/*
 * Copyright 2010-2017 Steve Chaloner
 *
 * 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 be.objectify.deadbolt.java.actions;

import be.objectify.deadbolt.java.ConstraintLogic;
import be.objectify.deadbolt.java.DeadboltHandler;
import be.objectify.deadbolt.java.ExecutionContextProvider;
import be.objectify.deadbolt.java.cache.HandlerCache;
import play.Configuration;
import play.mvc.Http;
import play.mvc.Result;
import scala.concurrent.ExecutionContextExecutor;

import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.function.Supplier;

/**
 * @author Steve Chaloner (steve@objectify.be)
 */
public abstract class AbstractSubjectAction<T> extends AbstractDeadboltAction<T>
{
    private final ConstraintLogic constraintLogic;

    AbstractSubjectAction(final HandlerCache handlerCache,
                          final Configuration config,
                          final ExecutionContextProvider ecProvider,
                          final ConstraintLogic constraintLogic)
    {
        super(handlerCache,
              config,
              ecProvider);
        this.constraintLogic = constraintLogic;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public CompletionStage<Result> execute(final Http.Context content) throws Exception
    {
        final CompletionStage<Result> result;
        final Config config = config();
        if (isActionUnauthorised(content))
        {
            result = onAuthFailure(getDeadboltHandler(config.handlerKey),
                                   config.content,
                                   content);
        }
        else if (isActionAuthorised(content))
        {
            result = delegate.call(content);
        }
        else
        {
            final DeadboltHandler deadboltHandler = getDeadboltHandler(config.handlerKey);
            final ExecutionContextExecutor executor = executor();
            result = preAuth(config.forceBeforeAuthCheck,
                             content,
                             deadboltHandler)
                    .thenComposeAsync(maybePreAuth -> maybePreAuth.map(CompletableFuture::completedFuture)
                                                                  .orElseGet(testSubject(constraintLogic,
                                                                                         content,
                                                                                         config,
                                                                                         deadboltHandler)),
                                      executor);
        }
        return maybeBlock(result);
    }

    abstract Supplier<CompletableFuture<Result>> testSubject(final ConstraintLogic constraintLogic,
                                                              final Http.Context context,
                                                              final Config config,
                                                              final DeadboltHandler deadboltHandler);

    abstract Config config();

    abstract CompletionStage<Result> present(Http.Context context,
                                             DeadboltHandler handler,
                                             Optional<String> content);

    abstract CompletionStage<Result> notPresent(Http.Context context,
                                                DeadboltHandler handler,
                                                Optional<String> content);

    class Config
    {
        public final boolean forceBeforeAuthCheck;
        public final String handlerKey;
        public final Optional<String> content;

        Config(final boolean forceBeforeAuthCheck,
               final String handlerKey,
               final String content)
        {
            this.forceBeforeAuthCheck = forceBeforeAuthCheck;
            this.handlerKey = handlerKey;
            this.content = Optional.ofNullable(content);
        }
    }
}