/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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 com.google.inject.internal;

import com.google.inject.Binder;
import com.google.inject.Binding;
import com.google.inject.Key;
import com.google.inject.Provider;
import com.google.inject.spi.ConstructorBinding;
import com.google.inject.spi.ConvertedConstantBinding;
import com.google.inject.spi.ExposedBinding;
import com.google.inject.spi.InjectionPoint;
import com.google.inject.spi.InstanceBinding;
import com.google.inject.spi.LinkedKeyBinding;
import com.google.inject.spi.PrivateElements;
import com.google.inject.spi.ProviderBinding;
import com.google.inject.spi.ProviderInstanceBinding;
import com.google.inject.spi.ProviderKeyBinding;
import com.google.inject.spi.UntargettedBinding;
import java.util.Set;

/**
 * Handles {@link Binder#bind} and {@link Binder#bindConstant} elements.
 *
 * @author crazybob@google.com (Bob Lee)
 * @author jessewilson@google.com (Jesse Wilson)
 */
final class BindingProcessor extends AbstractBindingProcessor {

  private final Initializer initializer;

  BindingProcessor(Errors errors, Initializer initializer, ProcessedBindingData bindingData) {
    super(errors, bindingData);
    this.initializer = initializer;
  }

  @Override
  public <T> Boolean visit(Binding<T> command) {
    Class<?> rawType = command.getKey().getTypeLiteral().getRawType();
    if (Void.class.equals(rawType)) {
      if (command instanceof ProviderInstanceBinding
          && ((ProviderInstanceBinding) command).getUserSuppliedProvider()
              instanceof ProviderMethod) {
        errors.voidProviderMethod();
      } else {
        errors.missingConstantValues();
      }
      return true;
    }

    if (rawType == Provider.class) {
      errors.bindingToProvider();
      return true;
    }

    return command.acceptTargetVisitor(
        new Processor<T, Boolean>((BindingImpl<T>) command) {
          @Override
          public Boolean visit(ConstructorBinding<? extends T> binding) {
            prepareBinding();
            try {
              ConstructorBindingImpl<T> onInjector =
                  ConstructorBindingImpl.create(
                      injector,
                      key,
                      binding.getConstructor(),
                      source,
                      scoping,
                      errors,
                      false,
                      false);
              scheduleInitialization(onInjector);
              putBinding(onInjector);
            } catch (ErrorsException e) {
              errors.merge(e.getErrors());
              putBinding(invalidBinding(injector, key, source));
            }
            return true;
          }

          @Override
          public Boolean visit(InstanceBinding<? extends T> binding) {
            prepareBinding();
            Set<InjectionPoint> injectionPoints = binding.getInjectionPoints();
            T instance = binding.getInstance();
            @SuppressWarnings("unchecked") // safe to cast to binding<T> because
            // the processor was constructed w/ it
            Initializable<T> ref =
                initializer.requestInjection(
                    injector, instance, (Binding<T>) binding, source, injectionPoints);
            ConstantFactory<? extends T> factory = new ConstantFactory<>(ref);
            InternalFactory<? extends T> scopedFactory =
                Scoping.scope(key, injector, factory, source, scoping);
            putBinding(
                new InstanceBindingImpl<T>(
                    injector, key, source, scopedFactory, injectionPoints, instance));
            return true;
          }

          @Override
          public Boolean visit(ProviderInstanceBinding<? extends T> binding) {
            prepareBinding();
            javax.inject.Provider<? extends T> provider = binding.getUserSuppliedProvider();
            if (provider instanceof InternalProviderInstanceBindingImpl.Factory) {
              @SuppressWarnings("unchecked")
              InternalProviderInstanceBindingImpl.Factory<T> asProviderMethod =
                  (InternalProviderInstanceBindingImpl.Factory<T>) provider;
              return visitInternalProviderInstanceBindingFactory(asProviderMethod);
            }
            Set<InjectionPoint> injectionPoints = binding.getInjectionPoints();
            Initializable<? extends javax.inject.Provider<? extends T>> initializable =
                initializer.<javax.inject.Provider<? extends T>>requestInjection(
                    injector, provider, null, source, injectionPoints);
            // always visited with Binding<T>
            @SuppressWarnings("unchecked")
            InternalFactory<T> factory =
                new InternalFactoryToInitializableAdapter<T>(
                    initializable,
                    source,
                    injector.provisionListenerStore.get((ProviderInstanceBinding<T>) binding));
            InternalFactory<? extends T> scopedFactory =
                Scoping.scope(key, injector, factory, source, scoping);
            putBinding(
                new ProviderInstanceBindingImpl<T>(
                    injector, key, source, scopedFactory, scoping, provider, injectionPoints));
            return true;
          }

          @Override
          public Boolean visit(ProviderKeyBinding<? extends T> binding) {
            prepareBinding();
            Key<? extends javax.inject.Provider<? extends T>> providerKey =
                binding.getProviderKey();
            // always visited with Binding<T>
            @SuppressWarnings("unchecked")
            BoundProviderFactory<T> boundProviderFactory =
                new BoundProviderFactory<T>(
                    injector,
                    providerKey,
                    source,
                    injector.provisionListenerStore.get((ProviderKeyBinding<T>) binding));
            bindingData.addCreationListener(boundProviderFactory);
            InternalFactory<? extends T> scopedFactory =
                Scoping.scope(
                    key,
                    injector,
                    (InternalFactory<? extends T>) boundProviderFactory,
                    source,
                    scoping);
            putBinding(
                new LinkedProviderBindingImpl<T>(
                    injector, key, source, scopedFactory, scoping, providerKey));
            return true;
          }

          @Override
          public Boolean visit(LinkedKeyBinding<? extends T> binding) {
            prepareBinding();
            Key<? extends T> linkedKey = binding.getLinkedKey();
            if (key.equals(linkedKey)) {
              errors.recursiveBinding();
            }

            FactoryProxy<T> factory = new FactoryProxy<>(injector, key, linkedKey, source);
            bindingData.addCreationListener(factory);
            InternalFactory<? extends T> scopedFactory =
                Scoping.scope(key, injector, factory, source, scoping);
            putBinding(
                new LinkedBindingImpl<T>(injector, key, source, scopedFactory, scoping, linkedKey));
            return true;
          }

          /** Handle ProviderMethods specially. */
          private Boolean visitInternalProviderInstanceBindingFactory(
              InternalProviderInstanceBindingImpl.Factory<T> provider) {
            InternalProviderInstanceBindingImpl<T> binding =
                new InternalProviderInstanceBindingImpl<T>(
                    injector,
                    key,
                    source,
                    provider,
                    Scoping.scope(key, injector, provider, source, scoping),
                    scoping);
            switch (binding.getInitializationTiming()) {
              case DELAYED:
                scheduleDelayedInitialization(binding);
                break;
              case EAGER:
                scheduleInitialization(binding);
                break;
              default:
                throw new AssertionError();
            }
            putBinding(binding);
            return true;
          }

          @Override
          public Boolean visit(UntargettedBinding<? extends T> untargetted) {
            return false;
          }

          @Override
          public Boolean visit(ExposedBinding<? extends T> binding) {
            throw new IllegalArgumentException("Cannot apply a non-module element");
          }

          @Override
          public Boolean visit(ConvertedConstantBinding<? extends T> binding) {
            throw new IllegalArgumentException("Cannot apply a non-module element");
          }

          @Override
          public Boolean visit(ProviderBinding<? extends T> binding) {
            throw new IllegalArgumentException("Cannot apply a non-module element");
          }

          @Override
          protected Boolean visitOther(Binding<? extends T> binding) {
            throw new IllegalStateException("BindingProcessor should override all visitations");
          }
        });
  }

  @Override
  public Boolean visit(PrivateElements privateElements) {
    for (Key<?> key : privateElements.getExposedKeys()) {
      bindExposed(privateElements, key);
    }
    return false; // leave the private elements for the PrivateElementsProcessor to handle
  }

  private <T> void bindExposed(PrivateElements privateElements, Key<T> key) {
    ExposedKeyFactory<T> exposedKeyFactory = new ExposedKeyFactory<>(key, privateElements);
    bindingData.addCreationListener(exposedKeyFactory);
    putBinding(
        new ExposedBindingImpl<T>(
            injector,
            privateElements.getExposedSource(key),
            key,
            exposedKeyFactory,
            privateElements));
  }
}