package com.atlassian.marketplace.client.model;
   
   import java.net.URI;
   import java.util.Map;
   
   import com.atlassian.fugue.Option;
   import com.atlassian.marketplace.client.api.UriTemplate;
   
   import com.google.common.collect.ImmutableList;
  import com.google.common.collect.ImmutableMap;
  
  import static com.atlassian.fugue.Option.none;
  import static com.atlassian.fugue.Option.option;
  import static com.atlassian.fugue.Option.some;
  
  /**
   * A links map in the HAL-JSON format used by the Marketplace version 2 API.  For each link rel (key),
   * there can be either a single URI, a single URI template, or an array of either.  Example of a
   * valid links map:
   * <code>
   *   {
   *     "simple": { "href": "/uri" },
   *     "multiple": [ { "href": "/uri1" }, { "href": "/uri2" } ],
   *     "withContentType": { "href": "/uri", "type": "text/html" },
   *     "isATemplate": { "href": "/uri/{var}", "templated": true }
   *   }
   * </code>
   */
  public final class Links
  {
      public static final String REST_TYPE = "application/json";
      public static final String WEB_TYPE = "text/html";
  
      private final Map<String, ImmutableList<Link>> items;
  
      public Links(Map<String, ImmutableList<Link>> items)
      {
          this.items = ImmutableMap.copyOf(items);
      }
  
      /**
       * Used internally.
       */
      public Map<String, ImmutableList<Link>> getItems()
      {
          return items;       
      }
  
      URI requireUri(String rel)
      {
          for (URI uri: getUri(rel))
          {
              return uri;
          }
          throw new IllegalArgumentException("missing required REST link: " + rel);
      }
      
      /**
       * Returns the first {@link Link} matching the given key, if any.
       */
      public Option<Link> getLink(String rel)
      {
          for (Link link: getLinks(rel))
          {
              return some(link);
          }
          return none();
      }
  
      /**
       * Returns the first {@link Link} matching the given key and the given content type, if any.
       */
      public Option<Link> getLink(String rel, String contentType)
      {
          for (Link link: getLinks(rel))
          {
              if (link.getType().isEmpty() && contentType.equals(REST_TYPE))
              {
                  return some(link);
              }
              for (String type: link.getType())
              {
                  if (type.equalsIgnoreCase(contentType))
                  {
                      return some(link);
                  }
              }
          }
          return none();
      }
  
      /**
       * Returns every {@link Link} that matches the given key.
       */
      public Iterable<Link> getLinks(String rel)
      {
          return option(items.get(rel)).getOrElse(ImmutableList.<Link>of());
      }
  
     /**
      * Shortcut for getting the URI of the first {@link Link} that matches the given key.
      */
     public Option<URI> getUri(String rel)
     {
         for (Link link: getLink(rel))
         {
             return some(link.getUri());
         }
         return none();
     }
 
     /**
      * Shortcut for getting the URI of the first {@link Link} that matches the given key and content type.
      */
     public Option<URI> getUri(String rel, String contentType)
     {
         for (Link link: getLink(rel, contentType))
         {
             return some(link.getUri());
         }
         return none();
     }
 
     /**
      * Shortcut for getting the template of the first {@link Link} that matches the given key,
      * if it is a template.
      */
     public Option<UriTemplate> getUriTemplate(String rel)
     {
         for (Link link: getLink(rel))
         {
             return link.getUriTemplate();
         }
         return none();
     }
     
     /**
      * Shortcut for getting the template of the first {@link Link} that matches the given key
      * and content type, if it is a template.
      */
     public Option<UriTemplate> getUriTemplate(String rel, String contentType)
     {
         for (Link link: getLink(rel, contentType))
         {
             return link.getUriTemplate();
         }
         return none();
     }
 }