package com.atlassian.plugin.webresource;
   
   import java.util.ArrayList;
   import java.util.HashMap;
   import java.util.Iterator;
   import java.util.List;
   import java.util.Map;
   import java.util.Set;
   import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.commons.lang.StringEscapeUtils;
  import org.apache.commons.lang.StringUtils;
  
  /**
   * The WebResourceFormatter should take a PluginResource and add the BatchResourceContents dependency information to 
   * the output as required.
   */
  class BatchResourceContentsWebFormatter
  {
      /**
       * Match the opening of an HTML tag up to the first attribute or a tag with no attributes at
       * all (i.e. followed immediately with the > symbol).
       */
      private static final Pattern TAG_NAME_PATTERN = Pattern.compile("(<\\w+)[\\s|>]");
      
      /**
       * Modify the supplied formattedResource to contain any necessary data attributes required to carry additional
       * information about the PluginResource being written.
       * 
       * @param resource
       * @param formattedResource
       * @return
       */
      static String insertBatchResourceContents(final PluginResource resource, String formattedResource)
      {
          Map<String,String> dependencyAttributes = createDependencyAttributes(resource);
          if (dependencyAttributes.isEmpty())
              return formattedResource;
          
          List<String> nameValues = new ArrayList<String>(dependencyAttributes.size());
          for (Map.Entry<String,String> attr : dependencyAttributes.entrySet())
          {
              String nameValuePair = StringEscapeUtils.escapeHtml(attr.getKey()) + "=\"" + StringEscapeUtils.escapeHtml(attr.getValue()) + "\"";
              nameValues.add(nameValuePair);
          }
          
          String nameValuesStr = StringUtils.join(nameValues, ' ');
          
          Matcher matcher = TAG_NAME_PATTERN.matcher(formattedResource);
          if (matcher.find())
          {
              StringBuilder builder = new StringBuilder(formattedResource);
              builder.insert(matcher.end(1), " " + nameValuesStr);
              return builder.toString();
          }
          
          return formattedResource;
      }
      
      static private Map<String,String> createDependencyAttributes(final PluginResource resource)
      {
          Map<String,String> dependencyAttributes = new HashMap<String,String>();
          
         Set<BatchedWebResourceDescriptor> descriptors = resource.getBatchedWebResourceDescriptors();
          List<String> dependencyValues = new ArrayList<String>(descriptors.size());
          for (BatchedWebResourceDescriptor descriptor : descriptors)
          {
              String attributeValue = descriptor.getCompleteKey() + "[" + descriptor.getPluginVersion() + "]";
              dependencyValues.add(attributeValue);
          }
          
          if (!dependencyValues.isEmpty())
          {
              dependencyAttributes.put("data-atlassian-webresource-contents", StringUtils.join(dependencyValues, ','));
          }
          
          if (resource instanceof ContextBatchPluginResource)
          {
              ContextBatchPluginResource contextBatchPluginResource = (ContextBatchPluginResource)resource;
              
              Iterator<String> contextsIterator = contextBatchPluginResource.getContexts().iterator();
              if (contextsIterator.hasNext())
              {
                  dependencyAttributes.put("data-atlassian-webresource-contexts", StringUtils.join(contextsIterator, ','));
              }
  
              Iterator<String> excludedContextsIterator = contextBatchPluginResource.getExcludedContexts().iterator();
              if (excludedContextsIterator.hasNext())
              {
                  dependencyAttributes.put("data-atlassian-webresource-excluded-contexts", StringUtils.join(excludedContextsIterator,','));                
              }
          }
          
          return dependencyAttributes;
      }
  }