// ***************************************************************************************************************************
// * 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.juneau.reflect;

import static org.apache.juneau.internal.CollectionUtils.*;

import java.beans.*;
import java.lang.annotation.*;
import java.lang.reflect.*;
import java.util.*;
import java.util.function.*;

import org.apache.juneau.*;
import org.apache.juneau.annotation.*;
import org.apache.juneau.internal.*;

/**
 * Lightweight utility class for introspecting information about a method.
 */
@BeanIgnore
public final class MethodInfo extends ExecutableInfo implements Comparable<MethodInfo> {

   private ClassInfo returnType;
   private final Method m;
   private List<Method> matching;

   //-----------------------------------------------------------------------------------------------------------------
   // Instantiation.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Constructor.
    *
    * @param declaringClass The class that declares this method.
    * @param m The method being wrapped.
    */
   protected MethodInfo(ClassInfo declaringClass, Method m) {
      super(declaringClass, m);
      this.m = m;
   }

   /**
    * Convenience method for instantiating a {@link MethodInfo};
    *
    * @param declaringClass The class that declares this method.
    * @param m The method being wrapped.
    * @return A new {@link MethodInfo} object, or <jk>null</jk> if the method was null;
    */
   public static MethodInfo of(ClassInfo declaringClass, Method m) {
      if (m == null)
         return null;
      return new MethodInfo(declaringClass, m);
   }

   /**
    * Convenience method for instantiating a {@link MethodInfo};
    *
    * @param m The method being wrapped.
    * @return A new {@link MethodInfo} object, or <jk>null</jk> if the method was null;
    */
   public static MethodInfo of(Method m) {
      if (m == null)
         return null;
      return new MethodInfo(ClassInfo.of(m.getDeclaringClass()), m);
   }

   /**
    * Returns the wrapped method.
    *
    * @return The wrapped method.
    */
   public Method inner() {
      return m;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Matching methods.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Finds all declared methods with the same name and arguments on all superclasses and interfaces.
    *
    * @return
    *    All matching methods including this method itself.
    *    <br>Methods are ordered from child-to-parent order.
    */
   public List<Method> getMatching() {
      if (matching == null)
         matching = Collections.unmodifiableList(findMatching(new ArrayList<>(), m, m.getDeclaringClass()));
      return matching;
   }

   /**
    * Convenience method for retrieving values in {@link #getMatching()} in parent-to-child order.
    *
    * @return
    *    All matching methods including this method itself.
    *    <br>Methods are ordered from parent-to-child order.
    */
   public Iterable<Method> getMatchingParentFirst() {
      return iterable(getMatching(), true);
   }

   private static List<Method> findMatching(List<Method> l, Method m, Class<?> c) {
      for (Method m2 : c.getDeclaredMethods())
         if (m.getName().equals(m2.getName()) && Arrays.equals(m.getParameterTypes(), m2.getParameterTypes()))
            l.add(m2);
      Class<?> pc = c.getSuperclass();
      if (pc != null)
         findMatching(l, m, pc);
      for (Class<?> ic : c.getInterfaces())
         findMatching(l, m, ic);
      return l;
   }

   private Method findMatchingOnClass(ClassInfo c) {
      for (Method m2 : c.inner().getDeclaredMethods())
         if (m.getName().equals(m2.getName()) && Arrays.equals(m.getParameterTypes(), m2.getParameterTypes()))
            return m2;
      return null;
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Annotations
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Returns all annotations of the specified type defined on the specified method.
    *
    * <p>
    * Searches all methods with the same signature on the parent classes or interfaces
    * and the return type on the method.
    *
    * @param a
    *    The annotation to search for.
    * @return
    *    A list of all matching annotations found in child-to-parent order, or an empty list if none found.
    */
   public <T extends Annotation> List<T> getAnnotations(Class<T> a) {
      return appendAnnotations(new ArrayList<>(), a);
   }

   /**
    * Identical to {@link #getAnnotations(Class)} but returns the list in reverse (parent-to-child) order.
    *
    * @param a
    *    The annotation to search for.
    * @return
    *    A list of all matching annotations found or an empty list if none found.
    */
   public <T extends Annotation> List<T> getAnnotationsParentFirst(Class<T> a) {
      return appendAnnotationsParentFirst(new ArrayList<>(), a);
   }

   /**
    * Finds and appends the specified annotation on the specified method and methods on superclasses/interfaces to the specified
    * list.
    *
    * <p>
    * Results are ordered in child-to-parent order.
    *
    * @param l The list of annotations.
    * @param a The annotation.
    * @return The same list.
    */
   @SuppressWarnings("unchecked")
   public <T extends Annotation> List<T> appendAnnotations(List<T> l, Class<T> a) {
      for (Method m2 : getMatching())
         for (Annotation a2 :  m2.getDeclaredAnnotations())
            if (a.isInstance(a2))
               l.add((T)a2);
      getReturnType().resolved().appendAnnotations(l, a);
      declaringClass.appendAnnotations(l, a);
      return l;
   }

   /**
    * Finds and appends the specified annotation on the specified class and superclasses/interfaces to the specified
    * list.
    *
    * @param l The list of annotations.
    * @param a The annotation.
    * @return The same list.
    */
   @SuppressWarnings("unchecked")
   public <T extends Annotation> List<T> appendAnnotationsParentFirst(List<T> l, Class<T> a) {
      declaringClass.appendAnnotationsParentFirst(l, a);
      for (Method m2 : getMatchingParentFirst())
         for (Annotation a2 :  m2.getDeclaredAnnotations())
            if (a.isInstance(a2))
               l.add((T)a2);
      getReturnType().resolved().appendAnnotations(l, a);
      return l;
   }

   /**
    * Returns the first annotation in the specified list on this method.
    *
    * @param c The annotations that cannot be present on the method.
    * @return <jk>true</jk> if this method does not have any of the specified annotations.
    */
   @SafeVarargs
   public final Annotation getAnnotation(Class<? extends Annotation>...c) {
      for (Class<? extends Annotation> cc : c) {
         Annotation a = getAnnotation(cc);
         if (a != null)
            return a;
      }
      return null;
   }

   /**
    * Constructs an {@link AnnotationList} of all annotations found on this method.
    *
    * <p>
    * Annotations are appended in the following orders:
    * <ol>
    *    <li>On this method and matching methods ordered child-to-parent.
    *    <li>On this class.
    *    <li>On parent classes ordered child-to-parent.
    *    <li>On interfaces ordered child-to-parent.
    *    <li>On the package of this class.
    * </ol>
    *
    * @param filter
    *    Optional filter to apply to limit which annotations are added to the list.
    *    <br>Can be <jk>null</jk> for no filtering.
    * @return A new {@link AnnotationList} object on every call.
    */
   public AnnotationList getAnnotationList(Predicate<AnnotationInfo<?>> filter) {
      return appendAnnotationList(new AnnotationList(filter));
   }

   /**
    * Constructs an {@link AnnotationList} of all annotations found on this method.
    *
    * <p>
    * Annotations are appended in the following orders:
    * <ol>
    *    <li>On the package of this class.
    *    <li>On interfaces ordered parent-to-child.
    *    <li>On parent classes ordered parent-to-child.
    *    <li>On this class.
    *    <li>On this method and matching methods ordered parent-to-child.
    * </ol>
    *
    * @param filter
    *    Optional filter to apply to limit which annotations are added to the list.
    *    <br>Can be <jk>null</jk> for no filtering.
    * @return A new {@link AnnotationList} object on every call.
    */
   public AnnotationList getAnnotationListParentFirst(Predicate<AnnotationInfo<?>> filter) {
      return appendAnnotationListParentFirst(new AnnotationList(filter));
   }

   /**
    * Same as {@link #getAnnotationListParentFirst(Predicate)} except only returns annotations defined on methods.
    *
    * @param filter
    *    Optional filter to apply to limit which annotations are added to the list.
    *    <br>Can be <jk>null</jk> for no filtering.
    * @return A new {@link AnnotationList} object on every call.
    */
   public AnnotationList getAnnotationListMethodOnlyParentFirst(Predicate<AnnotationInfo<?>> filter) {
      return appendAnnotationListMethodOnlyParentFirst(new AnnotationList(filter));
   }

   /**
    * Returns <jk>true</jk> if this method or parent methods have any annotations annotated with {@link PropertyStoreApply}.
    *
    * @return <jk>true</jk> if this method or parent methods have any annotations annotated with {@link PropertyStoreApply}.
    */
   public boolean hasConfigAnnotations() {
      for (Method m2 : getMatching())
         for (Annotation a2 :  m2.getAnnotations())
            if (a2.annotationType().getAnnotation(PropertyStoreApply.class) != null)
               return true;
      return false;
   }

   @Override
   @SuppressWarnings("unchecked")
   protected <T extends Annotation> T findAnnotation(Class<T> a) {
      for (Method m2 : getMatching())
         for (Annotation a2 :  m2.getAnnotations())
            if (a.isInstance(a2))
               return (T)a2;
      return getReturnType().resolved().getAnnotation(a);
   }

   AnnotationList appendAnnotationList(AnnotationList al) {
      ClassInfo c = this.declaringClass;
      for (ClassInfo ci : c.getParents()) {
         appendMethodAnnotations(al, ci);
         appendAnnotations(al, ci);
      }
      for (ClassInfo ci : c.getInterfaces()) {
         appendMethodAnnotations(al, ci);
         appendAnnotations(al, ci);
      }
      appendAnnotations(al, c.getPackage());
      return al;
   }

   AnnotationList appendAnnotationListParentFirst(AnnotationList al) {
      ClassInfo c = this.declaringClass;
      appendAnnotations(al, c.getPackage());
      for (ClassInfo ci : c.getInterfacesParentFirst()) {
         appendAnnotations(al, ci);
         appendMethodAnnotations(al, ci);
      }
      for (ClassInfo ci : c.getParentsParentFirst()) {
         appendAnnotations(al, ci);
         appendMethodAnnotations(al, ci);
      }
      return al;
   }

   AnnotationList appendAnnotationListMethodOnlyParentFirst(AnnotationList al) {
      ClassInfo c = this.declaringClass;
      for (ClassInfo ci : c.getInterfacesParentFirst())
         appendMethodAnnotations(al, ci);
      for (ClassInfo ci : c.getParentsParentFirst())
         appendMethodAnnotations(al, ci);
      return al;
   }

   void appendAnnotations(AnnotationList al, Package p) {
      if (p != null)
         for (Annotation a : p.getDeclaredAnnotations())
            al.add(AnnotationInfo.of(p, a));
   }

   void appendAnnotations(AnnotationList al, ClassInfo ci) {
      if (ci != null)
         for (Annotation a : ci.c.getDeclaredAnnotations())
            al.add(AnnotationInfo.of(ci, a));
   }

   void appendMethodAnnotations(AnnotationList al, ClassInfo ci) {
      Method m = findMatchingOnClass(ci);
      if (m != null)
         for (Annotation a : m.getDeclaredAnnotations())
            al.add(AnnotationInfo.of(MethodInfo.of(m), a));
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Return type.
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Returns the generic return type of this method as a {@link ClassInfo} object.
    *
    * @return The generic return type of this method.
    */
   public ClassInfo getReturnType() {
      if (returnType == null)
         returnType = ClassInfo.of(m.getReturnType(), m.getGenericReturnType());
      return returnType;
   }

   /**
    * Returns <jk>true</jk> if this method has this return type.
    *
    * @param c The return type to test for.
    * @return <jk>true</jk> if this method has this return type.
    */
   public boolean hasReturnType(Class<?> c) {
      return m.getReturnType() == c;
   }

   /**
    * Returns <jk>true</jk> if this method has this return type.
    *
    * @param ci The return type to test for.
    * @return <jk>true</jk> if this method has this return type.
    */
   public boolean hasReturnType(ClassInfo ci) {
      return hasReturnType(ci.inner());
   }

   /**
    * Returns <jk>true</jk> if this method has this parent return type.
    *
    * @param c The return type to test for.
    * @return <jk>true</jk> if this method has this parent return type.
    */
   public boolean hasReturnTypeParent(Class<?> c) {
      return ClassInfo.of(c).isParentOf(m.getReturnType());
   }

   /**
    * Returns <jk>true</jk> if this method has this parent return type.
    *
    * @param ci The return type to test for.
    * @return <jk>true</jk> if this method has this parent return type.
    */
   public boolean hasReturnTypeParent(ClassInfo ci) {
      return hasReturnTypeParent(ci.inner());
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Other methods
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Shortcut for calling the invoke method on the underlying method.
    *
    * @param obj the object the underlying method is invoked from.
    * @param args the arguments used for the method call
    * @return The object returned from the method.
    * @throws ExecutableException Exception occurred on invoked constructor/method/field.
    */
   @SuppressWarnings("unchecked")
   public <T> T invoke(Object obj, Object...args) throws ExecutableException {
      try {
         return (T)m.invoke(obj, args);
      } catch (IllegalAccessException | InvocationTargetException e) {
         throw new ExecutableException(e);
      }
   }

   /**
    * Invokes the specified method using fuzzy-arg matching.
    *
    * <p>
    * Arguments will be matched to the parameters based on the parameter types.
    * <br>Arguments can be in any order.
    * <br>Extra arguments will be ignored.
    * <br>Missing arguments will be left <jk>null</jk>.
    *
    * <p>
    * Note that this only works for methods that have distinguishable argument types.
    * <br>It's not going to work on methods with generic argument types like <c>Object</c>
    *
    * @param pojo
    *    The POJO the method is being called on.
    *    <br>Can be <jk>null</jk> for static methods.
    * @param args
    *    The arguments to pass to the method.
    * @return
    *    The results of the method invocation.
    * @throws ExecutableException Exception occurred on invoked constructor/method/field.
    */
   public Object invokeFuzzy(Object pojo, Object...args) throws ExecutableException {
      try {
         return m.invoke(pojo, ClassUtils.getMatchingArgs(m.getParameterTypes(), args));
      } catch (IllegalAccessException | InvocationTargetException e) {
         throw new ExecutableException(e);
      }
   }

   /**
    * Returns the signature of this method.
    *
    * <p>
    * For no-arg methods, the signature will be a simple string such as <js>"toString"</js>.
    * For methods with one or more args, the arguments will be fully-qualified class names (e.g.
    * <js>"append(java.util.StringBuilder,boolean)"</js>)
    *
    * @return The methods signature.
    */
   public String getSignature() {
      StringBuilder sb = new StringBuilder(128);
      sb.append(m.getName());
      Class<?>[] pt = rawParamTypes();
      if (pt.length > 0) {
         sb.append('(');
         List<ParamInfo> mpi = getParams();
         for (int i = 0; i < pt.length; i++) {
            if (i > 0)
               sb.append(',');
            mpi.get(i).getParameterType().appendFullName(sb);
         }
         sb.append(')');
      }
      return sb.toString();
   }

   /**
    * Returns the bean property name if this is a getter or setter.
    *
    * @return The bean property name, or <jk>null</jk> if this isn't a getter or setter.
    */
   public String getPropertyName() {
      String n = m.getName();
      if ((n.startsWith("get") || n.startsWith("set")) && n.length() > 3)
         return Introspector.decapitalize(n.substring(3));
      if (n.startsWith("is") && n.length() > 2)
         return Introspector.decapitalize(n.substring(2));
      return n;
   }

   /**
    * Returns <jk>true</jk> if the parameters on the method only consist of the types specified in the list.
    *
    * <h5 class='figure'>Example:</h5>
    * <p class='bpcode w800'>
    *
    *  <jc>// Example method:</jc>
    *    <jk>public void</jk> foo(String bar, Integer baz);
    *
    *    argsOnlyOfType(fooMethod, String.<jk>class</jk>, Integer.<jk>class</jk>);  <jc>// True.</jc>
    *    argsOnlyOfType(fooMethod, String.<jk>class</jk>, Integer.<jk>class</jk>, Map.<jk>class</jk>);  <jc>// True.</jc>
    *    argsOnlyOfType(fooMethod, String.<jk>class</jk>);  <jc>// False.</jc>
    * </p>
    *
    * @param args The valid class types (exact) for the arguments.
    * @return <jk>true</jk> if the method parameters only consist of the types specified in the list.
    */
   public boolean argsOnlyOfType(Class<?>...args) {
      for (Class<?> c1 : rawParamTypes()) {
         boolean foundMatch = false;
         for (Class<?> c2 : args)
            if (c1 == c2)
               foundMatch = true;
         if (! foundMatch)
            return false;
      }
      return true;
   }

   /**
    * Returns <jk>true</jk> if this method is a bridge method.
    *
    * @return <jk>true</jk> if this method is a bridge method.
    */
   public boolean isBridge() {
      return m.isBridge();
   }

   @Override
   public int compareTo(MethodInfo o) {
      int i = getSimpleName().compareTo(o.getSimpleName());
      if (i == 0) {
         i = rawParamTypes().length - o.rawParamTypes().length;
         if (i == 0) {
            for (int j = 0; j < rawParamTypes().length && i == 0; j++) {
               i = rawParamTypes()[j].getName().compareTo(o.rawParamTypes()[j].getName());
            }
         }
      }
      return i;
   }
}