package org.codehaus.plexus.util.io;
   
   /*
    * Copyright The Codehaus Foundation.
    *
    * 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.
   */
  
  import java.io.IOException;
  import java.io.Writer;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.nio.file.attribute.FileTime;
  import java.util.Objects;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  public class CachingWriterTest {
  
      Path tempDir;
      Path checkLastModified;
  
      @BeforeEach
      public void setup() throws IOException {
          Path dir = Paths.get("target/io");
          Files.createDirectories(dir);
          tempDir = Files.createTempDirectory(dir, "temp-");
          checkLastModified = tempDir.resolve(".check");
      }
  
      private void waitLastModified() throws IOException, InterruptedException {
          Files.newOutputStream(checkLastModified).close();
          FileTime lm = Files.getLastModifiedTime(checkLastModified);
          while (true) {
              Files.newOutputStream(checkLastModified).close();
              FileTime nlm = Files.getLastModifiedTime(checkLastModified);
              if (!Objects.equals(nlm, lm)) {
                  break;
              }
              Thread.sleep(10);
          }
      }
  
      @Test
      public void testNoOverwriteWithFlush() throws IOException, InterruptedException {
          String data = "Hello world!";
          Path path = tempDir.resolve("file-bigger.txt");
          assertFalse(Files.exists(path));
  
          try (Writer w = Files.newBufferedWriter(path, StandardCharsets.UTF_8)) {
              for (int i = 0; i < 10; i++) {
                  w.write(data);
              }
          }
          FileTime modified = Files.getLastModifiedTime(path);
  
          waitLastModified();
  
          try (Writer w = new CachingWriter(path, StandardCharsets.UTF_8)) {
              for (int i = 0; i < 10; i++) {
                  w.write(data);
                  w.flush();
              }
          }
          FileTime newModified = Files.getLastModifiedTime(path);
          assertEquals(modified, newModified);
      }
  
      @Test
      public void testWriteNoExistingFile() throws IOException, InterruptedException {
          String data = "Hello world!";
          Path path = tempDir.resolve("file.txt");
          assertFalse(Files.exists(path));
  
          try (CachingWriter cos = new CachingWriter(path, StandardCharsets.UTF_8, 4)) {
              cos.write(data);
          }
          assertTrue(Files.exists(path));
          String read = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
          assertEquals(data, read);
          FileTime modified = Files.getLastModifiedTime(path);
 
         waitLastModified();
 
         try (CachingWriter cos = new CachingWriter(path, StandardCharsets.UTF_8, 4)) {
             cos.write(data);
         }
         assertTrue(Files.exists(path));
         read = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
         assertEquals(data, read);
         FileTime newModified = Files.getLastModifiedTime(path);
         assertEquals(modified, newModified);
         modified = newModified;
 
         waitLastModified();
 
         // write longer data
         data = "Good morning!";
         try (CachingWriter cos = new CachingWriter(path, StandardCharsets.UTF_8, 4)) {
             cos.write(data);
         }
         assertTrue(Files.exists(path));
         read = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
         assertEquals(data, read);
         newModified = Files.getLastModifiedTime(path);
         assertNotEquals(modified, newModified);
         modified = newModified;
 
         waitLastModified();
 
         // different data same size
         data = "Good mornong!";
         try (CachingWriter cos = new CachingWriter(path, StandardCharsets.UTF_8, 4)) {
             cos.write(data);
         }
         assertTrue(Files.exists(path));
         read = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
         assertEquals(data, read);
         newModified = Files.getLastModifiedTime(path);
         assertNotEquals(modified, newModified);
         modified = newModified;
 
         waitLastModified();
 
         // same data but shorter
         data = "Good mornon";
         try (CachingWriter cos = new CachingWriter(path, StandardCharsets.UTF_8, 4)) {
             cos.write(data);
         }
         assertTrue(Files.exists(path));
         read = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
         assertEquals(data, read);
         newModified = Files.getLastModifiedTime(path);
         assertNotEquals(modified, newModified);
         modified = newModified;
     }
 }