/**
    *    Copyright 2009-2019 the original author or authors.
    *
    *    Licensed 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.ibatis.reflection;
  
  import java.lang.reflect.Array;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Field;
  import java.lang.reflect.GenericArrayType;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  import java.lang.reflect.ParameterizedType;
  import java.lang.reflect.ReflectPermission;
  import java.lang.reflect.Type;
  import java.text.MessageFormat;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Map.Entry;
  
  import org.apache.ibatis.reflection.invoker.AmbiguousMethodInvoker;
  import org.apache.ibatis.reflection.invoker.GetFieldInvoker;
  import org.apache.ibatis.reflection.invoker.Invoker;
  import org.apache.ibatis.reflection.invoker.MethodInvoker;
  import org.apache.ibatis.reflection.invoker.SetFieldInvoker;
  import org.apache.ibatis.reflection.property.PropertyNamer;
  
  /**
   * This class represents a cached set of class definition information that
   * allows for easy mapping between property names and getter/setter methods.
   *
   * @author Clinton Begin
   */
  public class Reflector {
  
    private final Class<?> type;
    private final String[] readablePropertyNames;
    private final String[] writablePropertyNames;
    private final Map<String, Invoker> setMethods = new HashMap<>();
    private final Map<String, Invoker> getMethods = new HashMap<>();
    private final Map<String, Class<?>> setTypes = new HashMap<>();
    private final Map<String, Class<?>> getTypes = new HashMap<>();
    private Constructor<?> defaultConstructor;
  
    private Map<String, String> caseInsensitivePropertyMap = new HashMap<>();
  
    public Reflector(Class<?> clazz) {
      type = clazz;
      addDefaultConstructor(clazz);
      addGetMethods(clazz);
      addSetMethods(clazz);
      addFields(clazz);
      readablePropertyNames = getMethods.keySet().toArray(new String[0]);
      writablePropertyNames = setMethods.keySet().toArray(new String[0]);
      for (String propName : readablePropertyNames) {
        caseInsensitivePropertyMap.put(propName.toUpperCase(Locale.ENGLISH), propName);
      }
      for (String propName : writablePropertyNames) {
        caseInsensitivePropertyMap.put(propName.toUpperCase(Locale.ENGLISH), propName);
      }
    }
  
    private void addDefaultConstructor(Class<?> clazz) {
      Constructor<?>[] constructors = clazz.getDeclaredConstructors();
      Arrays.stream(constructors).filter(constructor -> constructor.getParameterTypes().length == 0)
        .findAny().ifPresent(constructor -> this.defaultConstructor = constructor);
    }
  
    private void addGetMethods(Class<?> clazz) {
      Map<String, List<Method>> conflictingGetters = new HashMap<>();
      Method[] methods = getClassMethods(clazz);
      Arrays.stream(methods).filter(m -> m.getParameterTypes().length == 0 && PropertyNamer.isGetter(m.getName()))
        .forEach(m -> addMethodConflict(conflictingGetters, PropertyNamer.methodToProperty(m.getName()), m));
      resolveGetterConflicts(conflictingGetters);
    }
  
    private void resolveGetterConflicts(Map<String, List<Method>> conflictingGetters) {
      for (Entry<String, List<Method>> entry : conflictingGetters.entrySet()) {
        Method winner = null;
        String propName = entry.getKey();
        boolean isAmbiguous = false;
        for (Method candidate : entry.getValue()) {
          if (winner == null) {
           winner = candidate;
           continue;
         }
         Class<?> winnerType = winner.getReturnType();
         Class<?> candidateType = candidate.getReturnType();
         if (candidateType.equals(winnerType)) {
           if (!boolean.class.equals(candidateType)) {
             isAmbiguous = true;
             break;
           } else if (candidate.getName().startsWith("is")) {
             winner = candidate;
           }
         } else if (candidateType.isAssignableFrom(winnerType)) {
           // OK getter type is descendant
         } else if (winnerType.isAssignableFrom(candidateType)) {
           winner = candidate;
         } else {
           isAmbiguous = true;
           break;
         }
       }
       addGetMethod(propName, winner, isAmbiguous);
     }
   }
 
   private void addGetMethod(String name, Method method, boolean isAmbiguous) {
     MethodInvoker invoker = isAmbiguous
         ? new AmbiguousMethodInvoker(method, MessageFormat.format(
             "Illegal overloaded getter method with ambiguous type for property ''{0}'' in class ''{1}''. This breaks the JavaBeans specification and can cause unpredictable results.",
             name, method.getDeclaringClass().getName()))
         : new MethodInvoker(method);
     getMethods.put(name, invoker);
     Type returnType = TypeParameterResolver.resolveReturnType(method, type);
     getTypes.put(name, typeToClass(returnType));
   }
 
   private void addSetMethods(Class<?> clazz) {
     Map<String, List<Method>> conflictingSetters = new HashMap<>();
     Method[] methods = getClassMethods(clazz);
     Arrays.stream(methods).filter(m -> m.getParameterTypes().length == 1 && PropertyNamer.isSetter(m.getName()))
       .forEach(m -> addMethodConflict(conflictingSetters, PropertyNamer.methodToProperty(m.getName()), m));
     resolveSetterConflicts(conflictingSetters);
   }
 
   private void addMethodConflict(Map<String, List<Method>> conflictingMethods, String name, Method method) {
     if (isValidPropertyName(name)) {
       List<Method> list = conflictingMethods.computeIfAbsent(name, k -> new ArrayList<>());
       list.add(method);
     }
   }
 
   private void resolveSetterConflicts(Map<String, List<Method>> conflictingSetters) {
     for (String propName : conflictingSetters.keySet()) {
       List<Method> setters = conflictingSetters.get(propName);
       Class<?> getterType = getTypes.get(propName);
       boolean isGetterAmbiguous = getMethods.get(propName) instanceof AmbiguousMethodInvoker;
       boolean isSetterAmbiguous = false;
       Method match = null;
       for (Method setter : setters) {
         if (!isGetterAmbiguous && setter.getParameterTypes()[0].equals(getterType)) {
           // should be the best match
           match = setter;
           break;
         }
         if (!isSetterAmbiguous) {
           match = pickBetterSetter(match, setter, propName);
           isSetterAmbiguous = match == null;
         }
       }
       if (match != null) {
         addSetMethod(propName, match);
       }
     }
   }
 
   private Method pickBetterSetter(Method setter1, Method setter2, String property) {
     if (setter1 == null) {
       return setter2;
     }
     Class<?> paramType1 = setter1.getParameterTypes()[0];
     Class<?> paramType2 = setter2.getParameterTypes()[0];
     if (paramType1.isAssignableFrom(paramType2)) {
       return setter2;
     } else if (paramType2.isAssignableFrom(paramType1)) {
       return setter1;
     }
     MethodInvoker invoker = new AmbiguousMethodInvoker(setter1,
         MessageFormat.format(
             "Ambiguous setters defined for property ''{0}'' in class ''{1}'' with types ''{2}'' and ''{3}''.",
             property, setter2.getDeclaringClass().getName(), paramType1.getName(), paramType2.getName()));
     setMethods.put(property, invoker);
     Type[] paramTypes = TypeParameterResolver.resolveParamTypes(setter1, type);
     setTypes.put(property, typeToClass(paramTypes[0]));
     return null;
   }
 
   private void addSetMethod(String name, Method method) {
     MethodInvoker/MethodInvoker.html#MethodInvoker">MethodInvoker invoker = new MethodInvoker(method);
     setMethods.put(name, invoker);
     Type[] paramTypes = TypeParameterResolver.resolveParamTypes(method, type);
     setTypes.put(name, typeToClass(paramTypes[0]));
   }
 
   private Class<?> typeToClass(Type src) {
     Class<?> result = null;
     if (src instanceof Class) {
       result = (Class<?>) src;
     } else if (src instanceof ParameterizedType) {
       result = (Class<?>) ((ParameterizedType) src).getRawType();
     } else if (src instanceof GenericArrayType) {
       Type componentType = ((GenericArrayType) src).getGenericComponentType();
       if (componentType instanceof Class) {
         result = Array.newInstance((Class<?>) componentType, 0).getClass();
       } else {
         Class<?> componentClass = typeToClass(componentType);
         result = Array.newInstance(componentClass, 0).getClass();
       }
     }
     if (result == null) {
       result = Object.class;
     }
     return result;
   }
 
   private void addFields(Class<?> clazz) {
     Field[] fields = clazz.getDeclaredFields();
     for (Field field : fields) {
       if (!setMethods.containsKey(field.getName())) {
         // issue #379 - removed the check for final because JDK 1.5 allows
         // modification of final fields through reflection (JSR-133). (JGB)
         // pr #16 - final static can only be set by the classloader
         int modifiers = field.getModifiers();
         if (!(Modifier.isFinal(modifiers) && Modifier.isStatic(modifiers))) {
           addSetField(field);
         }
       }
       if (!getMethods.containsKey(field.getName())) {
         addGetField(field);
       }
     }
     if (clazz.getSuperclass() != null) {
       addFields(clazz.getSuperclass());
     }
   }
 
   private void addSetField(Field field) {
     if (isValidPropertyName(field.getName())) {
       setMethods.put(field.getName(), new SetFieldInvoker(field));
       Type fieldType = TypeParameterResolver.resolveFieldType(field, type);
       setTypes.put(field.getName(), typeToClass(fieldType));
     }
   }
 
   private void addGetField(Field field) {
     if (isValidPropertyName(field.getName())) {
       getMethods.put(field.getName(), new GetFieldInvoker(field));
       Type fieldType = TypeParameterResolver.resolveFieldType(field, type);
       getTypes.put(field.getName(), typeToClass(fieldType));
     }
   }
 
   private boolean isValidPropertyName(String name) {
     return !(name.startsWith("$") || "serialVersionUID".equals(name) || "class".equals(name));
   }
 
   /**
    * This method returns an array containing all methods
    * declared in this class and any superclass.
    * We use this method, instead of the simpler <code>Class.getMethods()</code>,
    * because we want to look for private methods as well.
    *
    * @param clazz The class
    * @return An array containing all methods in this class
    */
   private Method[] getClassMethods(Class<?> clazz) {
     Map<String, Method> uniqueMethods = new HashMap<>();
     Class<?> currentClass = clazz;
     while (currentClass != null && currentClass != Object.class) {
       addUniqueMethods(uniqueMethods, currentClass.getDeclaredMethods());
 
       // we also need to look for interface methods -
       // because the class may be abstract
       Class<?>[] interfaces = currentClass.getInterfaces();
       for (Class<?> anInterface : interfaces) {
         addUniqueMethods(uniqueMethods, anInterface.getMethods());
       }
 
       currentClass = currentClass.getSuperclass();
     }
 
     Collection<Method> methods = uniqueMethods.values();
 
     return methods.toArray(new Method[0]);
   }
 
   private void addUniqueMethods(Map<String, Method> uniqueMethods, Method[] methods) {
     for (Method currentMethod : methods) {
       if (!currentMethod.isBridge()) {
         String signature = getSignature(currentMethod);
         // check to see if the method is already known
         // if it is known, then an extended class must have
         // overridden a method
         if (!uniqueMethods.containsKey(signature)) {
           uniqueMethods.put(signature, currentMethod);
         }
       }
     }
   }
 
   private String getSignature(Method method) {
     StringBuilder sb = new StringBuilder();
     Class<?> returnType = method.getReturnType();
     if (returnType != null) {
       sb.append(returnType.getName()).append('#');
     }
     sb.append(method.getName());
     Class<?>[] parameters = method.getParameterTypes();
     for (int i = 0; i < parameters.length; i++) {
       sb.append(i == 0 ? ':' : ',').append(parameters[i].getName());
     }
     return sb.toString();
   }
 
   /**
    * Checks whether can control member accessible.
    *
    * @return If can control member accessible, it return {@literal true}
    * @since 3.5.0
    */
   public static boolean canControlMemberAccessible() {
     try {
       SecurityManager securityManager = System.getSecurityManager();
       if (null != securityManager) {
         securityManager.checkPermission(new ReflectPermission("suppressAccessChecks"));
       }
     } catch (SecurityException e) {
       return false;
     }
     return true;
   }
 
   /**
    * Gets the name of the class the instance provides information for.
    *
    * @return The class name
    */
   public Class<?> getType() {
     return type;
   }
 
   public Constructor<?> getDefaultConstructor() {
     if (defaultConstructor != null) {
       return defaultConstructor;
     } else {
       throw new ReflectionException("There is no default constructor for " + type);
     }
   }
 
   public boolean hasDefaultConstructor() {
     return defaultConstructor != null;
   }
 
   public Invoker getSetInvoker(String propertyName) {
     Invoker method = setMethods.get(propertyName);
     if (method == null) {
       throw new ReflectionException("There is no setter for property named '" + propertyName + "' in '" + type + "'");
     }
     return method;
   }
 
   public Invoker getGetInvoker(String propertyName) {
     Invoker method = getMethods.get(propertyName);
     if (method == null) {
       throw new ReflectionException("There is no getter for property named '" + propertyName + "' in '" + type + "'");
     }
     return method;
   }
 
   /**
    * Gets the type for a property setter.
    *
    * @param propertyName - the name of the property
    * @return The Class of the property setter
    */
   public Class<?> getSetterType(String propertyName) {
     Class<?> clazz = setTypes.get(propertyName);
     if (clazz == null) {
       throw new ReflectionException("There is no setter for property named '" + propertyName + "' in '" + type + "'");
     }
     return clazz;
   }
 
   /**
    * Gets the type for a property getter.
    *
    * @param propertyName - the name of the property
    * @return The Class of the property getter
    */
   public Class<?> getGetterType(String propertyName) {
     Class<?> clazz = getTypes.get(propertyName);
     if (clazz == null) {
       throw new ReflectionException("There is no getter for property named '" + propertyName + "' in '" + type + "'");
     }
     return clazz;
   }
 
   /**
    * Gets an array of the readable properties for an object.
    *
    * @return The array
    */
   public String[] getGetablePropertyNames() {
     return readablePropertyNames;
   }
 
   /**
    * Gets an array of the writable properties for an object.
    *
    * @return The array
    */
   public String[] getSetablePropertyNames() {
     return writablePropertyNames;
   }
 
   /**
    * Check to see if a class has a writable property by name.
    *
    * @param propertyName - the name of the property to check
    * @return True if the object has a writable property by the name
    */
   public boolean hasSetter(String propertyName) {
     return setMethods.keySet().contains(propertyName);
   }
 
   /**
    * Check to see if a class has a readable property by name.
    *
    * @param propertyName - the name of the property to check
    * @return True if the object has a readable property by the name
    */
   public boolean hasGetter(String propertyName) {
     return getMethods.keySet().contains(propertyName);
   }
 
   public String findPropertyName(String name) {
     return caseInsensitivePropertyMap.get(name.toUpperCase(Locale.ENGLISH));
   }
 }