package org.gcube.data_catalogue.grsf_publish_ws.utils;

import java.beans.PropertyDescriptor;
import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletContext;

import org.gcube.common.homelibrary.home.exceptions.InternalErrorException;
import org.gcube.common.homelibrary.home.workspace.WorkspaceFolder;
import org.gcube.common.homelibrary.home.workspace.WorkspaceItem;
import org.gcube.common.homelibrary.home.workspace.exceptions.InsufficientPrivilegesException;
import org.gcube.common.homelibrary.home.workspace.exceptions.ItemAlreadyExistException;
import org.gcube.common.homelibrary.home.workspace.folder.items.ExternalFile;
import org.gcube.data_catalogue.grsf_publish_ws.custom_annotations.CkanResource;
import org.gcube.data_catalogue.grsf_publish_ws.custom_annotations.CustomField;
import org.gcube.data_catalogue.grsf_publish_ws.custom_annotations.Group;
import org.gcube.data_catalogue.grsf_publish_ws.custom_annotations.Tag;
import org.gcube.data_catalogue.grsf_publish_ws.json.input.Common;
import org.gcube.data_catalogue.grsf_publish_ws.json.input.Resource;
import org.gcube.data_catalogue.grsf_publish_ws.json.input.TimeSeriesBean;
import org.gcube.data_catalogue.grsf_publish_ws.utils.groups.Status;
import org.gcube.datacatalogue.ckanutillibrary.DataCatalogue;
import org.gcube.datacatalogue.ckanutillibrary.DataCatalogueFactory;
import org.gcube.datacatalogue.ckanutillibrary.DataCatalogueImpl;
import org.gcube.datacatalogue.ckanutillibrary.models.ResourceBean;
import org.slf4j.LoggerFactory;

import eu.trentorise.opendata.jackan.internal.org.apache.http.HttpResponse;
import eu.trentorise.opendata.jackan.internal.org.apache.http.client.methods.HttpGet;
import eu.trentorise.opendata.jackan.internal.org.apache.http.impl.client.CloseableHttpClient;
import eu.trentorise.opendata.jackan.internal.org.apache.http.impl.client.HttpClientBuilder;
import eu.trentorise.opendata.jackan.model.CkanLicense;


/**
 * Helper methods
 * @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
 */
@SuppressWarnings({"unchecked","rawtypes"})
public abstract class HelperMethods {

	private static final org.slf4j.Logger logger = LoggerFactory.getLogger(HelperMethods.class);

	// to be retrieved from the web.xml
	private static final String PENDING_CONTEX_KEY = "PendingContext";
	private static final String CONFIRMED_CONTEX_KEY = "ConfirmedContext";
	private static final int TIME_SERIES_TAKE_LAST_VALUES = 5;
	private static final String CSV_MIME = "text/csv";
	private static final String PATH_SEPARATOR = "/";
	private static final String REGEX_TAGS = "[^\\s\\w-_.]";


	/**
	 * Convert a group name to its id on ckan
	 * @param origName
	 * @return
	 */
	public static String getGroupNameOnCkan(String origName){

		if(origName == null)
			throw new IllegalArgumentException("origName cannot be null");

		String modified = origName.trim().toLowerCase().replaceAll("[^A-Za-z0-9-]", "-");
		if(modified.startsWith("-"))
			modified = modified.substring(1);
		if(modified.endsWith("-"))
			modified = modified.substring(0, modified.length() -1);

		return modified;
	}

	/**
	 * Retrieve the running instance of the data catalogue for this scope
	 * @return
	 * @throws Exception 
	 */
	public static DataCatalogue getDataCatalogueRunningInstance(String scope){

		try{
			DataCatalogueImpl instance = DataCatalogueFactory.getFactory().getUtilsPerScope(scope);
			return instance;
		}catch(Exception e){
			logger.error("Failed to instanciate data catalogue lib", e);
		}

		return null;
	}

	/**
	 * Retrieve the list of tags for this object
	 */
	public static void getTags(List<String> tags, Common record){

		Class<?> current = record.getClass();
		do{
			Field[] fields = current.getDeclaredFields();
			for (Field field : fields) {
				if(field.isAnnotationPresent(Tag.class)){
					try{
						Object f = new PropertyDescriptor(field.getName(), current).getReadMethod().invoke(record);
						if(f != null){
							if(f instanceof List<?>){
								List asList = ((List) f);
								if(!asList.isEmpty()){

									logger.debug("The object annotated with @Tag is a list. Adding ... ");

									int elementsToConsider = asList.size();

									// check if it is a time series, in this take the last X elements
									if(asList.get(0).getClass().equals(TimeSeriesBean.class)){
										elementsToConsider = Math.min(elementsToConsider, TIME_SERIES_TAKE_LAST_VALUES);

										for (int i = (asList.size() - elementsToConsider); i < asList.size(); i++) {
											String finalTag = asList.get(i).toString().trim().replaceAll(REGEX_TAGS, "");
											logger.debug(finalTag);
											tags.add(finalTag);	
										}
									}else{
										// else add all the available elements
										for (int i = 0; i < elementsToConsider; i++) {
											String finalTag = asList.get(i).toString().trim().replaceAll(REGEX_TAGS, "");
											logger.debug(finalTag);
											tags.add(finalTag);	
										}
									}
								}
							}else{
								logger.debug("The object annotated with @Tag is a simple one. Adding ... ");
								String finalTag = f.toString().trim().replaceAll(REGEX_TAGS, "");
								logger.debug(finalTag);
								tags.add(finalTag);	
							}

						}
					}catch(Exception e){
						logger.error("Failed ot read value for field " + field.getName() + " skipping", e);
					}
				}
			}
		}
		while((current = current.getSuperclass())!=null); // start from the inherited class up to the Object.class

		logger.info("Tags are " + tags);
	}

	/**
	 * Retrieve the list of groups' names for this object
	 */
	public static void getGroups(List<String> groups, Common record){

		Class<?> current = record.getClass();
		do{
			Field[] fields = current.getDeclaredFields();
			for (Field field : fields) {
				if(field.isAnnotationPresent(Group.class)){
					try{
						Object f = new PropertyDescriptor(field.getName(), current).getReadMethod().invoke(record);
						if(f != null){

							// also convert to the group name that should be on ckan
							String groupName = getGroupNameOnCkan(f.toString().trim());
							if(!groups.contains(groupName))
								groups.add(groupName);

						}
					}catch(Exception e){
						logger.error("Failed ot read value for field " + field.getName() + " skipping", e);
					}
				}
			}
		}
		while((current = current.getSuperclass())!=null); // start from the inherited class up to the Object.class

		logger.info("Groups is " + groups);
	}

	/**
	 * Retrieve the list of extras for this object
	 */
	public static void getExtras(Map<String, List<String>> extras, Common record){

		Class<?> current = record.getClass();
		do{
			Field[] fields = current.getDeclaredFields();
			for (Field field : fields) {
				if(field.isAnnotationPresent(CustomField.class)){
					try{
						Object f = new PropertyDescriptor(field.getName(), current).getReadMethod().invoke(record);
						String keyField = field.getAnnotation(CustomField.class).key();
						if(f != null){
							List<String> valuesForKey = new ArrayList<String>();

							// check if the map already contains this key
							if(extras.containsKey(keyField))
								valuesForKey = extras.get(keyField);

							if(f instanceof List<?>){
								logger.debug("The object " + field.getName() + " is a list and is annotated with @CustomField. Adding ...");
								List asList = (List)f;
								if(!asList.isEmpty()){

									int elementsToConsider = asList.size();

									// check if it is a time series, in this case take the last X elements 
									if(asList.get(0).getClass().equals(TimeSeriesBean.class)){
										elementsToConsider = Math.min(elementsToConsider, TIME_SERIES_TAKE_LAST_VALUES);

										for (int i = (asList.size() - elementsToConsider); i < asList.size(); i++) {
											logger.debug(asList.get(i).toString().trim());
											valuesForKey.add(asList.get(i).toString().trim());
										}

									}else{	
										for (int i = 0; i < elementsToConsider; i++) {
											logger.debug(asList.get(i).toString().trim());
											valuesForKey.add(asList.get(i).toString().trim());
										}
									}
								}
							}else{
								valuesForKey.add(f.toString().trim());
							}

							// add to the map
							extras.put(keyField, valuesForKey);
						}
					}catch(Exception e){
						logger.error("Failed ot read value for field " + field.getName() + " skipping", e);
					}
				}
			}
		}
		while((current = current.getSuperclass())!=null); // start from the inherited class up to the Object.class

		logger.info("Extras is " + extras);
	}

	/**
	 * Retrieve the organization name in which the user wants to publish starting from the scope
	 * @param contextInWhichPublish
	 * @return
	 */
	public static String retrieveOrgNameFromScope(String scope) {

		String[] splittedScope = scope.split("/");
		return splittedScope[splittedScope.length - 1].toLowerCase();

	}

	/**
	 * Return the context in which the user wants to publish by the status information
	 * @param status
	 * @param contextServlet
	 * @return
	 */
	public static String getContextFromStatus(Status status, ServletContext contextServlet) {

		String toReturn = null;
		switch(status){
		case Confirmed : 
			toReturn = (String)contextServlet.getInitParameter(CONFIRMED_CONTEX_KEY);
			break;
		case Pending: 
			toReturn = (String)contextServlet.getInitParameter(PENDING_CONTEX_KEY);
			break;
		default: break;

		}
		logger.debug("Context evaluated is " + toReturn);
		return toReturn;
	}

	/**
	 * Validate the name the product will have
	 * @param futureName
	 * @return
	 */
	public static boolean isNameValid(String futureName) {

		if(futureName == null || futureName.isEmpty())
			return false;
		else{
			return futureName.matches("[\\sA-Za-z0-9_.-]+");
		}
	}

	/**
	 * Retrieve the user's email given his/her username
	 * @param context
	 * @param token
	 * @return
	 * @throws Exception 
	 */
	public static String getUserEmail(String context, String token){

		String baseUrl = new ServiceEndPointReaderSocial(context).getBasePath();
		String url = baseUrl + "users/getUserEmail?gcube-token=" + token;
		logger.debug("Request url is " + url);
		return executGETHttpRequest(url, 200);

	}

	/**
	 * Retrieve the user's fullname given his/her username
	 * @param context 
	 * @param token 
	 * @return
	 * @throws Exception 
	 */
	public static String getUserFullname(String context, String token){

		String baseUrl = new ServiceEndPointReaderSocial(context).getBasePath();
		String url = baseUrl + "users/getUserFullname?gcube-token=" + token;
		logger.debug("Request url is " + url);
		return executGETHttpRequest(url, 200);

	}

	/**
	 * Execute the GET http request at this url, and return the result as string
	 * @return
	 */
	private static String executGETHttpRequest(String url, int expectedCodeOnSuccess){

		try(CloseableHttpClient client = HttpClientBuilder.create().build();){

			HttpGet getRequest = new HttpGet(url);
			HttpResponse response = client.execute(getRequest);

			if (response.getStatusLine().getStatusCode() != expectedCodeOnSuccess) {
				throw new RuntimeException("Failed : HTTP error code : "
						+ response.getStatusLine().getStatusCode());
			}

			BufferedReader br = new BufferedReader(
					new InputStreamReader((response.getEntity().getContent())));

			String res = "";
			String temp = null;

			while ((temp = br.readLine()) != null) {
				res += temp;
			}

			return res;
		}catch(Exception e){
			logger.error("error while performing post method " + e.toString());
		}

		return null;

	}

	/**
	 * Retrieve the list of ckan licenses and build up a map <license_id, license_title>
	 * @return
	 * @throws Exception 
	 */
	public static Map<String, String> getLicenses(DataCatalogue catalogue) throws Exception {

		Map<String, String> toReturn = new HashMap<String, String>();
		List<CkanLicense> licenses = catalogue.getLicenses();

		for (CkanLicense ckanLicense : licenses) {
			toReturn.put(ckanLicense.getId(), ckanLicense.getTitle());
		}
		return toReturn;
	}

	/**
	 * Check that the given license id is in CKAN
	 * @param license id to check
	 * @return
	 * @throws Exception 
	 */
	public static boolean existsLicenseId(String license, DataCatalogue catalogue) throws Exception {

		List<CkanLicense> licenses = catalogue.getLicenses();
		for (CkanLicense ckanLicense : licenses) {
			if(ckanLicense.getId().equals(license))
				return true;
		}
		return false;
	}

	/**
	 * Retrieve the ResourceBean given the record (extract resources from Database Sources and Source of Information and others)
	 * @param record
	 * @param username
	 * @param tags 
	 * @param groups 
	 * @return 
	 */
	public static List<ResourceBean> getResourcesFromBean(Common record, String username, List<String> tags, List<String> groups){

		List<ResourceBean> toReturn = new ArrayList<ResourceBean>();
		Class<?> current = record.getClass();
		do{
			Field[] fields = current.getDeclaredFields();
			for (Field field : fields) {
				if(field.isAnnotationPresent(CkanResource.class)){
					try{
						Object f = new PropertyDescriptor(field.getName(), current).getReadMethod().invoke(record);
						if(f != null){

							if(f instanceof List<?>){

								List<Resource> listOfResources = (List<Resource>)f;

								for (Resource resource : listOfResources) {
									toReturn.add(new ResourceBean(resource.getUrl(), resource.getName().toString(), resource.getDescription(), null, username, null, null));
								}

							}else{

								Resource res = (Resource)f;
								toReturn.add(new ResourceBean(res.getUrl(), res.getName().toString(), res.getDescription(), null, username, null, null));

							}
						}
					}catch(Exception e){
						logger.error("Failed ot read value for field " + field.getName() + " skipping", e);
					}
				}
			}
		}
		while((current = current.getSuperclass())!=null); // iterate from the inherited class up to the Object.class

		logger.info("Returning resources " + toReturn);
		return toReturn;
	}

	/**
	 * Upload a file in the shared folder
	 * @param resourceFormatFolder
	 * @param resourceToAttachName
	 * @param description
	 * @param csvFile
	 * @return
	 */
	public static ExternalFile uploadExternalFile(WorkspaceFolder resourceFormatFolder, String resourceToAttachName, String description, File csvFile) {
		try {
			return resourceFormatFolder.createExternalFileItem(resourceToAttachName, description, CSV_MIME, csvFile);
		} catch (InsufficientPrivilegesException | ItemAlreadyExistException
				| InternalErrorException e) {
			logger.error("Failed to upload the file into the workspace shared folder for " + resourceToAttachName, e);
		}
		return null;
	}

	/**
	 * Create subfolders in cascade, returning the last created ones
	 * It could be also used for getting them if they already exists
	 * @param folder
	 * @param subPath
	 * @return null if an error occurred
	 */
	public static WorkspaceFolder createOrGetSubFoldersByPath(WorkspaceFolder folder, String subPath){

		WorkspaceFolder parentFolder = folder;
		if(folder == null)
			throw new IllegalArgumentException("Root folder is null!");

		if(subPath == null || subPath.isEmpty())
			throw new IllegalArgumentException("subPath is null/empty!");

		try{
			if(subPath.startsWith(PATH_SEPARATOR))
				subPath = subPath.replaceFirst(PATH_SEPARATOR, "");

			if(subPath.endsWith(PATH_SEPARATOR))
				subPath = subPath.substring(0, subPath.length() - 1);

			logger.debug("Splitting path " + subPath);

			String[] splittedPaths = subPath.split(PATH_SEPARATOR);

			for (String path : splittedPaths) {
				WorkspaceFolder createdFolder = getFolderOrCreate(parentFolder, path, "");
				logger.debug("Created subfolder with path " + createdFolder.getPath());
				parentFolder = createdFolder;
			}

		}catch(Exception e){
			logger.error("Failed to create the subfolders by path " + subPath);
			return null;
		}

		return parentFolder;
	}

	/**
	 * Get a folder within the catalogue folder or create it if it doesn't exist.
	 * @return
	 */
	public static WorkspaceFolder getFolderOrCreate(WorkspaceFolder folder, String relativePath, String descriptionFolder){
		WorkspaceFolder result = null;
		try {
			WorkspaceItem foundFolder = folder.find(relativePath);
			if(foundFolder != null && foundFolder.isFolder())
				result = (WorkspaceFolder)foundFolder;

			if(result != null)
				logger.debug("Folder found with name " + result.getName() + ", it has id " + result.getId());
			else
				throw new Exception("There is no folder with name " + relativePath + " under folder " + folder.getName());
		} catch (Exception e) {
			logger.debug("Probably the folder doesn't exist");
			try{
				result = folder.createFolder(relativePath, descriptionFolder);
			} catch (InsufficientPrivilegesException | InternalErrorException | ItemAlreadyExistException e2) {
				logger.error("Failed to get or generate this folder", e2);
			}
		}
		return result;
	}
}