package org.gcube.dataharvest.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

import org.gcube.common.scope.impl.ScopeBean;
import org.gcube.dataharvest.datamodel.HarvestedData;
import org.gcube.dataharvest.utils.DateUtils;
import org.postgresql.util.PSQLException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Eric Perrone (ISTI - CNR)
 * @author Luca Frosini (ISTI - CNR)
 */
public class Dao {
	private Connection conn = null;
	private static Logger logger = LoggerFactory.getLogger(Dao.class);
	
	/**
	 * Class constructor. This method must be called before any other class
	 * method.
	 * 
	 * @throws DaoException
	 */
	public void init() throws DaoException {
		try {
			Class.forName("org.postgresql.Driver");
		} catch(ClassNotFoundException ex) {
			logger.error(ex.getLocalizedMessage());
			throw new DaoException(ex.getLocalizedMessage(), ex.getCause());
		}
	}
	
	/**
	 * Connect a database
	 * 
	 * @param url
	 * @param user
	 * @param password
	 * @throws DaoException
	 */
	public void connect(String url, String user, String password) throws DaoException {
		try {
			conn = DriverManager.getConnection(url, user, password);
			logger.debug("Connected to: " + url);
		} catch(SQLException ex) {
			logger.error(ex.getLocalizedMessage());
			throw new DaoException(ex.getLocalizedMessage(), ex.getCause());
		}
	}
	
	/**
	 * Release a database connection
	 *
	 * @throws DaoException
	 */
	public void disconnect() throws DaoException {
		try {
			if(conn != null) {
				conn.close();
				conn = null;
				logger.debug("Disconnecting from database");
			}
		} catch(SQLException ex) {
			logger.error(ex.getLocalizedMessage());
			throw new DaoException(ex.getLocalizedMessage(), ex.getCause());
		}
	}
	
	/**
	 * Check the connection with the database.
	 * 
	 * @return true|false
	 */
	public boolean isConnected() {
		return (!(conn == null));
	}
	
	/**
	 * Getter for the database connection
	 * 
	 * @return Connection class
	 */
	public Connection getConnection() {
		return conn;
	}
	
	/**
	 * Read on the database all active VRES
	 * 
	 * @return
	 */
	public String[] getActiveVres() {
		String query = "select dname from context where dname is not null and dismissed is null";
		logger.debug(query);
		Statement s = null;
		ResultSet rs = null;
		ArrayList<String> list = new ArrayList<>();
		try {
			s = conn.createStatement();
			rs = s.executeQuery(query);
			while(rs.next()) {
				list.add(rs.getString("dname"));
			}
			
			return list.toArray(new String[list.size()]);
		} catch(Exception ex) {
			logger.error(ex.getLocalizedMessage());
			return null;
		} finally {
			if(rs != null) {
				try {
					rs.close();
				} catch(SQLException ex) {
					// do nothing
				}
			}
			if(s != null) {
				try {
					s.close();
				} catch(SQLException ex) {
					// do nothing
				}
			}
		}
	}
	
	/**
	 * This method insert/update data in the monthly_measure database table.
	 * 
	 * @param data
	 * @param from
	 * @param to
	 * @throws DaoException
	 */
	public void insertMonthlyMeasure(List<HarvestedData> data, Date from, Date to, boolean doUpdate)
			throws DaoException {
		// first of all: check if data of the same type are already in the
		// database.
		// In this case data will be updated.
		Calendar cFrom = DateUtils.dateToCalendar(from);
		Calendar cTo = DateUtils.dateToCalendar(to);
		int monthFrom = cFrom.get(Calendar.MONTH);
		int yearFrom = cFrom.get(Calendar.YEAR);
		int monthTo = cTo.get(Calendar.MONTH);
		int yearTo = cTo.get(Calendar.YEAR);
		
		if((monthFrom != monthTo) || (yearFrom != yearTo)) {
			String err = "Invalid time period. The time period MUST refer one month.";
			logger.error(err);
			throw new DaoException(err, null);
		}
		
		if(data == null || data.size() <= 0) {
			String err = "No data passed in input. Aborting operation.";
			logger.error(err);
			throw new DaoException(err, null);
		}
		monthFrom++; // because january = 0...
		
		try {
			for(HarvestedData harvestedData : data) {
				int contextId = getOrInsertContextId(harvestedData.getContext());
				
				String query = "select id from monthly_measure where measure_type_id=" + harvestedData.getDataType()
						+ " and context_id=" + contextId + " and month=" + monthFrom + " and year=" + yearFrom;
				logger.debug(query);
				Statement sel = conn.createStatement();
				ResultSet rs = sel.executeQuery(query);
				if(rs.next()) {
					if(doUpdate) {
						// record found: update it
						Statement s = conn.createStatement();
						int id = rs.getInt("id");
						String update = "update monthly_measure set measure=" + harvestedData.getMeasure() + " where id="
								+ id;
						logger.debug(update);
						s.execute(update);
						s.close();
					} else {
						logger.warn("Skipped " + harvestedData.getContext());
					}
				} else {
					// record not found: insert new record
					Statement s = conn.createStatement();
					String insert = "insert into monthly_measure (year, month, measure, measure_type_id, context_id, day) values (";
					insert += yearFrom + "," + monthFrom + "," + harvestedData.getMeasure() + "," + harvestedData.getDataType()
							+ ",";
					insert += "(select id from context where dname='" + harvestedData.getContext() + "'),";
					insert += "'" + yearFrom + "-" + monthFrom + "-01'";
					insert += ")";
					logger.debug(insert);
					s.execute(insert);
					s.close();
				}
				
				rs.close();
				sel.close();
				
			}
		} catch(PSQLException x) {
			// handled exception: try to iterate...
			logger.error(x.getLocalizedMessage());
		} catch(Exception x) {
			// not handled exception: stop
			logger.error(x.getLocalizedMessage());
			throw new DaoException(x.getClass().getName() + "::" + x.getLocalizedMessage(), x);
		}
	}
	
	public enum contextType {
		INFRASTRUCTURE, VO, VRE
	}
	
	public int getOrInsertContextId(String contextFullName) throws SQLException {
		String query = "select id from context where dname='" + contextFullName + "'";
		logger.debug(query);
		Statement sel = conn.createStatement();
		ResultSet rs = sel.executeQuery(query);
		if(rs.next()) {
			// context found
			int id = rs.getInt("id");
			logger.debug("Context {} has id {}", contextFullName, id);
			return id;
		} else {
			// context not found: insert new record
			int parentId = 0; // The id of D4Science infrastructure as aggregator
			int lastIndexOfSlash = contextFullName.lastIndexOf("/");
			if(lastIndexOfSlash!=0) {
				String parentContextFullName = contextFullName.substring(0, contextFullName.lastIndexOf("/"));
				parentId = getOrInsertContextId(parentContextFullName);
			}
			
			// It is a new context and we don't know which context type is. Using 0 for ROOT, 1 for VO, 2 for VRE
			int contextTypeId = contextType.INFRASTRUCTURE.ordinal();
			ScopeBean scopeBean = new ScopeBean(contextFullName);
			switch(scopeBean.type()) {
				case INFRASTRUCTURE:
					contextTypeId = contextType.INFRASTRUCTURE.ordinal();
					break;
				case VO:
					contextTypeId = contextType.VO.ordinal();
					break;
				case VRE:
					contextTypeId = contextType.VRE.ordinal();
					break;
				default:
					break;
			}
			
			Statement s = conn.createStatement();
			String insert = "insert into context (name, context_id, context_type_id, dname) values ('";
			insert += contextFullName + "'," + parentId + "," + contextTypeId + ", '" + contextFullName;
			insert += "')";
			logger.debug(insert);
			
			s.execute(insert);
			s.close();
			
		}
		
		rs.close();
		sel.close();
		
		return getOrInsertContextId(contextFullName);
	}
	
	public ArrayList<Integer> getSubTree(Integer rootId) throws DaoException {
		String queryBase = "select id from context where context_id in (%%)";
		ArrayList<Integer> subTree = new ArrayList<>();
		ArrayList<Integer> temp = new ArrayList<>();
		Statement s = null;
		ResultSet rs = null;
		temp.add(rootId);
		subTree.add(rootId);
		boolean again = true;
		for(int i = 0; (i < 10) && (again); i++) {
			try {
				String listId = "";
				for(Integer id : temp) {
					listId += "," + id;
				}
				listId = listId.substring(1);
				
				String query = queryBase.replace("%%", listId);
				s = conn.createStatement();
				rs = s.executeQuery(query);
				if(rs.next()) {
					temp = new ArrayList<>();
					Integer dbId = rs.getInt("id");
					subTree.add(dbId);
					temp.add(dbId);
					while(rs.next()) {
						dbId = rs.getInt("id");
						subTree.add(dbId);
						temp.add(dbId);
					}
				} else {
					again = false;
				}
				rs.close();
				s.close();
			} catch(Exception x) {
				logger.error(x.getLocalizedMessage());
				throw new DaoException(x.getClass().getName() + "::" + x.getLocalizedMessage(), x);
			}
		}
		
		return subTree;
	}
	
	public void createSocialReport(int contextId, int orderBy) throws DaoException {
		Statement rep = null;
		ResultSet rs = null;
		try {
			String report = "insert into report (context_id, name, orderby, chart_type, x_text, y_text) values ";
			report += "(" + contextId + ", \'VRE Social\', " + orderBy
					+ ", \'column\', \'Period\', \'Social interaction\')";
			logger.debug(report);
			rep = conn.createStatement();
			rep.execute(report);
			String query = "select id from report where name=\'VRE Social\' order by id desc";
			rs = rep.executeQuery(query);
			if(rs.next()) {
				int id = rs.getInt("id");
				String reportItem = "insert into report_item (report_id, type_id_1, type_id_1_name) ";
				reportItem += "values (" + id + ", 8, \'mt\'), (" + id + ", 9, \'mt\'), (" + id + ", 10, \'mt\')";
				rep.execute(reportItem);
			} else
				throw new DaoException("No report id.", null);
			
		} catch(SQLException ex) {
			logger.error(ex.getLocalizedMessage());
			throw new DaoException(ex.getLocalizedMessage(), ex.getCause());
		} finally {
			try {
				if(rs != null) {
					rs.close();
				}
				if(rep != null) {
					rep.close();
				}
			} catch(SQLException ex) {
				logger.error(ex.getLocalizedMessage());
			}
		}
	}
	
	/**
	 * Dummy tester
	 * 
	 * @Deprecated
	 * @param originator
	 * @throws DaoException
	 * 
	 */
	public void dummyTest(String originator) throws DaoException {
		String insert = "insert into dummy (now, originator) values(current_timestamp, '" + originator + "')";
		logger.debug(insert);
		Statement s = null;
		try {
			s = conn.createStatement();
			s.execute(insert);
		} catch(SQLException ex) {
			logger.error(ex.getLocalizedMessage());
			throw new DaoException(ex.getLocalizedMessage(), ex.getCause());
		} finally {
			if(s != null)
				try {
					s.close();
				} catch(SQLException ex) {
					logger.error(ex.getLocalizedMessage());
				}
		}
	}
	
}