/*
 * Copyright 2019 The Closure Compiler Authors.
 *
 * 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.
 */

package com.google.javascript.jscomp.diagnostic;

import com.google.errorprone.annotations.FormatMethod;
import com.google.errorprone.annotations.FormatString;
import com.google.errorprone.annotations.MustBeClosed;
import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.function.Supplier;

/**
 * An implementation that adapts a {@link BufferedWriter} and writes to a real file.
 *
 * <p>This class is designed to be super-sourceable by J2CL, since JS environments often don't have
 * file APIs. Doing so enables logging statements to be checked-in.
 */
final class WritingLogFile extends LogFile {

  @MustBeClosed
  static LogFile create(Path file) {
    try {
      Path dir = file.getParent();
      Files.createDirectories(dir);
      return new WritingLogFile(Files.newBufferedWriter(file));
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  private final BufferedWriter writer;

  private WritingLogFile(BufferedWriter writer) {
    this.writer = writer;
  }

  @Override
  public LogFile log(Object value) {
    return logInternal(value.toString());
  }

  @Override
  public LogFile log(String value) {
    return logInternal(value);
  }

  @Override
  public LogFile log(Supplier<String> value) {
    return logInternal(value.get());
  }

  @Override
  @FormatMethod
  public LogFile log(@FormatString String template, Object... values) {
    return logInternal(String.format(template, values));
  }

  private LogFile logInternal(String value) {
    try {
      // It's fine to pass a fully rendered string because we know we're going to use it by the
      // time this method is called.
      writer.append(value).append('\n');
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
    return this;
  }

  @Override
  public void close() {
    try {
      writer.close();
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }
}

@@ -936,16 +936,57 @@
 e.Path;%0A
+import java.nio.file.StandardOpenOption;%0A
 import j
@@ -1490,16 +1490,27 @@
 LogFile(
+%0A          
 Files.ne
@@ -1525,20 +1525,157 @@
 dWriter(
-file
+%0A              file,%0A              StandardOpenOption.CREATE,%0A              StandardOpenOption.APPEND,%0A              StandardOpenOption.WRITE
 ));%0A    

Correct `WritingLogFile` to append to files rather than overwrite them.