package org.gcube.datacatalogue.ckanutillibrary.db;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import org.gcube.datacatalogue.ckanutillibrary.shared.RolesCkanGroupOrOrg;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// TODO: Auto-generated Javadoc
/**
 * The Class DBCaller.
 *
 * @author Francesco Mangiacrapa at ISTI-CNR Pisa (Italy)
 * Jun 1, 2020
 */
public class DBCaller {
	
	private static final Logger LOG = LoggerFactory.getLogger(DBCaller.class);
	
	private String CKAN_DB_URL;
	private Integer CKAN_DB_PORT;
	private String CKAN_DB_NAME;
	private String CKAN_DB_USER;
	private String CKAN_DB_PASSWORD;
	
	/**
	 * Instantiates a new DB caller.
	 */
	public DBCaller() {
	}
	
	/**
	 * Instantiates a new DB caller.
	 *
	 * @param cKAN_DB_URL the c KA N D B URL
	 * @param cKAN_DB_PORT the c KA N D B PORT
	 * @param cKAN_DB_NAME the c KA N D B NAME
	 * @param cKAN_DB_USER the c KA N D B USER
	 * @param cKAN_DB_PASSWORD the c KA N D B PASSWORD
	 */
	public DBCaller(String cKAN_DB_URL, Integer cKAN_DB_PORT, String cKAN_DB_NAME, String cKAN_DB_USER,
			String cKAN_DB_PASSWORD) {
		CKAN_DB_URL = cKAN_DB_URL;
		CKAN_DB_PORT = cKAN_DB_PORT;
		CKAN_DB_NAME = cKAN_DB_NAME;
		CKAN_DB_USER = cKAN_DB_USER;
		CKAN_DB_PASSWORD = cKAN_DB_PASSWORD;
	}

	
	/**
	 * Retrieve connection from the pool.
	 *
	 * @return a connection available within the pool
	 * @throws SQLException the SQL exception
	 * @throws ClassNotFoundException the class not found exception
	 */
	private Connection getConnection() throws SQLException, ClassNotFoundException{

		LOG.trace("CONNECTION REQUEST");
		// create db connection
		Class.forName("org.postgresql.Driver");
		
		String dbBaseConnectionURL = String.format("jdbc:postgresql://%s", CKAN_DB_URL);
		
		if(CKAN_DB_PORT!=null)
			dbBaseConnectionURL+=":" + CKAN_DB_PORT;
		
		dbBaseConnectionURL+="/" + CKAN_DB_NAME;
		
		LOG.debug("DB CONNECTION URL: "+dbBaseConnectionURL);
		
		Connection connection = DriverManager.getConnection(dbBaseConnectionURL, CKAN_DB_USER, CKAN_DB_PASSWORD);
		
//		Connection connection = DriverManager.getConnection(
//				"jdbc:postgresql://" + CKAN_DB_URL + ":" + CKAN_DB_PORT + "/" + CKAN_DB_NAME, CKAN_DB_USER, CKAN_DB_PASSWORD);
		return connection;

	}
	
	/**
	 * Retrieve the map (groups id, capacity) with the groups to which the user belongs by querying directly the database.
	 *
	 * @param username the username
	 * @return the groups by user from DB
	 */
	public Map<String, RolesCkanGroupOrOrg> getGroupsByUserFromDB(String username){
		checkNotNull(username);
		LOG.debug("Get groups by user called");

		//couples (groups id, capacity) of the user in the group
		
		Map<String, RolesCkanGroupOrOrg> toReturn = new HashMap<String, RolesCkanGroupOrOrg>();
		Connection connection = null;
		try{

			String userId = getUserIdForUsername(username);

			connection = getConnection();
			
			String joinQuery = "SELECT \"group_id\",\"capacity\" FROM \"public\".\"member\" "
					+ "JOIN \"public\".\"group\" ON \"member\".\"group_id\" = \"group\".\"id\" where \"table_id\"=?"
					+ " and \"table_name\"='user' and \"member\".\"state\"='active' and \"group\".\"state\"='active' and \"group\".\"is_organization\"=?;";
			
			LOG.debug("Performing query: "+joinQuery);

			PreparedStatement preparedStatement = connection.prepareStatement(joinQuery);
			preparedStatement.setString(1, userId);
			preparedStatement.setBoolean(2, false);
			ResultSet rs = preparedStatement.executeQuery();

			while (rs.next()) {

				toReturn.put(rs.getString("group_id"), RolesCkanGroupOrOrg.convertFromCapacity(rs.getString("capacity")));
			}

		}catch(Exception e){
			LOG.error("Failed to retrieve the groups to whom the user belongs. Error is " + e.getMessage());
			return null;
		}finally{
			closeConnection(connection);
		}
		return toReturn;
	}
	
	
	/**
	 * Gets the user id for username.
	 *
	 * @param username the username
	 * @return the user id for username
	 */
	private String getUserIdForUsername(String username) {
		LOG.debug("Get user id for username called");
		
		Connection connection = null;
		String userId = null;
		try{

			connection = getConnection();

			String selQuery = "SELECT \"id\" FROM \"public\".\"user\" WHERE \"name\"=?;";
			
			LOG.info("Performing query: "+selQuery);

			PreparedStatement preparedStatement = connection.prepareStatement(selQuery);
			preparedStatement.setString(1, username);
			ResultSet rs = preparedStatement.executeQuery();

			while (rs.next()) {
				userId = rs.getString("id");
				break;
			}
			
			LOG.debug("For username "+username+" returning the user id: "+userId);
			return userId;
			
		}catch(Exception e){
			LOG.error("Failed to retrieve the user id for username:"+username+". Error is " + e.getMessage());
			return null;
		}finally{
			closeConnection(connection);
		}

	}
	
	/**
	 * Retrieve the map (organisation id, capacity) with the organisations to which the user belongs by querying directly the database.
	 *
	 * @param username the username
	 * @return the organizations by user from DB
	 */
	public Map<String, RolesCkanGroupOrOrg> getOrganizationsByUserFromDB(String username){
		LOG.debug("Get organisations by user called");
		checkNotNull(username);

		Map<String, RolesCkanGroupOrOrg> toReturn = new HashMap<String, RolesCkanGroupOrOrg>();
		Connection connection = null;
		try{
			
			String userId = getUserIdForUsername(username);

			connection = getConnection();
			ResultSet rs;

			String joinQuery = "SELECT \"group_id\",\"capacity\" FROM \"public\".\"member\" "
					+ "JOIN \"public\".\"group\" ON \"member\".\"group_id\" = \"group\".\"id\" where \"table_id\"=?"
					+ " and \"table_name\"='user' and \"member\".\"state\"='active' and \"group\".\"state\"='active' and \"group\".\"is_organization\"=?;";


			PreparedStatement preparedStatement = connection.prepareStatement(joinQuery);
			preparedStatement.setString(1, userId);
			preparedStatement.setBoolean(2, true);
			rs = preparedStatement.executeQuery();

			while (rs.next()) {

				toReturn.put(rs.getString("group_id"), RolesCkanGroupOrOrg.convertFromCapacity(rs.getString("capacity")));
			}

		}catch(Exception e){
			LOG.error("Failed to retrieve the groups to whom the user belongs. Error is " + e.getMessage());
			return null;
		}finally{
			closeConnection(connection);
		}
		return toReturn;
	}
	

	/**
	 * Gets the api key from username.
	 *
	 * @param username the username
	 * @param state the state
	 * @return the api key from username
	 */
	public String getApiKeyFromUsername(String username, String state) {

		LOG.debug("Request api key for user = " + username);

		// checks
		checkNotNull(username);
		checkArgument(!username.isEmpty());

		// the connection
		Connection connection = null;
		String apiToReturn = null;

		try{

			connection = getConnection();

			String query = "SELECT \"apikey\" FROM \"user\" WHERE \"name\"=? and \"state\"=?;";
			PreparedStatement preparedStatement = connection.prepareStatement(query);
			preparedStatement.setString(1, username);
			preparedStatement.setString(2, state);

			ResultSet rs = preparedStatement.executeQuery();
			while (rs.next()) {
				apiToReturn = rs.getString("apikey");
				LOG.debug("Api key "+apiToReturn.substring(0,10)+" MASKED-TOKEN retrieved for user " + username);
				break;
			}

			return apiToReturn;

		}catch(Exception e){
			LOG.error("Unable to retrieve key for user " + username, e);
		}finally{
			closeConnection(connection);
		}

		return null;
	}

	
	/**
	 * Tries to close a connection.
	 *
	 * @param connection the connection
	 */
	private void closeConnection(Connection connection){

		if(connection != null){
			try{
				connection.close();
				LOG.trace("CONNECTION CLOSED");
			}catch(Exception e){
				LOG.error("Unable to close this connection ", e);
			}
		}

	}

}