package org.gcube.accounting.aggregator.persistence;

import java.io.Serializable;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.TimeZone;
import java.util.UUID;

import org.gcube.accounting.aggregator.aggregation.AggregationInfo;
import org.gcube.accounting.aggregator.aggregation.AggregationType;
import org.gcube.accounting.aggregator.status.AggregationState;
import org.gcube.accounting.aggregator.status.AggregationStateEvent;
import org.gcube.accounting.aggregator.status.AggregationStatus;
import org.gcube.accounting.aggregator.utility.Constant;
import org.gcube.accounting.aggregator.utility.Utility;
import org.gcube.accounting.analytics.persistence.AccountingPersistenceBackendQueryConfiguration;
import org.gcube.accounting.analytics.persistence.postgresql.AccountingPersistenceQueryPostgreSQL;
import org.gcube.accounting.datamodel.AggregatedUsageRecord;
import org.gcube.accounting.persistence.AccountingPersistenceConfiguration;
import org.gcube.accounting.utility.postgresql.RecordToDBFields;
import org.gcube.accounting.utility.postgresql.RecordToDBMapping;
import org.gcube.com.fasterxml.jackson.databind.JsonNode;
import org.gcube.documentstore.records.AggregatedRecord;
import org.gcube.documentstore.records.DSMapper;
import org.gcube.documentstore.records.Record;
import org.gcube.documentstore.records.RecordUtility;
import org.postgresql.core.Utils;

/**
 * @author Luca Frosini (ISTI-CNR)
 */
public class PostgreSQLConnector extends AccountingPersistenceQueryPostgreSQL {

	private static final String UTC_TIME_ZONE = "UTC";
	public static final TimeZone DEFAULT_TIME_ZONE = TimeZone.getTimeZone(UTC_TIME_ZONE);
	
	protected Connection connection;
	
	private static PostgreSQLConnector postgreSQLConnector;
	
	public static PostgreSQLConnector getPostgreSQLConnector() throws Exception {
		if(postgreSQLConnector == null) {
			postgreSQLConnector = new PostgreSQLConnector();
		}
		return postgreSQLConnector;
	}
	
	private PostgreSQLConnector() throws Exception {
		this.configuration = new AccountingPersistenceBackendQueryConfiguration(AccountingPersistenceQueryPostgreSQL.class);
		Map<String, Class<? extends AggregatedRecord<?,?>>> aggregatedRecords = RecordUtility.getAggregatedRecordClassesFound();
		for(String typeName : aggregatedRecords.keySet()) {
			try {
				Class<? extends AggregatedRecord<?,?>> clz = aggregatedRecords.get(typeName); 
				RecordToDBMapping.addRecordToDB(clz, configuration);
			} catch (Exception e) {
				new RuntimeException(e);
			}
		}
	}
	
	protected Connection getConnection() throws Exception {
		if(connection==null) {
			Class.forName("org.postgresql.Driver");
			String url = configuration.getProperty(AccountingPersistenceQueryPostgreSQL.URL_PROPERTY_KEY);
			String username = configuration.getProperty(AccountingPersistenceConfiguration.USERNAME_PROPERTY_KEY);
			String password = configuration.getProperty(AccountingPersistenceConfiguration.PASSWORD_PROPERTY_KEY);
			
			connection = DriverManager.getConnection(url, username, password);
			logger.trace("Database {} opened successfully", url);
			connection.setAutoCommit(false);
		}
		return connection;
	}
	
	protected String getQuotedString(String string) throws SQLException {
		StringBuilder builder = new StringBuilder();
		builder.append("'");
		Utils.escapeLiteral(builder, string, false);
		builder.append("'");
		return builder.toString();
	}
	
	protected String getValue(Serializable serializable) throws SQLException {
		if(serializable == null) {
			return "null";
		}
		
		if(serializable instanceof Number) {
			return serializable.toString();
		}
		
		if(serializable instanceof Calendar) {
			Calendar calendar = (Calendar) serializable;
			SimpleDateFormat simpleDateFormat = new SimpleDateFormat(DATETIME_PATTERN);
			simpleDateFormat.setTimeZone(DEFAULT_TIME_ZONE);
			Date date = calendar.getTime();
			String dateString = simpleDateFormat.format(date);
			return getQuotedString(dateString);
		}
		
		if(serializable instanceof Date) {
			Date date = (Date) serializable;
			SimpleDateFormat simpleDateFormat = new SimpleDateFormat(DATETIME_PATTERN);
			simpleDateFormat.setTimeZone(DEFAULT_TIME_ZONE);
			String dateString = simpleDateFormat.format(date);
			return getQuotedString(dateString);
		}
		
		
		if(serializable instanceof Enum) {
			Enum<?> e = (Enum<?>) serializable;
			return getQuotedString(e.name());
		}
		
		// String, URI etc
		return getQuotedString(serializable.toString());
	}
	
	public String getInsertAggregationStatusQuery(AggregationStatus aggregationStatus, boolean upsert) throws SQLException {
		StringBuffer stringBuffer = new StringBuffer();
		
		stringBuffer.append("INSERT INTO ");
		stringBuffer.append("aggregation_status");
		stringBuffer.append(" (id, ");
		stringBuffer.append("record_type, aggregation_type, aggregation_start_date, aggregation_end_date, ");
		stringBuffer.append("original_records_number, aggregated_records_number, recovered_records_number, malformed_records_number,  percentage, ");
		stringBuffer.append("context, current_aggregation_state, last_update_time, previous)");
		stringBuffer.append(" VALUES (");
		stringBuffer.append(getValue(aggregationStatus.getUUID().toString()));
		
		AggregationInfo aggregationInfo = aggregationStatus.getAggregationInfo();
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationInfo.getRecordType()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationInfo.getAggregationType()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationInfo.getAggregationStartDate()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationInfo.getAggregationEndDate()));
		stringBuffer.append(", ");
		
		stringBuffer.append(getValue(aggregationStatus.getOriginalRecordsNumber()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getAggregatedRecordsNumber()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getRecoveredRecordNumber()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getMalformedRecordNumber()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getPercentage()));
		
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getContext()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getAggregationState()));
		stringBuffer.append(", ");
		stringBuffer.append(getValue(aggregationStatus.getLastUpdateTime()));
		stringBuffer.append(", ");
		
		AggregationStatus previous = aggregationStatus.getPrevious();
		if(previous!=null) {
			stringBuffer.append(getValue(previous.getUUID().toString()));
		}else {
			stringBuffer.append(getValue(null));
		}
		
		if(upsert) {
			stringBuffer.append(") ON CONFLICT (id) DO UPDATE SET ");
			stringBuffer.append("original_records_number=EXCLUDED.original_records_number, aggregated_records_number=EXCLUDED.aggregated_records_number, recovered_records_number=EXCLUDED.recovered_records_number, malformed_records_number=EXCLUDED.malformed_records_number,  percentage=EXCLUDED.percentage, ");
			stringBuffer.append("current_aggregation_state=EXCLUDED.current_aggregation_state, last_update_time=EXCLUDED.last_update_time, previous=EXCLUDED.previous;");
		}else {
			stringBuffer.append(");");
		}
		
		return stringBuffer.toString();
	}
	
	public String getInsertAggregationStateQuery(AggregationStatus aggregationStatus) throws SQLException {
		StringBuffer stringBuffer = new StringBuffer();
		for(AggregationStateEvent aggregationStateEvent : aggregationStatus.getAggregationStateEvents()) {
			stringBuffer.append("INSERT INTO ");
			stringBuffer.append("aggregation_status_event");
			stringBuffer.append(" ( aggregation_state, start_time, end_time, aggregation_status)");
			stringBuffer.append(" VALUES (");
			stringBuffer.append(getValue(aggregationStateEvent.getAggregationState()));
			stringBuffer.append(", ");
			stringBuffer.append(getValue(aggregationStateEvent.getStartTime()));
			stringBuffer.append(", ");
			stringBuffer.append(getValue(aggregationStateEvent.getEndTime()));
			stringBuffer.append(", ");
			stringBuffer.append(getValue(aggregationStatus.getUUID().toString()));
			stringBuffer.append(") ON CONFLICT DO NOTHING;");
		}
		return stringBuffer.toString();
	}
	
	
	public void upsertAggregationStatus(AggregationStatus aggregationStatus) throws Exception {
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		String sqlCommand = getInsertAggregationStatusQuery(aggregationStatus, true);
		statement.executeUpdate(sqlCommand);
		sqlCommand = getInsertAggregationStateQuery(aggregationStatus);
		statement.executeUpdate(sqlCommand);
		statement.close();
		connection.commit();
	}
	
//	private Calendar getCalendar(ResultSet resultSet, String columnLabel) throws SQLException {
//		Date date = resultSet.getDate(columnLabel);
//		Calendar calendar = Calendar.getInstance();
//		calendar.setTime(date);
//		return calendar;
//	}
	
	private Date getDateFromResultSet(ResultSet resultSet, String columnLabel) throws Exception {
		String dateString = resultSet.getString(columnLabel);
		DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ssX");
		Date date = dateFormat.parse(dateString);
		return date;
	}
	
	public AggregationStatus getAggregationStatusFromResultSet(ResultSet resultSet) throws Exception {
		String recordType = resultSet.getString("record_type");
		String aggregationTypeString = resultSet.getString("aggregation_type");
		AggregationType aggregationType = AggregationType.valueOf(aggregationTypeString);
		
		
		Date aggregationStartDate = getDateFromResultSet(resultSet,"aggregation_start_date");
		Date aggregationEndDate = getDateFromResultSet(resultSet,"aggregation_end_date");
		AggregationInfo aggregationInfo = new AggregationInfo(recordType, aggregationType, aggregationStartDate, aggregationEndDate);
		
		AggregationStatus aggregationStatus = new AggregationStatus(aggregationInfo);
		
		UUID uuid = UUID.fromString(resultSet.getString("id"));
		aggregationStatus.setUUID(uuid);
		
		int originalRecordsNumber = resultSet.getInt("original_records_number");
		int aggregatedRecordsNumber = resultSet.getInt("aggregated_records_number");
		int malformedRecordNumber = resultSet.getInt("malformed_records_number");
		aggregationStatus.setRecordNumbers(originalRecordsNumber, aggregatedRecordsNumber, malformedRecordNumber);
		
		String context = resultSet.getString("context");
		aggregationStatus.setContext(context);
		
		String current_aggregation_state = resultSet.getString("current_aggregation_state");
		AggregationState aggregationState = AggregationState.valueOf(current_aggregation_state);
		aggregationStatus.setAggregationState(aggregationState);
		
		Date last_update_time = resultSet.getDate("last_update_time");
		Calendar lastUpdateTime = Calendar.getInstance();
		lastUpdateTime.setTime(last_update_time);
		aggregationStatus.setLastUpdateTime(lastUpdateTime);
		
		return aggregationStatus;
	}
	
	public AggregationStatus getLast(String recordType, AggregationType aggregationType, Date aggregationStartDate, Date aggregationEndDate) throws Exception{
		
		/*
		 * SELECT * FROM aggregation_status
		 * 
		 * WHERE 
		 * 		record_type = 'ServiceUsageRecord' AND
		 * 		aggregation_type = 'DAILY' AND
		 * 		aggregation_start_date >= '2017-05-01 00:00:00.000 +0000' AND
		 * 		aggregation_start_date <= '2017-05-31 00:00:00.000 +0000'
		 * 
		 * ORDER BY last_update_time DESC LIMIT 1
		 * 
		 */
		
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("SELECT * ");
		stringBuffer.append("FROM aggregation_status");
		
		stringBuffer.append(" WHERE ");
		stringBuffer.append("record_type = ");
		stringBuffer.append(getValue(recordType));
		
		stringBuffer.append(" AND ");
		stringBuffer.append("aggregation_type = ");
		stringBuffer.append(getValue(aggregationType.name()));
		
		if(aggregationStartDate!=null && aggregationEndDate!=null) {
			stringBuffer.append(" AND ");
			stringBuffer.append("aggregation_start_date >= ");
			stringBuffer.append(getValue(aggregationStartDate));
			
			stringBuffer.append(" AND ");
			stringBuffer.append("aggregation_start_date <= ");
			stringBuffer.append(getValue(aggregationEndDate));
		}
		
		stringBuffer.append(" ORDER BY ");
		stringBuffer.append("aggregation_start_date DESC LIMIT 1");
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlQuery = stringBuffer.toString();
				
		logger.trace("Going to request the following query: {}", sqlQuery);
		ResultSet resultSet = statement.executeQuery(sqlQuery);
		
		AggregationStatus aggregationStatus = null;
		
		while(resultSet.next()) {
			aggregationStatus = getAggregationStatusFromResultSet(resultSet);
			break;
		}
		
		return aggregationStatus;
		
	}
	
//	public List<AggregationStatus> getUnterminated(Date aggregationStartDate, Date aggregationEndDate, boolean forceRestart) throws Exception{
//		return getUnterminated(null, null, aggregationStartDate, aggregationEndDate, forceRestart);
//	}
	
	public List<AggregationStatus> getUnterminated(String recordType, AggregationType aggregationType, Date aggregationStartDate, Date aggregationEndDate, boolean forceRestart) throws Exception{
		
		/*
		 * SELECT * 
		 * FROM aggregation_status
		 * WHERE 
		 * 		aggregation_state != "COMPLETED" AND
		 * 		last_update_time < "2017-07-31 09:31:10.984 +0000" AND
		 * 		record_type = "ServiceUsageRecord" AND 
		 * 		aggregation_type` = "DAILY" AND
		 * 		aggregation_start_date >= "2017-05-01 00:00:00.000 +0000"
		 * 		aggregation_start_date <= "2017-05-31 00:00:00.000 +0000"
		 * 		
		 * ORDER BY aggregation_start_date ASC
		 */
		
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("SELECT * ");
		stringBuffer.append("FROM aggregation_status");
		
		stringBuffer.append(" WHERE ");
		stringBuffer.append("current_aggregation_state != ");
		stringBuffer.append(getValue(AggregationState.COMPLETED));
		
		if(!forceRestart) {
			Calendar now = Utility.getUTCCalendarInstance();
			now.add(Constant.CALENDAR_FIELD_TO_SUBSTRACT_TO_CONSIDER_UNTERMINATED, -Constant.UNIT_TO_SUBSTRACT_TO_CONSIDER_UNTERMINATED);
			stringBuffer.append(" AND ");
			stringBuffer.append("last_update_time < ");
			stringBuffer.append(getValue(now));
		}
		
		if(recordType!=null) {
			stringBuffer.append(" AND ");
			stringBuffer.append("record_type = ");
			stringBuffer.append(getValue(recordType));
		}
		
		if(aggregationType!=null) {
			stringBuffer.append(" AND ");
			stringBuffer.append("aggregation_type = ");
			stringBuffer.append(getValue(aggregationType));
		}
		
		if(aggregationStartDate!=null && aggregationEndDate!=null) {
			stringBuffer.append(" AND ");
			stringBuffer.append("aggregation_start_date >= ");
			stringBuffer.append(getValue(aggregationStartDate));
			
			stringBuffer.append(" AND ");
			stringBuffer.append("aggregation_end_date <= ");
			stringBuffer.append(getValue(aggregationEndDate));
		}
		
		stringBuffer.append(" ORDER BY ");
		stringBuffer.append("aggregation_start_date ASC");
		
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlQuery = stringBuffer.toString();
				
		logger.trace("Going to request the following query: {}", sqlQuery);
		ResultSet resultSet = statement.executeQuery(sqlQuery);
		
		List<AggregationStatus> aggregationStatuses = new ArrayList<>();
		
		while(resultSet.next()) {
			AggregationStatus aggregationStatus = getAggregationStatusFromResultSet(resultSet);
			aggregationStatuses.add(aggregationStatus);
		}
		
		return aggregationStatuses;
		
	}
	
	public List<AggregationStatus> getAll() throws Exception{
		
		/*
		 * SELECT * 
		 * FROM aggregation_status
		 * ORDER BY aggregation_start_date ASC
		 */
		
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("SELECT * ");
		stringBuffer.append("FROM aggregation_status");
		stringBuffer.append("ORDER BY  aggregation_start_date ASC");
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlQuery = stringBuffer.toString();
				
		logger.trace("Going to request the following query: {}", sqlQuery);
		ResultSet resultSet = statement.executeQuery(sqlQuery);
		
		List<AggregationStatus> aggregationStatuses = new ArrayList<>();
		
		while(resultSet.next()) {
			AggregationStatus aggregationStatus = getAggregationStatusFromResultSet(resultSet);
			aggregationStatuses.add(aggregationStatus);
		}
		
		return aggregationStatuses;
		
		
	}
	
	
	public AggregationStatus getAggregationStatus(String recordType, AggregationType aggregationType, Date aggregationStartDate) throws Exception{
		
		/*
		 * SELECT * 
		 * FROM aggregation_status 
		 * WHERE 
		 * 		record_type = "ServiceUsageRecord" AND 
		 * 		aggregation_type = "DAILY" AND 
		 * 		aggregation_start_date` = "2017-06-24 00:00:00.000 +0000"
		 * ORDER BY aggregation_start_date DESC LIMIT 1
		 */
		

		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("SELECT * ");
		stringBuffer.append("FROM aggregation_status");
		
		stringBuffer.append(" WHERE ");
		stringBuffer.append("record_type = ");
		stringBuffer.append(getValue(recordType));
		
		stringBuffer.append(" AND ");
		stringBuffer.append("aggregation_type = ");
		stringBuffer.append(getValue(aggregationType.name()));
		
		stringBuffer.append(" AND ");
		stringBuffer.append("aggregation_start_date = ");
		stringBuffer.append(getValue(aggregationStartDate));
		
		stringBuffer.append(" ORDER BY ");
		stringBuffer.append("last_update_time DESC LIMIT 1");
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlQuery = stringBuffer.toString();
				
		logger.trace("Going to request the following query: {}", sqlQuery);
		ResultSet resultSet = statement.executeQuery(sqlQuery);
		

		AggregationStatus aggregationStatus = null;
		while(resultSet.next()) {
			aggregationStatus = getAggregationStatusFromResultSet(resultSet);
			break;
		}
		
		return aggregationStatus;
	}

	public void deleteRecord(JsonNode jsonNode) throws Exception {
		Record record = DSMapper.unmarshal(Record.class, jsonNode.toString());
		Class<? extends Record> clz = record.getClass();
		String type = RecordToDBMapping.getRecordTypeByClass(clz);
		String tableName = RecordToDBFields.getKey(type);
		
		String id = jsonNode.get(Record.ID).asText();
		
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("DELETE ");
		stringBuffer.append("FROM ");
		stringBuffer.append(tableName);
		stringBuffer.append(" WHERE ");
		stringBuffer.append("id = ");
		stringBuffer.append(getValue(id));
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlCommand = stringBuffer.toString();
		logger.trace("Going to execute {}", sqlCommand);
		statement.execute(sqlCommand);
		
		statement.close();
		connection.commit();
		
	}

	public ResultSet getResultSetOfRecordToBeAggregated(AggregationStatus aggregationStatus) throws Exception {
		AggregationInfo aggregationInfo = aggregationStatus.getAggregationInfo();
		
		String tableName = RecordToDBFields.getKey(aggregationInfo.getRecordType());
		
		String startTimeColumnName = RecordToDBFields.getKey(AggregatedUsageRecord.START_TIME);
		
		StringBuffer stringBuffer = new StringBuffer();
		stringBuffer.append("SELECT *");
		stringBuffer.append(" FROM ");
		stringBuffer.append(tableName);
		stringBuffer.append(" WHERE ");
		stringBuffer.append(startTimeColumnName);
		stringBuffer.append(" >= ");
		stringBuffer.append(getValue(aggregationInfo.getAggregationStartDate()));
		stringBuffer.append(" AND ");
		stringBuffer.append(startTimeColumnName);
		stringBuffer.append(" < ");
		stringBuffer.append(getValue(aggregationInfo.getAggregationEndDate()));
		
		Connection connection = getConnection();
		Statement statement = connection.createStatement();
		
		String sqlQuery = stringBuffer.toString();
				
		logger.trace("Going to request the following query: {}", sqlQuery);
		ResultSet resultSet = statement.executeQuery(sqlQuery);
		
		return resultSet;
	}
	
}