/*
 * Copyright (c) 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * 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 io.helidon.integrations.jta.cdi;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.context.Destroyed;
import javax.enterprise.context.Initialized;
import javax.enterprise.event.Event;
import javax.inject.Inject;
import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.SystemException;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager; // for javadoc only
import javax.transaction.TransactionScoped;

import com.arjuna.ats.jta.common.JTAEnvironmentBean;

/**
 * A {@link DelegatingTransactionManager} in {@linkplain
 * ApplicationScoped application scope} that uses the return value
 * that results from invoking the {@link
 * JTAEnvironmentBean#getTransactionManager()} method as its backing
 * implementation.
 *
 * @see com.arjuna.ats.jta.common.JTAEnvironmentBean#getTransactionManager()
 */
@ApplicationScoped
class NarayanaTransactionManager extends DelegatingTransactionManager {


    /*
     * Instance fields.
     */


    /**
     * An {@link Event} capable of {@linkplain Event#fire(Object)
     * firing} a {@link Transaction} when {@linkplain
     * TransactionScoped transaction scope} has begun.
     *
     * <p>This field may be {@code null}.</p>
     */
    private final Event<Transaction> transactionScopeInitializedBroadcaster;

    /**
     * An {@link Event} capable of {@linkplain Event#fire(Object)
     * firing} an {@link Object} when {@linkplain TransactionScoped
     * transaction scope} has ended.
     *
     * <p>This field may be {@code null}.</p>
     */
    private final Event<Object> transactionScopeDestroyedBroadcaster;


    /*
     * Constructors.
     */


    /**
     * Creates a new, <strong>nonfunctional</strong> {@link
     * NarayanaTransactionManager}.
     *
     * <p>This constructor exists only to conform with <a
     * href="http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#unproxyable">section
     * 3.15 of the CDI specification</a>.</p>
     *
     * @deprecated This constructor exists only to conform with <a
     * href="http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#unproxyable">section
     * 3.15 of the CDI specification</a>.
     *
     * @see <a
     * href="http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#unproxyable">Section
     * 3.15 of the CDI specification</a>
     */
    @Deprecated
    NarayanaTransactionManager() {
        this(null, null, null);
    }

    /**
     * Creates a new {@link NarayanaTransactionManager}.
     *
     * @param jtaEnvironmentBean a {@link JTAEnvironmentBean} used to
     * acquire this {@link NarayanaTransactionManager}'s delegate; may
     * be {@code null} but then a {@link SystemException} will be
     * thrown by every method in this class when invoked
     *
     * @param transactionScopeInitializedBroadcaster an {@link Event}
     * capable of {@linkplain Event#fire(Object) firing} {@link
     * Transaction} instances; may be {@code null}
     *
     * @param transactionScopeDestroyedBroadcaster an {@link Event}
     * capable of {@linkplain Event#fire(Object) firing} {@link
     * Object} instances; may be {@code null}
     *
     * @see #begin()
     *
     * @see #commit()
     *
     * @see #rollback()
     */
    @Inject
    NarayanaTransactionManager(final JTAEnvironmentBean jtaEnvironmentBean,
                               @Initialized(TransactionScoped.class)
                               final Event<Transaction> transactionScopeInitializedBroadcaster,
                               @Destroyed(TransactionScoped.class)
                               final Event<Object> transactionScopeDestroyedBroadcaster) {
        super(jtaEnvironmentBean == null ? null : jtaEnvironmentBean.getTransactionManager());
        this.transactionScopeInitializedBroadcaster = transactionScopeInitializedBroadcaster;
        this.transactionScopeDestroyedBroadcaster = transactionScopeDestroyedBroadcaster;
    }


    /*
     * Instance methods.
     */


    /**
     * Overrides {@link DelegatingTransactionManager#begin()} to
     * additionally {@linkplain Event#fire(Object) fire} an {@link
     * Object} representing the {@linkplain Initialized
     * initialization} of the {@linkplain TransactionScoped
     * transaction scope}.
     *
     * @exception NotSupportedException if the thread is already
     * associated with a transaction and this {@link
     * TransactionManager} implementation does not support nested
     * transactions
     *
     * @exception SystemException if this {@link TransactionManager}
     * encounters an unexpected error condition
     *
     * @see DelegatingTransactionManager#begin()
     *
     * @see Event#fire(Object)
     *
     * @see Initialized
     *
     * @see TransactionScoped
     */
    @Override
    public void begin() throws NotSupportedException, SystemException {
        super.begin();
        if (this.transactionScopeInitializedBroadcaster != null) {
            this.transactionScopeInitializedBroadcaster.fire(this.getTransaction());
        }
    }

    /**
     * Overrides {@link DelegatingTransactionManager#commit()} to
     * additionally {@linkplain Event#fire(Object) fire} an {@link
     * Object} representing the {@linkplain Destroyed destruction} of
     * the {@linkplain TransactionScoped transaction scope}.
     *
     * @exception RollbackException if the transaction has been rolled
     * back rather than committed
     *
     * @exception HeuristicMixedException if a heuristic decision was
     * made and that some relevant updates have been committed while
     * others have been rolled back
     *
     * @exception HeuristicRollbackException if a heuristic decision
     * was made and all relevant updates have been rolled back
     *
     * @exception SecurityException if the thread is not allowed to
     * commit the transaction
     *
     * @exception IllegalStateException if the current thread is not
     * associated with a transaction
     *
     * @exception SystemException if this {@link TransactionManager}
     * encounters an unexpected error condition
     *
     * @see DelegatingTransactionManager#commit()
     *
     * @see Event#fire(Object)
     *
     * @see Destroyed
     *
     * @see TransactionScoped
     */
    @Override
    public void commit() throws HeuristicMixedException, HeuristicRollbackException, RollbackException, SystemException {
        try {
            super.commit();
        } finally {
            if (this.transactionScopeDestroyedBroadcaster != null) {
                this.transactionScopeDestroyedBroadcaster.fire(this.toString());
            }
        }
    }

    /**
     * Overrides {@link DelegatingTransactionManager#rollback()} to
     * additionally {@linkplain Event#fire(Object) fire} an {@link
     * Object} representing the {@linkplain Destroyed destruction} of
     * the {@linkplain TransactionScoped transaction scope}.
     *
     * @exception SecurityException if the thread is not allowed to
     * roll back the transaction
     *
     * @exception IllegalStateException if the current thread is not
     * associated with a transaction
     *
     * @exception SystemException if this {@link TransactionManager}
     * encounters an unexpected error condition
     *
     * @see DelegatingTransactionManager#rollback()
     *
     * @see Event#fire(Object)
     *
     * @see Destroyed
     *
     * @see TransactionScoped
     */
    @Override
    public void rollback() throws SystemException {
        try {
            super.rollback();
        } finally {
            if (this.transactionScopeDestroyedBroadcaster != null) {
                this.transactionScopeDestroyedBroadcaster.fire(this.toString());
            }
        }
    }

}
