/*
    *    Copyright 2009-2023 the original author or 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
    *
    *       https://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 org.apache.ibatis.io;
  
  import java.io.IOException;
  import java.lang.reflect.Method;
  
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  /**
   * Unit test for VFS getInstance method in multi-thread environment
   *
   * @author jasonleaster
   */
  class VFSTest {
  
    @Test
    void getInstanceShouldNotBeNull() {
      VFS vsf = VFS.getInstance();
      Assertions.assertNotNull(vsf);
    }
  
    @Test
    void getInstanceShouldNotBeNullInMultiThreadEnv() throws InterruptedException {
      final int threadCount = 3;
  
      Thread[] threads = new Thread[threadCount];
      InstanceGetterProcedure[] procedures = new InstanceGetterProcedure[threadCount];
  
      for (int i = 0; i < threads.length; i++) {
        String threadName = "Thread##" + i;
  
        procedures[i] = new InstanceGetterProcedure();
        threads[i] = new Thread(procedures[i], threadName);
      }
  
      for (Thread thread : threads) {
        thread.start();
      }
  
      for (Thread thread : threads) {
        thread.join();
      }
  
      // All caller got must be the same instance
      for (int i = 0; i < threadCount - 1; i++) {
        Assertions.assertEquals(procedures[i].instanceGot, procedures[i + 1].instanceGot);
      }
    }
  
    @Test
    void getExistMethod() {
      Method method = VFS.getMethod(VFS.class, "list", String.class);
      Assertions.assertNotNull(method);
    }
  
    @Test
    void getNotExistMethod() {
      Method method = VFS.getMethod(VFS.class, "listXxx", String.class);
      Assertions.assertNull(method);
    }
  
    @Test
    void invoke() throws IOException, NoSuchMethodException {
      VFS vfs = VFS.invoke(VFS.class.getMethod("getInstance"), VFS.class);
      Assertions.assertEquals(vfs, VFS.getInstance());
  
      Assertions.assertThrows(RuntimeException.class, () -> {
        // java.lang.IllegalArgumentException: wrong number of arguments
        VFS.invoke(VFS.class.getMethod("getInstance"), VFS.class, "unnecessaryArgument");
      });
  
      Assertions.assertThrows(IOException.class, () -> {
        // InvocationTargetException.getTargetException -> IOException
        VFS.invoke(Resources.class.getMethod("getResourceAsProperties", String.class), Resources.class,
            "invalidResource");
      });
  
      Assertions.assertThrows(RuntimeException.class, () -> {
        // Other InvocationTargetException
        VFS.invoke(Integer.class.getMethod("valueOf", String.class), Resources.class, "InvalidIntegerNumber");
      });
  
    }
  
   private static class InstanceGetterProcedure implements Runnable {
 
     volatile VFS instanceGot;
 
     @Override
     public void run() {
       instanceGot = VFS.getInstance();
     }
   }
 }