/*
 * Copyright (c) 2009 Concurrent, Inc.
 *
 * This work has been released into the public domain
 * by the copyright holder. This applies worldwide.
 *
 * In case this is not legally possible:
 * The copyright holder grants any entity the right
 * to use this work for any purpose, without any
 * conditions, unless such conditions are required by law.
 */
/**
 * 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 parallelai.spyglass.jdbc.db;

import org.apache.hadoop.conf.Configuration;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * A container for configuration property names for jobs with DB input/output. <br> The job can be
 * configured using the static methods in this class, {@link DBInputFormat}, and {@link
 * DBOutputFormat}. <p/> Alternatively, the properties can be set in the configuration with proper
 * values.
 */
public class DBConfiguration {

    /** The JDBC Driver class name */
    public static final String DRIVER_CLASS_PROPERTY = "mapred.jdbc.driver.class";

    /** JDBC Database access URL */
    public static final String URL_PROPERTY = "mapred.jdbc.url";

    /** User name to access the database */
    public static final String USERNAME_PROPERTY = "mapred.jdbc.username";

    /** Password to access the database */
    public static final String PASSWORD_PROPERTY = "mapred.jdbc.password";

    /** Input table name */
    public static final String INPUT_TABLE_NAME_PROPERTY = "mapred.jdbc.input.table.name";

    /** Field names in the Input table */
    public static final String INPUT_FIELD_NAMES_PROPERTY = "mapred.jdbc.input.field.names";

    /** WHERE clause in the input SELECT statement */
    public static final String INPUT_CONDITIONS_PROPERTY = "mapred.jdbc.input.conditions";

    /** ORDER BY clause in the input SELECT statement */
    public static final String INPUT_ORDER_BY_PROPERTY = "mapred.jdbc.input.orderby";

    /** Whole input query, exluding LIMIT...OFFSET */
    public static final String INPUT_QUERY = "mapred.jdbc.input.query";

    /** The number of records to LIMIT, useful for testing */
    public static final String INPUT_LIMIT = "mapred.jdbc.input.limit";

    /** Input query to get the count of records */
    public static final String INPUT_COUNT_QUERY = "mapred.jdbc.input.count.query";

    /** Class name implementing DBWritable which will hold input tuples */
    public static final String INPUT_CLASS_PROPERTY = "mapred.jdbc.input.class";

    /** Output table name */
    public static final String OUTPUT_TABLE_NAME_PROPERTY = "mapred.jdbc.output.table.name";

    /** Field names in the Output table */
    public static final String OUTPUT_FIELD_NAMES_PROPERTY = "mapred.jdbc.output.field.names";

    /** Field names in the Output table */
    public static final String OUTPUT_UPDATE_FIELD_NAMES_PROPERTY =
        "mapred.jdbc.output.update.field.names";

    /** The number of statements to batch before executing */
    public static final String BATCH_STATEMENTS_PROPERTY = "mapred.jdbc.batch.statements.num";

    /** The number of splits allowed, becomes max concurrent reads. */
    public static final String CONCURRENT_READS_PROPERTY = "mapred.jdbc.concurrent.reads.num";

    /**
     * Sets the DB access related fields in the Configuration.
     *
     * @param job         the job
     * @param driverClass JDBC Driver class name
     * @param dbUrl       JDBC DB access URL.
     * @param userName    DB access username
     * @param passwd      DB access passwd
     */
    public static void configureDB(Configuration job, String driverClass, String dbUrl,
        String userName, String passwd) {
        job.set(DRIVER_CLASS_PROPERTY, driverClass);
        job.set(URL_PROPERTY, dbUrl);

        if (userName != null) { job.set(USERNAME_PROPERTY, userName); }

        if (passwd != null) { job.set(PASSWORD_PROPERTY, passwd); }
    }

    /**
     * Sets the DB access related fields in the Configuration.
     *
     * @param job         the job
     * @param driverClass JDBC Driver class name
     * @param dbUrl       JDBC DB access URL.
     */
    public static void configureDB(Configuration job, String driverClass, String dbUrl) {
        configureDB(job, driverClass, dbUrl, null, null);
    }

    private Configuration job;

    DBConfiguration(Configuration job) {
        this.job = job;
    }

    /**
     * Returns a connection object to the DB
     *
     * @throws ClassNotFoundException
     * @throws SQLException
     */
    Connection getConnection() throws IOException {
        try {
            Class.forName(job.get(DBConfiguration.DRIVER_CLASS_PROPERTY));
        } catch (ClassNotFoundException exception) {
            throw new IOException("unable to load conection driver", exception);
        }

        try {
            if (job.get(DBConfiguration.USERNAME_PROPERTY) == null) {
                return DriverManager.getConnection(job.get(DBConfiguration.URL_PROPERTY));
            } else {
                return DriverManager.getConnection(job.get(DBConfiguration.URL_PROPERTY), job
                    .get(DBConfiguration.USERNAME_PROPERTY), job
                    .get(DBConfiguration.PASSWORD_PROPERTY));
            }
        } catch (SQLException exception) {
            throw new IOException("unable to create connection", exception);
        }
    }

    String getInputTableName() {
        return job.get(DBConfiguration.INPUT_TABLE_NAME_PROPERTY);
    }

    void setInputTableName(String tableName) {
        job.set(DBConfiguration.INPUT_TABLE_NAME_PROPERTY, tableName);
    }

    String[] getInputFieldNames() {
        return job.getStrings(DBConfiguration.INPUT_FIELD_NAMES_PROPERTY);
    }

    void setInputFieldNames(String... fieldNames) {
        job.setStrings(DBConfiguration.INPUT_FIELD_NAMES_PROPERTY, fieldNames);
    }

    String getInputConditions() {
        return job.get(DBConfiguration.INPUT_CONDITIONS_PROPERTY);
    }

    void setInputConditions(String conditions) {
        if (conditions != null && conditions.length() > 0) {
            job.set(DBConfiguration.INPUT_CONDITIONS_PROPERTY, conditions);
        }
    }

    String getInputOrderBy() {
        return job.get(DBConfiguration.INPUT_ORDER_BY_PROPERTY);
    }

    void setInputOrderBy(String orderby) {
        if (orderby != null && orderby.length() > 0) {
            job.set(DBConfiguration.INPUT_ORDER_BY_PROPERTY, orderby);
        }
    }

    String getInputQuery() {
        return job.get(DBConfiguration.INPUT_QUERY);
    }

    void setInputQuery(String query) {
        if (query != null && query.length() > 0) { job.set(DBConfiguration.INPUT_QUERY, query); }
    }

    long getInputLimit() {
        return job.getLong(DBConfiguration.INPUT_LIMIT, -1);
    }

    void setInputLimit(long limit) {
        job.setLong(DBConfiguration.INPUT_LIMIT, limit);
    }

    String getInputCountQuery() {
        return job.get(DBConfiguration.INPUT_COUNT_QUERY);
    }

    void setInputCountQuery(String query) {
        if (query != null && query.length() > 0) {
            job.set(DBConfiguration.INPUT_COUNT_QUERY, query);
        }
    }

    Class<?> getInputClass() {
        return job
            .getClass(DBConfiguration.INPUT_CLASS_PROPERTY, DBInputFormat.NullDBWritable.class);
    }

    void setInputClass(Class<? extends DBWritable> inputClass) {
        job.setClass(DBConfiguration.INPUT_CLASS_PROPERTY, inputClass, DBWritable.class);
    }

    String getOutputTableName() {
        return job.get(DBConfiguration.OUTPUT_TABLE_NAME_PROPERTY);
    }

    void setOutputTableName(String tableName) {
        job.set(DBConfiguration.OUTPUT_TABLE_NAME_PROPERTY, tableName);
    }

    String[] getOutputFieldNames() {
        return job.getStrings(DBConfiguration.OUTPUT_FIELD_NAMES_PROPERTY);
    }

    void setOutputFieldNames(String... fieldNames) {
        job.setStrings(DBConfiguration.OUTPUT_FIELD_NAMES_PROPERTY, fieldNames);
    }

    String[] getOutputUpdateFieldNames() {
        return job.getStrings(DBConfiguration.OUTPUT_UPDATE_FIELD_NAMES_PROPERTY);
    }

    void setOutputUpdateFieldNames(String... fieldNames) {
        job.setStrings(DBConfiguration.OUTPUT_UPDATE_FIELD_NAMES_PROPERTY, fieldNames);
    }

    int getBatchStatementsNum() {
        return job.getInt(DBConfiguration.BATCH_STATEMENTS_PROPERTY, 1000);
    }

    void setBatchStatementsNum(int batchStatementsNum) {
        job.setInt(DBConfiguration.BATCH_STATEMENTS_PROPERTY, batchStatementsNum);
    }

    int getMaxConcurrentReadsNum() {
        return job.getInt(DBConfiguration.CONCURRENT_READS_PROPERTY, 0);
    }

    void setMaxConcurrentReadsNum(int maxConcurrentReads) {
        if (maxConcurrentReads < 0) {
            throw new IllegalArgumentException("maxConcurrentReads must be a positive value");
        }

        job.setInt(DBConfiguration.CONCURRENT_READS_PROPERTY, maxConcurrentReads);
    }

}