content: /*
   * Copyright 1999-2023 Alibaba Group Holding Ltd.
   *
   * 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.alibaba.nacos.sys.file;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.common.utils.ByteUtils;
  import com.alibaba.nacos.common.utils.ConcurrentHashSet;
  import com.alibaba.nacos.common.utils.StringUtils;
  import com.alibaba.nacos.common.utils.ThreadUtils;
  import com.alibaba.nacos.sys.utils.DiskUtils;
  import org.junit.jupiter.api.AfterAll;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.Test;
  import org.springframework.test.util.ReflectionTestUtils;
  
  import java.io.File;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Paths;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.Executor;
  import java.util.concurrent.Executors;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.function.Consumer;
  
  import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.mockito.ArgumentMatchers.any;
  import static org.mockito.ArgumentMatchers.anyString;
  import static org.mockito.Mockito.atLeastOnce;
  import static org.mockito.Mockito.doNothing;
  import static org.mockito.Mockito.doThrow;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.verify;
  import static org.mockito.Mockito.when;
  
  class WatchFileCenterTest {
      
      private static final String PATH = Paths.get(System.getProperty("user.home"), "/watch_file_change_test").toString();
      
      private static final Executor EXECUTOR = Executors.newFixedThreadPool(32);
      
      final Object monitor = new Object();
      
      @BeforeAll
      static void beforeCls() throws Exception {
          DiskUtils.deleteDirThenMkdir(PATH);
      }
      
      @AfterAll
      static void afterCls() throws Exception {
          DiskUtils.deleteDirectory(PATH);
      }
      
      @AfterEach
      void afterEach() throws Exception {
          WatchFileCenter.deregisterAllWatcher(PATH);
      }
      
      // The last file change must be notified
      
      @Test
      void testHighConcurrencyModify() throws Exception {
          AtomicInteger count = new AtomicInteger(0);
          Set<String> set = new ConcurrentHashSet<>();
          
          final String fileName = "test2_file_change";
          final File file = Paths.get(PATH, fileName).toFile();
          
          func(fileName, file, content -> {
              set.add(content);
              count.incrementAndGet();
          });
          
          ThreadUtils.sleep(5_000L);
      }
      
      @Test
      void testModifyFileMuch() throws Exception {
          final String fileName = "modify_file_much";
          final File file = Paths.get(PATH, fileName).toFile();
          DiskUtils.writeFile(file, ByteUtils.toBytes("start_test"), false);
          
          CountDownLatch latch = new CountDownLatch(3);
          AtomicInteger count = new AtomicInteger(0);
          
          WatchFileCenter.registerWatcher(PATH, new FileWatcher() {
              @Override
              public void onChange(FileChangeEvent event) {
                  try {
                      System.out.println(event);
                      System.out.println(DiskUtils.readFile(file));
                      count.incrementAndGet();
                  } finally {
                      latch.countDown();
                  }
              }
              
              @Override
              public boolean interest(String context) {
                  return StringUtils.contains(context, fileName);
              }
          });
          ThreadUtils.sleep(1000L);
          for (int i = 0; i < 3; i++) {
              DiskUtils.writeFile(file, ByteUtils.toBytes(("test_modify_file_" + i)), false);
              ThreadUtils.sleep(10_000L);
          }
          latch.await(10_000L, TimeUnit.MILLISECONDS);
          
          assertTrue(count.get() >= 3);
      }
      
      @Test
      void testMultiFileModify() throws Exception {
          CountDownLatch latch = new CountDownLatch(10);
          for (int i = 0; i < 10; i++) {
              AtomicInteger count = new AtomicInteger(0);
              Set<String> set = new ConcurrentHashSet<>();
              
              final String fileName = "test2_file_change_" + i;
              final File file = Paths.get(PATH, fileName).toFile();
              
              EXECUTOR.execute(() -> {
                  try {
                      func(fileName, file, content -> {
                          set.add(content);
                          count.incrementAndGet();
                      });
                  } catch (Throwable ex) {
                      ex.printStackTrace();
                  } finally {
                      latch.countDown();
                  }
              });
          }
          latch.await(10_000L, TimeUnit.MILLISECONDS);
          
          ThreadUtils.sleep(5_000L);
      }
      
      @Test
      void testRegisterNewPathWithException() {
          URL url = getClass().getClassLoader().getResource("application.properties");
          String path = url.getPath();
          assertThrows(IllegalArgumentException.class, () -> WatchFileCenter.registerWatcher(path, new FileWatcher() {
              @Override
              public void onChange(FileChangeEvent event) {
              
              }
              
              @Override
              public boolean interest(String context) {
                  return false;
              }
          }));
      }
      
      @Test
      void testDeregisterWatcher() throws NacosException {
          FileWatcher watcher = new FileWatcher() {
              @Override
              public void onChange(FileChangeEvent event) {
              
              }
              
              @Override
              public boolean interest(String context) {
                  return false;
              }
          };
          assertFalse(WatchFileCenter.deregisterWatcher(PATH, watcher));
          WatchFileCenter.registerWatcher(PATH, watcher);
          assertTrue(WatchFileCenter.deregisterWatcher(PATH, watcher));
      }
      
      @Test
      void testRegisterWatcherAfterShutDown() {
          try {
              FileWatcher fileWatcher = mock(FileWatcher.class);
              assertDoesNotThrow(() -> WatchFileCenter.registerWatcher(PATH, fileWatcher));
              WatchFileCenter.shutdown();
              assertThrows(IllegalStateException.class, () -> WatchFileCenter.registerWatcher(PATH, fileWatcher));
          } finally {
              ((AtomicBoolean) ReflectionTestUtils.getField(WatchFileCenter.class, "CLOSED")).set(false);
          }
      }
      
      @Test
      void testCallBackWatcherWithException() throws NacosException {
          FileWatcher fileWatcher = mock(FileWatcher.class);
          when(fileWatcher.interest(anyString())).thenReturn(true);
          doThrow(new RuntimeException("test")).when(fileWatcher).onChange(any(FileChangeEvent.class));
          WatchFileCenter.registerWatcher(PATH, fileWatcher);
          FileWatcher fileWatcher2 = mock(FileWatcher.class);
          when(fileWatcher2.interest(anyString())).thenReturn(true);
          WatchFileCenter.registerWatcher(PATH, fileWatcher2);
          ThreadUtils.sleep(1000L);
          final String fileName = "modify_file_for_exception";
          final File file = Paths.get(PATH, fileName).toFile();
          DiskUtils.writeFile(file, ByteUtils.toBytes("start_test"), false);
          ThreadUtils.sleep(10_000L);
          verify(fileWatcher2, atLeastOnce()).onChange(any(FileChangeEvent.class));
      }
      
      @Test
      void testCallBackWatcherByExecutor() throws NacosException {
          FileWatcher fileWatcher = mock(FileWatcher.class);
          when(fileWatcher.interest(anyString())).thenReturn(true);
          Executor executor = mock(Executor.class);
          doNothing().when(executor).execute(any(Runnable.class));
          when(fileWatcher.executor()).thenReturn(executor);
          WatchFileCenter.registerWatcher(PATH, fileWatcher);
          ThreadUtils.sleep(1000L);
          final String fileName = "modify_file_for_executor";
          final File file = Paths.get(PATH, fileName).toFile();
          DiskUtils.writeFile(file, ByteUtils.toBytes("start_test"), false);
          ThreadUtils.sleep(10_000L);
          verify(executor, atLeastOnce()).execute(any(Runnable.class));
      }
      
      @Test
      void testOverFlowEvent()
              throws NoSuchMethodException, URISyntaxException, NacosException, InvocationTargetException, IllegalAccessException {
          File file = new File(getClass().getClassLoader().getResource("test-file-watcher-overflow/test.properties").toURI());
          final String path = file.getParentFile().getAbsolutePath();
          AtomicBoolean containAssert = new AtomicBoolean(false);
          WatchFileCenter.registerWatcher(path, new FileWatcher() {
              @Override
              public void onChange(FileChangeEvent event) {
                  try {
                      assertEquals("test.properties", event.getContext());
                      assertEquals(path, event.getPaths());
                  } catch (AssertionError e) {
                      System.out.println(e.getMessage());
                      containAssert.set(true);
                  }
              }
              
              @Override
              public boolean interest(String context) {
                  return true;
              }
          });
          Map<String, WatchFileCenter.WatchDirJob> map = (Map<String, WatchFileCenter.WatchDirJob>) ReflectionTestUtils.getField(
                  WatchFileCenter.class, "MANAGER");
          WatchFileCenter.WatchDirJob job = map.get(path);
          Method method = WatchFileCenter.WatchDirJob.class.getDeclaredMethod("eventOverflow");
          method.setAccessible(true);
          method.invoke(job);
          assertFalse(containAssert.get());
      }
      
      private void func(final String fileName, final File file, final Consumer<String> consumer) throws Exception {
          CountDownLatch latch = new CountDownLatch(100);
          DiskUtils.touch(file);
          WatchFileCenter.registerWatcher(PATH, new FileWatcher() {
              @Override
              public void onChange(FileChangeEvent event) {
                  final File file = Paths.get(PATH, fileName).toFile();
                  final String content = DiskUtils.readFile(file);
                  consumer.accept(content);
              }
              
              @Override
              public boolean interest(String context) {
                  return StringUtils.contains(context, fileName);
              }
          });
          
          final AtomicInteger id = new AtomicInteger(0);
          final AtomicReference<String> finalContent = new AtomicReference<>(null);
          for (int i = 0; i < 100; i++) {
              EXECUTOR.execute(() -> {
                  final String j = fileName + "_" + id.incrementAndGet();
                  try {
                      final File file1 = Paths.get(PATH, fileName).toFile();
                      synchronized (monitor) {
                          finalContent.set(j);
                          DiskUtils.writeFile(file1, j.getBytes(StandardCharsets.UTF_8), false);
                      }
                  } finally {
                      latch.countDown();
                  }
              });
          }
      }
      
  }