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/*
 * Copyright 2016-2024 Talsma ICT
 *
 * 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 nl.talsmasoftware.context.core.function;

import nl.talsmasoftware.context.Context;
import nl.talsmasoftware.context.ContextManagers;
import nl.talsmasoftware.context.ContextSnapshot;

import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.logging.Level;
import java.util.logging.Logger;

import static java.util.Objects.requireNonNull;

/**
 * A wrapper for {@link Function} that {@link ContextSnapshot#reactivate() reactivates a context snapshot} before
 * calling a delegate.
 *
 * @author Sjoerd Talsma
 */
public class FunctionWithContext extends WrapperWithContextAndConsumer> implements Function {
    private static final Logger LOGGER = Logger.getLogger(FunctionWithContext.class.getName());

    public FunctionWithContext(ContextSnapshot snapshot, Function delegate) {
        this(snapshot, delegate, null);
    }

    public FunctionWithContext(ContextSnapshot snapshot, Function delegate, Consumer consumer) {
        super(snapshot, delegate, consumer);
    }

    protected FunctionWithContext(Supplier supplier, Function delegate, Consumer consumer) {
        super(supplier, delegate, consumer);
    }

    public OUT apply(IN in) {
        try (Context context = snapshot().reactivate()) {
            try { // inner 'try' is needed: https://github.com/talsma-ict/context-propagation/pull/56#discussion_r201590623
                LOGGER.log(Level.FINEST, "Delegating apply method with {0} to {1}.", new Object[]{context, delegate()});
                return delegate().apply(in);
            } finally {
                if (contextSnapshotConsumer != null) {
                    ContextSnapshot resultSnapshot = ContextManagers.createContextSnapshot();
                    LOGGER.log(Level.FINEST, "Captured context snapshot after delegation: {0}", resultSnapshot);
                    contextSnapshotConsumer.accept(resultSnapshot);
                }
            }
        }
    }

    public  Function compose(Function before) {
        requireNonNull(before, "Cannot compose with before function .");
        return (V v) -> {
            try (Context context = snapshot().reactivate()) {
                try { // inner 'try' is needed: https://github.com/talsma-ict/context-propagation/pull/56#discussion_r201590623
                    LOGGER.log(Level.FINEST, "Delegating compose method with {0} to {1}.", new Object[]{context, delegate()});
                    return delegate().apply(before.apply(v));
                } finally {
                    if (contextSnapshotConsumer != null) {
                        ContextSnapshot resultSnapshot = ContextManagers.createContextSnapshot();
                        LOGGER.log(Level.FINEST, "Captured context snapshot after delegation: {0}", resultSnapshot);
                        contextSnapshotConsumer.accept(resultSnapshot);
                    }
                }
            }
        };
    }

    public  Function andThen(Function after) {
        requireNonNull(after, "Cannot transform with after function .");
        return (IN in) -> {
            try (Context context = snapshot().reactivate()) {
                try { // inner 'try' is needed: https://github.com/talsma-ict/context-propagation/pull/56#discussion_r201590623
                    LOGGER.log(Level.FINEST, "Delegating andThen method with {0} to {1}.", new Object[]{context, delegate()});
                    return after.apply(delegate().apply(in));
                } finally {
                    if (contextSnapshotConsumer != null) {
                        ContextSnapshot resultSnapshot = ContextManagers.createContextSnapshot();
                        LOGGER.log(Level.FINEST, "Captured context snapshot after delegation: {0}", resultSnapshot);
                        contextSnapshotConsumer.accept(resultSnapshot);
                    }
                }
            }
        };
    }
}