequest,
							this.getClass(), helpURI);
				}

				String dataMinerURL = String.format("%s/%s?%s=%s", analyticsGetResolverURL, vreName,
						DATAMINER_INVOCATION_MODEL, publicLinkToDMInvFile);
				logger.info("Returning Analytics URL: " + dataMinerURL);
				return Response.ok(dataMinerURL).header("Location", dataMinerURL).build();

			} else {
				logger.error("The input scope " + scope + " is not a VRE");
				throw ExceptionManager.badRequestException(req,
						"Working in the " + scope + " scope that is not a VRE. Use a token of VRE", this.getClass(),
						helpURI);
			}

		} catch (Exception e) {

			if (!(e instanceof WebApplicationException)) {
				// UNEXPECTED EXCEPTION managing it as WebApplicationException
				String error = "Error occurred on creating the Analytics for the request " + body
						+ ". 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;
		}
	}

	/**
	 * Reads the Application Token from Service Endpoint
	 * {@link AnalyticsCreateResolver#ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME}
	 *
	 * @param req   the req
	 * @param scope the scope
	 * @return the string
	 */
	private static String readApplicationTokenFromSE(HttpServletRequest req, String scope) {

		String callerScope = null;
		String gCubeAppToken = null;
		try {
			callerScope = ScopeProvider.instance.get();
			ScopeProvider.instance.set(scope);
			logger.info("Searching SE " + ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + " configurations in the scope: "
					+ ScopeProvider.instance.get());

			SimpleQuery query = queryFor(ServiceEndpoint.class);
			query.addCondition("$resource/Profile/Name/text() eq '" + ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + "'");
			query.addCondition("$resource/Profile/Category/text() eq 'Service'");

			DiscoveryClient<ServiceEndpoint> client = clientFor(ServiceEndpoint.class);
			List<ServiceEndpoint> toReturn = client.submit(query);

			logger.info("The query returned " + toReturn.size() + " ServiceEndpoint/s");

			if (toReturn.size() == 0) {
				String errorMessage = "No " + ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + " registered in the scope: "
						+ ScopeProvider.instance.get();
				logger.error(errorMessage);
				throw ExceptionManager.internalErrorException(req, errorMessage, AnalyticsCreateResolver.class,
						helpURI);
			}

			ServiceEndpoint se = toReturn.get(0);
			Collection<AccessPoint> theAccessPoints = se.profile().accessPoints().asCollection();
			for (AccessPoint accessPoint : theAccessPoints) {
				Collection<Property> properties = accessPoint.properties().asCollection();
				for (Property property : properties) {
					if (property.name().equalsIgnoreCase(GCUBE_TOKEN)) {
						logger.info("gcube-token as property was found, returning it");
						gCubeAppToken = property.value();
						break;
					}
				}

				if (gCubeAppToken != null)
					break;
			}

			if (gCubeAppToken != null) {
				String decryptedPassword = StringEncrypter.getEncrypter().decrypt(gCubeAppToken);
				logger.info("Returning decrypted Application Token registered into "
						+ ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + " SE: "
						+ decryptedPassword.substring(0, decryptedPassword.length() / 2) + "....");
				return decryptedPassword;
			}

			String errorMessage = "No " + GCUBE_TOKEN + " as Property saved in the "
					+ ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME + " SE registered in the scope: "
					+ ScopeProvider.instance.get();
			logger.error(errorMessage);
			throw ExceptionManager.internalErrorException(req, errorMessage, AnalyticsCreateResolver.class, helpURI);

		} catch (Exception e) {
			String errorMessage = "Error occurred on reading the " + ANALYTICS_RESOLVER_SERVICE_ENDPOINT_NAME
					+ " SE registered in the scope: " + ScopeProvider.instance.get();
			logger.error(errorMessage, e);
			throw ExceptionManager.internalErrorException(req, errorMessage, AnalyticsCreateResolver.class, helpURI);

		} finally {
			if (callerScope != null) {
				logger.info("Setting to the callerScope scope: " + callerScope);
				ScopeProvider.instance.set(callerScope);
			} else {
				logger.info("Reset scope");
				ScopeProvider.instance.reset();
			}
		}

	}

	/**
	 * Creates the temp file.
	 *
	 * @param fileName  the file name
	 * @param extension the extension
	 * @param data      the data
	 * @return the file
	 * @throws IOException Signals that an I/O exception has occurred.
	 */
	private static File createTempFile(String fileName, String extension, byte[] data) throws IOException {
		// Since Java 1.7 Files and Path API simplify operations on files
		java.nio.file.Path path = Files.createTempFile(fileName, extension);
		File file = path.toFile();
		// writing sample data
		Files.write(path, data);
		logger.info("Created the Temp File: " + file.getAbsolutePath());
		return file;
	}

	/**
	 * Creates the dm invocation file name.
	 *
	 * @param operatorId the operator id
	 * @return the string
	 */
	private static String createDMInvocationFileName(String operatorId) {
		String fileName = "dim";
		int index = operatorId.lastIndexOf(".");
		if (index > 0 && index < operatorId.length()) {
			fileName += "-" + operatorId.substring(index + 1, operatorId.length());
		}
		fileName += "-" + System.currentTimeMillis();
		return fileName;
	}
}