package org.gcube.dataharvest.harvester;

import static org.gcube.resources.discovery.icclient.ICFactory.clientFor;
import static org.gcube.resources.discovery.icclient.ICFactory.queryFor;

import java.io.IOException;
import java.security.GeneralSecurityException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;

import org.gcube.accounting.accounting.summary.access.model.ScopeDescriptor;
import org.gcube.accounting.accounting.summary.access.model.update.AccountingRecord;
import org.gcube.common.encryption.encrypter.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.resources.gcore.utils.Group;
import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.dataharvest.AccountingDashboardHarvesterPlugin;
import org.gcube.dataharvest.datamodel.AnalyticsReportCredentials;
import org.gcube.dataharvest.datamodel.HarvestedDataKey;
import org.gcube.dataharvest.datamodel.VREAccessesReportRow;
import org.gcube.resources.discovery.client.api.DiscoveryClient;
import org.gcube.resources.discovery.client.queries.api.SimpleQuery;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.analytics.data.v1beta.BetaAnalyticsDataClient;
import com.google.analytics.data.v1beta.BetaAnalyticsDataSettings;
import com.google.analytics.data.v1beta.DateRange;
import com.google.analytics.data.v1beta.DateRange.Builder;
import com.google.analytics.data.v1beta.Dimension;
import com.google.analytics.data.v1beta.Metric;
import com.google.analytics.data.v1beta.Row;
import com.google.analytics.data.v1beta.RunReportRequest;
import com.google.analytics.data.v1beta.RunReportResponse;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.gax.core.FixedCredentialsProvider;
import com.google.auth.oauth2.ServiceAccountCredentials;


public class VREAccessesHarvester extends BasicHarvester {

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

	private static final JsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();

	private static final String SERVICE_ENDPOINT_CATEGORY = "OnlineService";
	private static final String SERVICE_ENDPOINT_NAME = "GA4AnalyticsDataService";
	private static final String AP_VIEWS_PROPERTY = "views";
	private static final String AP_CLIENT_ID = "client_id";
	private static final String AP_PRIVATEKEY_ID_PROPERTY = "private_key_id";


	private List<VREAccessesReportRow> vreAccesses;

	public VREAccessesHarvester(Date start, Date end) throws Exception {
		super(start, end);
		vreAccesses = getAllAccesses(start, end);
	}

	@Override
	public List<AccountingRecord> getAccountingRecords() throws Exception {
		try {
			String context = org.gcube.dataharvest.utils.Utils.getCurrentContext();

			ArrayList<AccountingRecord> accountingRecords = new ArrayList<AccountingRecord>();

			int measure = 0;

			ScopeBean scopeBean = new ScopeBean(context);
			String lowerCasedContext = scopeBean.name().toLowerCase();
			String case1 = lowerCasedContext + "/";
			String case2 = lowerCasedContext + "?";
			for(VREAccessesReportRow row : vreAccesses) {
				String pagePath = row.getPagePath();
				if (!pagePath.contains("_redirect=/group") && !pagePath.contains("workspace")) {
					if(pagePath.endsWith(lowerCasedContext)) {
						logger.debug("Matched endsWith({}) : {}", lowerCasedContext, pagePath);
						measure += row.getVisitNumber();
					} else if(pagePath.contains(case1) || pagePath.contains(case2)) {
						logger.debug("Matched contains({}) || contains({}) : {}", case1, case2, pagePath);
						measure += row.getVisitNumber();
					}
				}
			}

			ScopeDescriptor scopeDescriptor = AccountingDashboardHarvesterPlugin.getScopeDescriptor();

			AccountingRecord ar = new AccountingRecord(scopeDescriptor, instant, getDimension(HarvestedDataKey.ACCESSES), (long) measure);
			logger.debug("{} : {}", ar.getDimension().getId(), ar.getMeasure());
			accountingRecords.add(ar);

			return accountingRecords;

		} catch(Exception e) {
			throw e;
		}
	}

	/**
	 * 
	 * @return a list of {@link VREAccessesReportRow} objects containing the pagePath and the visit number e.g.
	 * VREAccessesReportRow [pagePath=/group/agroclimaticmodelling/add-new-users, visitNumber=1]
	 * VREAccessesReportRow [pagePath=/group/agroclimaticmodelling/administration, visitNumber=2]
	 * VREAccessesReportRow [pagePath=/group/agroclimaticmodelling/agroclimaticmodelling, visitNumber=39]	
	 */
	private static List<VREAccessesReportRow> getAllAccesses(Date start, Date end) throws Exception {
		Builder dateRangeBuilder = getDateRangeBuilderForAnalytics(start, end);
		logger.debug("Getting accesses in this time range {}", dateRangeBuilder.toString());

		AnalyticsReportCredentials credentialsFromD4S = getAuthorisedApplicationInfoFromIs();
		
		logger.debug("Getting credentials credentialsFromD4S");
		
		BetaAnalyticsDataSettings serviceSettings = initializeAnalyticsReporting(credentialsFromD4S);
		
		logger.debug("initializeAnalyticsReporting service settings");
		
		
		HashMap<String,List<RunReportResponse>> responses = getReportResponses(serviceSettings, credentialsFromD4S.getViewIds(), dateRangeBuilder);
		List<VREAccessesReportRow> totalAccesses = new ArrayList<>();

		for(String view : responses.keySet()) {
			List<VREAccessesReportRow> viewReport = parseResponse(view, responses.get(view));
			logger.debug("Got {} entries from view id={}", viewReport.size(), view);
			totalAccesses.addAll(viewReport);
		}
		logger.debug("Merged in {} total entries from all views", totalAccesses.size());
		return totalAccesses;
	}

	/**
	 * Initializes an Google Analytics Data API service object.
	 *
	 * @return An authorized Google Analytics Data API 
	 * @throws IOException
	 * @throws GeneralSecurityException
	 */
	private static BetaAnalyticsDataSettings initializeAnalyticsReporting(AnalyticsReportCredentials cred) throws IOException {
		return BetaAnalyticsDataSettings.newBuilder()
				.setCredentialsProvider(FixedCredentialsProvider.create(
						ServiceAccountCredentials.fromPkcs8(cred.getClientId(), cred.getClientEmail(), cred.getPrivateKeyPem(), cred.getPrivateKeyId(), null)))
				.build();
	}

	/**
	 * Queries Analytics Data API service 
	 *
	 * @param service Analytics Data API service  service settings.
	 * @return Row Analytics Data API service 
	 * @throws IOException
	 */
	private static HashMap<String,List<RunReportResponse>> getReportResponses(BetaAnalyticsDataSettings betaAnalyticsDataSettings,
			List<String> viewIDs, Builder dateRangeBuilder) throws IOException {

		HashMap<String,List<RunReportResponse>> reports = new HashMap<>();

		try (BetaAnalyticsDataClient analyticsData = BetaAnalyticsDataClient.create(betaAnalyticsDataSettings)) {

			for(String propertyId : viewIDs) {
				List<RunReportResponse> gReportResponses = new ArrayList<>();
				logger.debug("Getting data from Analytics Data API for propertyId: " + propertyId);
				RunReportRequest request =
						RunReportRequest.newBuilder()
						.setProperty("properties/" + propertyId)
						.addDimensions(Dimension.newBuilder().setName("pagePath"))
						.addMetrics(Metric.newBuilder().setName("screenPageViews"))
						.addDateRanges(dateRangeBuilder)
						.build();

				// Make the request.
				RunReportResponse response = analyticsData.runReport(request);
				gReportResponses.add(response);
				// Iterate through every row of the API response.
//				for (Row row : response.getRowsList()) {
//					System.out.printf(
//							"%s, %s%n", row.getDimensionValues(0).getValue(), row.getMetricValues(0).getValue());
//				}				
				reports.put(propertyId, gReportResponses);
			}
		}
		return reports;
	}

	/**
	 * Parses and prints the Analytics Data API service respose
	 *
	 * @param response An Analytics Data API service response.
	 */
	private static List<VREAccessesReportRow> parseResponse(String viewId,  List<RunReportResponse> responses) {
		logger.debug("parsing Response for propertyID=" + viewId);

		List<VREAccessesReportRow> toReturn = new ArrayList<>();
		for (RunReportResponse response : responses) {
			for (Row row: response.getRowsList()) {
				String dimension = row.getDimensionValues(0).getValue();
				String metric = row.getMetricValues(0).getValue();
				VREAccessesReportRow var = new VREAccessesReportRow();
				boolean validEntry = false;
				String pagePath = dimension;
				if (pagePath.startsWith("/group") || pagePath.startsWith("/web")) {
					var.setPagePath(dimension);
					validEntry = true;
				}
				if (validEntry) {
					var.setVisitNumber(Integer.parseInt(metric));
					toReturn.add(var);
				}
			}
		}
		return toReturn;
	}

	private static List<ServiceEndpoint> getAnalyticsReportingConfigurationFromIS(String infrastructureScope)
			throws Exception {
		String scope = infrastructureScope;
		String currScope = ScopeProvider.instance.get();
		ScopeProvider.instance.set(scope);
		SimpleQuery query = queryFor(ServiceEndpoint.class);
		query.addCondition("$resource/Profile/Category/text() eq '" + SERVICE_ENDPOINT_CATEGORY + "'");
		query.addCondition("$resource/Profile/Name/text() eq '" + SERVICE_ENDPOINT_NAME + "'");
		DiscoveryClient<ServiceEndpoint> client = clientFor(ServiceEndpoint.class);
		List<ServiceEndpoint> toReturn = client.submit(query);
		ScopeProvider.instance.set(currScope);
		return toReturn;
	}

	/**
	 * l
	 * @throws Exception 
	 */
	private static AnalyticsReportCredentials getAuthorisedApplicationInfoFromIs() throws Exception {
		AnalyticsReportCredentials reportCredentials = new AnalyticsReportCredentials();

		String context = org.gcube.dataharvest.utils.Utils.getCurrentContext();
		try {
			List<ServiceEndpoint> list = getAnalyticsReportingConfigurationFromIS(context);
			if(list.size() > 1) {
				logger.error("Too many Service Endpoints having name " + SERVICE_ENDPOINT_NAME
						+ " in this scope having Category " + SERVICE_ENDPOINT_CATEGORY);
			} else if(list.size() == 0) {
				logger.warn("There is no Service Endpoint having name " + SERVICE_ENDPOINT_NAME + " and Category "
						+ SERVICE_ENDPOINT_CATEGORY + " in this context: " + context);
			} else {

				for(ServiceEndpoint res : list) {
					Group<AccessPoint> apGroup = res.profile().accessPoints();
					AccessPoint[] accessPoints = (AccessPoint[]) apGroup.toArray(new AccessPoint[apGroup.size()]);
					AccessPoint found = accessPoints[0];
					reportCredentials.setClientEmail(found.username());
					String decryptedPrivateKey = StringEncrypter.getEncrypter().decrypt(found.password());
					reportCredentials.setPrivateKeyPem(decryptedPrivateKey.trim());
				
					for(Property prop : found.properties()) {
						if(prop.name().compareTo(AP_VIEWS_PROPERTY) == 0) {
							String decryptedValue = StringEncrypter.getEncrypter().decrypt(prop.value());
							String[] views = decryptedValue.split(";");
							reportCredentials.setViewIds(Arrays.asList(views));
						}
						if(prop.name().compareTo(AP_CLIENT_ID) == 0) {
							String decryptedValue = StringEncrypter.getEncrypter().decrypt(prop.value());
							reportCredentials.setClientId(decryptedValue);
						}
						if(prop.name().compareTo(AP_PRIVATEKEY_ID_PROPERTY) == 0) {
							String decryptedValue = StringEncrypter.getEncrypter().decrypt(prop.value());
							reportCredentials.setPrivateKeyId(decryptedValue);
						}
					}
				}
			}
		} catch(Exception e) {
			e.printStackTrace();
			return null;
		}
		return reportCredentials;
	}

	private static LocalDate asLocalDate(Date date) {
		return Instant.ofEpochMilli(date.getTime()).atZone(ZoneId.systemDefault()).toLocalDate();
	}

	private static Builder getDateRangeBuilderForAnalytics(Date start, Date end) {
		DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd"); //required by Analytics
		String startDate = asLocalDate(start).format(formatter);
		String endDate = asLocalDate(end).format(formatter);
		Builder dateRangeBuilder = DateRange.newBuilder().setStartDate(startDate).setEndDate(endDate);

		return dateRangeBuilder;
	}

}