/*
 * 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.mongo;

import com.epam.dlab.core.DBAdapterBase;
import com.epam.dlab.core.aggregate.UsageDataList;
import com.epam.dlab.exceptions.AdapterException;
import com.epam.dlab.exceptions.InitializationException;
import com.epam.dlab.exceptions.ParseException;
import com.epam.dlab.model.aws.ReportLine;
import com.epam.dlab.module.ModuleName;
import com.fasterxml.jackson.annotation.JsonClassDescription;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.google.common.base.MoreObjects.ToStringHelper;
import com.mongodb.client.MongoCollection;
import org.bson.Document;

import java.util.ArrayList;
import java.util.List;
import java.util.TreeSet;

/**
 * The adapter for file system.
 */
@JsonTypeName(ModuleName.ADAPTER_MONGO_DLAB)
@JsonClassDescription(
		"Mongo DB adapter.\n" +
				"Write converted data to the Mongo database. Can be used for AdapterOut only.\n" +
				"  - type: " + ModuleName.ADAPTER_MONGO_DLAB + "\n" +
				"    host: <host>             - the host name or IP address.\n" +
				"    port: <port>             - the port number.\n" +
				"    database: <database>     - the name of database.\n" +
				"    username: <username>     - the name of user.\n" +
				"    password: <password>     - the password of user.\n" +
				"    [bufferSize: <number>]   - the size of buffer, default is 10000 records.\n" +
				"    [upsert: <false | true>] - if true then upsert is enabled."
)
public class AdapterMongoDb extends DBAdapterBase {

	/**
	 * The size of buffer for bulk insert. Not applicable for upsert mode.
	 */
	@JsonProperty
	private int bufferSize = 10000;

	/**
	 * The upsert mode if set to <b>true</b>.
	 */
	@JsonProperty
	private boolean upsert = false;

	/**
	 * Return the size of buffer for bulk insert.
	 */
	public int getBufferSize() {
		return bufferSize;
	}

	/**
	 * Set the size of buffer for bulk insert.
	 *
	 * @throws InitializationException
	 */
	public void setBufferSize(int bufferSize) throws InitializationException {
		if (upsert && bufferSize <= 0) {
			throw new InitializationException("The bufferSize must be greater than zero when upsert mode is switched" +
					" " +
					"on");
		}
		this.bufferSize = bufferSize;
	}

	/**
	 * Return the <b>true</b> if upsert mode switched on.
	 */
	public boolean isUpsert() {
		return upsert;
	}

	/**
	 * Set the upsert mode.
	 *
	 * @throws InitializationException
	 */
	public void setUpsert(boolean upsert) throws InitializationException {
		if (upsert && bufferSize <= 0) {
			throw new InitializationException("Upsert mode cannot be enabled if the bufferSize is zero or less than " +
					"zero");
		}
		this.upsert = upsert;
	}


	/**
	 * Custom connection to Mongo database.
	 */
	private MongoDbConnection connection;

	/**
	 * Mongo collection.
	 */
	private MongoCollection<Document> collection;

	/**
	 * DAO of DLab's resource type.
	 */
	private DlabResourceTypeDAO resourceTypeDAO;

	/**
	 * Buffer for insert operations.
	 */
	private List<Document> buffer;

	/**
	 * List of dates for delete from MongoDB.
	 */
	private UsageDataList usageDateList;


	@Override
	public void open() throws AdapterException {
		if (connection == null) {
			if (getMode() != Mode.WRITE) {
				throw new AdapterException("Mode of " + getType() + " adapter may be " + Mode.WRITE + " only.");
			}
			connection = new MongoDbConnection(getHost(), getPort(), getDatabase(), getUsername(), getPassword());
			collection = connection.getCollection(MongoConstants.COLLECTION_BILLING);
			try {
				resourceTypeDAO = new DlabResourceTypeDAO(connection);
			} catch (InitializationException e) {
				throw new AdapterException("Cannot initialize billing transformer to DLab format. " + e
						.getLocalizedMessage(), e);
			}

			connection.createBillingIndexes();
			usageDateList = new UsageDataList();
			buffer = (upsert || bufferSize > 0 ? new ArrayList<>(bufferSize) : null);
		} else {
			throw new AdapterException("Connection is already opened");
		}
	}

	@Override
	public void close() throws AdapterException {
		if (connection != null) {
			if (upsert) {
				connection.upsertRows(collection, buffer, usageDateList);
			} else if (bufferSize > 0) {
				connection.insertRows(collection, buffer);
			}
			buffer = null;
			updateTotal();

			try {
				connection.close();
			} catch (Exception e) {
				throw new AdapterException("Cannot close connection to database " +
						getDatabase() + ". " + e.getLocalizedMessage(), e);
			} finally {
				connection = null;
			}
		}
	}

	@Override
	public String getEntryName() {
		return MongoConstants.COLLECTION_BILLING;
	}

	@Override
	public String readLine() throws AdapterException {
		throw new AdapterException("Unimplemented method called.");
	}

	@Override
	public void writeHeader(List<String> header) throws AdapterException {
		// Nothing to do
	}

	@Override
	public void writeRow(ReportLine row) throws AdapterException {
		Document document;
		try {
			document = resourceTypeDAO.transform(row);
		} catch (ParseException e) {
			throw new AdapterException("Cannot transform report line. " + e.getLocalizedMessage(), e);
		}

		usageDateList.append(row.getUsageDate());
		if (upsert) {
			buffer.add(document);
			if (buffer.size() >= bufferSize) {
				connection.upsertRows(collection, buffer, usageDateList);
			}
		} else if (bufferSize > 0) {
			buffer.add(document);
			if (buffer.size() >= bufferSize) {
				connection.insertRows(collection, buffer);
			}
		} else {
			connection.insertOne(collection, document);
		}
	}

	/**
	 * Update total cost of resources.
	 */
	private void updateTotal() throws AdapterException {
		TreeSet<String> months = new TreeSet<>();
		try {
			for (String date : usageDateList) {
				months.add(date.substring(0, 7));
			}
			for (String month : months) {
				resourceTypeDAO.updateMonthTotalCost(month);
			}
		} catch (Exception e) {
			throw new AdapterException("Cannot update total monthly cost. " + e.getLocalizedMessage(), e);
		}
		try {
			if (months.size() > 0) {
				resourceTypeDAO.updateExploratoryCost();
			}
		} catch (Exception e) {
			throw new AdapterException("Cannot update total cost of exploratory. " + e.getLocalizedMessage(), e);
		}
	}

	@Override
	public ToStringHelper toStringHelper(Object self) {
		return super.toStringHelper(self)
				.add("bufferSize", bufferSize)
				.add("upsert", upsert);
	}
}