/*
    * 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.di.impl;
  
  import java.lang.annotation.Annotation;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.function.Consumer;
  import java.util.function.Function;
  import java.util.function.Supplier;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import org.apache.maven.di.Key;
  
  import static java.util.stream.Collectors.joining;
  
  public abstract class Binding<T> {
      private final Set<Key<?>> dependencies;
      private Annotation scope;
      private int priority;
      private Key<?> originalKey;
  
      protected Binding(Key<? extends T> originalKey, Set<Key<?>> dependencies) {
          this(originalKey, dependencies, null, 0);
      }
  
      protected Binding(Key<?> originalKey, Set<Key<?>> dependencies, Annotation scope, int priority) {
          this.originalKey = originalKey;
          this.dependencies = dependencies;
          this.scope = scope;
          this.priority = priority;
      }
  
      public static <T> Binding<T> toInstance(T instance) {
          return new BindingToInstance<>(instance);
      }
  
      public static <R> Binding<R> to(Key<R> originalKey, TupleConstructorN<R> constructor, Class<?>[] types) {
          return Binding.to(
                  originalKey, constructor, Stream.of(types).map(Key::of).toArray(Key<?>[]::new));
      }
  
      public static <R> Binding<R> to(Key<R> originalKey, TupleConstructorN<R> constructor, Key<?>[] dependencies) {
          return to(originalKey, constructor, dependencies, 0);
      }
  
      public static <R> Binding<R> to(
              Key<R> originalKey, TupleConstructorN<R> constructor, Key<?>[] dependencies, int priority) {
          return new BindingToConstructor<>(originalKey, constructor, dependencies, priority);
      }
  
      // endregion
  
      public Binding<T> scope(Annotation scope) {
          this.scope = scope;
          return this;
      }
  
      public Binding<T> prioritize(int priority) {
          this.priority = priority;
          return this;
      }
  
      public Binding<T> withKey(Key<?> key) {
          this.originalKey = key;
          return this;
      }
  
      public Binding<T> initializeWith(BindingInitializer<T> bindingInitializer) {
          return new Binding<T>(
                  this.originalKey,
                  Stream.of(this.dependencies, bindingInitializer.getDependencies())
                          .flatMap(Set::stream)
                          .collect(Collectors.toSet()),
                  this.scope,
                  this.priority) {
              @Override
              public Supplier<T> compile(Function<Key<?>, Supplier<?>> compiler) {
                  final Supplier<T> compiledBinding = Binding.this.compile(compiler);
                  final Consumer<T> consumer = bindingInitializer.compile(compiler);
                 return () -> {
                     T instance = compiledBinding.get();
                     consumer.accept(instance);
                     return instance;
                 };
             }
 
             @Override
             public String toString() {
                 return Binding.this.toString();
             }
         };
     }
 
     public abstract Supplier<T> compile(Function<Key<?>, Supplier<?>> compiler);
 
     public Set<Key<?>> getDependencies() {
         return dependencies;
     }
 
     public Annotation getScope() {
         return scope;
     }
 
     public String getDisplayString() {
         return dependencies.stream().map(Key::getDisplayString).collect(joining(", ", "[", "]"));
     }
 
     public Key<?> getOriginalKey() {
         return originalKey;
     }
 
     public int getPriority() {
         return priority;
     }
 
     @Override
     public String toString() {
         return "Binding" + dependencies.toString();
     }
 
     @FunctionalInterface
     public interface TupleConstructorN<R> {
         R create(Object... args);
     }
 
     public static class BindingToInstance<T> extends Binding<T> {
         final T instance;
 
         public BindingToInstance(T instance) {
             super(null, Collections.emptySet());
             this.instance = instance;
         }
 
         @Override
         public Supplier<T> compile(Function<Key<?>, Supplier<?>> compiler) {
             return () -> instance;
         }
 
         @Override
         public String toString() {
             return "BindingToInstance[" + instance + "]" + getDependencies();
         }
     }
 
     public static class BindingToConstructor<T> extends Binding<T> {
         final TupleConstructorN<T> constructor;
         final Key<?>[] args;
 
         BindingToConstructor(
                 Key<? extends T> key, TupleConstructorN<T> constructor, Key<?>[] dependencies, int priority) {
             super(key, new HashSet<>(Arrays.asList(dependencies)), null, priority);
             this.constructor = constructor;
             this.args = dependencies;
         }
 
         @Override
         public Supplier<T> compile(Function<Key<?>, Supplier<?>> compiler) {
             return () -> {
                 Object[] args =
                         Stream.of(this.args).map(compiler).map(Supplier::get).toArray();
                 return constructor.create(args);
             };
         }
 
         @Override
         public String toString() {
             return "BindingToConstructor[" + constructor + "]" + getDependencies();
         }
     }
 }