package com.atlassian.plugin.webresource;
   
   import com.atlassian.plugin.PluginAccessor;
   import com.atlassian.plugin.elements.ResourceLocation;
   import com.atlassian.plugin.servlet.DownloadableResource;
   import com.atlassian.plugin.webresource.transformer.WebResourceTransformerModuleDescriptor;
   import org.apache.commons.lang.Validate;
   import org.dom4j.Element;
   import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.Collections;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Represents a set of transformer invocations for a specific web resource set and extension.  Transformers are retrieved
   * from the plugin system on request, not plugin initialisation, since plugin start order is indeterminate.
   *
   * @since 2.5.0
   */
  public class WebResourceTransformation
  {
      private final String extension;
      private final Map<String, Element> transformerElements;
      private Logger log = LoggerFactory.getLogger(WebResourceTransformation.class);
  
      public WebResourceTransformation(Element element)
      {
          Validate.notNull(element.attribute("extension"));
          
          this.extension = "." + element.attributeValue("extension");
  
          LinkedHashMap<String, Element> transformers = new LinkedHashMap<String, Element>();
          for (Element transformElement : (List<Element>)element.elements("transformer"))
          {
              transformers.put(transformElement.attributeValue("key"), transformElement);
          }
          transformerElements = Collections.unmodifiableMap(transformers);
      }
  
      public boolean matches(ResourceLocation location)
      {
          String loc = location.getLocation();
          if (loc == null || "".equals(loc.trim()))
          {
              loc = location.getName();
          }
          return loc.endsWith(extension);
      }
  
      public DownloadableResource transformDownloadableResource(PluginAccessor pluginAccessor, DownloadableResource resource, ResourceLocation resourceLocation, String filePath)
      {
          DownloadableResource lastResource = resource;
          for (Map.Entry<String, Element> entry : transformerElements.entrySet())
          {
              boolean found = false;
              for (WebResourceTransformerModuleDescriptor descriptor : pluginAccessor.getEnabledModuleDescriptorsByClass(WebResourceTransformerModuleDescriptor.class))
              {
                  if (descriptor.getKey().equals(entry.getKey()))
                  {
                      found = true;
                      lastResource = descriptor.getModule().transform(entry.getValue(), resourceLocation, filePath, lastResource);
                  }
              }
              if (!found)
              {
                  log.warn("Web resource transformer " + entry.getKey() + " not found for resource " + resourceLocation.getName() + ", skipping");
              }
          }
          return lastResource;
      }
  
  }