/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.client;

import org.apache.flink.api.dag.Pipeline;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.runtime.jobgraph.JobGraph;

/**
 * Utility for transforming {@link Pipeline FlinkPipelines} into a {@link JobGraph}. This uses
 * reflection or service discovery to find the right {@link FlinkPipelineTranslator} for a given
 * subclass of {@link Pipeline}.
 */
public final class FlinkPipelineTranslationUtil {

    /** Transmogrifies the given {@link Pipeline} to a {@link JobGraph}. */
    public static JobGraph getJobGraph(
            ClassLoader userClassloader,
            Pipeline pipeline,
            Configuration optimizerConfiguration,
            int defaultParallelism) {

        FlinkPipelineTranslator pipelineTranslator =
                getPipelineTranslator(userClassloader, pipeline);

        return pipelineTranslator.translateToJobGraph(
                pipeline, optimizerConfiguration, defaultParallelism);
    }

    /**
     * Transmogrifies the given {@link Pipeline} under the userClassloader to a {@link JobGraph}.
     */
    public static JobGraph getJobGraphUnderUserClassLoader(
            final ClassLoader userClassloader,
            final Pipeline pipeline,
            final Configuration configuration,
            final int defaultParallelism) {
        final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
        try {
            Thread.currentThread().setContextClassLoader(userClassloader);
            return FlinkPipelineTranslationUtil.getJobGraph(
                    userClassloader, pipeline, configuration, defaultParallelism);
        } finally {
            Thread.currentThread().setContextClassLoader(contextClassLoader);
        }
    }

    /** Extracts the execution plan (as JSON) from the given {@link Pipeline}. */
    public static String translateToJSONExecutionPlan(
            ClassLoader userClassloader, Pipeline pipeline) {
        FlinkPipelineTranslator pipelineTranslator =
                getPipelineTranslator(userClassloader, pipeline);
        return pipelineTranslator.translateToJSONExecutionPlan(pipeline);
    }

    private static FlinkPipelineTranslator getPipelineTranslator(
            ClassLoader userClassloader, Pipeline pipeline) {
        PlanTranslator planTranslator = new PlanTranslator();

        if (planTranslator.canTranslate(pipeline)) {
            return planTranslator;
        }

        StreamGraphTranslator streamGraphTranslator = new StreamGraphTranslator(userClassloader);

        if (streamGraphTranslator.canTranslate(pipeline)) {
            return streamGraphTranslator;
        }

        throw new RuntimeException(
                "Translator "
                        + streamGraphTranslator
                        + " cannot translate "
                        + "the given pipeline "
                        + pipeline
                        + ".");
    }
}
