content: /*
   * Created on Feb 9, 2008
   *
   * 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.
   *
   * Copyright @2008-2013 the original author or authors.
   */
  package org.fest.assertions.internal;
  
  import static java.lang.String.format;
  
  import static org.fest.util.Closeables.closeQuietly;
  import static org.fest.util.Objects.areEqual;
  import static org.fest.util.Strings.quote;
  
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.LineNumberReader;
  import java.nio.charset.Charset;
  
  /**
   * Compares the contents of two files.
   *
   * @author David DIDIER
   * @author Alex Ruiz
   * @author Yvonne Wang
   */
  class FileContentComparator {
    private static final String EOF = "EOF";
  
    FileDiffs compareContents(File actual, File expected, Charset charset) throws IOException {
      LineNumberReader readerForActual = null;
      LineNumberReader readerForExpected = null;
      try {
        readerForActual = readerFor(actual, charset);
        readerForExpected = readerFor(expected, charset);
        return compare(readerForActual, readerForExpected);
      } finally {
        closeQuietly(readerForActual);
        closeQuietly(readerForExpected);
      }
    }
  
    private LineNumberReader readerFor(File file, Charset charset) throws IOException {
      FileInputStream in = new FileInputStream(file);
      return new LineNumberReader(new BufferedReader(new InputStreamReader(in, charset)));
    }
  
    private FileDiffs compare(LineNumberReader readerOfActual, LineNumberReader readerOfExpected) throws IOException {
      FileDiffs diffs = new FileDiffs();
      while (readerOfActual.ready() && readerOfExpected.ready()) {
        int lineNumber = readerOfActual.getLineNumber();
        String lineInExpected = readerOfExpected.readLine();
        String lineInActual = readerOfActual.readLine();
        if (!areEqual(lineInExpected, lineInActual)) {
          diffs.add(diff(lineNumber, quote(lineInExpected), quote(lineInActual)));
        }
      }
      if (!readerOfActual.ready() && readerOfExpected.ready()) {
        int lineNumber = readerOfExpected.getLineNumber();
        String lineInExpected = readerOfExpected.readLine();
        diffs.add(diff(lineNumber, quote(lineInExpected), EOF));
      }
      if (readerOfActual.ready() && !readerOfExpected.ready()) {
        int lineNumber = readerOfActual.getLineNumber();
        String lineInActual = readerOfActual.readLine();
        diffs.add(diff(lineNumber, EOF, quote(lineInActual)));
      }
      return diffs;
    }
  
    private String diff(int lineNumber, String expected, String actual) {
      return format("line:<%d>, expected:<%s> but was:<%s>", lineNumber, expected, actual);
    }
  }
  