/*
    * 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.lang3.reflect;
  
  import java.lang.reflect.AccessibleObject;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Member;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  
  import org.apache.commons.lang3.ClassUtils;
  
  /**
   * Contains common code for working with {@link java.lang.reflect.Method Methods}/{@link java.lang.reflect.Constructor Constructors},
   * extracted and refactored from {@link MethodUtils} when it was imported from Commons BeanUtils.
   *
   * @since 2.5
   */
  final class MemberUtils {
      // TODO extract an interface to implement compareParameterSets(...)?
  
      /**
       *  A class providing a subset of the API of java.lang.reflect.Executable in Java 1.8,
       * providing a common representation for function signatures for Constructors and Methods.
       */
      private static final class Executable {
        private static Executable of(final Constructor<?> constructor) {
            return new Executable(constructor);
        }
        private static Executable of(final Method method) {
            return new Executable(method);
        }
  
        private final Class<?>[] parameterTypes;
  
        private final boolean  isVarArgs;
  
        private Executable(final Constructor<?> constructor) {
          parameterTypes = constructor.getParameterTypes();
          isVarArgs = constructor.isVarArgs();
        }
  
        private Executable(final Method method) {
          parameterTypes = method.getParameterTypes();
          isVarArgs = method.isVarArgs();
        }
  
        public Class<?>[] getParameterTypes() {
            return parameterTypes;
        }
  
        public boolean isVarArgs() {
            return isVarArgs;
        }
      }
  
      private static final int ACCESS_TEST = Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
  
      /** Array of primitive number types ordered by "promotability" */
      private static final Class<?>[] ORDERED_PRIMITIVE_TYPES = { Byte.TYPE, Short.TYPE,
              Character.TYPE, Integer.TYPE, Long.TYPE, Float.TYPE, Double.TYPE };
  
      /**
       * Compares the relative fitness of two Constructors in terms of how well they
       * match a set of runtime parameter types, such that a list ordered
       * by the results of the comparison would return the best match first
       * (least).
       *
       * @param left the "left" Constructor
       * @param right the "right" Constructor
       * @param actual the runtime parameter types to match against
       * {@code left}/{@code right}
       * @return int consistent with {@code compare} semantics
       * @since 3.5
       */
      static int compareConstructorFit(final Constructor<?> left, final Constructor<?> right, final Class<?>[] actual) {
        return compareParameterTypes(Executable.of(left), Executable.of(right), actual);
      }
  
      /**
       * Compares the relative fitness of two Methods in terms of how well they
       * match a set of runtime parameter types, such that a list ordered
       * by the results of the comparison would return the best match first
       * (least).
       *
      * @param left the "left" Method
      * @param right the "right" Method
      * @param actual the runtime parameter types to match against
      * {@code left}/{@code right}
      * @return int consistent with {@code compare} semantics
      * @since 3.5
      */
     static int compareMethodFit(final Method left, final Method right, final Class<?>[] actual) {
       return compareParameterTypes(Executable.of(left), Executable.of(right), actual);
     }
 
     /**
      * Compares the relative fitness of two Executables in terms of how well they
      * match a set of runtime parameter types, such that a list ordered
      * by the results of the comparison would return the best match first
      * (least).
      *
      * @param left the "left" Executable
      * @param right the "right" Executable
      * @param actual the runtime parameter types to match against
      * {@code left}/{@code right}
      * @return int consistent with {@code compare} semantics
      */
     private static int compareParameterTypes(final Executable left, final Executable right, final Class<?>[] actual) {
         final float leftCost = getTotalTransformationCost(actual, left);
         final float rightCost = getTotalTransformationCost(actual, right);
         return Float.compare(leftCost, rightCost);
     }
 
     /**
      * Gets the number of steps needed to turn the source class into
      * the destination class. This represents the number of steps in the object
      * hierarchy graph.
      * @param srcClass The source class
      * @param destClass The destination class
      * @return The cost of transforming an object
      */
     private static float getObjectTransformationCost(Class<?> srcClass, final Class<?> destClass) {
         if (destClass.isPrimitive()) {
             return getPrimitivePromotionCost(srcClass, destClass);
         }
         float cost = 0.0f;
         while (srcClass != null && !destClass.equals(srcClass)) {
             if (destClass.isInterface() && ClassUtils.isAssignable(srcClass, destClass)) {
                 // slight penalty for interface match.
                 // we still want an exact match to override an interface match,
                 // but
                 // an interface match should override anything where we have to
                 // get a superclass.
                 cost += 0.25f;
                 break;
             }
             cost++;
             srcClass = srcClass.getSuperclass();
         }
         /*
          * If the destination class is null, we've traveled all the way up to
          * an Object match. We'll penalize this by adding 1.5 to the cost.
          */
         if (srcClass == null) {
             cost += 1.5f;
         }
         return cost;
     }
 
     /**
      * Gets the number of steps required to promote a primitive number to another
      * type.
      * @param srcClass the (primitive) source class
      * @param destClass the (primitive) destination class
      * @return The cost of promoting the primitive
      */
     private static float getPrimitivePromotionCost(final Class<?> srcClass, final Class<?> destClass) {
         if (srcClass == null) {
             return 1.5f;
         }
         float cost = 0.0f;
         Class<?> cls = srcClass;
         if (!cls.isPrimitive()) {
             // slight unwrapping penalty
             cost += 0.1f;
             cls = ClassUtils.wrapperToPrimitive(cls);
         }
         for (int i = 0; cls != destClass && i < ORDERED_PRIMITIVE_TYPES.length; i++) {
             if (cls == ORDERED_PRIMITIVE_TYPES[i]) {
                 cost += 0.1f;
                 if (i < ORDERED_PRIMITIVE_TYPES.length - 1) {
                     cls = ORDERED_PRIMITIVE_TYPES[i + 1];
                 }
             }
         }
         return cost;
     }
 
     /**
      * Returns the sum of the object transformation cost for each class in the
      * source argument list.
      * @param srcArgs The source arguments
      * @param executable The executable to calculate transformation costs for
      * @return The total transformation cost
      */
     private static float getTotalTransformationCost(final Class<?>[] srcArgs, final Executable executable) {
         final Class<?>[] destArgs = executable.getParameterTypes();
         final boolean isVarArgs = executable.isVarArgs();
 
         // "source" and "destination" are the actual and declared args respectively.
         float totalCost = 0.0f;
         final long normalArgsLen = isVarArgs ? destArgs.length - 1 : destArgs.length;
         if (srcArgs.length < normalArgsLen) {
             return Float.MAX_VALUE;
         }
         for (int i = 0; i < normalArgsLen; i++) {
             totalCost += getObjectTransformationCost(srcArgs[i], destArgs[i]);
         }
         if (isVarArgs) {
             // When isVarArgs is true, srcArgs and dstArgs may differ in length.
             // There are two special cases to consider:
             final boolean noVarArgsPassed = srcArgs.length < destArgs.length;
             final boolean explicitArrayForVarargs = srcArgs.length == destArgs.length && srcArgs[srcArgs.length - 1] != null
                 && srcArgs[srcArgs.length - 1].isArray();
 
             final float varArgsCost = 0.001f;
             final Class<?> destClass = destArgs[destArgs.length - 1].getComponentType();
             if (noVarArgsPassed) {
                 // When no varargs passed, the best match is the most generic matching type, not the most specific.
                 totalCost += getObjectTransformationCost(destClass, Object.class) + varArgsCost;
             } else if (explicitArrayForVarargs) {
                 final Class<?> sourceClass = srcArgs[srcArgs.length - 1].getComponentType();
                 totalCost += getObjectTransformationCost(sourceClass, destClass) + varArgsCost;
             } else {
                 // This is typical varargs case.
                 for (int i = destArgs.length - 1; i < srcArgs.length; i++) {
                     final Class<?> srcClass = srcArgs[i];
                     totalCost += getObjectTransformationCost(srcClass, destClass) + varArgsCost;
                 }
             }
         }
         return totalCost;
     }
 
     /**
      * Tests whether a {@link Member} is accessible.
      *
      * @param member Member to test, may be null.
      * @return {@code true} if {@code m} is accessible
      */
     static boolean isAccessible(final Member member) {
         return isPublic(member) && !member.isSynthetic();
     }
 
     static boolean isMatchingConstructor(final Constructor<?> method, final Class<?>[] parameterTypes) {
         return isMatchingExecutable(Executable.of(method), parameterTypes);
     }
 
     private static boolean isMatchingExecutable(final Executable method, final Class<?>[] parameterTypes) {
         final Class<?>[] methodParameterTypes = method.getParameterTypes();
         if (ClassUtils.isAssignable(parameterTypes, methodParameterTypes, true)) {
             return true;
         }
         if (method.isVarArgs()) {
             int i;
             for (i = 0; i < methodParameterTypes.length - 1 && i < parameterTypes.length; i++) {
                 if (!ClassUtils.isAssignable(parameterTypes[i], methodParameterTypes[i], true)) {
                     return false;
                 }
             }
             final Class<?> varArgParameterType = methodParameterTypes[methodParameterTypes.length - 1].getComponentType();
             for (; i < parameterTypes.length; i++) {
                 if (!ClassUtils.isAssignable(parameterTypes[i], varArgParameterType, true)) {
                     return false;
                 }
             }
             return true;
         }
         return false;
     }
 
     static boolean isMatchingMethod(final Method method, final Class<?>[] parameterTypes) {
       return isMatchingExecutable(Executable.of(method), parameterTypes);
     }
 
     /**
      * Tests whether a given set of modifiers implies package access.
      *
      * @param modifiers to test
      * @return {@code true} unless {@code package}/{@code protected}/{@code private} modifier detected
      */
     static boolean isPackageAccess(final int modifiers) {
         return (modifiers & ACCESS_TEST) == 0;
     }
 
     /**
      * Tests whether a {@link Member} is public.
      *
      * @param member Member to test, may be null.
      * @return {@code true} if {@code m} is public
      */
     static boolean isPublic(final Member member) {
         return member != null && Modifier.isPublic(member.getModifiers());
     }
 
     /**
      * Tests whether a {@link Member} is static.
      *
      * @param member Member to test, may be null.
      * @return {@code true} if {@code m} is static
      */
     static boolean isStatic(final Member member) {
         return member != null && Modifier.isStatic(member.getModifiers());
     }
 
     /**
      * Default access superclass workaround.
      * <p>
      * When a {@code public} class has a default access superclass with {@code public} members,
      * these members are accessible. Calling them from compiled code works fine.
      * Unfortunately, on some JVMs, using reflection to invoke these members
      * seems to (wrongly) prevent access even when the modifier is {@code public}.
      * Calling {@code setAccessible(true)} solves the problem but will only work from
      * sufficiently privileged code. Better workarounds would be gratefully
      * accepted.
      * </p>
      *
      * @param obj the AccessibleObject to set as accessible, may be null.
      * @return a boolean indicating whether the accessibility of the object was set to true.
      */
     static <T extends AccessibleObject> T setAccessibleWorkaround(final T obj) {
         if (obj == null || obj.isAccessible()) {
             return obj;
         }
         final Member m = (Member) obj;
         if (!obj.isAccessible() && isPublic(m) && isPackageAccess(m.getDeclaringClass().getModifiers())) {
             try {
                 obj.setAccessible(true);
                 return obj;
             } catch (final SecurityException ignored) {
                 // ignore in favor of subsequent IllegalAccessException
             }
         }
         return obj;
     }
 
 }