package com.atlassian.plugins.rest.common.error.jersey;
   
   import java.io.PrintWriter;
   import java.io.StringWriter;
   import java.util.List;
   
   import javax.ws.rs.core.MediaType;
   import javax.ws.rs.core.Request;
   import javax.ws.rs.core.Response;
  import javax.ws.rs.core.Variant;
  import javax.xml.bind.annotation.XmlElement;
  import javax.xml.bind.annotation.XmlRootElement;
  
  import com.atlassian.plugins.rest.common.Status;
  
  /**
   * An analog of {@link Status} specifically for uncaught exceptions. The stack trace is
   * included.
   */
  @XmlRootElement(name = "status")
  public class UncaughtExceptionEntity {
      private static final Integer INTERNAL_SERVER_ERROR_CODE =
              Integer.valueOf(Response.Status.INTERNAL_SERVER_ERROR.getStatusCode());
  
      /**
       * This is a redundant duplicate of the HTTP error code but it may be clearer in
       * a browser.
       */
      @XmlElement(name = "status-code")
      private final Integer code = INTERNAL_SERVER_ERROR_CODE;
  
      /**
       * A humane readable message for the given status.
       */
      @XmlElement
      private final String message;
  
      @XmlElement(name = "stack-trace")
      private final String stackTrace;
  
      /**
       * JAXB requires a default constructor.
       */
      public UncaughtExceptionEntity() {
          this.message = null;
          this.stackTrace = "";
      }
  
      public UncaughtExceptionEntity(Throwable t) {
          this.message = t.getMessage();
  
          StringWriter sw = new StringWriter();
  
          PrintWriter pw = new PrintWriter(sw);
          t.printStackTrace(pw);
  
          this.stackTrace = sw.toString();
      }
  
      public String getMessage() {
          return message;
      }
  
      public String getStackTrace() {
          return stackTrace;
      }
  
      private static final MediaType TEXT_PLAIN_UTF8_TYPE = MediaType.valueOf("text/plain; charset=utf-8");
  
      /**
       * These are the media types that an UncaughtExceptionEntity can be represented as.
       */
      private static final List<Variant> POSSIBLE_VARIANTS = Variant.mediaTypes(
              MediaType.APPLICATION_XML_TYPE,
              MediaType.APPLICATION_JSON_TYPE,
              MediaType.TEXT_PLAIN_TYPE).add().build();
  
      public static MediaType variantFor(Request request) {
          Variant v = request.selectVariant(POSSIBLE_VARIANTS);
          if (v == null) {
              v = POSSIBLE_VARIANTS.get(0);
          }
  
          /* If we include the charset in the variant then it gets prioritised as a default. Select
           * it as text/plain and then switch in the variant with the charset here.
           */
          MediaType t = v.getMediaType();
  
          if (t.equals(MediaType.TEXT_PLAIN_TYPE)) {
              return TEXT_PLAIN_UTF8_TYPE;
          } else {
              return t;
          }
      }
  }