/*
    * 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.maven.model.interpolation.reflection;
  
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.util.Hashtable;
  import java.util.Map;
  
  /**
   * A cache of introspection information for a specific class instance.
   * Keys {@link Method} objects by a concatenation of the
   * method name and the names of classes that make up the parameters.
   *
   * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
   */
  @Deprecated(since = "4.0.0")
  class ClassMap {
      private static final class CacheMiss {}
  
      private static final CacheMiss CACHE_MISS = new CacheMiss();
  
      private static final Object OBJECT = new Object();
  
      /**
       * Class passed into the constructor used to as
       * the basis for the Method map.
       */
      private final Class<?> clazz;
  
      /**
       * Cache of Methods, or CACHE_MISS, keyed by method
       * name and actual arguments used to find it.
       */
      private final Map<String, Object> methodCache = new Hashtable<>();
  
      private MethodMap methodMap = new MethodMap();
  
      /**
       * Standard constructor
       * @param clazz The class.
       */
      ClassMap(Class<?> clazz) {
          this.clazz = clazz;
          populateMethodCache();
      }
  
      /**
       * @return the class object whose methods are cached by this map.
       */
      Class<?> getCachedClass() {
          return clazz;
      }
  
      /**
       * <p>Find a Method using the methodKey provided.</p>
       * <p>Look in the methodMap for an entry. If found,
       * it'll either be a CACHE_MISS, in which case we
       * simply give up, or it'll be a Method, in which
       * case, we return it.</p>
       * <p>If nothing is found, then we must actually go
       * and introspect the method from the MethodMap.</p>
       * @param name Method name.
       * @param params Method parameters.
       * @return The found method.
       * @throws MethodMap.AmbiguousException in case of duplicate methods.
       */
      public Method findMethod(String name, Object... params) throws MethodMap.AmbiguousException {
          String methodKey = makeMethodKey(name, params);
          Object cacheEntry = methodCache.get(methodKey);
  
          if (cacheEntry == CACHE_MISS) {
              return null;
          }
  
          if (cacheEntry == null) {
              try {
                  cacheEntry = methodMap.find(name, params);
              } catch (MethodMap.AmbiguousException ae) {
                  // that's a miss :)
                  methodCache.put(methodKey, CACHE_MISS);
                  throw ae;
              }
 
             if (cacheEntry == null) {
                 methodCache.put(methodKey, CACHE_MISS);
             } else {
                 methodCache.put(methodKey, cacheEntry);
             }
         }
 
         // Yes, this might just be null.
         return (Method) cacheEntry;
     }
 
     /**
      * Populate the Map of direct hits. These
      * are taken from all the public methods
      * that our class provides.
      */
     private void populateMethodCache() {
         // get all publicly accessible methods
         Method[] methods = getAccessibleMethods(clazz);
 
         // map and cache them
         for (Method method : methods) {
             // now get the 'public method', the method declared by a
             // public interface or class (because the actual implementing
             // class may be a facade...)
 
             Method publicMethod = getPublicMethod(method);
 
             // it is entirely possible that there is no public method for
             // the methods of this class; i.e. in the facade, a method
             // that isn't on any of the interfaces or superclass
             // in which case, ignore it. Otherwise, map and cache.
             if (publicMethod != null) {
                 methodMap.add(publicMethod);
                 methodCache.put(makeMethodKey(publicMethod), publicMethod);
             }
         }
     }
 
     /**
      * Make a methodKey for the given method using
      * the concatenation of the name and the
      * types of the method parameters.
      */
     private String makeMethodKey(Method method) {
         Class<?>[] parameterTypes = method.getParameterTypes();
 
         StringBuilder methodKey = new StringBuilder(method.getName());
 
         for (Class<?> parameterType : parameterTypes) {
             // If the argument type is primitive then we want
             // to convert our primitive type signature to the
             // corresponding Object type so introspection for
             // methods with primitive types will work correctly.
             if (parameterType.isPrimitive()) {
                 if (parameterType.equals(Boolean.TYPE)) {
                     methodKey.append("java.lang.Boolean");
                 } else if (parameterType.equals(Byte.TYPE)) {
                     methodKey.append("java.lang.Byte");
                 } else if (parameterType.equals(Character.TYPE)) {
                     methodKey.append("java.lang.Character");
                 } else if (parameterType.equals(Double.TYPE)) {
                     methodKey.append("java.lang.Double");
                 } else if (parameterType.equals(Float.TYPE)) {
                     methodKey.append("java.lang.Float");
                 } else if (parameterType.equals(Integer.TYPE)) {
                     methodKey.append("java.lang.Integer");
                 } else if (parameterType.equals(Long.TYPE)) {
                     methodKey.append("java.lang.Long");
                 } else if (parameterType.equals(Short.TYPE)) {
                     methodKey.append("java.lang.Short");
                 }
             } else {
                 methodKey.append(parameterType.getName());
             }
         }
 
         return methodKey.toString();
     }
 
     private static String makeMethodKey(String method, Object... params) {
         StringBuilder methodKey = new StringBuilder().append(method);
 
         for (Object param : params) {
             Object arg = param;
 
             if (arg == null) {
                 arg = OBJECT;
             }
 
             methodKey.append(arg.getClass().getName());
         }
 
         return methodKey.toString();
     }
 
     /**
      * Retrieves public methods for a class. In case the class is not
      * public, retrieves methods with same signature as its public methods
      * from public superclasses and interfaces (if they exist). Basically
      * upcasts every method to the nearest acccessible method.
      */
     private static Method[] getAccessibleMethods(Class<?> clazz) {
         Method[] methods = clazz.getMethods();
 
         // Short circuit for the (hopefully) majority of cases where the
         // clazz is public
         if (Modifier.isPublic(clazz.getModifiers())) {
             return methods;
         }
 
         // No luck - the class is not public, so we're going the longer way.
         MethodInfo[] methodInfos = new MethodInfo[methods.length];
         for (int i = methods.length; i-- > 0; ) {
             methodInfos[i] = new MethodInfo(methods[i]);
         }
 
         int upcastCount = getAccessibleMethods(clazz, methodInfos, 0);
 
         // Reallocate array in case some method had no accessible counterpart.
         if (upcastCount < methods.length) {
             methods = new Method[upcastCount];
         }
 
         int j = 0;
         for (MethodInfo methodInfo : methodInfos) {
             if (methodInfo.upcast) {
                 methods[j++] = methodInfo.method;
             }
         }
         return methods;
     }
 
     /**
      * Recursively finds a match for each method, starting with the class, and then
      * searching the superclass and interfaces.
      *
      * @param clazz       Class to check
      * @param methodInfos array of methods we are searching to match
      * @param upcastCount current number of methods we have matched
      * @return count of matched methods
      */
     private static int getAccessibleMethods(Class<?> clazz, MethodInfo[] methodInfos, int upcastCount) {
         int l = methodInfos.length;
 
         // if this class is public, then check each of the currently
         // 'non-upcasted' methods to see if we have a match
         if (Modifier.isPublic(clazz.getModifiers())) {
             for (int i = 0; i < l && upcastCount < l; ++i) {
                 try {
                     MethodInfo methodInfo = methodInfos[i];
                     if (!methodInfo.upcast) {
                         methodInfo.tryUpcasting(clazz);
                         upcastCount++;
                     }
                 } catch (NoSuchMethodException e) {
                     // Intentionally ignored - it means it wasn't found in the current class
                 }
             }
 
             /*
              *  Short circuit if all methods were upcast
              */
 
             if (upcastCount == l) {
                 return upcastCount;
             }
         }
 
         // Examine superclass
         Class<?> superclazz = clazz.getSuperclass();
         if (superclazz != null) {
             upcastCount = getAccessibleMethods(superclazz, methodInfos, upcastCount);
 
             // Short circuit if all methods were upcast
             if (upcastCount == l) {
                 return upcastCount;
             }
         }
 
         // Examine interfaces. Note we do it even if superclazz == null.
         // This is redundant as currently java.lang.Object does not implement
         // any interfaces, however nothing guarantees it will not in the future.
         Class<?>[] interfaces = clazz.getInterfaces();
         for (int i = interfaces.length; i-- > 0; ) {
             upcastCount = getAccessibleMethods(interfaces[i], methodInfos, upcastCount);
 
             // Short circuit if all methods were upcast
             if (upcastCount == l) {
                 return upcastCount;
             }
         }
 
         return upcastCount;
     }
 
     /**
      * For a given method, retrieves its publicly accessible counterpart.
      * This method will look for a method with same name
      * and signature declared in a public superclass or implemented interface of this
      * method's declaring class. This counterpart method is publicly callable.
      *
      * @param method a method whose publicly callable counterpart is requested.
      * @return the publicly callable counterpart method. Note that if the parameter
      *         method is itself declared by a public class, this method is an identity
      *         function.
      */
     private static Method getPublicMethod(Method method) {
         Class<?> clazz = method.getDeclaringClass();
 
         // Short circuit for (hopefully the majority of) cases where the declaring
         // class is public.
         if ((clazz.getModifiers() & Modifier.PUBLIC) != 0) {
             return method;
         }
 
         return getPublicMethod(clazz, method.getName(), method.getParameterTypes());
     }
 
     /**
      * Looks up the method with specified name and signature in the first public
      * superclass or implemented interface of the class.
      *
      * @param clazz      the class whose method is sought
      * @param name       the name of the method
      * @param paramTypes the classes of method parameters
      */
     private static Method getPublicMethod(Class<?> clazz, String name, Class<?>... paramTypes) {
         // if this class is public, then try to get it
         if ((clazz.getModifiers() & Modifier.PUBLIC) != 0) {
             try {
                 return clazz.getMethod(name, paramTypes);
             } catch (NoSuchMethodException e) {
                 // If the class does not have the method, then neither its superclass
                 // nor any of its interfaces has it so quickly return null.
                 return null;
             }
         }
 
         //  try the superclass
         Class<?> superclazz = clazz.getSuperclass();
 
         if (superclazz != null) {
             Method superclazzMethod = getPublicMethod(superclazz, name, paramTypes);
 
             if (superclazzMethod != null) {
                 return superclazzMethod;
             }
         }
 
         // and interfaces
         Class<?>[] interfaces = clazz.getInterfaces();
 
         for (Class<?> anInterface : interfaces) {
             Method interfaceMethod = getPublicMethod(anInterface, name, paramTypes);
 
             if (interfaceMethod != null) {
                 return interfaceMethod;
             }
         }
 
         return null;
     }
 
     /**
      * Used for the iterative discovery process for public methods.
      */
     private static final class MethodInfo {
         Method method;
 
         String name;
 
         Class<?>[] parameterTypes;
 
         boolean upcast;
 
         MethodInfo(Method method) {
             this.method = null;
             name = method.getName();
             parameterTypes = method.getParameterTypes();
             upcast = false;
         }
 
         void tryUpcasting(Class<?> clazz) throws NoSuchMethodException {
             method = clazz.getMethod(name, parameterTypes);
             name = null;
             parameterTypes = null;
             upcast = true;
         }
     }
 }