/*
    * 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.beanutils2;
  
  import java.beans.IntrospectionException;
  import java.beans.PropertyDescriptor;
  import java.lang.ref.Reference;
  import java.lang.ref.SoftReference;
  import java.lang.ref.WeakReference;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.util.Objects;
  
  /**
   * A MappedPropertyDescriptor describes one mapped property. Mapped properties are multivalued properties like indexed properties but that are accessed with a
   * String key instead of an index. Such property values are typically stored in a Map collection. For this class to work properly, a mapped value must have
   * getter and setter methods of the form
   * <p>
   * {@code get<strong>Property</strong>(String key)} and
   * <p>
   * {@code set<strong>Property</strong>(String key, Object value)},
   * <p>
   * where {@code <strong>Property</strong>} must be replaced by the name of the property.
   *
   * @see java.beans.PropertyDescriptor
   */
  public class MappedPropertyDescriptor extends PropertyDescriptor {
  
      /**
       * Holds a {@link Method} in a {@link SoftReference} so that it it doesn't prevent any ClassLoader being garbage collected, but tries to re-create the
       * method if the method reference has been released.
       *
       * See https://issues.apache.org/jira/browse/BEANUTILS-291
       */
      private static final class MappedMethodReference {
          private String className;
          private String methodName;
          private Reference<Method> methodRef;
          private Reference<Class<?>> classRef;
          private Reference<Class<?>> writeParamTypeRef0;
          private Reference<Class<?>> writeParamTypeRef1;
          private String[] writeParamClassNames;
  
          MappedMethodReference(final Method m) {
              if (m != null) {
                  className = m.getDeclaringClass().getName();
                  methodName = m.getName();
                  methodRef = new SoftReference<>(m);
                  classRef = new WeakReference<>(m.getDeclaringClass());
                  final Class<?>[] types = m.getParameterTypes();
                  if (types.length == 2) {
                      writeParamTypeRef0 = new WeakReference<>(types[0]);
                      writeParamTypeRef1 = new WeakReference<>(types[1]);
                      writeParamClassNames = new String[2];
                      writeParamClassNames[0] = types[0].getName();
                      writeParamClassNames[1] = types[1].getName();
                  }
              }
          }
  
          private Method get() {
              if (methodRef == null) {
                  return null;
              }
              Method m = methodRef.get();
              if (m == null) {
                  Class<?> clazz = classRef.get();
                  if (clazz == null) {
                      clazz = reLoadClass();
                      if (clazz != null) {
                          classRef = new WeakReference<>(clazz);
                      }
                  }
                  Objects.requireNonNull(clazz, () -> "Method " + methodName + " for " + className + " could not be reconstructed - class reference has gone");
                  Class<?>[] paramTypes = null;
                  if (writeParamClassNames != null) {
                      paramTypes = new Class[2];
                      paramTypes[0] = writeParamTypeRef0.get();
                      if (paramTypes[0] == null) {
                          paramTypes[0] = reLoadClass(writeParamClassNames[0]);
                          if (paramTypes[0] != null) {
                              writeParamTypeRef0 = new WeakReference<>(paramTypes[0]);
                          }
                      }
                     paramTypes[1] = writeParamTypeRef1.get();
                     if (paramTypes[1] == null) {
                         paramTypes[1] = reLoadClass(writeParamClassNames[1]);
                         if (paramTypes[1] != null) {
                             writeParamTypeRef1 = new WeakReference<>(paramTypes[1]);
                         }
                     }
                 } else {
                     paramTypes = STRING_CLASS_PARAMETER;
                 }
                 try {
                     m = clazz.getMethod(methodName, paramTypes);
                     // Un-comment following line for testing
                     // System.out.println("Recreated Method " + methodName + " for " + className);
                 } catch (final NoSuchMethodException e) {
                     throw new IllegalStateException("Method " + methodName + " for " + className + " could not be reconstructed - method not found");
                 }
                 methodRef = new SoftReference<>(m);
             }
             return m;
         }
 
         /**
          * Try to re-load the class
          */
         private Class<?> reLoadClass() {
             return reLoadClass(className);
         }
 
         /**
          * Try to re-load the class
          */
         private Class<?> reLoadClass(final String name) {
 
             ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
 
             // Try the context class loader
             if (classLoader != null) {
                 try {
                     return classLoader.loadClass(name);
                 } catch (final ClassNotFoundException e) {
                     // ignore
                 }
             }
 
             // Try this class's class loader
             classLoader = MappedPropertyDescriptor.class.getClassLoader();
             try {
                 return classLoader.loadClass(name);
             } catch (final ClassNotFoundException e) {
                 return null;
             }
         }
     }
 
     /**
      * The parameter types array for the reader method signature.
      */
     private static final Class<?>[] STRING_CLASS_PARAMETER = new Class[] { String.class };
 
     /**
      * Gets a capitalized version of the specified property name.
      *
      * @param s The property name
      */
     private static String capitalizePropertyName(final String s) {
         if (s.isEmpty()) {
             return s;
         }
 
         final char[] chars = s.toCharArray();
         chars[0] = Character.toUpperCase(chars[0]);
         return new String(chars);
     }
 
     /**
      * Find a method on a class with a specified parameter list.
      */
     private static Method getMethod(final Class<?> clazz, final String methodName, final Class<?>[] parameterTypes) throws IntrospectionException {
         if (methodName == null) {
             return null;
         }
 
         final Method method = MethodUtils.getMatchingAccessibleMethod(clazz, methodName, parameterTypes);
         if (method != null) {
             return method;
         }
 
         final int parameterCount = parameterTypes == null ? 0 : parameterTypes.length;
 
         // No Method found
         throw new IntrospectionException("No method \"" + methodName + "\" with " + parameterCount + " parameter(s) of matching types.");
     }
 
     /**
      * Find a method on a class with a specified number of parameters.
      */
     private static Method getMethod(final Class<?> clazz, final String methodName, final int parameterCount) throws IntrospectionException {
         if (methodName == null) {
             return null;
         }
 
         final Method method = internalGetMethod(clazz, methodName, parameterCount);
         if (method != null) {
             return method;
         }
 
         // No Method found
         throw new IntrospectionException("No method \"" + methodName + "\" with " + parameterCount + " parameter(s)");
     }
 
     /**
      * Find a method on a class with a specified number of parameters.
      */
     private static Method internalGetMethod(final Class<?> initial, final String methodName, final int parameterCount) {
         // For overridden methods we need to find the most derived version.
         // So we start with the given class and walk up the superclass chain.
         for (Class<?> clazz = initial; clazz != null; clazz = clazz.getSuperclass()) {
             final Method[] methods = clazz.getDeclaredMethods();
             for (final Method method : methods) {
                 if (method == null) {
                     continue;
                 }
                 // skip static methods.
                 final int mods = method.getModifiers();
                 if (!Modifier.isPublic(mods) || Modifier.isStatic(mods)) {
                     continue;
                 }
                 if (method.getName().equals(methodName) && method.getParameterTypes().length == parameterCount) {
                     return method;
                 }
             }
         }
 
         // Now check any inherited interfaces. This is necessary both when
         // the argument class is itself an interface, and when the argument
         // class is an abstract class.
         final Class<?>[] interfaces = initial.getInterfaces();
         for (final Class<?> interface1 : interfaces) {
             final Method method = internalGetMethod(interface1, methodName, parameterCount);
             if (method != null) {
                 return method;
             }
         }
 
         return null;
     }
 
     /**
      * The underlying data type of the property we are describing.
      */
     private Reference<Class<?>> mappedPropertyTypeRef;
 
     /**
      * The reader method for this property (if any).
      */
     private MappedMethodReference mappedReadMethodRef;
 
     /**
      * The writer method for this property (if any).
      */
     private MappedMethodReference mappedWriteMethodRef;
 
     /**
      * Constructs a MappedPropertyDescriptor for a property that follows the standard Java convention by having getFoo and setFoo accessor methods, with the
      * addition of a String parameter (the key). Thus if the argument name is "fred", it will assume that the writer method is "setFred" and the reader method
      * is "getFred". Note that the property name should start with a lower case character, which will be capitalized in the method names.
      *
      * @param propertyName The programmatic name of the property.
      * @param beanClass    The Class object for the target bean. For example sun.beans.OurButton.class.
      * @throws IntrospectionException if an exception occurs during introspection.
      */
     public MappedPropertyDescriptor(final String propertyName, final Class<?> beanClass) throws IntrospectionException {
         super(propertyName, null, null);
 
         if (propertyName == null || propertyName.isEmpty()) {
             throw new IntrospectionException("bad property name: " + propertyName + " on class: " + beanClass.getClass().getName());
         }
 
         setName(propertyName);
         final String base = capitalizePropertyName(propertyName);
 
         // Look for mapped read method and matching write method
         Method mappedReadMethod = null;
         Method mappedWriteMethod = null;
         try {
             try {
                 mappedReadMethod = getMethod(beanClass, "get" + base, STRING_CLASS_PARAMETER);
             } catch (final IntrospectionException e) {
                 mappedReadMethod = getMethod(beanClass, "is" + base, STRING_CLASS_PARAMETER);
             }
             final Class<?>[] params = { String.class, mappedReadMethod.getReturnType() };
             mappedWriteMethod = getMethod(beanClass, "set" + base, params);
         } catch (final IntrospectionException e) {
             /*
              * Swallow IntrospectionException TODO: Why?
              */
         }
 
         // If there's no read method, then look for just a write method
         if (mappedReadMethod == null) {
             mappedWriteMethod = getMethod(beanClass, "set" + base, 2);
         }
 
         if (mappedReadMethod == null && mappedWriteMethod == null) {
             throw new IntrospectionException("Property '" + propertyName + "' not found on " + beanClass.getName());
         }
         mappedReadMethodRef = new MappedMethodReference(mappedReadMethod);
         mappedWriteMethodRef = new MappedMethodReference(mappedWriteMethod);
 
         findMappedPropertyType();
     }
 
     /**
      * This constructor takes the name of a mapped property, and method names for reading and writing the property.
      *
      * @param propertyName     The programmatic name of the property.
      * @param beanClass        The Class object for the target bean. For example sun.beans.OurButton.class.
      * @param mappedGetterName The name of the method used for reading one of the property values. May be null if the property is write-only.
      * @param mappedSetterName The name of the method used for writing one of the property values. May be null if the property is read-only.
      * @throws IntrospectionException if an exception occurs during introspection.
      */
     public MappedPropertyDescriptor(final String propertyName, final Class<?> beanClass, final String mappedGetterName, final String mappedSetterName)
             throws IntrospectionException {
         super(propertyName, null, null);
 
         if (propertyName == null || propertyName.isEmpty()) {
             throw new IntrospectionException("bad property name: " + propertyName);
         }
         setName(propertyName);
 
         // search the mapped get and set methods
         Method mappedReadMethod;
         Method mappedWriteMethod = null;
         mappedReadMethod = getMethod(beanClass, mappedGetterName, STRING_CLASS_PARAMETER);
 
         if (mappedReadMethod != null) {
             final Class<?>[] params = { String.class, mappedReadMethod.getReturnType() };
             mappedWriteMethod = getMethod(beanClass, mappedSetterName, params);
         } else {
             mappedWriteMethod = getMethod(beanClass, mappedSetterName, 2);
         }
         mappedReadMethodRef = new MappedMethodReference(mappedReadMethod);
         mappedWriteMethodRef = new MappedMethodReference(mappedWriteMethod);
 
         findMappedPropertyType();
     }
 
     /**
      * This constructor takes the name of a mapped property, and Method objects for reading and writing the property.
      *
      * @param propertyName The programmatic name of the property.
      * @param mappedGetter The method used for reading one of the property values. May be null if the property is write-only.
      * @param mappedSetter The method used for writing one the property values. May be null if the property is read-only.
      * @throws IntrospectionException if an exception occurs during introspection.
      */
     public MappedPropertyDescriptor(final String propertyName, final Method mappedGetter, final Method mappedSetter) throws IntrospectionException {
         super(propertyName, mappedGetter, mappedSetter);
 
         if (propertyName == null || propertyName.isEmpty()) {
             throw new IntrospectionException("bad property name: " + propertyName);
         }
 
         setName(propertyName);
         mappedReadMethodRef = new MappedMethodReference(mappedGetter);
         mappedWriteMethodRef = new MappedMethodReference(mappedSetter);
         findMappedPropertyType();
     }
 
     /**
      * Introspect our bean class to identify the corresponding getter and setter methods.
      */
     private void findMappedPropertyType() throws IntrospectionException {
         final Method mappedReadMethod = getMappedReadMethod();
         final Method mappedWriteMethod = getMappedWriteMethod();
         Class<?> mappedPropertyType = null;
         if (mappedReadMethod != null) {
             if (mappedReadMethod.getParameterTypes().length != 1) {
                 throw new IntrospectionException("bad mapped read method arg count");
             }
             mappedPropertyType = mappedReadMethod.getReturnType();
             if (mappedPropertyType == Void.TYPE) {
                 throw new IntrospectionException("mapped read method " + mappedReadMethod.getName() + " returns void");
             }
         }
 
         if (mappedWriteMethod != null) {
             final Class<?>[] params = mappedWriteMethod.getParameterTypes();
             if (params.length != 2) {
                 throw new IntrospectionException("bad mapped write method arg count");
             }
             if (mappedPropertyType != null && mappedPropertyType != params[1]) {
                 throw new IntrospectionException("type mismatch between mapped read and write methods");
             }
             mappedPropertyType = params[1];
         }
         mappedPropertyTypeRef = new SoftReference<>(mappedPropertyType);
     }
 
     /**
      * Gets the Class object for the property values.
      *
      * @return The Java type info for the property values. Note that the "Class" object may describe a built-in Java type such as "int". The result may be
      *         "null" if this is a mapped property that does not support non-keyed access.
      *         <p>
      *         This is the type that will be returned by the mappedReadMethod.
      */
     public Class<?> getMappedPropertyType() {
         return mappedPropertyTypeRef.get();
     }
 
     /**
      * Gets the method that should be used to read one of the property value.
      *
      * @return The method that should be used to read the property value. May return null if the property can't be read.
      */
     public Method getMappedReadMethod() {
         return mappedReadMethodRef.get();
     }
 
     /**
      * Gets the method that should be used to write one of the property value.
      *
      * @return The method that should be used to write one of the property value. May return null if the property can't be written.
      */
     public Method getMappedWriteMethod() {
         return mappedWriteMethodRef.get();
     }
 
     /**
      * Sets the method that should be used to read one of the property value.
      *
      * @param mappedGetter The mapped getter method.
      * @throws IntrospectionException If an error occurs finding the mapped property
      */
     public void setMappedReadMethod(final Method mappedGetter) throws IntrospectionException {
         mappedReadMethodRef = new MappedMethodReference(mappedGetter);
         findMappedPropertyType();
     }
 
     /**
      * Sets the method that should be used to write the property value.
      *
      * @param mappedSetter The mapped setter method.
      * @throws IntrospectionException If an error occurs finding the mapped property
      */
     public void setMappedWriteMethod(final Method mappedSetter) throws IntrospectionException {
         mappedWriteMethodRef = new MappedMethodReference(mappedSetter);
         findMappedPropertyType();
     }
 }