/**
 * 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.hcatalog.pig;

import java.io.IOException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.security.Credentials;
import org.apache.hcatalog.common.HCatConstants;
import org.apache.hcatalog.common.HCatContext;
import org.apache.hcatalog.common.HCatException;
import org.apache.hcatalog.data.schema.HCatSchema;
import org.apache.hcatalog.mapreduce.HCatOutputFormat;
import org.apache.hcatalog.mapreduce.OutputJobInfo;
import org.apache.hcatalog.shims.HCatHadoopShims;
import org.apache.pig.PigException;
import org.apache.pig.ResourceSchema;
import org.apache.pig.impl.logicalLayer.FrontendException;
import org.apache.pig.impl.logicalLayer.schema.Schema;
import org.apache.pig.impl.util.ObjectSerializer;
import org.apache.pig.impl.util.UDFContext;

/**
 * HCatStorer.
 *
 */

public class HCatStorer extends HCatBaseStorer {

    // Signature for wrapped storer, see comments in LoadFuncBasedInputDriver.initialize
    final public static String INNER_SIGNATURE = "hcatstorer.inner.signature";
    final public static String INNER_SIGNATURE_PREFIX = "hcatstorer_inner_signature";
    // A hash map which stores job credentials. The key is a signature passed by Pig, which is
    //unique to the store func and out file name (table, in our case).
    private static Map<String, Credentials> jobCredentials = new HashMap<String, Credentials>();


    public HCatStorer(String partSpecs, String schema) throws Exception {
        super(partSpecs, schema);
    }

    public HCatStorer(String partSpecs) throws Exception {
        this(partSpecs, null);
    }

    public HCatStorer() throws Exception {
        this(null, null);
    }

    @Override
    public OutputFormat getOutputFormat() throws IOException {
        return new HCatOutputFormat();
    }

    @Override
    public void setStoreLocation(String location, Job job) throws IOException {
        HCatContext.INSTANCE.setConf(job.getConfiguration()).getConf().get()
            .setBoolean(HCatConstants.HCAT_DATA_TINY_SMALL_INT_PROMOTION, false);

        Configuration config = job.getConfiguration();
        config.set(INNER_SIGNATURE, INNER_SIGNATURE_PREFIX + "_" + sign);
        Properties udfProps = UDFContext.getUDFContext().getUDFProperties(
            this.getClass(), new String[]{sign});
        String[] userStr = location.split("\\.");

        if (udfProps.containsKey(HCatConstants.HCAT_PIG_STORER_LOCATION_SET)) {
            for (Enumeration<Object> emr = udfProps.keys(); emr.hasMoreElements(); ) {
                PigHCatUtil.getConfigFromUDFProperties(udfProps, config, emr.nextElement().toString());
            }
            Credentials crd = jobCredentials.get(INNER_SIGNATURE_PREFIX + "_" + sign);
            if (crd != null) {
                job.getCredentials().addAll(crd);
            }
        } else {
            Job clone = new Job(job.getConfiguration());
            OutputJobInfo outputJobInfo;
            if (userStr.length == 2) {
                outputJobInfo = OutputJobInfo.create(userStr[0], userStr[1], partitions);
            } else if (userStr.length == 1) {
                outputJobInfo = OutputJobInfo.create(null, userStr[0], partitions);
            } else {
                throw new FrontendException("location " + location
                    + " is invalid. It must be of the form [db.]table",
                    PigHCatUtil.PIG_EXCEPTION_CODE);
            }
            Schema schema = (Schema) ObjectSerializer.deserialize(udfProps.getProperty(PIG_SCHEMA));
            if (schema != null) {
                pigSchema = schema;
            }
            if (pigSchema == null) {
                throw new FrontendException(
                    "Schema for data cannot be determined.",
                    PigHCatUtil.PIG_EXCEPTION_CODE);
            }
            String externalLocation = (String) udfProps.getProperty(HCatConstants.HCAT_PIG_STORER_EXTERNAL_LOCATION);
            if (externalLocation != null) {
                outputJobInfo.setLocation(externalLocation);
            }
            try {
                HCatOutputFormat.setOutput(job, outputJobInfo);
            } catch (HCatException he) {
                // pass the message to the user - essentially something about
                // the table
                // information passed to HCatOutputFormat was not right
                throw new PigException(he.getMessage(),
                    PigHCatUtil.PIG_EXCEPTION_CODE, he);
            }
            HCatSchema hcatTblSchema = HCatOutputFormat.getTableSchema(job);
            try {
                doSchemaValidations(pigSchema, hcatTblSchema);
            } catch (HCatException he) {
                throw new FrontendException(he.getMessage(), PigHCatUtil.PIG_EXCEPTION_CODE, he);
            }
            computedSchema = convertPigSchemaToHCatSchema(pigSchema, hcatTblSchema);
            HCatOutputFormat.setSchema(job, computedSchema);
            udfProps.setProperty(COMPUTED_OUTPUT_SCHEMA, ObjectSerializer.serialize(computedSchema));

            // We will store all the new /changed properties in the job in the
            // udf context, so the the HCatOutputFormat.setOutput and setSchema
            // methods need not be called many times.
            for (Entry<String, String> keyValue : job.getConfiguration()) {
                String oldValue = clone.getConfiguration().getRaw(keyValue.getKey());
                if ((oldValue == null) || (keyValue.getValue().equals(oldValue) == false)) {
                    udfProps.put(keyValue.getKey(), keyValue.getValue());
                }
            }
            //Store credentials in a private hash map and not the udf context to
            // make sure they are not public.
            jobCredentials.put(INNER_SIGNATURE_PREFIX + "_" + sign, job.getCredentials());
            udfProps.put(HCatConstants.HCAT_PIG_STORER_LOCATION_SET, true);
        }
    }

    @Override
    public void storeSchema(ResourceSchema schema, String arg1, Job job) throws IOException {
        HCatHadoopShims.Instance.get().commitJob(getOutputFormat(), job);
    }

    @Override
    public void cleanupOnFailure(String location, Job job) throws IOException {
        HCatHadoopShims.Instance.get().abortJob(getOutputFormat(), job);
    }
}