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    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2024 wcm.io
    * %%
    * 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.
   * #L%
   */
  package io.wcm.handler.mediasource.ngdm.impl;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.apache.commons.lang3.StringUtils;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  
  /**
   * Parses and validates Next Generation Dynamic Media references.
   * <p>
   * Example: <code>/urn:aaid:aem:12345678-abcd-abcd-abcd-abcd12345678/my-image.jpg</code>
   * </p>
   */
  public final class NextGenDynamicMediaReference {
  
    private static final Pattern REFERENCE_PATTERN = Pattern.compile("^/(urn:[^/]+)/([^/]+)$");
    private static final String ASSET_ID_PREFIX = "urn:";
  
    private final String assetId;
    private final String fileName;
  
    /**
     * @param assetId Asset ID (has to start with "urn:")
     * @param fileName File name
     */
    public NextGenDynamicMediaReference(@NotNull String assetId, @NotNull String fileName) {
      if (!StringUtils.startsWith(assetId, ASSET_ID_PREFIX)) {
        throw new IllegalArgumentException("Asset ID must start with '" + ASSET_ID_PREFIX + "'");
      }
      this.assetId = assetId;
      this.fileName = fileName;
    }
  
    /**
     * @return Asset ID
     */
    public @NotNull String getAssetId() {
      return assetId;
    }
  
    /**
     * @return File name
     */
    public @NotNull String getFileName() {
      return fileName;
    }
  
    /**
     * @return Reference
     */
    public @NotNull String toReference() {
      return "/" + assetId + "/" + fileName;
    }
  
    /**
     * Parses a next generation dynamic media reference.
     * @param reference Reference
     * @return Parsed reference or null if reference is invalid
     */
    public static @Nullable NextGenDynamicMediaReference fromReference(@Nullable String reference) {
      if (reference == null) {
        return null;
      }
      Matcher matcher = REFERENCE_PATTERN.matcher(reference);
      if (!matcher.matches()) {
        return null;
      }
      String assetId = matcher.group(1);
      String fileName = matcher.group(2);
      return new NextGenDynamicMediaReference(assetId, fileName);
    }
  
    /**
     * Checks if given string is a valid next generation dynamic media reference.
     * @param reference Reference
     * @return true if reference is valid
     */
    public static boolean isReference(@Nullable String reference) {
     return reference != null && REFERENCE_PATTERN.matcher(reference).matches();
   }
 
   @Override
   public String toString() {
     return toReference();
   }
 
 }