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.extensions.tabular.pdf.factory.internal;
  
  import org.apache.pdfbox.pdmodel.PDDocument;
  import org.apache.pdfbox.pdmodel.PDPage;
  import org.apache.pdfbox.pdmodel.common.PDRectangle;
  
  import lombok.Getter;
  
  final class PageProvider {
  
      @Getter private final PDDocument document;
      private final PDRectangle size;
      private int currentPageIndex = -1;
  
      PageProvider(final PDDocument document, final PDRectangle size) {
          this.document = document;
          this.size = size;
      }
  
      public PDPage createPage() {
          currentPageIndex = document.getNumberOfPages();
          return getCurrentPage();
      }
  
      public PDPage nextPage() {
          if (currentPageIndex == -1) {
              currentPageIndex = document.getNumberOfPages();
          } else {
              currentPageIndex++;
          }
          return getCurrentPage();
      }
  
      public PDPage previousPage() {
          currentPageIndex--;
          if (currentPageIndex < 0) {
              currentPageIndex = 0;
          }
          return getCurrentPage();
      }
  
      private PDPage getCurrentPage() {
          if (currentPageIndex >= document.getNumberOfPages()) {
              final PDPage newPage = new PDPage(size);
              document.addPage(newPage);
              return newPage;
          }
          return document.getPage(currentPageIndex);
      }
  
  }
  