/**
    * Copyright 2005-2013 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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 org.kuali.rice.krad.messages.providers;
  
  import org.apache.commons.lang.StringUtils;
  import org.kuali.rice.core.api.CoreApiServiceLocator;
  import org.kuali.rice.core.api.exception.RiceRuntimeException;
  import org.kuali.rice.krad.messages.Message;
  import org.kuali.rice.krad.messages.MessageProvider;
  import org.kuali.rice.krad.messages.MessageService;
  import org.kuali.rice.krad.service.KRADServiceLocatorWeb;
  import org.kuali.rice.krad.service.ModuleService;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.ResourceBundle;
  
  /**
   * Implementation of {@link MessageProvider} that stores messages in resource files
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class ResourceMessageProvider implements MessageProvider {
  
      private static final String COMPONENT_PLACEHOLDER_BEGIN = "@cmp{";
      private static final String COMPONENT_PLACEHOLDER_END = "}";
  
      protected Map<String, List<ResourceBundle>> cachedResourceBundles;
  
      public ResourceMessageProvider() {
          cachedResourceBundles = new HashMap<String, List<ResourceBundle>>();
      }
  
      /**
       * Iterates through the resource bundles for the give namespace (or the application if namespace is not given)
       * and finds the message that matches the given key
       *
       * <p>
       * If the message is found in more than one bundle, the text from the bundle that is loaded last will be used
       * </p>
       *
       * <p>
       * If the given component code is the default component, resource keys that do not have a component defined
       * and match the given key will also be considered matches
       * </p>
       *
       * @see org.kuali.rice.krad.messages.MessageProvider#getMessage(java.lang.String, java.lang.String,
       *      java.lang.String, java.lang.String)
       */
      public Message getMessage(String namespace, String component, String key, String locale) {
          Message message = null;
  
          List<ResourceBundle> bundles = getCachedResourceBundles(namespace, locale);
  
          // iterate through bundles and find message text, if more than one bundle contains the message
          // the last one iterated over will be used
          String messageText = null;
          for (ResourceBundle bundle : bundles) {
              // check for key with component first
              String resourceKey = COMPONENT_PLACEHOLDER_BEGIN + component + COMPONENT_PLACEHOLDER_END + key;
              if (bundle.containsKey(resourceKey)) {
                  messageText = bundle.getString(resourceKey);
              }
              // if component is default then check for key without component code
              else if (MessageService.DEFAULT_COMPONENT_CODE.equals(component) && bundle.containsKey(key)) {
                  messageText = bundle.getString(key);
              }
          }
  
          // if message text was found build message object
          if (StringUtils.isNotBlank(messageText)) {
              message = buildMessage(namespace, component, key, messageText, locale);
          }
  
          return message;
      }
  
      /**
       * Iterates through the resource bundles for the give namespace (or the application if namespace is not given)
       * and finds all messages that match the given namespace
      *
      * <p>
      * If the same resource key is found in more than one bundle, the text from the bundle that is
      * loaded last will be used
      * </p>
      *
      * <p>
      * If the given component code is the default component, resource keys that do not have a component defined
      * and match the given key will also be considered matches
      * </p>
      *
      * @see org.kuali.rice.krad.messages.MessageProvider#getAllMessagesForComponent(java.lang.String, java.lang.String,
      *      java.lang.String)
      */
     public Collection<Message> getAllMessagesForComponent(String namespace, String component, String locale) {
         List<ResourceBundle> bundles = getCachedResourceBundles(namespace, locale);
 
         Map<String, Message> messagesByKey = new HashMap<String, Message>();
         for (ResourceBundle bundle : bundles) {
             Enumeration<String> resourceKeys = bundle.getKeys();
             while (resourceKeys.hasMoreElements()) {
                 String resourceKey = resourceKeys.nextElement();
 
                 boolean match = false;
                 if (StringUtils.contains(resourceKey,
                         COMPONENT_PLACEHOLDER_BEGIN + component + COMPONENT_PLACEHOLDER_END)) {
                     match = true;
                 } else if (MessageService.DEFAULT_COMPONENT_CODE.equals(component) && !StringUtils.contains(resourceKey,
                         COMPONENT_PLACEHOLDER_BEGIN)) {
                     match = true;
                 }
 
                 if (match) {
                     String messageText = bundle.getString(resourceKey);
 
                     resourceKey = cleanResourceKey(resourceKey);
                     Message message = buildMessage(namespace, component, resourceKey, messageText, locale);
                     messagesByKey.put(resourceKey, message);
                 }
             }
         }
 
         return messagesByKey.values();
     }
 
     /**
      * Removes any component declaration within the given resource key
      *
      * @param resourceKey resource key to clean
      * @return String cleaned resource key
      */
     protected String cleanResourceKey(String resourceKey) {
         String cleanedKey = resourceKey;
 
         String component = StringUtils.substringBetween(cleanedKey, COMPONENT_PLACEHOLDER_BEGIN,
                 COMPONENT_PLACEHOLDER_END);
         if (StringUtils.isNotBlank(component)) {
             cleanedKey = StringUtils.remove(cleanedKey,
                     COMPONENT_PLACEHOLDER_BEGIN + component + COMPONENT_PLACEHOLDER_END);
         }
 
         return cleanedKey;
     }
 
     /**
      * Helper method to build a {@link Message} object from the given parameters
      *
      * @param namespace namespace for the message
      * @param component component code for the message
      * @param key message key
      * @param messageText text for the message
      * @param locale locale of the message
      * @return Message instance populated with parameters
      */
     protected Message buildMessage(String namespace, String component, String key, String messageText, String locale) {
         Message message = new Message();
 
         message.setNamespaceCode(namespace);
         message.setComponentCode(component);
 
         key = cleanResourceKey(key);
         message.setKey(key);
 
         message.setText(messageText);
         message.setLocale(locale);
 
         return message;
     }
 
     /**
      * Retrieves the list of resource bundles for the given namespace or locale from cache if present, otherwise
      * the list is retrieved and then stored in cache for subsequent calls
      *
      * @param namespace namespace to retrieve bundles for
      * @param localeCode locale code to use in selecting bundles
      * @return List<ResourceBundle> list of resource bundles for the namespace or empty list if none were found
      */
     protected List<ResourceBundle> getCachedResourceBundles(String namespace, String localeCode) {
         if (StringUtils.isBlank(namespace)) {
             namespace = MessageService.DEFAULT_NAMESPACE_CODE;
         }
 
         String cacheKey = namespace + "|" + localeCode;
         if (cachedResourceBundles.containsKey(cacheKey)) {
             return cachedResourceBundles.get(cacheKey);
         }
 
         List<ResourceBundle> bundles = null;
         if (StringUtils.isBlank(namespace) || MessageService.DEFAULT_NAMESPACE_CODE.equals(namespace)) {
             bundles = getResourceBundlesForApplication(localeCode);
         } else {
             bundles = getResourceBundlesForNamespace(namespace, localeCode);
         }
 
         cachedResourceBundles.put(cacheKey, bundles);
 
         return bundles;
     }
 
     /**
      * Retrieves the configured {@link ResourceBundle} instances for the given namespace and locale
      *
      * @param namespace namespace to retrieve bundles for
      * @param localeCode locale code to use in selecting bundles
      * @return List<ResourceBundle> list of resource bundles for the namespace or empty list if none were found
      */
     protected List<ResourceBundle> getResourceBundlesForNamespace(String namespace, String localeCode) {
         List<String> resourceBundleNames = getResourceBundleNamesForNamespace(namespace);
 
         return getResourceBundles(resourceBundleNames, localeCode);
     }
 
     /**
      * Retrieves the configured {@link ResourceBundle} instances for the application using the given locale code
      *
      * @param localeCode locale code to use in selecting bundles
      * @return List<ResourceBundle> list of resource bundles for the application or empty list if none were found
      */
     protected List<ResourceBundle> getResourceBundlesForApplication(String localeCode) {
         List<String> resourceBundleNames = getResourceBundleNamesForApplication();
 
         return getResourceBundles(resourceBundleNames, localeCode);
     }
 
     /**
      * Helper method to build a list of resource bundles for the given list of bundle names and locale code
      *
      * <p>
      * For details on how resource bundles are selected given a bundle name and locale code see
      * {@link ResourceBundle}
      * </p>
      *
      * @param resourceBundleNames list of bundle names to get bundles for
      * @param localeCode locale code to use when selecting bundles
      * @return List<ResourceBundle> list of resource bundles (one for each bundle name if found)
      */
     protected List<ResourceBundle> getResourceBundles(List<String> resourceBundleNames, String localeCode) {
         List<ResourceBundle> resourceBundles = new ArrayList<ResourceBundle>();
 
         String[] localeIdentifiers = StringUtils.split(localeCode, "-");
         if ((localeIdentifiers == null) || (localeIdentifiers.length != 2)) {
             throw new RiceRuntimeException("Invalid locale code: " + (localeCode == null ? "Null" : localeCode));
         }
 
         Locale locale = new Locale(localeIdentifiers[0], localeIdentifiers[1]);
 
         if (resourceBundleNames != null) {
             for (String bundleName : resourceBundleNames) {
                 ResourceBundle bundle = ResourceBundle.getBundle(bundleName, locale);
                 if (bundle != null) {
                     resourceBundles.add(bundle);
                 }
             }
         }
 
         return resourceBundles;
     }
 
     /**
      * Retrieves the list of configured bundle names for the namespace
      *
      * <p>
      * Resource bundle names are configured for a namespace using the property <code>resourceBundleNames</code>
      * on the corresponding {@link org.kuali.rice.krad.bo.ModuleConfiguration}
      * </p>
      *
      * @param namespace namespace to retrieve configured bundle names for
      * @return List<String> list of bundle names or null if module was not found for given namespace
      */
     protected List<String> getResourceBundleNamesForNamespace(String namespace) {
         ModuleService moduleService = KRADServiceLocatorWeb.getKualiModuleService().getModuleServiceByNamespaceCode(
                 namespace);
         if (moduleService != null) {
             return moduleService.getModuleConfiguration().getResourceBundleNames();
         }
 
         return null;
     }
 
     /**
      * Retrieves the list of configured bundle names for the application
      *
      * <p>
      * Resource bundle names are configured for the application using the configuration property
      * <code>resourceBundleNames</code>
      * </p>
      *
      * @return List<String> list of bundle names configured for the application
      */
     protected List<String> getResourceBundleNamesForApplication() {
         String resourceBundleNamesConfig = CoreApiServiceLocator.getKualiConfigurationService().getPropertyValueAsString(
                 "resourceBundleNames");
         if (StringUtils.isNotBlank(resourceBundleNamesConfig)) {
             String[] resourceBundleNames = StringUtils.split(resourceBundleNamesConfig, ",");
 
             return Arrays.asList(resourceBundleNames);
         }
 
         return null;
     }
 }