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package org.glassfish.jersey.internal.inject;

import java.lang.annotation.Annotation;
import java.util.Collections;
import java.util.Set;

import javax.inject.Singleton;

import javax.ws.rs.RuntimeType;

import org.glassfish.jersey.model.ContractProvider;
import org.glassfish.jersey.model.internal.ComponentBag;

import org.glassfish.hk2.api.ActiveDescriptor;
import org.glassfish.hk2.api.DynamicConfiguration;
import org.glassfish.hk2.api.PerLookup;
import org.glassfish.hk2.api.ServiceLocator;
import org.glassfish.hk2.utilities.AliasDescriptor;
import org.glassfish.hk2.utilities.BuilderHelper;
import org.glassfish.hk2.utilities.binding.ScopedBindingBuilder;

import com.google.common.base.Predicate;
import com.google.common.collect.Sets;

/**
 * Class used for registration of the custom providers into HK2 service locator.
 * <p>
 * Custom providers are classes that implements specific JAX-RS or Jersey
 * SPI interfaces (e.g. {@link javax.ws.rs.ext.MessageBodyReader}) and are
 * supplied by the user. These providers will be bound into the HK2 service locator
 * annotated by a {@link Custom &#64;Custom} qualifier annotation.
 * </p>
 * <p>
 * Use the {@code &#64;Custom} qualifier annotation to retrieve these providers
 * from HK2 service locator. You may also use a one of the provider accessor utility
 * method defined in {@link Providers} class.
 * </p>
 *
 * @author Miroslav Fuksa (miroslav.fuksa at oracle.com)
 * @author Marek Potociar (marek.potociar at oracle.com)
 * @author Michal Gajdos (michal.gajdos at oracle.com)
 */
public class ProviderBinder {
    private final ServiceLocator locator;

    /**
     * Create new provider binder instance.
     *
     * @param locator HK2 service locator the binder will use to bind the
     *                providers into.
     */
    public ProviderBinder(ServiceLocator locator) {
        this.locator = locator;
    }

    /**
     * Register/bind custom provider instances. Registered providers will be handled
     * always as Singletons.
     *
     * @param instances custom provider instances.
     */
    public void bindInstances(Iterable<Object> instances) {
        final DynamicConfiguration dc = Injections.getConfiguration(locator);
        for (Object instance : instances) {
            bindInstance(instance, dc);
        }
        dc.commit();
    }


    /**
     * Register/bind custom provider classes. Registered providers will be handled
     * always as Singletons unless annotated by {@link PerLookup}.
     *
     * @param classes custom provider classes.
     */
    public void bindClasses(Class<?>... classes) {
        if (classes != null && classes.length > 0) {
            final DynamicConfiguration dc = Injections.getConfiguration(locator);
            for (Class<?> clazz : classes) {
                bindClass(clazz, locator, dc, false);
            }
            dc.commit();
        }
    }

    /**
     * Register/bind custom provider classes. Registered providers will be handled
     * always as Singletons unless annotated by {@link PerLookup}.
     *
     * @param classes custom provider classes.
     */
    public void bindClasses(Iterable<Class<?>> classes) {
        bindClasses(classes, false);
    }

    /**
     * Register/bind custom provider classes that may also be resources. Registered
     * providers/resources will be handled always as Singletons unless annotated by
     * {@link PerLookup}.
     *
     * <p>
     * If {@code bindAsResources} is set to {@code true}, the providers will also be bound
     * as resources.
     * </p>
     *
     * @param classes       custom provider classes.
     * @param bindResources if {@code true}, the provider classes will also be bound as
     *                      resources.
     */
    public void bindClasses(Iterable<Class<?>> classes, boolean bindResources) {
        if (classes == null || !classes.iterator().hasNext()) {
            return;
        }

        final DynamicConfiguration dc = Injections.getConfiguration(locator);
        for (Class<?> clazz : classes) {
            bindClass(clazz, locator, dc, bindResources);
        }
        dc.commit();
    }

    /**
     * Bind contract provider model to a provider class using the supplied HK2 dynamic configuration.
     *
     * @param providerClass provider class.
     * @param model      contract provider model.
     * @param dc            HK2 dynamic service locator configuration.
     */
    public static void bindProvider(
            final Class<?> providerClass, final ContractProvider model, final DynamicConfiguration dc) {

        for (Class contract : model.getContracts()) {
            final ScopedBindingBuilder bindingBuilder = Injections.newBinder(providerClass)
                    .in(model.getScope())
                    .qualifiedBy(new CustomAnnotationImpl());

            //noinspection unchecked
            bindingBuilder.to(contract);

            final int priority = model.getPriority(contract);
            if (priority > ContractProvider.NO_PRIORITY) {
                bindingBuilder.ranked(priority);
            }

            Injections.addBinding(bindingBuilder, dc);
        }
    }

    /**
     * Bind contract provider model to a provider instance using the supplied
     * HK2 dynamic configuration.
     *
     * Scope value specified in the {@link ContractProvider contract provider model}
     * is ignored as instances can only be bound as "singletons".
     *
     * @param providerInstance provider instance.
     * @param model         contract provider model.
     * @param dc               HK2 dynamic service locator configuration.
     */
    public static void bindProvider(
            final Object providerInstance, final ContractProvider model, final DynamicConfiguration dc) {

        for (Class contract : model.getContracts()) {
            final ScopedBindingBuilder bindingBuilder = Injections.
                    newBinder(providerInstance).
                    qualifiedBy(new CustomAnnotationImpl());

            //noinspection unchecked
            bindingBuilder.to(contract);

            final int priority = model.getPriority(contract);
            if (priority > ContractProvider.NO_PRIORITY) {
                bindingBuilder.ranked(priority);
            }

            Injections.addBinding(bindingBuilder, dc);
        }
    }

    /**
     * Bind all providers contained in {@code providerBag} (classes and instances) using HK2 service locator. Configuration is
     * also committed.
     *
     * @param componentBag bag of provider classes and instances.
     * @param locator      HK2 service locator the binder will use to bind the providers into.
     */
    public static void bindProviders(final ComponentBag componentBag, final ServiceLocator locator) {
        bindProviders(componentBag, null, Collections.<Class<?>>emptySet(), locator);
    }

    /**
     * Bind all providers contained in {@code providerBag} (classes and instances) using HK2 service locator. Configuration is
     * also committed.
     *
     * @param componentBag      bag of provider classes and instances.
     * @param constrainedTo     current runtime (client or server).
     * @param registeredClasses classes which are manually registered by the user (not found by the classpath scanning).
     * @param locator           HK2 service locator the binder will use to bind the providers into.
     */
    public static void bindProviders(final ComponentBag componentBag,
                                     final RuntimeType constrainedTo,
                                     final Set<Class<?>> registeredClasses,
                                     final ServiceLocator locator) {
        final DynamicConfiguration dc = Injections.getConfiguration(locator);
        bindProviders(componentBag, constrainedTo, registeredClasses, dc);
        dc.commit();
    }

    /**
     * Bind all providers contained in {@code providerBag} (classes and instances) using HK2 service locator. Configuration is
     * not committed.
     *
     * @param componentBag         bag of provider classes and instances.
     * @param constrainedTo        current runtime (client or server).
     * @param registeredClasses    classes which are manually registered by the user (not found by the classpath scanning).
     * @param dynamicConfiguration HK2 dynamic service locator configuration.
     */
    public static void bindProviders(final ComponentBag componentBag,
                                     final RuntimeType constrainedTo,
                                     final Set<Class<?>> registeredClasses,
                                     final DynamicConfiguration dynamicConfiguration) {
        Predicate<ContractProvider> filter = new Predicate<ContractProvider>() {
            @Override
            public boolean apply(ContractProvider input) {
                return ComponentBag.EXCLUDE_EMPTY.apply(input) && ComponentBag.EXCLUDE_META_PROVIDERS.apply(input);
            }
        };

        // Bind provider classes except for pure meta-providers and providers with empty contract models (e.g. resources)
        Set<Class<?>> classes = Sets.newLinkedHashSet(componentBag.getClasses(filter));
        if (constrainedTo != null) {
            classes = Sets.filter(classes, new Predicate<Class<?>>() {
                @Override
                public boolean apply(Class<?> componentClass) {
                    return Providers.checkProviderRuntime(
                            componentClass,
                            componentBag.getModel(componentClass),
                            constrainedTo,
                            registeredClasses == null || !registeredClasses.contains(componentClass),
                            false);
                }
            });
        }
        for (Class<?> providerClass : classes) {
            final ContractProvider model = componentBag.getModel(providerClass);
            ProviderBinder.bindProvider(providerClass, model, dynamicConfiguration);
        }

        // Bind pure provider instances except for pure meta-providers and providers with empty contract models (e.g. resources)
        Set<Object> instances = componentBag.getInstances(filter);
        if (constrainedTo != null) {
            instances = Sets.filter(instances, new Predicate<Object>() {
                @Override
                public boolean apply(Object component) {
                    final Class<?> componentClass = component.getClass();
                    return Providers.checkProviderRuntime(
                            componentClass,
                            componentBag.getModel(componentClass),
                            constrainedTo,
                            registeredClasses == null || !registeredClasses.contains(componentClass),
                            false);
                }
            });
        }
        for (Object provider : instances) {
            final ContractProvider model = componentBag.getModel(provider.getClass());
            ProviderBinder.bindProvider(provider, model, dynamicConfiguration);
        }
    }

    @SuppressWarnings("unchecked")
    private <T> void bindInstance(T instance, DynamicConfiguration dc) {
        for (Class contract : Providers.getProviderContracts(instance.getClass())) {
            Injections.addBinding(Injections.newBinder(instance).to(contract).qualifiedBy(new CustomAnnotationImpl()), dc);
        }
    }

    @SuppressWarnings("unchecked")
    private <T> void bindClass(Class<T> clazz, ServiceLocator locator, DynamicConfiguration dc, boolean isResource) {
        Class<? extends Annotation> scope = getProviderScope(clazz);

        if (isResource) {
            final ActiveDescriptor<?> descriptor = dc.bind(BuilderHelper.activeLink(clazz).to(clazz).in(scope).build());

            for (Class contract : Providers.getProviderContracts(clazz)) {
                AliasDescriptor aliasDescriptor = new AliasDescriptor(locator, descriptor, contract.getName(), null);
                aliasDescriptor.setScope(scope.getName());
                aliasDescriptor.addQualifierAnnotation(new CustomAnnotationImpl());

                dc.bind(aliasDescriptor);
            }
        } else {
            final ScopedBindingBuilder<T> bindingBuilder =
                    Injections.newBinder(clazz).in(scope).qualifiedBy(new CustomAnnotationImpl());
            for (Class contract : Providers.getProviderContracts(clazz)) {
                bindingBuilder.to(contract);
            }
            Injections.addBinding(bindingBuilder, dc);
        }
    }

    private Class<? extends Annotation> getProviderScope(Class<?> clazz) {
        Class<? extends Annotation> hk2Scope = Singleton.class;
        if (clazz.isAnnotationPresent(PerLookup.class)) {
            hk2Scope = PerLookup.class;
        }
        return hk2Scope;
    }
}
