/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package com.foxinmy.weixin4j.http.apache.mime;
  
  import java.util.List;
  
  import com.foxinmy.weixin4j.http.ContentType;
  import com.foxinmy.weixin4j.http.apache.content.AbstractContentBody;
  import com.foxinmy.weixin4j.http.apache.content.ContentBody;
  
  /**
   * Builder for individual {@link com.foxinmy.weixin4j.http.apache.mime.FormBodyPart}s.
   *
   * @since 4.4
   */
  public class FormBodyPartBuilder {
  
      private String name;
      private ContentBody body;
      private final Header header;
  
      public static FormBodyPartBuilder create(final String name, final ContentBody body) {
          return new FormBodyPartBuilder(name, body);
      }
  
      public static FormBodyPartBuilder create() {
          return new FormBodyPartBuilder();
      }
  
      FormBodyPartBuilder(final String name, final ContentBody body) {
          this();
          this.name = name;
          this.body = body;
      }
  
      FormBodyPartBuilder() {
          this.header = new Header();
      }
  
      public FormBodyPartBuilder setName(final String name) {
          this.name = name;
          return this;
      }
  
      public FormBodyPartBuilder setBody(final ContentBody body) {
          this.body = body;
          return this;
      }
  
      public FormBodyPartBuilder addField(final String name, final String value) {
          this.header.addField(new MinimalField(name, value));
          return this;
      }
  
      public FormBodyPartBuilder setField(final String name, final String value) {
          this.header.setField(new MinimalField(name, value));
          return this;
      }
  
      public FormBodyPartBuilder removeFields(final String name) {
          this.header.removeFields(name);
          return this;
      }
  
      public FormBodyPart build() {
          final Header headerCopy = new Header();
          final List<MinimalField> fields = this.header.getFields();
          for (final MinimalField field: fields) {
              headerCopy.addField(field);
          }
          if (headerCopy.getField(MIME.CONTENT_DISPOSITION) == null) {
              final StringBuilder buffer = new StringBuilder();
              buffer.append("form-data; name=\"");
              buffer.append(encodeForHeader(this.name));
             buffer.append("\"");
             if (this.body.getFilename() != null) {
                 buffer.append("; filename=\"");
                 buffer.append(encodeForHeader(this.body.getFilename()));
                 buffer.append("\"");
             }
             headerCopy.addField(new MinimalField(MIME.CONTENT_DISPOSITION, buffer.toString()));
         }
         if (headerCopy.getField(MIME.CONTENT_TYPE) == null) {
             final ContentType contentType;
             if (body instanceof AbstractContentBody) {
                 contentType = ((AbstractContentBody) body).getContentType();
             } else {
                 contentType = null;
             }
             if (contentType != null) {
                 headerCopy.addField(new MinimalField(MIME.CONTENT_TYPE, contentType.toString()));
             } else {
                 final StringBuilder buffer = new StringBuilder();
                 buffer.append(this.body.getMimeType()); // MimeType cannot be null
                 if (this.body.getCharset() != null) { // charset may legitimately be null
                     buffer.append("; charset=");
                     buffer.append(this.body.getCharset());
                 }
                 headerCopy.addField(new MinimalField(MIME.CONTENT_TYPE, buffer.toString()));
             }
         }
         if (headerCopy.getField(MIME.CONTENT_TRANSFER_ENC) == null) {
             // TE cannot be null
             headerCopy.addField(new MinimalField(MIME.CONTENT_TRANSFER_ENC, body.getTransferEncoding()));
         }
         return new FormBodyPart(this.name, this.body, headerCopy);
     }
 
     private static String encodeForHeader(final String headerName) {
         if (headerName == null) {
             return null;
         }
         final StringBuilder sb = new StringBuilder();
         for (int i = 0; i < headerName.length(); i++) {
             final char x = headerName.charAt(i);
             if (x == '"' || x == '\\' || x == '\r') {
                 sb.append("\\");
             }
             sb.append(x);
         }
         return sb.toString();
     }
 
 }