/*
 * 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;

import com.epam.dlab.exceptions.InitializationException;
import com.epam.dlab.mongo.MongoConstants;
import com.epam.dlab.mongo.MongoDbConnection;
import com.google.common.base.MoreObjects;
import com.google.common.base.MoreObjects.ToStringHelper;
import com.mongodb.client.FindIterable;
import com.mongodb.client.model.UpdateOptions;
import org.apache.commons.lang3.StringUtils;
import org.bson.Document;
import org.bson.conversions.Bson;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import static com.mongodb.client.model.Filters.*;

/**
 * Provides loading and storing the working data of modules.
 */
public class ModuleData {

	private static final String ID_FIELD = "_id";
	private static final String MODIFICATION_DATE = "lastModificationDate";
	public static final String ENTRIES_FIELD = "entries";
	/**
	 * Date formatter.
	 */
	private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX");
	private final MongoDbConnection connection;

	private String id;
	private Date modificationDate;

	/**
	 * Entries of data.
	 */
	private Map<String, String> entries = new HashMap<>();

	/**
	 * Flag modification of entries.
	 */
	private boolean modified;

	/**
	 * Return <b>true</b> if any entries was modify.
	 */
	public boolean isModified() {
		return modified;
	}

	/**
	 * Instantiate module data.
	 *
	 * @param connection the name of data file.
	 * @throws InitializationException
	 */
	public ModuleData(MongoDbConnection connection) {
		this.connection = connection;
	}

	public void setId(String id) {
		this.id = id;
	}

	public void setModificationDate(Date modificationDate) {
		this.modificationDate = modificationDate;
	}

	/**
	 * Return the value for given key or <b>null</b> if value not found.
	 *
	 * @param key the key of entry.
	 */
	public String getString(String key) {
		return entries.get(key);
	}

	/**
	 * Return the date value for given key or <b>null</b> if value not found.
	 *
	 * @param key the key of entry.
	 * @throws ParseException
	 */
	public Date getDate(String key) throws ParseException {
		String value = entries.get(key);
		return (value == null ? null : dateFormat.parse(value));
	}

	/**
	 * Set value for given key or delete entry if the value is <b>null</b>.
	 *
	 * @param key   the key of entry.
	 * @param value the value.
	 */
	public void set(String key, String value) {
		if (StringUtils.equals(entries.get(key), value)) {
			return;
		} else if (value == null) {
			entries.remove(key);
		} else {
			entries.put(key, value);
		}
		modified = true;
	}

	/**
	 * Set value for given key or delete entry if the value is <b>null</b>.
	 *
	 * @param key   the key of entry.
	 * @param value the date.
	 */
	public void set(String key, Date value) {
		set(key, dateFormat.format(value));
	}

	public void store() {
		//TODO refactor this module move working with db to DAO layer
		final Document document = new Document().append(ID_FIELD, id).append(MODIFICATION_DATE,
				modificationDate).append(ENTRIES_FIELD, entries);
		connection.getCollection(MongoConstants.BILLING_DATA_COLLECTION)
				.updateOne(eq(ID_FIELD, id), new Document("$set", document), new UpdateOptions().upsert(true));
		modified = false;
	}

	public boolean wasProcessed(String fileName, Date modificationDate, String datePrefix) {
		final Bson filePerBillingPeriodCondition = and(regex(ID_FIELD, "^" + datePrefix), gte(MODIFICATION_DATE,
				modificationDate));
		final Bson fileWithExactNameCondition = and(eq(ID_FIELD, fileName), gte(MODIFICATION_DATE, modificationDate));
		final FindIterable<Document> documents = connection.getCollection(MongoConstants.BILLING_DATA_COLLECTION)
				.find(or(fileWithExactNameCondition, filePerBillingPeriodCondition))
				.limit(1);
		return documents.iterator().hasNext();
	}

	public void closeMongoConnection() throws IOException {
		connection.close();
	}


	/**
	 * Returns a string representation of the object.
	 *
	 * @param self the object to generate the string for (typically this), used only for its class name.
	 */
	public ToStringHelper toStringHelper(Object self) {
		return MoreObjects.toStringHelper(self)
				.addValue(entries);
	}

	@Override
	public String toString() {
		return toStringHelper(this)
				.toString();
	}
}