/*
    * Copyright 2010 James Pether Sörling
    *
    * Licensed 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.
   *
   *	$Id$
   *  $HeadURL$
  */
  package com.hack23.cia.service.impl.action.application.translation;
  
  import java.io.IOException;
  import java.security.GeneralSecurityException;
  import java.util.Arrays;
  
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;
  import org.springframework.transaction.annotation.Propagation;
  import org.springframework.transaction.annotation.Transactional;
  
  import com.google.api.client.json.jackson2.JacksonFactory;
  import com.google.api.services.translate.Translate;
  import com.google.api.services.translate.model.TranslationsListResponse;
  import com.hack23.cia.model.internal.application.system.impl.ApplicationConfiguration;
  import com.hack23.cia.model.internal.application.system.impl.ConfigurationGroup;
  import com.hack23.cia.service.data.api.ApplicationConfigurationService;
  
  /**
   * The Class TranslationServiceImpl.
   */
  @Service
  @Transactional(propagation = Propagation.REQUIRED)
  final class TranslationServiceImpl implements TranslationService {
  
  	/** The Constant LOGGER. */
  	private static final Logger LOGGER = LoggerFactory.getLogger(TranslationServiceImpl.class);
  
  	/** The application configuration service. */
  	@Autowired
  	private ApplicationConfigurationService applicationConfigurationService;
  
  	/**
  	 * Instantiates a new translation service impl.
  	 */
  	public TranslationServiceImpl() {
  		super();
  	}
  
  	@Override
  	public String translate(final String translateText, final String targetLanguage) throws TranslationException {
  
  		final ApplicationConfiguration googleTranslateApiKey = applicationConfigurationService.checkValueOrLoadDefault(
  				"Google translate api accesskey", "Required for use of the translation service",
  				ConfigurationGroup.AUTHENTICATION, TranslationServiceImpl.class.getSimpleName(), "Translation Service",
  				"Responsible configure access credentials for google translate api",
  				"external.services.google.translate.api.accesskey", "");
  		final ApplicationConfiguration googleTranslateApiApplicationName = applicationConfigurationService
  				.checkValueOrLoadDefault("Google translate api application name",
  						"Required for use of the translation service", ConfigurationGroup.AUTHENTICATION,
  						TranslationServiceImpl.class.getSimpleName(), "Translation Service",
  						"Responsible configure application name for google translate api",
  						"external.services.google.translate.api.application.name", "");
  
  		if (!StringUtils.isBlank(googleTranslateApiKey.getPropertyValue())
  				&& !StringUtils.isBlank(googleTranslateApiApplicationName.getPropertyValue())) {
  
  			try {
  				final Translate t = new Translate.Builder(
  						com.google.api.client.googleapis.javanet.GoogleNetHttpTransport.newTrustedTransport(),
  						JacksonFactory.getDefaultInstance(), null)
  								.setApplicationName(googleTranslateApiApplicationName.getPropertyValue()).build();
  
  				final Translate.Translations.List list = t.new Translations().list(Arrays.asList(translateText),
  						targetLanguage);
  				list.setKey(googleTranslateApiKey.getPropertyValue());
  				list.setSource("EN");
  				final TranslationsListResponse response = list.execute();
  
  				return response.getTranslations().listIterator().next().getTranslatedText();
  
  			} catch (GeneralSecurityException | IOException e) {
  				final StringBuilder stringBuilder = new StringBuilder().append("Problem translation text:")
  						.append(translateText).append("to language:").append(targetLanguage);
  				LOGGER.warn(stringBuilder.toString(), e);
  				throw new TranslationException(stringBuilder.toString(), e);
  			}
  		}
 		throw new TranslationException("Missing google api key or application name", null);
 	}
 }