/**
 * Copyright 2014 Tampere University of Technology, Pori Department
 * 
 * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
 * 
 * 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 core.tut.pori.http;

import java.io.IOException;

import javax.servlet.http.HttpServletResponse;
import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlElementRef;
import javax.xml.bind.annotation.XmlEnum;
import javax.xml.bind.annotation.XmlRootElement;

import org.apache.log4j.Logger;

import core.tut.pori.utils.XMLFormatter;


/**
 * Basic HTTP response, which prints the given ResponseData as an xml.
 * 
 * By default, the status of the response is 200 OK
 */
@XmlRootElement(name=Definitions.ELEMENT_RESPONSE)
@XmlAccessorType(XmlAccessType.NONE)
public class Response {
  private static final Logger LOGGER = Logger.getLogger(Response.class);
  @XmlElementRef
  private ResponseData _responseData = null;
  @XmlAttribute(name=Definitions.ATTRIBUTE_METHOD)
  private String _method = null;
  @XmlElement(name=Definitions.ELEMENT_MESSAGE)
  private String _message = null;
  @XmlAttribute(name=Definitions.ATTRIBUTE_SERVICE)
  private String _service = null; 
  @XmlElement(name=Definitions.ELEMENT_STATUS)
  private Status _status = Status.OK;

  
  /**
   * HTTP Status code enumerations.
   * 
   * As defined by http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
   */
  @XmlEnum
  public enum Status{
    /** 200 OK response */
    OK(200),
    /** 204 No Content */
    NO_CONTENT(204),
    /** 400 Bad Request response */
    BAD_REQUEST(400),
    /** 401 Unauthorized response */
    UNAUTHORIZED(401),
    /** 403 Forbidden response */
    FORBIDDEN(403),
    /** 404 Not Found response */
    NOT_FOUND(404),
    /** 440 Login Timeout response, Microsoft/Outlook extension. In this case used more liberally for all login timeout cases. */
    LOGIN_TIMEOUT(440),
    /** 500 Internal Server Error response */
    INTERNAL_SERVER_ERROR(500),
    /** 503 Service Unavailable response */
    SERVICE_UNAVAILABLE(503);
    
    private int _code;
    
    /**
     * 
     * @param code
     */
    private Status(int code){
      _code = code;
    }
    
    /**
     * convert to HTTP status code
     * @return the status as HTTP status code
     */
    public int toStatusCode(){
      return _code;
    }
    
    /**
     * 
     * @param code
     * @return status code from the given integer code, returns INTERNAL_SERVER_ERROR on unknown error code
     */
    public static Status fromStatusCode(int code){
      for(Status s : Status.values()){
        if(s._code == code){
          return s;
        }
      }
      return INTERNAL_SERVER_ERROR;
    }
  } // enum Status
  
  /**
   * for serialization
   */
  public Response(){
    // nothing needed
  }
  
  /**
   * 
   * @param status
   */
  public Response(Status status){
    _status = status;
  }
  
  /**
   * 
   * @param status
   * @param message
   */
  public Response(Status status, String message){
    _status = status;
    _message = message;
  }
  
  /**
   * 
   * @param data
   */
  public Response(ResponseData data){
    _responseData = data;
  }
  
  /**
   * Write this response to the given response object.
   * 
   * This method can be overridden to provide custom responses.
   * 
   * By default this method writes this object to the stream as XML based on JAXB annotations
   * and sets the encoding ({@value core.tut.pori.http.Definitions#ENCODING_UTF8}) and content type ({@value core.tut.pori.http.Definitions#CONTENT_TYPE_XML}) to appropriate values.
   * These to parameters should be changed for the response if format is changed in the overriding method.
   * 
   * Additionally this method sets the HTTP basic authentication header if the status is set {@link core.tut.pori.http.Response.Status#UNAUTHORIZED}.
   * 
   * @param response
   * @see #setDefaultAuthenticationHeader(HttpServletResponse)
   * @see #setStatus(core.tut.pori.http.Response.Status)
   */
  public void writeTo(HttpServletResponse response){
    try {
      response.setContentType(Definitions.CONTENT_TYPE_XML);
      response.setCharacterEncoding(Definitions.ENCODING_UTF8);
      response.getWriter().write((new XMLFormatter()).toString(this));
    } catch (IOException ex) {
      LOGGER.error(ex, ex);
      _status = Status.INTERNAL_SERVER_ERROR;
    }
    
    if(_status != Status.OK){ // don't change defaults if there is OK status
      response.setStatus(_status.toStatusCode());
      if(_status == Status.UNAUTHORIZED){
        setDefaultAuthenticationHeader(response);
      }
    }
  }
  
  /**
   * Set the default HTTP authentication header in the response.
   * 
   * <a href="http://tools.ietf.org/html/rfc2617#section-2">HTTP Basic Authentication</a>
   * 
   * @param response
   */
  public static void setDefaultAuthenticationHeader(HttpServletResponse response){
    response.setHeader(Definitions.HEADER_AUTHENTICATE, Definitions.HEADER_AUTHENTICATE_VALUE);
  }

  /**
   * @return the status
   */
  public Status getStatus() {
    return _status;
  }

  /**
   * @param status the status to set
   */
  public void setStatus(Status status) {
    _status = status;
  }

  /**
   * @return the method
   */
  public String getMethod() {
    return _method;
  }

  /**
   * @param method the method to set
   */
  public void setMethod(String method) {
    _method = method;
  }

  /**
   * @return the service
   */
  public String getService() {
    return _service;
  }

  /**
   * @param service the service to set
   */
  public void setService(String service) {
    _service = service;
  }

  /**
   * @return the data
   */
  public ResponseData getResponseData() {
    return _responseData;
  }

  /**
   * @param data the data to set
   */
  public void setResponseData(ResponseData data) {
    _responseData = data;
  }

  /**
   * 
   * @return response message
   */
  public String getMessage() {
    return _message;
  }

  /**
   * Set an optional message to be shown with the response
   * 
   * @param message
   */
  public void setMessage(String message) {
    _message = message;
  }
}