package org.infinispan.cdi.common.util;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.enterprise.context.Dependent;
import javax.enterprise.context.spi.CreationalContext;
import javax.enterprise.inject.Default;
import javax.enterprise.inject.spi.Bean;
import javax.enterprise.inject.spi.InjectionPoint;

import org.infinispan.cdi.common.util.logging.Log;
import org.infinispan.commons.logging.LogFactory;

/**
 * <p>
 * A base class for implementing {@link Bean}. The attributes are immutable, and
 * collections are defensively copied on instantiation. It uses the defaults
 * from the specification for properties if not specified.
 * </p>
 * <p/>
 * <p>
 * This class does not provide any bean lifecycle operations
 * </p>
 *
 * @author Pete Muir
 * @see ImmutableBean
 * @see ImmutableNarrowingBean
 */
public abstract class AbstractImmutableBean<T> implements Bean<T> {

    private static final Log log = LogFactory.getLog(AbstractImmutableBean.class, Log.class);

    private final Class<?> beanClass;
    private final String name;
    private final Set<Annotation> qualifiers;
    private final Class<? extends Annotation> scope;
    private final Set<Class<? extends Annotation>> stereotypes;
    private final Set<Type> types;
    private final boolean alternative;
    private final boolean nullable;
    private final Set<InjectionPoint> injectionPoints;
    private final String toString;

    /**
     * Create a new, immutable bean. All arguments passed as collections are
     * defensively copied.
     *
     * @param beanClass       The Bean class, may not be null
     * @param name            The bean name
     * @param qualifiers      The bean's qualifiers, if null, a singleton set of
     *                        {@link Default} is used
     * @param scope           The bean's scope, if null, the default scope of
     *                        {@link Dependent} is used
     * @param stereotypes     The bean's stereotypes, if null, an empty set is used
     * @param types           The bean's types, if null, the beanClass and {@link Object}
     *                        will be used
     * @param alternative     True if the bean is an alternative
     * @param nullable        True if the bean is nullable
     * @param injectionPoints the bean's injection points, if null an empty set
     *                        is used
     * @param beanLifecycle   Handler for {@link #create(CreationalContext)} and
     *                        {@link #destroy(Object, CreationalContext)}
     * @throws IllegalArgumentException if the beanClass is null
     */
    public AbstractImmutableBean(Class<?> beanClass, String name, Set<Annotation> qualifiers, Class<? extends Annotation> scope, Set<Class<? extends Annotation>> stereotypes, Set<Type> types, boolean alternative, boolean nullable, Set<InjectionPoint> injectionPoints, String toString) {
        if (beanClass == null) {
            throw new IllegalArgumentException("beanClass cannot be null");
        }
        this.beanClass = beanClass;
        this.name = name;
        if (qualifiers == null) {
            this.qualifiers = Collections.<Annotation>singleton(DefaultLiteral.INSTANCE);
            log.trace("No qualifers provided for bean class " + beanClass + ", using singleton set of @Default");
        } else {
            this.qualifiers = new HashSet<Annotation>(qualifiers);
        }
        if (scope == null) {
            this.scope = Dependent.class;
            log.trace("No scope provided for bean class " + beanClass + ", using @Dependent");
        } else {
            this.scope = scope;
        }
        if (stereotypes == null) {
            this.stereotypes = Collections.emptySet();
        } else {
            this.stereotypes = new HashSet<Class<? extends Annotation>>(stereotypes);
        }
        if (types == null) {
            this.types = Arrays2.<Type>asSet(Object.class, beanClass);
            log.trace("No types provided for bean class " + beanClass + ", using [java.lang.Object.class, " + beanClass.getName() + ".class]");
        } else {
            this.types = new HashSet<Type>(types);
        }
        if (injectionPoints == null) {
            this.injectionPoints = Collections.emptySet();
        } else {
            this.injectionPoints = new HashSet<InjectionPoint>(injectionPoints);
        }
        this.alternative = alternative;
        this.nullable = nullable;
        if (toString != null) {
            this.toString = toString;
        } else {
            this.toString = "Custom Bean with bean class " + beanClass + " and qualifiers " + qualifiers;
        }
    }

    @Override
   public Class<?> getBeanClass() {
        return beanClass;
    }

    @Override
   public Set<InjectionPoint> getInjectionPoints() {
        return injectionPoints;
    }

    @Override
   public String getName() {
        return name;
    }

    @Override
   public Set<Annotation> getQualifiers() {
        return Collections.unmodifiableSet(qualifiers);
    }

    @Override
   public Class<? extends Annotation> getScope() {
        return scope;
    }

    @Override
   public Set<Class<? extends Annotation>> getStereotypes() {
        return Collections.unmodifiableSet(stereotypes);
    }

    @Override
   public Set<Type> getTypes() {
        return Collections.unmodifiableSet(types);
    }

    @Override
   public boolean isAlternative() {
        return alternative;
    }

    @Override
   public boolean isNullable() {
        return nullable;
    }

    @Override
    public String toString() {
        return toString;
    }

}
