/*
 * #%L
 * Netarchivesuite - harvester
 * %%
 * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library,
 *             the National Library of France and the Austrian National Library.
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
 * #L%
 */

package dk.netarkivet.harvester.datamodel;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import dk.netarkivet.common.exceptions.ArgumentNotValid;
import dk.netarkivet.common.exceptions.IOFailure;

/**
 * PostgreSQL-specific implementation of DB methods. Intended for PostgreSQL 8.3 and above.
 * <p>
 * PostgreSQL does not support the CLOB datatype but instead provides a "text" data type. See
 * http://www.postgresql.org/docs/current/static/datatype-character.html.
 */
public class PostgreSQLSpecifics extends DBSpecifics {

    /** The log. */
    private static final Logger log = LoggerFactory.getLogger(PostgreSQLSpecifics.class);

    /**
     * Get an instance of the PostgreSQL specifics class.
     *
     * @return Instance of the PostgreSQL specifics class.
     */
    public static DBSpecifics getInstance() {
        return new PostgreSQLSpecifics();
    }

    /**
     * Get a temporary table for short-time use. The table should be disposed of with dropTemporaryTable. The table has
     * two columns domain_name varchar(Constants.MAX_NAME_SIZE) config_name varchar(Constants.MAX_NAME_SIZE)
     *
     * @param c The DB connection to use.
     * @return The name of the created table
     * @throws SQLException if there is a problem getting the table.
     */
    public String getJobConfigsTmpTable(Connection c) throws SQLException {
        ArgumentNotValid.checkNotNull(c, "Connection c");
        PreparedStatement s = c.prepareStatement("CREATE TEMPORARY TABLE jobconfignames " + "( domain_name varchar("
                + Constants.MAX_NAME_SIZE + "), " + " config_name varchar(" + Constants.MAX_NAME_SIZE + ") )"
                + " ON COMMIT DROP");
        s.execute();
        s.close();
        return "jobconfignames";
    }

    /**
     * Dispose of a temporary table created with getTemporaryTable. This can be expected to be called from within a
     * finally clause, so it mustn't throw exceptions.
     *
     * @param c The DB connection to use.
     * @param tableName The name of the temporary table
     */
    public void dropJobConfigsTmpTable(Connection c, String tableName) {
    }

    /**
     * Get the name of the JDBC driver class that handles interfacing to this server.
     *
     * @return The name of a JDBC driver class
     */
    public String getDriverClassName() {
        return "org.postgresql.Driver";
    }

    @Override
    public String getOrderByLimitAndOffsetSubClause(long limit, long offset) {
        return "LIMIT " + limit + " OFFSET " + offset;
    }

    @Override
    public boolean supportsClob() {
        return false;
    }

    /**
     * Migrates the 'jobs' table from version 3 to version 4 consisting of a change of the field forcemaxbytes from int
     * to bigint and setting its default to -1. Furthermore the default value for field num_configs is set to 0.
     *
     * @throws IOFailure in case of problems in interacting with the database
     */
    protected synchronized void migrateJobsv3tov4() {
        String[] sqlStatements = {"ALTER TABLE jobs DROP COLUMN forcemaxbytes",
                "ALTER TABLE jobs ADD COLUMN forcemaxbytes bigint not null default -1",
                "ALTER TABLE jobs DROP COLUMN num_configs",
                "ALTER TABLE jobs ADD COLUMN num_configs int not null default 0"};
        HarvestDBConnection.updateTable("jobs", 4, sqlStatements);
    }

    /**
     * Migrates the 'jobs' table from version 4 to version 5 consisting of adding new fields 'resubmitted_as_job' and
     * 'submittedDate'.
     *
     * @throws IOFailure in case of problems in interacting with the database
     */
    protected synchronized void migrateJobsv4tov5() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN submitteddate datetime AFTER enddate",
                "ALTER TABLE jobs ADD COLUMN resubmitted_as_job bigint"};
        HarvestDBConnection.updateTable("jobs", 5, sqlStatements);
    }

    /**
     * Migrates the 'configurations' table from version 3 to version 4. This consists of altering the default value of
     * field 'maxbytes' to -1.
     */
    protected synchronized void migrateConfigurationsv3ov4() {
        // Update configurations table to version 4
        String[] sqlStatements = {"ALTER TABLE configurations ALTER maxbytes SET DEFAULT -1"};
        HarvestDBConnection.updateTable("configurations", 4, sqlStatements);
    }

    /**
     * Migrates the 'fullharvests' table from version 2 to version 3. This consists of altering the default value of
     * field 'maxbytes' to -1
     */
    protected synchronized void migrateFullharvestsv2tov3() {
        // Update fullharvests table to version 3
        String[] sqlStatements = {"ALTER TABLE fullharvests ALTER maxbytes SET DEFAULT -1"};
        HarvestDBConnection.updateTable("fullharvests", 3, sqlStatements);
    }

    @Override
    protected void createGlobalCrawlerTrapExpressions() {
        log.warn("Please use the provided SQL scripts to update the DB schema");
        HarvestDBConnection.updateTable("global_crawler_trap_expressions", 1);
    }

    @Override
    protected void createGlobalCrawlerTrapLists() {
        log.warn("Please use the provided SQL scripts to update the DB schema");
        HarvestDBConnection.updateTable("global_crawler_trap_lists", 1);
    }

    @Override
    public void createFrontierReportMonitorTable() {
        log.warn("Please use the provided SQL scripts to update the DB schema");
        HarvestDBConnection.updateTable("frontierreportmonitor", 1);
    }

    @Override
    public void createRunningJobsHistoryTable() {
        log.warn("Please use the provided SQL scripts to update the DB schema");
        HarvestDBConnection.updateTable("runningjobshistory", 1);
    }

    @Override
    public void createRunningJobsMonitorTable() {
        log.warn("Please use the provided SQL scripts to update the DB schema");
        HarvestDBConnection.updateTable("runningjobsmonitor", 1);
    }

    // Below DB changes introduced with development release 3.15
    // with changes to tables 'runningjobshistory', 'runningjobsmonitor',
    // 'configurations', 'fullharvests', and 'jobs'.

    /**
     * Migrates the 'runningjobshistory' table from version 1 to version 2. This consists of adding the new column
     * 'retiredQueuesCount'.
     */
    @Override
    protected void migrateRunningJobsHistoryTableV1ToV2() {
        String[] sqlStatements = {"ALTER TABLE runningjobshistory ADD COLUMN retiredQueuesCount bigint not null"};
        HarvestDBConnection.updateTable("runningjobshistory", 2, sqlStatements);
    }

    /**
     * Migrates the 'runningjobsmonitor' table from version 1 to version 2. This consists of adding the new column
     * 'retiredQueuesCount'.
     */
    @Override
    protected void migrateRunningJobsMonitorTableV1ToV2() {
        String[] sqlStatements = {"ALTER TABLE runningjobsmonitor ADD COLUMN retiredQueuesCount bigint not null"};
        HarvestDBConnection.updateTable("runningjobsmonitor", 2, sqlStatements);
    }

    @Override
    protected void migrateDomainsv2tov3() {
        String[] sqlStatements = {"ALTER TABLE domains ALTER COLUMN crawlertraps type text"};
        HarvestDBConnection.updateTable("domains", 3, sqlStatements);
    }

    @Override
    protected void migrateConfigurationsv4tov5() {
        // Update configurations table to version 5
        String[] sqlStatements = {"ALTER TABLE configurations ALTER COLUMN maxobjects TYPE bigint"};
        HarvestDBConnection.updateTable("configurations", 5, sqlStatements);
    }

    @Override
    protected void migrateFullharvestsv3tov4() {
        // Update fullharvests table to version 4
        String[] sqlStatements = {"ALTER TABLE fullharvests ADD COLUMN maxjobrunningtime bigint NOT NULL DEFAULT 0"};
        HarvestDBConnection.updateTable("fullharvests", 4, sqlStatements);
    }

    @Override
    protected void migrateJobsv5tov6() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN forcemaxrunningtime bigint NOT NULL DEFAULT 0"};
        HarvestDBConnection.updateTable("jobs", 6, sqlStatements);
    }

    @Override
    protected void migrateFullharvestsv4tov5() {
        // Update fullharvests table to version 5
        String[] sqlStatements = {"ALTER TABLE fullharvests ADD COLUMN isindexready bool NOT NULL DEFAULT false"};
        HarvestDBConnection.updateTable("fullharvests", 5, sqlStatements);

    }

    @Override
    protected void createExtendedFieldTypeTable() {
        String[] statements = new String[3];
        statements[0] = "CREATE TABLE extendedfieldtype " + "  ( "
                + "     extendedfieldtype_id BIGINT NOT NULL PRIMARY KEY, "
                + "     name             VARCHAR(50) NOT NULL " + "  )";

        statements[1] = "INSERT INTO extendedfieldtype ( extendedfieldtype_id, name )" + "VALUES ( 1, 'domains')";
        statements[2] = "INSERT INTO extendedfieldtype ( extendedfieldtype_id, name )"
                + " VALUES ( 2, 'harvestdefinitions')";

        HarvestDBConnection.updateTable("extendedfieldtype", 1, statements);
    }

    @Override
    protected void createExtendedFieldTable() {
        String createStatement = "" + "CREATE TABLE extendedfield " + "  ( "
                + "     extendedfield_id BIGINT NOT NULL PRIMARY KEY, " + "     extendedfieldtype_id BIGINT NOT NULL, "
                + "     name             VARCHAR(50) NOT NULL, " + "     format           VARCHAR(50) NOT NULL, "
                + "     defaultvalue     VARCHAR(50) NOT NULL, " + "     options          VARCHAR(50) NOT NULL, "
                + "     datatype         INT NOT NULL, " + "     mandatory        INT NOT NULL, "
                + "     sequencenr       INT " + "  )";

        HarvestDBConnection.updateTable("extendedfield", 1, createStatement);
    }

    @Override
    protected void createExtendedFieldValueTable() {
        String createStatement = "" + "CREATE TABLE extendedfieldvalue " + "  ( "
                + "     extendedfieldvalue_id BIGINT NOT NULL PRIMARY KEY, "
                + "     extendedfield_id      BIGINT NOT NULL, " + "     instance_id           BIGINT NOT NULL, "
                + "     content               VARCHAR(100) NOT NULL " + "  )";

        HarvestDBConnection.updateTable("extendedfieldvalue", 1, createStatement);
    }

    @Override
    protected synchronized void migrateJobsv6tov7() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN continuationof BIGINT DEFAULT NULL"};
        HarvestDBConnection.updateTable("jobs", 7, sqlStatements);
    }

    @Override
    protected void migrateJobsv7tov8() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN creationdate TIMESTAMP DEFAULT NULL"};
        HarvestDBConnection.updateTable("jobs", 8, sqlStatements);
    }

    @Override
    protected void migrateJobsv8tov9() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN harvestname_prefix VARCHAR(100) DEFAULT NULL"};
        HarvestDBConnection.updateTable("jobs", 9, sqlStatements);
    }

    @Override
    protected void migrateHarvestdefinitionsv2tov3() {
        String[] sqlStatements = {"ALTER TABLE harvestdefinitions ADD COLUMN audience VARCHAR(100) DEFAULT NULL"};
        HarvestDBConnection.updateTable("harvestdefinitions", 3, sqlStatements);
    }

    @Override
    protected void migrateHarvestdefinitionsv3tov4() {
        String[] sqlStatements = {"ALTER TABLE harvestdefinitions ADD COLUMN channel_id BIGINT DEFAULT NULL"};
        HarvestDBConnection.updateTable("harvestdefinitions", 4, sqlStatements);
    }

    @Override
    protected void migrateJobsv9tov10() {
        String[] sqlStatements = {"ALTER TABLE jobs ADD COLUMN channel VARCHAR(300) DEFAULT NULL",
                "ALTER TABLE jobs ADD COLUMN snapshot BOOL",
                "UPDATE jobs SET channel = 'LOWPRIORITY' WHERE priority=0;",
                "UPDATE jobs SET channel = 'HIGHPRIORITY' WHERE priority=1",
                "UPDATE jobs SET snapshot = true WHERE priority=0",
                "UPDATE jobs SET snapshot = false WHERE priority=1", "ALTER TABLE jobs DROP COLUMN priority"};
        HarvestDBConnection.updateTable("jobs", 10, sqlStatements);
    }

    @Override
    protected void createHarvestChannelTable() {
        String createStatement = "CREATE TABLE harvestchannel (" + "id BIGINT NOT NULL PRIMARY KEY, "
                + "name VARCHAR(300) NOT NULL UNIQUE," + "issnapshot BOOL NOT NULL," + "isdefault BOOL NOT NULL,"
                + "comments VARCHAR(30000)" + ")";
        String[] sqlStatements = {
                createStatement,
                "CREATE SEQUENCE harvestchannel_id_seq OWNED BY harvestchannel.id",
                "ALTER TABLE harvestchannel ALTER COLUMN id SET DEFAULT NEXTVAL('harvestchannel_id_seq')",
                "CREATE INDEX harvestchannelnameid on harvestchannel(name) TABLESPACE tsindex",
                "INSERT INTO harvestchannel(name, issnapshot, isdefault, comments) "
                        + " VALUES ('LOWPRIORITY', true, true, 'Channel for snapshot harvests')",
                "INSERT INTO harvestchannel(name, issnapshot, isdefault, comments) "
                        + "    VALUES ('HIGHPRIORITY', false, true, 'Channel for selective harvests')"};
        HarvestDBConnection.updateTable("harvestchannel", 1, sqlStatements);
    }

    /**
     * Migrates the 'ExtendedFieldTable' from version 1 to version 2 consisting of adding the maxlen field
     */
    protected void migrateExtendedFieldTableV1toV2() {
        String[] sqlStatements = {"ALTER TABLE extendedfield ADD COLUMN maxlen INT",
                "ALTER TABLE extendedfield ALTER COLUMN options TYPE VARCHAR(1000)"};
        HarvestDBConnection.updateTable("extendedfield", 2, sqlStatements);
    }

    /**
     * Migrates the 'ExtendedFieldValueTable' from version 1 to version 2 changing the maxlen of content to 30000
     */
    protected void migrateExtendedFieldTableValueV1toV2() {
        String[] sqlStatements = {"ALTER TABLE extendedfieldvalue ALTER COLUMN content TYPE VARCHAR(30000), ALTER COLUMN content SET NOT NULL"};
        HarvestDBConnection.updateTable("extendedfieldvalue", 2, sqlStatements);
    }

}