content: /*
   *  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.causeway.viewer.wicket.model.models;
  
  import java.awt.image.BufferedImage;
  import java.nio.charset.Charset;
  import java.util.Collections;
  import java.util.List;
  
  import org.apache.wicket.markup.html.form.upload.FileUpload;
  
  import org.jspecify.annotations.Nullable;
  
  import org.apache.causeway.applib.value.Blob;
  import org.apache.causeway.applib.value.Clob;
  
  import org.jspecify.annotations.NonNull;
  import lombok.SneakyThrows;
  import lombok.experimental.UtilityClass;
  
  @UtilityClass
  public class FileUploadModels {
      
      public ScalarConvertingModel<List<FileUpload>, Blob> blob(final @NonNull UiAttributeWkt attributeModel) {
          return new FileUploadConvertingModel<Blob>(attributeModel) {
  
              private static final long serialVersionUID = 1L;
  
              @Override
              Blob toScalarValue(@NonNull FileUpload fileUpload) {
                  final String contentType = fileUpload.getContentType();
                  final String clientFileName = fileUpload.getClientFileName();
                  final byte[] bytes = fileUpload.getBytes();
                  final Blob blob = new Blob(clientFileName, contentType, bytes);
                  return blob;
              }
  
          };
      }
  
      public ScalarConvertingModel<List<FileUpload>, Clob> clob(
              final @NonNull UiAttributeWkt attributeModel,
              final @NonNull Charset charset) {
  
          // Charset is not serializable.
          // (NB: can't reference 'charset' in constructor, as javac creates a hidden instance field in the inner class)
          final String charsetName = charset.name();
  
          return new FileUploadConvertingModel<Clob>(attributeModel) {
  
              private static final long serialVersionUID = 1L;
  
              @Override @SneakyThrows
              Clob toScalarValue(@NonNull FileUpload fileUpload) {
                  final String contentType = fileUpload.getContentType();
                  final String clientFileName = fileUpload.getClientFileName();
                  final String str = new String(fileUpload.getBytes(), charsetName);
                  final Clob clob = new Clob(clientFileName, contentType, str);
                  return clob;
              }
  
          };
      }
      
      public ScalarConvertingModel<List<FileUpload>, BufferedImage> image(final @NonNull UiAttributeWkt attributeModel) {
          return new FileUploadConvertingModel<BufferedImage>(attributeModel) {
  
              private static final long serialVersionUID = 1L;
  
              @Override
              BufferedImage toScalarValue(@NonNull FileUpload fileUpload) {
                  final String contentType = fileUpload.getContentType();
                  final String clientFileName = fileUpload.getClientFileName();
                  final byte[] bytes = fileUpload.getBytes();
                  final Blob blob = new Blob(clientFileName, contentType, bytes);
                  return blob.asImage().orElse(null);
              }
  
          };
      }
      
      // -- HELPER
      
      static abstract class FileUploadConvertingModel<T> extends ScalarConvertingModel<List<FileUpload>, T> {
          private static final long serialVersionUID = 1L;
          
          protected FileUploadConvertingModel(@NonNull UiAttributeWkt attributeModel) {
              super(attributeModel);
          }
          
          abstract T toScalarValue(final @NonNull FileUpload fileUpload);
          
          @Override
          protected final T toScalarValue(final @Nullable List<FileUpload> fileUploads) {
              if(fileUploads==null
                  || fileUploads.isEmpty()) {
                  return null;
              }
              final FileUpload fileUpload = fileUploads.get(0);
              if(fileUpload==null) return null;
              return toScalarValue(fileUpload);
          }
          
          @Override
          protected final List<FileUpload> fromScalarValue(final T t) {
              return t!=null
                      ? Collections.emptyList() //[CAUSEWAY-3203] just enough so we can distinguish the empty from the present case
                      : null;
          }
          
      }
  
  }
  