/*
 * 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.datalab.core;

import com.epam.datalab.exceptions.InitializationException;
import com.epam.datalab.mongo.MongoConstants;
import com.epam.datalab.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.and;
import static com.mongodb.client.model.Filters.eq;
import static com.mongodb.client.model.Filters.gte;
import static com.mongodb.client.model.Filters.or;
import static com.mongodb.client.model.Filters.regex;

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

    public static final String ENTRIES_FIELD = "entries";
    private static final String ID_FIELD = "_id";
    private static final String MODIFICATION_DATE = "lastModificationDate";
    /**
     * 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;

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

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

    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() {
        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();
    }
}