/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.commons.jexl3;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNotSame;
  import static org.junit.jupiter.api.Assertions.assertNull;
  import static org.junit.jupiter.api.Assertions.assertSame;
  
  import java.io.File;
  import java.lang.ref.Reference;
  import java.lang.ref.ReferenceQueue;
  import java.lang.ref.SoftReference;
  import java.lang.ref.WeakReference;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.commons.lang3.SystemProperties;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.Assumptions;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Basic check on automated class creation
   */
  @SuppressWarnings({"UnnecessaryBoxing", "AssertEqualsBetweenInconvertibleTypes"})
  class ClassCreatorTest extends JexlTestCase {
      public static class BigObject {
          @SuppressWarnings("unused")
          private final byte[] space = new byte[MEGA];
          private final int id;
  
          public BigObject(final int id) {
              this.id = id;
          }
  
          public int getId() {
              return id;
          }
      }
      // A weak reference on class
      static final class ClassReference extends WeakReference<Class<?>> {
          ClassReference(final Class<?> clazz, final ReferenceQueue<Object> queue) {
              super(clazz, queue);
          }
      }
      public static class ContextualCtor {
          int value = -1;
  
          public ContextualCtor(final JexlContext ctxt) {
              value = (Integer) ctxt.get("value");
          }
  
          public ContextualCtor(final JexlContext ctxt, final int v) {
              value = (Integer) ctxt.get("value") + v;
          }
  
          public int getValue() {
              return value;
          }
      }
      // A soft reference on instance
      static final class InstanceReference extends SoftReference<Object> {
          InstanceReference(final Object obj, final ReferenceQueue<Object> queue) {
              super(obj, queue);
          }
      }
  
      public static class NsTest implements JexlContext.NamespaceFunctor {
          private final String className;
  
          public NsTest(final String cls) {
              className = cls;
          }
          @Override
          public Object createFunctor(final JexlContext context) {
              final JexlEngine jexl = JexlEngine.getThreadEngine();
              return jexl.newInstance(className, context);
          }
 
     }
 
     public static class TwoCtors {
         int value;
 
         public TwoCtors(final int v) {
             this.value = v;
         }
 
         public TwoCtors(final Number x) {
             this.value = -x.intValue();
         }
 
         public int getValue() {
             return value;
         }
     }
 
     static final Log logger = LogFactory.getLog(JexlTestCase.class);
 
     static final int LOOPS = 8;
 
     // A space hog class
     static final int MEGA = 1024 * 1024;
 
     private File base;
 
     private JexlEngine jexl;
 
     public ClassCreatorTest() {
         super("ClassCreatorTest");
     }
 
     private void deleteDirectory(final File dir) {
         if (dir.isDirectory()) {
             for (final File file : dir.listFiles()) {
                 if (file.isFile()) {
                     file.delete();
                 }
             }
         }
         dir.delete();
     }
 
     void functorTwo(final Object nstest) throws Exception {
         // create jexl2 with a 'test' namespace
         final Map<String, Object> ns = new HashMap<>();
         ns.put("test", nstest);
         final JexlEngine jexl2 = new JexlBuilder().namespaces(ns).create();
         final JexlContext ctxt = new MapContext();
         ctxt.set("value", 1000);
 
         // inject 'foo2' as test namespace functor class
         final ClassCreator cctor = new ClassCreator(jexl, base);
         cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 10;");
         Class<?> foo1 = cctor.createClass(true);
         assertSame(foo1.getClassLoader(), cctor.getClassLoader());
         assertEquals("foo2", foo1.getSimpleName());
         Object result = cctor.newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         jexl2.setClassLoader(cctor.getClassLoader());
         cctor.clear();
 
         // check the namespace functor behavior
         final JexlScript script = jexl2.createScript("test:getValue()");
         result = script.execute(ctxt, foo1.getName());
         assertEquals(1010, result);
 
         // change the body
         cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 99;");
         final Class<?> foo11 = cctor.createClass(true);
         assertEquals("foo2", foo1.getSimpleName());
         assertNotSame(foo11, foo1);
         foo1 = foo11;
         result = cctor .newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         // drum rolll....
         jexl2.setClassLoader(foo1.getClassLoader());
         result = script.execute(ctxt, foo1.getName());
         // tada!
         assertEquals(1099, result);
     }
 
     @BeforeEach
     @Override
     public void setUp() throws Exception {
         base = new File(SystemProperties.getJavaIoTmpdir(), "jexl" + System.currentTimeMillis());
         jexl = JEXL;
 
     }
 
     @AfterEach
     @Override
     public void tearDown() {
         deleteDirectory(base);
     }
 
     @Test
     void testBasicCtor() {
         final JexlScript s = jexl.createScript("(c, v)->{ var ct2 = new(c, v); ct2.value; }");
         Object r = s.execute(null, TwoCtors.class, 10);
         assertEquals(10, r);
         r = s.execute(null, TwoCtors.class, 5 + 5);
         assertEquals(10, r);
         r = s.execute(null, TwoCtors.class, 10d);
         assertEquals(-10, r);
         r = s.execute(null, TwoCtors.class, 100f);
         assertEquals(-100, r);
     }
 
     @Test
     void testContextualCtor() {
         final MapContext ctxt = new MapContext();
         ctxt.set("value", 42);
         JexlScript s = jexl.createScript("(c)->{ new(c).value }");
         Object r = s.execute(ctxt, ContextualCtor.class);
         assertEquals(42, r);
         s = jexl.createScript("(c, v)->{ new(c, v).value }");
         r = s.execute(ctxt, ContextualCtor.class, 100);
         assertEquals(142, r);
     }
 
     @Test
     void testFunctor2Class() throws Exception {
         functorTwo(new NsTest(ClassCreator.GEN_CLASS + "foo2"));
     }
 
     @Test
     void testFunctor2Name() throws Exception {
         functorTwo(ClassCreator.GEN_CLASS + "foo2");
     }
 
     @Test
     void testFunctorOne() throws Exception {
         final JexlContext ctxt = new MapContext();
         ctxt.set("value", 1000);
 
         // create a class foo1 with a ctor whose body gets a value
         // from the context to initialize its value
         final ClassCreator cctor = new ClassCreator(jexl, base);
         cctor.setSeed(1);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 10;");
         Class<?> foo1 = cctor.createClass(true);
         assertSame(foo1.getClassLoader(), cctor.getClassLoader());
         assertEquals("foo1", foo1.getSimpleName());
         Object result = cctor.newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         jexl.setClassLoader(cctor.getClassLoader());
         cctor.clear();
 
         // check we can invoke that ctor using its name or class
         final JexlScript script = jexl.createScript("(c)->{ new(c).value; }");
         result = script.execute(ctxt, foo1);
         assertEquals(1010, result);
         result = script.execute(ctxt, foo1.getName());
         assertEquals(1010, result);
 
         // re-create foo1 with a different body!
         cctor.setSeed(1);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 99;");
         final Class<?> foo11 = cctor.createClass(true);
         assertEquals("foo1", foo1.getSimpleName());
         assertNotSame(foo11, foo1);
         foo1 = foo11;
         result = cctor.newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         // drum rolll....
         jexl.setClassLoader(foo1.getClassLoader());
         result = script.execute(ctxt, foo1.getName());
         // tada!
         assertEquals(1099, result);
         result = script.execute(ctxt, foo1);
         assertEquals(1099, result);
     }
 
     @Test
     void testFunctorThree() throws Exception {
         final JexlContext ctxt = new MapContext();
         ctxt.set("value", 1000);
 
         final ClassCreator cctor = new ClassCreator(jexl, base);
         cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 10;");
         Class<?> foo1 = cctor.createClass(true);
         assertSame(foo1.getClassLoader(), cctor.getClassLoader());
         assertEquals("foo2", foo1.getSimpleName());
         Object result = cctor.newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         jexl.setClassLoader(cctor.getClassLoader());
         cctor.clear();
 
         final Map<String, Object> ns = new HashMap<>();
         ns.put("test", foo1);
         final JexlEngine jexl2 = new JexlBuilder().namespaces(ns).create();
 
         final JexlScript script = jexl2.createScript("test:getValue()");
         result = script.execute(ctxt, foo1.getName());
         assertEquals(1010, result);
 
         cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 99;");
         final Class<?> foo11 = cctor.createClass(true);
         assertEquals("foo2", foo1.getSimpleName());
         assertNotSame(foo11, foo1);
         foo1 = foo11;
         result = cctor.newInstance(foo1, ctxt);
         assertEquals(foo1, result.getClass());
         // drum rolll....
         jexl2.setClassLoader(foo1.getClassLoader());
         result = script.execute(ctxt, foo1.getName());
         // tada!
         assertEquals(1099, result);
     }
 
     @Test
     void testMany() throws Exception {
         // FIXME: java 28 has a new GC that seems to prevent classes from being GCed, so this test fails
         Assumptions.assumeTrue(featureVersion() < 28, "testMany is known to fail on Java 28+");
         // abort test if class creator cannot run
         if (!ClassCreator.canRun) {
             return;
         }
         int pass = 0;
         int gced = -1;
         final ReferenceQueue<Object> queue = new ReferenceQueue<>();
         final List<Reference<?>> stuff = new ArrayList<>();
         // keeping a reference on methods prevent classes from being GCed
 //        List<Object> mm = new ArrayList<Object>();
         final JexlExpression expr = jexl.createExpression("foo.value");
         final JexlExpression newx = jexl.createExpression("foo = new(clazz)");
         final JexlEvalContext context = new JexlEvalContext();
         final JexlOptions options = context.getEngineOptions();
         options.setStrict(false);
         options.setSilent(true);
 
         final ClassCreator cctor = new ClassCreator(jexl, base);
         for (int i = 0; i < LOOPS && gced < 0; ++i) {
             cctor.setSeed(i);
             Class<?> clazz;
             if (pass == 0) {
                 clazz = cctor.createClass();
             } else {
                 clazz = cctor.getClassInstance();
                 if (clazz == null) {
                     assertEquals(i, gced);
                     break;
                 }
             }
             // this code verifies the assumption that holding a strong reference to a method prevents
             // its owning class from being GCed
 //          Method m = clazz.getDeclaredMethod("getValue", new Class<?>[0]);
 //          mm.add(m);
             // we should not be able to create foox since it is unknown to the JEXL classloader
             context.set("clazz", cctor.getClassName());
             context.set("foo", null);
             Object z = newx.evaluate(context);
             assertNull(z);
             // check with the class itself
             context.set("clazz", clazz);
             z = newx.evaluate(context);
             assertNotNull(z, clazz + ": class " + i + " could not be instantiated on pass " + pass);
             assertEquals(Integer.valueOf(i), expr.evaluate(context));
             // with the proper class loader, attempt to create an instance from the class name
             jexl.setClassLoader(cctor.getClassLoader());
             z = newx.evaluate(context);
             assertEquals(z.getClass(), clazz);
             assertEquals(Integer.valueOf(i), expr.evaluate(context));
             cctor.clear();
             jexl.setClassLoader(null);
 
             // on pass 0, attempt to force GC to run and collect generated classes
             if (pass == 0) {
                 // add a weak reference on the class
                 stuff.add(new ClassReference(clazz, queue));
                 // add a soft reference on an instance
                 stuff.add(new InstanceReference(clazz.getConstructor().newInstance(), queue));
 
                 // attempt to force GC:
                 // while we still have a MB free, create & store big objects
                 for (int b = 0; b < 1024 && Runtime.getRuntime().freeMemory() > MEGA; ++b) {
                     final BigObject big = new BigObject(b);
                     stuff.add(new InstanceReference(big, queue));
                 }
                 // hint it...
                 System.gc();
                 // let's see if some weak refs got collected
                 boolean qr = false;
                 while (queue.poll() != null) {
                     final Reference<?> ref = queue.remove(1);
                     if (ref instanceof ClassReference) {
                         gced = i;
                         qr = true;
                     }
                 }
                 if (qr) {
                     //logger.warn("may have GCed class around " + i);
                     pass = 1;
                     i = 0;
                 }
             }
         }
 
         if (gced < 0) {
             logger.warn("unable to force GC");
             //assertTrue(gced > 0);
         }
     }
 
     @Test
     void testOne() throws Exception {
         // abort test if class creator cannot run
         if (!ClassCreator.canRun) {
             logger.warn("unable to create classes");
             return;
         }
         final ClassCreator cctor = new ClassCreator(jexl, base);
         cctor.setSeed(1);
         final Class<?> foo1 = cctor.createClass();
         assertEquals("foo1", foo1.getSimpleName());
         cctor.clear();
     }
     @Test
     void test432() throws Exception {
         final ClassCreator cctor = new ClassCreator(jexl, base);
         cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 10;");
         Class<?> foo1 = cctor.createClass(true);
         assertSame(foo1.getClassLoader(), cctor.getClassLoader());
         assertEquals("foo2", foo1.getSimpleName());
         final Map<String, Object> ns = new HashMap<>();
         ns.put("test", foo1.getName());
         // use cache
         final JexlEngine jexl2 = new JexlBuilder().namespaces(ns).cache(16).create();
         jexl2.setClassLoader(cctor.getClassLoader());
         cctor.clear();
         final JexlContext ctxt = new MapContext();
         ctxt.set("value", 1000);
         final JexlScript script = jexl2.createScript("test:getValue()");
         Object result = script.execute(ctxt);
         assertEquals(1010, result);        cctor.setSeed(2);
         cctor.setCtorBody("value = (Integer) ctxt.get(\"value\") + 99;");
         final Class<?> foo11 = cctor.createClass(true);
         assertEquals("foo2", foo1.getSimpleName());
         assertNotSame(foo11, foo1);
         foo1 = foo11;
         // drum rolll....
         jexl2.setClassLoader(foo1.getClassLoader());
         result = script.execute(ctxt);
         // tada!
         assertEquals(1099, result);
     }
 }