/*******************************************************************************
 * Copyright 2013 SAP AG
 * 
 * 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.
 ******************************************************************************/
package com.sap.core.odata.processor.core.jpa.exception;

import java.util.Arrays;
import java.util.Formatter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.MissingFormatArgumentException;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

import com.sap.core.odata.api.exception.MessageReference;
import com.sap.core.odata.processor.api.jpa.exception.ODataJPAMessageService;
import com.sap.core.odata.processor.core.jpa.ODataJPAContextImpl;

public class ODataJPAMessageServiceDefault implements ODataJPAMessageService {

  private static final String BUNDLE_NAME = "jpaprocessor_msg"; //$NON-NLS-1$
  private static final Map<Locale, ODataJPAMessageService> LOCALE_2_MESSAGE_SERVICE = new HashMap<Locale, ODataJPAMessageService>();
  private static final ResourceBundle defaultResourceBundle = ResourceBundle.getBundle(BUNDLE_NAME);
  private final ResourceBundle resourceBundle;
  private final Locale lanLocale;

  @Override
  public String getLocalizedMessage(final MessageReference context, final Throwable exception) {

    Object[] contentAsArray = context.getContent().toArray(new Object[0]);

    if (contentAsArray.length == 0 && exception != null) {
      contentAsArray = new Object[2];
      contentAsArray[0] = exception.getStackTrace()[1].getClassName();
      contentAsArray[1] = exception.getMessage();
    }
    String value = null;
    String key = context.getKey();

    try {
      value = getMessage(key);
      StringBuilder builder = new StringBuilder();
      Formatter f = null;
      if (lanLocale == null) {
        f = new Formatter();
      } else {
        f = new Formatter(builder, lanLocale);
      }
      f.format(value, contentAsArray);
      f.close();
      return builder.toString();

    } catch (MissingResourceException e) {
      return "Missing message for key '" + key + "'!";
    } catch (MissingFormatArgumentException e) {
      return "Missing replacement for place holder in value '" + value
          + "' for following arguments '"
          + Arrays.toString(contentAsArray) + "'!";
    }
  }

  private ODataJPAMessageServiceDefault(final ResourceBundle resourceBundle,
      final Locale locale) {
    this.resourceBundle = resourceBundle;
    lanLocale = locale;
  }

  public static ODataJPAMessageService getInstance(final Locale locale) {

    Locale acceptedLocale = Locale.ENGLISH;
    if ((ODataJPAContextImpl.getContextInThreadLocal() != null) && (ODataJPAContextImpl.getContextInThreadLocal().getAcceptableLanguages() != null)) {

      List<Locale> acceptedLanguages = ODataJPAContextImpl.getContextInThreadLocal().getAcceptableLanguages();

      Iterator<Locale> itr = acceptedLanguages.iterator();

      while (itr.hasNext()) {

        Locale tempLocale = itr.next();
        if (ResourceBundle.getBundle(BUNDLE_NAME, tempLocale).getLocale().equals(tempLocale)) {
          acceptedLocale = tempLocale;
          break;
        }
      }
    }

    ODataJPAMessageService messagesInstance = LOCALE_2_MESSAGE_SERVICE
        .get(acceptedLocale);
    if (messagesInstance == null) {
      ResourceBundle resourceBundle = ResourceBundle.getBundle(BUNDLE_NAME, acceptedLocale);

      if (resourceBundle != null) {
        messagesInstance = new ODataJPAMessageServiceDefault(
            resourceBundle, acceptedLocale);
        LOCALE_2_MESSAGE_SERVICE.put(acceptedLocale, messagesInstance);
      } else if (defaultResourceBundle != null) {
        messagesInstance = new ODataJPAMessageServiceDefault(
            defaultResourceBundle, null);
      }

    }
    return messagesInstance;
  }

  private String getMessage(final String key) {
    return resourceBundle.getString(key);
  }
}