/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements. See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership. The ASF licenses this file
    * to you 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 org.apache.syncope.common.rest.api.batch;
  
  import java.util.List;
  import javax.ws.rs.core.HttpHeaders;
  import javax.ws.rs.core.Response;
  import org.apache.syncope.common.rest.api.service.JAXRSService;
  
  public final class BatchPayloadGenerator {
  
      private static final String HTTP_1_1 = "HTTP/1.1";
  
      public static <T extends BatchItem> String generate(final List<T> items, final String boundary) {
          StringBuilder payload = new StringBuilder();
  
          items.forEach(item -> {
              payload.append(boundary).append(JAXRSService.CRLF);
              payload.append(HttpHeaders.CONTENT_TYPE).append(": ").append("application/http").append('\n');
              payload.append("Content-Transfer-Encoding: binary").append('\n');
              payload.append(JAXRSService.CRLF);
  
              if (item instanceof BatchRequestItem) {
                  BatchRequestItem bri = BatchRequestItem.class.cast(item);
                  payload.append(bri.getMethod()).append(' ').append(bri.getRequestURI());
                  if (bri.getQueryString() != null) {
                      payload.append('?').append(bri.getQueryString());
                  }
                  payload.append(' ').append(HTTP_1_1).append('\n');
              }
  
              if (item instanceof BatchResponseItem) {
                  BatchResponseItem bri = BatchResponseItem.class.cast(item);
                  payload.append(HTTP_1_1).append(' ').
                          append(bri.getStatus()).append(' ').
                          append(Response.Status.fromStatusCode(bri.getStatus()).getReasonPhrase()).
                          append('\n');
              }
  
              if (item.getHeaders() != null && !item.getHeaders().isEmpty()) {
                  item.getHeaders().forEach((key, values) -> values.forEach(
                          value -> payload.append(key).append(": ").append(value).append('\n')));
                  payload.append(JAXRSService.CRLF);
              }
  
              if (item.getContent() != null) {
                  payload.append(item.getContent()).append('\n');
              }
          });
  
          payload.append(boundary).append(JAXRSService.DOUBLE_DASH).append('\n');
  
          return payload.toString();
      }
  
      private BatchPayloadGenerator() {
          // private constructor for static utility class
      }
  }