/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.epam.dlab.core.parser;

import com.epam.dlab.core.ModuleBase;
import com.epam.dlab.core.aggregate.AggregateGranularity;
import com.epam.dlab.exceptions.AdapterException;
import com.epam.dlab.exceptions.GenericException;
import com.epam.dlab.exceptions.InitializationException;
import com.epam.dlab.exceptions.ParseException;
import com.epam.dlab.model.aws.ReportLine;
import com.fasterxml.jackson.annotation.JsonIgnore;
import org.bson.Document;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Abstract module of parser by the line.<br>
 * See description of {@link ModuleBase} how to create your own parser.
 */
public abstract class ParserByLine extends ParserBase {
	private static final Logger LOGGER = LoggerFactory.getLogger(ParserByLine.class);

	/**
	 * Parse the header of source data and return it.
	 *
	 * @return the header of source data.
	 * @throws AdapterException
	 * @throws ParseException
	 */
	public abstract List<String> parseHeader() throws AdapterException, ParseException;

	/**
	 * Parse the row from source line and return result row.
	 *
	 * @param line the source line.
	 * @return the parsed row.
	 * @throws ParseException
	 */
	public abstract List<String> parseRow(String line) throws ParseException;

	/**
	 * Read the line from adapter and return it.
	 *
	 * @return the parsed row from adapterIn.
	 * @throws AdapterException
	 * @throws ParseException
	 */
	@JsonIgnore
	public String getNextRow() throws AdapterException, ParseException {
		String line = getAdapterIn().readLine();
		if (line == null) {
			return null;
		}
		getCurrentStatistics().incrRowReaded();
		return line;
	}

	/**
	 * Initialize ParserBase.
	 *
	 * @throws InitializationException
	 * @throws AdapterException
	 * @throws ParseException
	 */
	protected boolean init() throws InitializationException, AdapterException, ParseException {
		getAdapterIn().open();
		LOGGER.debug("Source data has multy entry {}", getAdapterIn().hasMultyEntry());
		if (!initEntry()) {
			return false;
		}
		getAdapterOut().open();
		return true;
	}

	/**
	 * Initialize for each entry ParserBase.
	 *
	 * @throws InitializationException
	 * @throws AdapterException
	 * @throws ParseException
	 */
	private boolean initEntry() throws InitializationException, AdapterException, ParseException {
		if (getAdapterIn().hasMultyEntry() && !getAdapterIn().hasEntryData()) {
			return false;
		}
		addStatistics(getAdapterIn().getEntryName());
		getCurrentStatistics().start();

		super.init(parseHeader());
		initialize();
		if (getFilter() != null) {
			getFilter().initialize();
		}
		return true;
	}

	/**
	 * Close adapters.
	 *
	 * @throws AdapterException
	 */
	protected void close(boolean silent) throws AdapterException {
		AdapterException ex = null;
		try {
			getAdapterIn().close();
		} catch (Exception e) {
			if (silent) {
				LOGGER.warn("Cannot close adapterIn. {}", e.getLocalizedMessage(), e);
			} else {
				ex = new AdapterException("Cannot close adapterIn. " + e.getLocalizedMessage(), e);
			}
		}
		try {
			getAdapterOut().close();
		} catch (Exception e) {
			if (silent || ex != null) {
				LOGGER.warn("Cannot close adapterOut. {}", e.getLocalizedMessage(), e);
			} else {
				ex = new AdapterException("Cannot close adapterOut. " + e.getLocalizedMessage(), e);
			}
		}
		try {
			getModuleData().closeMongoConnection();
		} catch (IOException e) {
			if (silent || ex != null) {
				LOGGER.warn("Cannot close mongo connection. {}", e.getLocalizedMessage(), e);
			} else {
				ex = new AdapterException("Cannot close mongo connection. " + e.getLocalizedMessage(), e);
			}
		}
		if (!silent && ex != null) {
			throw ex;
		}
	}

	/**
	 * Parse the source data to common format and write it to output adapter.
	 *
	 * @return list of billing data
	 * @throws InitializationException
	 * @throws AdapterException
	 * @throws ParseException
	 */
	public List<Document> parse() throws InitializationException, AdapterException, ParseException {
		List<Document> billingData = new ArrayList<>();
		try {
			if (init()) {
				String line;
				List<String> row;
				ReportLine reportLine;
				do {
					while ((line = getNextRow()) != null) {
						if (getFilter() != null && (line = getFilter().canParse(line)) == null) {
							getCurrentStatistics().incrRowFiltered();
							continue;
						}

						row = parseRow(line);
						if ((getFilter() != null && (row = getFilter().canTransform(row)) == null)) {
							getCurrentStatistics().incrRowFiltered();
							continue;
						}
						try {
							if (getCondition() != null && !getCondition().evaluate(row)) {
								getCurrentStatistics().incrRowFiltered();
								continue;
							}
						} catch (ParseException e) {
							throw new ParseException(e.getLocalizedMessage() + "\nEntry name: " + getCurrentStatistics
									().getEntryName() +
									"\nSource line[" +
									getCurrentStatistics().getRowReaded() + "]: " + line, e);
						} catch (Exception e) {
							throw new ParseException("Cannot evaluate condition " + getWhereCondition() + ". " +
									e.getLocalizedMessage() + "\nEntry name: " + getCurrentStatistics().getEntryName()
									+ "\nSource line[" + getCurrentStatistics().getRowReaded() + "]: " + line, e);
						}

						try {
							reportLine = getCommonFormat().toCommonFormat(row);
						} catch (ParseException e) {
							throw new ParseException("Cannot cast row to common format. " +
									e.getLocalizedMessage() + "\nEntry name: " + getCurrentStatistics().getEntryName
									() +
									"\nSource line[" + getCurrentStatistics().getRowReaded() + "]: " + line, e);
						}
						if (getFilter() != null && (reportLine = getFilter().canAccept(reportLine)) == null) {
							getCurrentStatistics().incrRowFiltered();
							continue;
						}

						getCurrentStatistics().incrRowParsed();
						if (getAggregate() != AggregateGranularity.NONE) {
							getAggregator().append(reportLine);
						} else {
							billingData.add(getAdapterOut().writeRow(reportLine));
							getCurrentStatistics().incrRowWritten();
						}
					}

					if (getAggregate() != AggregateGranularity.NONE) {
						for (int i = 0; i < getAggregator().size(); i++) {
							billingData.add(getAdapterOut().writeRow(getAggregator().get(i)));
							getCurrentStatistics().incrRowWritten();
						}
					}

					if (getAdapterIn().hasMultyEntry()) {
						if (getAdapterIn().openNextEntry()) {
							// Search entry with data
							while (!initEntry()) {
								if (!getAdapterIn().openNextEntry()) {
									break;
								}
							}
						} else {
							break;
						}
					}
				} while (getAdapterIn().hasMultyEntry() && getAdapterIn().hasEntryData());
			}
		} catch (GenericException e) {
			close(true);
			if (getCurrentStatistics() != null) {
				getCurrentStatistics().stop();
			}
			throw e;
		} catch (Exception e) {
			close(true);
			if (getCurrentStatistics() != null) {
				getCurrentStatistics().stop();
			}
			throw new ParseException("Unknown parser error. " + e.getLocalizedMessage(), e);
		}

		close(false);
		if (getCurrentStatistics() != null) {
			getCurrentStatistics().stop();
		}
		return billingData;
	}
}