/*
    * 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
    *
    *      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 org.apache.commons.jexl3.internal.introspection;
  
  import java.beans.IntrospectionException;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  
  import org.apache.commons.jexl3.JexlException;
  import org.apache.commons.jexl3.introspection.JexlMethod;
  
  /**
   * A JexlMethod that wraps a constructor.
   */
  public final class ConstructorMethod implements JexlMethod {
      /**
       * Discovers a class constructor and wrap it as a JexlMethod.
       * @param is the introspector
       * @param ctorHandle a class or class name
       * @param args constructor arguments
       * @return a {@link JexlMethod}
       */
      public static ConstructorMethod discover(final Introspector is, final Object ctorHandle, final Object... args) {
          String className;
          Class<?> clazz = null;
          if (ctorHandle instanceof Class<?>) {
              clazz = (Class<?>) ctorHandle;
              className = clazz.getName();
          } else if (ctorHandle != null) {
              className = ctorHandle.toString();
          } else {
              return null;
          }
          final Constructor<?> ctor = is.getConstructor(clazz, new MethodKey(className, args));
          if (ctor != null) {
              return new ConstructorMethod(ctor);
          }
          return null;
      }
  
      /** The wrapped constructor. */
      private final Constructor<?> ctor;
      /**
       * Creates a constructor method.
       * @param theCtor the constructor to wrap
       */
      ConstructorMethod(final Constructor<?> theCtor) {
          this.ctor = theCtor;
      }
  
      @Override
      public Class<?> getReturnType() {
          return ctor.getDeclaringClass();
      }
  
      @Override
      public Object invoke(final Object obj, final Object... params) throws Exception {
          final Class<?> ctorClass = ctor.getDeclaringClass();
          boolean invoke = true;
          if (obj != null) {
              if (obj instanceof Class<?>) {
                  invoke = ctorClass.equals(obj);
              } else {
                  invoke = ctorClass.getName().equals(obj.toString());
              }
          }
          if (invoke) {
                  return ctor.newInstance(params);
              }
          throw new IntrospectionException("constructor resolution error");
      }
  
      @Override
      public boolean isCacheable() {
          return true;
      }
  
      @Override
      public boolean tryFailed(final Object rval) {
          return rval == Uberspect.TRY_FAILED;
      }
  
      @Override
      public Object tryInvoke(final String name, final Object obj, final Object... args) {
          // Don't try to invoke if no parameter but call has arguments
         if (ctor.getParameterCount() > 0 || args.length == 0) {
             try {
                 final Class<?> ctorClass = ctor.getDeclaringClass();
                 boolean invoke = true;
                 if (obj != null) {
                     if (obj instanceof Class<?>) {
                         invoke = ctorClass.equals(obj);
                     } else {
                         invoke = ctorClass.getName().equals(obj.toString());
                     }
                 }
                 invoke &= name == null || ctorClass.getName().equals(name);
                 if (invoke) {
                     return ctor.newInstance(args);
                 }
             } catch (InstantiationException | IllegalArgumentException | IllegalAccessException xinstance) {
                 return Uberspect.TRY_FAILED;
             } catch (final InvocationTargetException xinvoke) {
                 throw JexlException.tryFailed(xinvoke); // throw
             }
         }
         return Uberspect.TRY_FAILED;
     }
 
 }