/*
 * 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.backendapi.service;

import com.epam.dlab.auth.UserInfo;
import com.epam.dlab.backendapi.dao.BaseBillingDAO;
import com.epam.dlab.backendapi.dao.BillingDAO;
import com.epam.dlab.backendapi.resources.dto.BillingFilter;
import com.epam.dlab.backendapi.util.CSVFormatter;
import com.epam.dlab.exceptions.DlabException;
import com.google.inject.Inject;
import jersey.repackaged.com.google.common.collect.Lists;
import lombok.extern.slf4j.Slf4j;
import org.bson.Document;

import java.text.ParseException;
import java.util.List;

@Slf4j
public abstract class BillingService {

    @Inject
    private BillingDAO billingDAO;

    public Document getReport(UserInfo userInfo, BillingFilter filter) {
        log.trace("Get billing report for user {} with filter {}", userInfo.getName(), filter);
        try {
            return billingDAO.getReport(userInfo, filter);
        } catch (RuntimeException t) {
            log.error("Cannot load billing report for user {} with filter {}", userInfo.getName(), filter, t);
            throw new DlabException("Cannot load billing report: " + t.getLocalizedMessage(), t);
        }
    }

    protected String getValueOrEmpty(Document document, String key) {
        String value = document.getString(key);
        return value == null ? "" : value;
    }

    String getHeaders(boolean full) {
        return CSVFormatter.formatLine(getHeadersList(full), CSVFormatter.SEPARATOR);
    }

    public Document getBillingReport(UserInfo userInfo, BillingFilter filter) {
        filter.getUser().replaceAll(s -> s.equalsIgnoreCase(BaseBillingDAO.SHARED_RESOURCE_NAME) ? null : s);
        return getReport(userInfo, filter);
    }

    public byte[] downloadReport(UserInfo userInfo, BillingFilter filter) {
        return prepareReport(getReport(userInfo, filter)).getBytes();
    }

    String prepareReport(Document document) {
        try {
            StringBuilder builder =
                    new StringBuilder(CSVFormatter.formatLine(Lists.newArrayList(getFirstLine(document)),
                            CSVFormatter.SEPARATOR, '\"'));

            Boolean full = (Boolean) document.get(BaseBillingDAO.FULL_REPORT);
            builder.append(getHeaders(full));

            @SuppressWarnings("unchecked")
            List<Document> items = (List<Document>) document.get(BaseBillingDAO.ITEMS);

            items.forEach(d -> builder.append(getLine(full, d)));

            builder.append(getTotal(full, document));

            return builder.toString();
        } catch (ParseException e) {
            throw new DlabException("Cannot prepare CSV file", e);
        }
    }

    public abstract String getFirstLine(Document document) throws ParseException;

    public abstract List<String> getHeadersList(boolean full);

    public abstract String getLine(boolean full, Document document);

    public abstract String getTotal(boolean full, Document document);

    public abstract String getReportFileName(UserInfo userInfo, BillingFilter filter);
}