/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates.
 *
 * 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 org.drools.core.runtime;

import org.drools.core.command.impl.RegistryContext;
import org.drools.core.fluent.impl.Batch;
import org.drools.core.fluent.impl.BatchImpl;
import org.drools.core.fluent.impl.InternalExecutable;
import org.drools.core.runtime.impl.ExecutionResultImpl;
import org.kie.api.command.BatchExecutionCommand;
import org.kie.api.command.Command;
import org.kie.api.runtime.Context;
import org.kie.api.runtime.Executable;
import org.kie.api.runtime.ExecutableRunner;
import org.kie.api.runtime.RequestContext;

import java.util.List;

import static java.util.Collections.singletonList;

public interface InternalLocalRunner extends ExecutableRunner<RequestContext> {
    default RequestContext execute(Executable executable) {
        return execute( executable, createContext() );
    }

    default <T> T execute( Command<T> command ) {
        Context ctx = execute( new SingleCommandExecutable( command ) );
        return command instanceof BatchExecutionCommand ?
               (T) ( (RegistryContext) ctx ).lookup( ExecutionResultImpl.class ) :
               (T) ( (RequestContext) ctx ).getResult();
    }

    default <T> T execute( Command<T> command, Context ctx ) {
        execute( new SingleCommandExecutable( command ), (RequestContext) ctx );
        return command instanceof BatchExecutionCommand ?
               (T) ( (RegistryContext) ctx ).lookup( ExecutionResultImpl.class ) :
               (T) ( (RequestContext) ctx ).getResult();
    }

    class SingleBatchExecutable implements InternalExecutable {
        private final Batch batch;

        public SingleBatchExecutable( Batch batch ) {
            this.batch = batch;
        }

        @Override
        public List<Batch> getBatches() {
            return singletonList( batch );
        }
    }

    class SingleCommandExecutable extends SingleBatchExecutable {

        public SingleCommandExecutable( Command command ) {
            super(new BatchImpl().addCommand( command ) );
        }
    }
}