/*******************************************************************************
 * Copyright 2018 A-SIT Plus GmbH
 * AT-specific eIDAS Connector has been developed in a cooperation between EGIZ, 
 * A-SIT Plus GmbH, A-SIT, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "License");
 * You may not use this work except in compliance with the License.
 * You may obtain a copy of the License at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
package at.asitplus.eidas.specific.connector.controller;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.TransformerFactoryConfigurationError;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.params.HttpClientParams;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.text.StringEscapeUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import at.asitplus.eidas.specific.connector.MSeIDASNodeConstants;
import at.gv.egiz.eaaf.core.api.data.EAAFConstants;
import at.gv.egiz.eaaf.core.api.idp.IConfigurationWithSP;
import at.gv.egiz.eaaf.core.api.storage.ITransactionStorage;
import at.gv.egiz.eaaf.core.exceptions.EAAFException;
import at.gv.egiz.eaaf.core.impl.utils.DOMUtils;
import at.gv.egiz.eaaf.core.impl.utils.Random;
import at.gv.egiz.eaaf.modules.pvp2.api.metadata.IPVPMetadataBuilderConfiguration;
import at.gv.egiz.eaaf.modules.pvp2.api.metadata.IPVPMetadataConfigurationFactory;
import at.gv.egiz.eaaf.modules.pvp2.impl.builder.PVPMetadataBuilder;
import at.gv.egiz.eaaf.modules.pvp2.impl.utils.AbstractCredentialProvider;

@Controller
public class MonitoringController {
	private static final Logger log = LoggerFactory.getLogger(MonitoringController.class);
	
	private static final String MESSAGE_OK = "OK";
	private static final String MESSAGE_ERROR = "ERROR";
	private static final String MESSAGE_SKIPPED = "SKIPPED";
	
	private static final String TEST_STORAGE = "Storage: ";
	private static final String TEST_CONFIG = "Config: ";
	private static final String TEST_PVPMETADATA = "PVP_metadata: ";
	private static final String TEST_EIDASNODEMETADATA = "eIDASNode_metadata: ";
	
	@Autowired private ITransactionStorage storage;
	@Autowired private IConfigurationWithSP config;
	
	@Autowired private PVPMetadataBuilder metadatabuilder;
	@Autowired private IPVPMetadataConfigurationFactory configFactory;	
	private AbstractCredentialProvider pvpIDPCredentials;
	
	/**
	 * Sets a specific credential provider for PVP S-Profile IDP component.
	 * @param pvpIDPCredentials credential provider
	 */
	public void setPvpIDPCredentials(AbstractCredentialProvider pvpIDPCredentials) {
		this.pvpIDPCredentials = pvpIDPCredentials;
		
	} 
	
	@ExceptionHandler({Throwable.class})
	public void genericExceptionHandler(HttpServletResponse resp, Exception exception) throws IOException {
		log.error("Monitoring Servlet receives an error." , exception);
		resp.setContentType(EAAFConstants.CONTENTTYPE_HTML_UTF8);
		resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
		resp.getWriter().write("Reason: " 
				+ StringEscapeUtils.escapeHtml4(StringEscapeUtils.escapeEcmaScript(exception.getMessage())));
		return;
		
	}
	
	@RequestMapping(value = {MSeIDASNodeConstants.ENDPOINT_MONITORING_MONITOR}, 
					method = {RequestMethod.GET} )
	public void startFullTest(HttpServletRequest req, HttpServletResponse resp) throws IOException {
		resp.setContentType(EAAFConstants.CONTENTTYPE_HTML_UTF8);
		
		try {
			testConfig();
			testStorage();
			testPVPMetadata();
			testEidasNodeMetadata();
			resp.setStatus(HttpServletResponse.SC_OK);
			resp.getWriter().write(MESSAGE_OK);
			
		} catch (Exception e) {		
			resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
			resp.getWriter().write(MESSAGE_ERROR);
			
		}
		
		
	}
	
	@RequestMapping(value = {MSeIDASNodeConstants.ENDPOINT_MONITORING_VERIFY}, 
			method = {RequestMethod.GET} )
	
	public void startSingleTests(HttpServletRequest req, HttpServletResponse resp) throws IOException {
		String result = StringUtils.EMPTY;
		try {
			result += testConfig() + "<br>";
		} catch (Exception e) {
			result += e.getMessage() + "<br>";
		}
		
		try {
			result += testStorage() + "<br>";
		} catch (Exception e) {
			result += e.getMessage() + "<br>";
		}
		
		try {
			result += testPVPMetadata() + "<br>";
		} catch (Exception e) {
			result += e.getMessage() + "<br>";
		}
		
		try {
			result += testEidasNodeMetadata() + "<br>";
		} catch (Exception e) {
			result += e.getMessage() + "<br>";
		}
		
		resp.setContentType(EAAFConstants.CONTENTTYPE_HTML_UTF8);
		resp.setStatus(HttpServletResponse.SC_OK);
		resp.getWriter().write(result);
		
	}
	
	private String testStorage( ) throws Exception {
		try {
			String key = Random.nextHexRandom16();
			String value = Random.nextHexRandom16();
				
			storage.put(key, value, -1);			
			String result = storage.get(key, String.class);
			storage.remove(key);
			
			if (result != null && result.equals(value))
				return TEST_STORAGE + MESSAGE_OK;
			else
				log.warn("Montioring: TestValue: " + value + " does NOT match in Storage test");
			
		} catch (EAAFException e) {
			log.warn("Montioring: Can not read/write to storage.", e);
			
		}
		
		throw new Exception(TEST_STORAGE + MESSAGE_ERROR);
		
	}
	
	private String testConfig( ) throws Exception {
		try {
			if (config.getBasicConfigurationWithPrefix(MSeIDASNodeConstants.PROP_CONFIG_SP_LIST_PREFIX) != null 
					&& config.getBasicConfigurationWithPrefix(MSeIDASNodeConstants.PROP_CONFIG_SP_LIST_PREFIX).size() > 0)
				return TEST_CONFIG + MESSAGE_OK;
			
			else
				log.warn("Montioring: Can not read from configuration file.");
						
		} catch (Exception e) {
			log.warn("Montioring: Can not read from configuration file.", e);
		}
		
		throw new Exception(TEST_CONFIG + MESSAGE_ERROR);
		
	}
	
	private String testPVPMetadata() throws Exception {
		try {
			//build metadata
			IPVPMetadataBuilderConfiguration metadataConfig = 
				configFactory.generateMetadataBuilderConfiguration(
						"http://localhost/monitoring", 
						pvpIDPCredentials);									
			metadatabuilder.buildPVPMetadata(metadataConfig);			
			return TEST_PVPMETADATA + MESSAGE_OK;
			
		} catch (Exception | TransformerFactoryConfigurationError e) {
			log.warn("Monitoring: Has an error in '" + TEST_PVPMETADATA + "': " + e.getMessage(), e);
			throw new Exception(TEST_PVPMETADATA + MESSAGE_ERROR, e);
			
		}
		
	}
	
	private String testEidasNodeMetadata() throws Exception {
		try {
			String urlString = config.getBasicConfiguration(MSeIDASNodeConstants.PROP_CONFIG_MONITORING_EIDASNODE_METADATAURL);
			if (StringUtils.isEmpty(urlString)) {
				log.debug("No eIDASNode metadata URL. Skipping test ... ");
				return TEST_EIDASNODEMETADATA + MESSAGE_SKIPPED;
				
			}

			//create HTTP client
			//TODO: update if we switch to openSAML3
			HttpClient httpClient = new HttpClient();
			
			//set parameters
			HttpClientParams params = new HttpClientParams();
			params.setSoTimeout(5*1000);
			httpClient.setParams(params );

			//request URL
			HttpMethod method = new GetMethod(urlString);
			int respCode = httpClient.executeMethod(method);
			if (respCode != 200) {
				log.warn("Monitoring: Has an error in '" + TEST_EIDASNODEMETADATA + "': " + " HTTP responsecode: " + respCode);
				throw new Exception(TEST_EIDASNODEMETADATA + MESSAGE_ERROR);
				
			}
			
			//parse metadata
			DOMUtils.parseXmlNonValidating(method.getResponseBodyAsStream());
						
			return TEST_EIDASNODEMETADATA + MESSAGE_OK;
			
		} catch (Exception | TransformerFactoryConfigurationError e) {
			log.warn("Monitoring: Has an error in '" + TEST_EIDASNODEMETADATA + "': " + e.getMessage(), e);
			throw new Exception(TEST_EIDASNODEMETADATA + MESSAGE_ERROR, e);
			
		}
		
	}
	
}