/*
    * The MIT License (MIT)
    *
    * Copyright (c) 2013 - 2023, Tapio Rautonen
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy
    * of this software and associated documentation files (the "Software"), to deal
    * in the Software without restriction, including without limitation the rights
    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  package org.eluder.coveralls.maven.plugin.source;
  
  import org.apache.commons.io.IOUtils;
  import org.eluder.coveralls.maven.plugin.domain.Source;
  import org.eluder.coveralls.maven.plugin.util.Sha521DigestInputStream;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.net.URI;
  import java.nio.charset.Charset;
  import java.security.NoSuchAlgorithmException;
  
  public abstract class AbstractSourceLoader implements SourceLoader {
  
      private final Charset sourceEncoding;
      private final String directoryPrefix;
  
      protected AbstractSourceLoader(final URI base, final URI sourceBase, final String sourceEncoding) {
          this.sourceEncoding = Charset.forName(sourceEncoding);
          this.directoryPrefix = base.relativize(sourceBase).toString();
      }
  
      @Override
      public Source load(final String sourceFile) throws IOException {
          InputStream stream = locate(sourceFile);
          if (stream != null) {
              try (Sha521DigestInputStream ds = new Sha521DigestInputStream(stream);
                      InputStreamReader reader = new InputStreamReader(ds, getSourceEncoding())) {
                  String source = IOUtils.toString(reader);
                  return new Source(getFileName(sourceFile), source, ds.getDigestHex());
              } catch (NoSuchAlgorithmException ex) {
                  throw new IOException("Sha-512 algorithm not available", ex);
              }
          } else {
              return null;
          }
      }
  
      protected Charset getSourceEncoding() {
          return sourceEncoding;
      }
  
      protected String getFileName(final String sourceFile) {
          return directoryPrefix + sourceFile;
      }
  
      protected abstract InputStream locate(String sourceFile) throws IOException;
  }