/*
    * SPDX-FileCopyrightText: Copyright (c) 2012-2025 Yegor Bugayenko
    * SPDX-License-Identifier: MIT
    */
   package com.jcabi.xml;
   
   import java.io.File;
   import java.io.IOException;
   import java.nio.file.Files;
  import javax.xml.transform.Source;
  import javax.xml.transform.TransformerException;
  import javax.xml.transform.stream.StreamSource;
  import lombok.EqualsAndHashCode;
  
  /**
   * Sources in file system.
   *
   * If you have some resources in files, just configure your
   * XSL with this "sources":
   *
   * <pre> XSL xsl = new XSLDocument(input).with(
   *   new FileSources("/tmp/my-resources")
   * );</pre>
   *
   * @since 0.18
   */
  @EqualsAndHashCode(of = "path")
  public final class FileSources implements Sources {
  
      /**
       * Directory.
       */
      private final transient File path;
  
      /**
       * Public ctor.
       */
      public FileSources() {
          this("");
      }
  
      /**
       * Public ctor.
       * @param dir Directory
       */
      public FileSources(final String dir) {
          this(new File(dir));
      }
  
      /**
       * Public ctor.
       * @param dir Directory
       */
      public FileSources(final File dir) {
          this.path = dir;
      }
  
      @Override
      public Source resolve(final String href, final String base)
          throws TransformerException {
          File file = new File(this.path, href);
          if (!file.exists()) {
              if (base == null) {
                  file = new File(href);
              } else {
                  file = new File(new File(base), href);
              }
              if (!file.exists()) {
                  throw new TransformerException(
                      String.format(
                          "File \"%s\" not found in \"%s\" and in base \"%s\"",
                          href, this.path, base
                      )
                  );
              }
          }
          try {
              return new StreamSource(Files.newInputStream(file.toPath()));
          } catch (final IOException ex) {
              throw new TransformerException(
                  String.format("Can't read from file '%s'", file),
                  ex
              );
          }
      }
  }