/*
    * 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.commons.imaging.formats.tiff.fieldtypes;
  
  import java.nio.ByteOrder;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  
  import org.apache.commons.imaging.ImagingException;
  import org.apache.commons.imaging.common.Allocator;
  import org.apache.commons.imaging.formats.tiff.TiffField;
  
  public class FieldTypeAscii extends AbstractFieldType {
      public FieldTypeAscii(final int type, final String name) {
          super(type, name, 1);
      }
  
      @Override
      public Object getValue(final TiffField entry) {
          // According to EXIF specification
          // "2 = ASCII An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL."
          final byte[] bytes = entry.getByteArrayValue();
          int nullCount = 1;
          for (int i = 0; i < bytes.length - 1; i++) {
              if (bytes[i] == 0) {
                  nullCount++;
              }
          }
          final String[] strings = Allocator.array(nullCount, String[]::new, 24);
          int stringsAdded = 0;
          strings[0] = ""; // if we have a 0 length string
          int nextStringPos = 0;
          // According to the Exiftool FAQ, [BROKEN URL] http://www.metadataworkinggroup.org
          // specifies that the TIFF ASCII fields are actually UTF-8.
          // Exiftool however allows you to configure the charset used.
          for (int i = 0; i < bytes.length; i++) {
              if (bytes[i] == 0) {
                  final String string = new String(bytes, nextStringPos, i - nextStringPos, StandardCharsets.UTF_8);
                  strings[stringsAdded++] = string;
                  nextStringPos = i + 1;
              }
          }
          if (nextStringPos < bytes.length) {
              // Buggy file, string wasn't null terminated
              final String string = new String(bytes, nextStringPos, bytes.length - nextStringPos, StandardCharsets.UTF_8);
              strings[stringsAdded++] = string;
          }
          if (strings.length == 1) {
              return strings[0];
          }
          return strings;
      }
  
      @Override
      public byte[] writeData(final Object o, final ByteOrder byteOrder) throws ImagingException {
          if (o instanceof byte[]) {
              final byte[] bytes = (byte[]) o;
              final byte[] result = Arrays.copyOf(bytes, bytes.length + 1);
              result[result.length - 1] = 0;
              return result;
          }
          if (o instanceof String) {
              final byte[] bytes = ((String) o).getBytes(StandardCharsets.UTF_8);
              final byte[] result = Arrays.copyOf(bytes, bytes.length + 1);
              result[result.length - 1] = 0;
              return result;
          }
          if (!(o instanceof String[])) {
              throw new ImagingException("Unknown data type: " + o);
          }
          final String[] strings = (String[]) o;
          int totalLength = 0;
          for (final String string : strings) {
              final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
              totalLength += bytes.length + 1;
          }
          final byte[] result = Allocator.byteArray(totalLength);
          int position = 0;
          for (final String string : strings) {
              final byte[] bytes = string.getBytes(StandardCharsets.UTF_8);
              System.arraycopy(bytes, 0, result, position, bytes.length);
              position += bytes.length + 1;
          }
          return result;
      }
 
 }