/*
 * 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.commons.inject;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import static org.apache.juneau.commons.utils.Shorts.*;

import java.lang.annotation.*;
import java.util.*;

import org.apache.juneau.commons.*;
import org.apache.juneau.commons.reflect.*;

/**
 * Utility classes and methods for the {@link Bean @Bean} annotation.
 *
 */
public class BeanAnnotation {

   /**
    * Private constructor to prevent instantiation.
    */
   private BeanAnnotation() {
      // Utility class - prevent instantiation
   }

   /**
    * A collection of {@link Bean @Bean} annotations.
    */
   @Documented
   @Target({ FIELD, METHOD, TYPE })
   @Retention(RUNTIME)
   @Inherited
   public static @interface Array {

      /**
       * The child annotations.
       *
       * @return The annotation value.
       */
      Bean[] value();
   }

   /**
    * Builder class.
    *
    * <h5 class='section'>See Also:</h5><ul>
    *    <li class='jm'>{@code MarshallingContext.Builder<?>#annotations(Annotation...)}
    * </ul>
    */
   public static class Builder extends AppliedAnnotationObject.BuilderM {

      private String[] description = {};
      private String name;
      private String value;
      private String[] methodScope;

      /**
       * Constructor.
       */
      protected Builder() {
         super(Bean.class);
      }

      /**
       * Instantiates a new {@link Bean @Bean} object initialized with this builder.
       *
       * @return A new {@link Bean @Bean} object.
       */
      public Bean build() {
         return new Object(this);
      }

      /**
       * Sets the description property on this annotation.
       *
       * @param value The new value for this property.  Can be <jk>null</jk>, in which case an empty array is used.
       * @return This object.
       */
      public Builder description(String...value) {
         description = value;
         return this;
      }

      /**
       * Sets the {@link Bean#methodScope()} property on this annotation.
       *
       * @param value The new value for this property.  Can be <jk>null</jk>, in which case an empty array is used.
       * @return This object.
       */
      public Builder methodScope(String...value) {
         methodScope = value;
         return this;
      }

      /**
       * Sets the {@link Bean#name()} property on this annotation.
       *
       * @param value The new value for this property.  Can be <jk>null</jk>, in which case an empty string is used.
       * @return This object.
       */
      public Builder name(String value) {
         name = value;
         return this;
      }

      /**
       * Sets the {@link Bean#value()} property on this annotation.
       *
       * @param value The new value for this property.  Can be <jk>null</jk>, in which case an empty string is used.
       * @return This object.
       */
      public Builder value(String value) {
         this.value = value;
         return this;
      }

      @Override /* Overridden from AppliedAnnotationObject.Builder */
      public Builder on(String...value) {
         super.on(value);
         return this;
      }
      @Override /* Overridden from AppliedAnnotationObject.BuilderM */
      public Builder on(java.lang.reflect.Method...value) {
         super.on(value);
         return this;
      }


      @Override /* Overridden from AppliedAnnotationObject.BuilderM */
      public Builder on(org.apache.juneau.commons.reflect.MethodInfo...value) {
         super.on(value);
         return this;
      }

   }

   @SuppressWarnings({
      "annotationSuperInterface", // Eclipse JDT: intentional concrete implementation of annotation interface for runtime-built annotation instances
      "java:S2160" // equals() inherited from AnnotationObject compares all annotation interface methods; subclass fields are accessed via those methods
   })
   private static class Object extends AppliedAnnotationObject implements Bean {

      private static final String[] EMPTY_STRINGS = new String[0];

      private final String[] description;
      private final String name;
      private final String value;
      private final String[] methodScope;

      Object(BeanAnnotation.Builder b) {
         super(b);
         // Mirror the compile-time defaults declared on @Bean (empty strings / empty arrays) so
         // callers iterating the runtime instance see annotation-equivalent values instead of nulls.
         description = b.description != null ? cp(b.description) : EMPTY_STRINGS;
         name = b.name != null ? b.name : "";
         value = b.value != null ? b.value : "";
         methodScope = b.methodScope != null ? cp(b.methodScope) : EMPTY_STRINGS;
      }

      @Override /* Overridden from Bean */
      public String[] methodScope() {
         return cp(methodScope);
      }

      @Override /* Overridden from Bean */
      public String name() {
         return name;
      }

      @Override /* Overridden from Bean */
      public String value() {
         return value;
      }

      @Override /* Overridden from annotation */
      public String[] description() {
         return cp(description);
      }

      @Override /* Overridden from Bean */
      public int priority() {
         return Integer.MAX_VALUE / 2;
      }
   }

   /** Default value */
   public static final Bean DEFAULT = create().build();

   /**
    * Instantiates a new builder for this class.
    *
    * @return A new builder object.
    */
   public static Builder create() {
      return new Builder();
   }

   /**
    * Pulls the name/value attribute from a {@link Bean} annotation.
    *
    * @param a The annotation to check.  Can be <jk>null</jk> (returns an empty string).
    * @return The annotation value, or an empty string if the annotation is <jk>null</jk>.
    */
   public static String name(Bean a) {
      if (a == null)
         return "";
      if (! a.name().isEmpty())
         return a.name();
      return a.value();
   }

   /**
    * Finds the {@link Bean @Bean} annotation that applies to the specified method.
    *
    * <p>
    * The result is the method's <em>own</em> declared {@link Bean @Bean}, or else the one declared on a method it
    * truly overrides.  A parent method only counts as overridden when it is non-private, non-static, not a
    * bridge/synthetic method, and (when package-private) declared in the same package as the method.
    * This is stricter than {@link MethodInfo#getAnnotations()}, which also merges annotations from same-signature
    * private or static parent methods that are not overrides.
    *
    * <p>
    * Bridge and synthetic methods always return {@link Optional#empty()}.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jk>public class</jk> Parent {
    *       <ja>@Bean</ja>(name=<js>"db"</js>)
    *       <jk>public</jk> HealthIndicator dbIndicator() { ... }
    *    }
    *
    *    <jk>public class</jk> Child <jk>extends</jk> Parent {
    *       <ja>@Override</ja>
    *       <jk>public</jk> HealthIndicator dbIndicator() { ... }  <jc>// Not annotated, but overrides an annotated method.</jc>
    *    }
    *
    *    MethodInfo <jv>mi</jv> = ClassInfo.<jsm>of</jsm>(Child.<jk>class</jk>).getDeclaredMethod(<jv>x</jv> -&gt; <jv>x</jv>.hasName(<js>"dbIndicator"</js>)).get();
    *    Optional&lt;Bean&gt; <jv>bean</jv> = BeanAnnotation.<jsm>find</jsm>(<jv>mi</jv>);  <jc>// Present, name="db".</jc>
    * </p>
    *
    * @param method The method to inspect.  Must not be <jk>null</jk>.
    * @return The applicable annotation, or {@link Optional#empty()} if none applies.
    */
   public static Optional<Bean> find(MethodInfo method) {
      reqnn("method", method);
      if (method.isBridge() || method.isSynthetic())
         return Optional.empty();
      var own = method.inner().getAnnotation(Bean.class);
      if (own != null)
         return Optional.of(own);
      if (method.isPrivate() || method.isStatic())
         return Optional.empty();
      var pkg = method.inner().getDeclaringClass().getPackageName();
      var matching = method.getMatchingMethods();
      for (var i = 1; i < matching.size(); i++) {
         var parent = matching.get(i);
         if (! isInheritableFrom(parent, pkg))
            continue;
         var a = parent.inner().getAnnotation(Bean.class);
         if (a != null)
            return Optional.of(a);
      }
      return Optional.empty();
   }

   private static boolean isInheritableFrom(MethodInfo parent, String pkg) {
      if (parent.isPrivate() || parent.isStatic() || parent.isBridge() || parent.isSynthetic())
         return false;
      return parent.isPublic() || parent.isProtected() || pkg.equals(parent.inner().getDeclaringClass().getPackageName());
   }
}