/*
 * 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.
 */

package parallelai.spyglass.jdbc;

import cascading.flow.FlowProcess;
import cascading.scheme.Scheme;
import cascading.scheme.SinkCall;
import cascading.scheme.SourceCall;
import cascading.tap.Tap;
import cascading.tap.TapException;
import cascading.tuple.Fields;
import cascading.tuple.Tuple;
import cascading.tuple.TupleEntry;
import cascading.util.Util;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.RecordReader;

import parallelai.spyglass.jdbc.db.DBInputFormat;
import parallelai.spyglass.jdbc.db.DBOutputFormat;

import java.io.IOException;
import java.util.Arrays;

/**
 * Class JDBCScheme defines what its parent Tap will select and insert/update into the sql database.
 * <p/>
 * If updateBy column names are given, a SQL UPDATE statement will be generated if the values in those columns
 * for the given Tuple are all not {@code null}. Otherwise an INSERT statement will be generated.
 * <p/>
 * Some constructors take columnFields and updateByFields. These values will be used during field name resolution
 * to bind this Scheme to the source and sink branches in a give assembly. These fields 'alias' the column names
 * in the respective arrays. In other words, if your DB TABLE has different column names than your assembly exepects,
 * use the Fields arguments to bind the assembly to the table. Both Fields and array must be the same size.
 * <p/>
 * Override this class, {@link DBInputFormat}, and {@link DBOutputFormat} to specialize for a given vendor database.
 */
public class JDBCScheme extends Scheme<JobConf, RecordReader, OutputCollector, Object[], Object[]>
{
    private Class<? extends DBInputFormat> inputFormatClass;
    private Class<? extends DBOutputFormat> outputFormatClass;
    private String[] columns;
    private String[] orderBy;
    private String conditions;
    private String[] updateBy;
    private Fields updateValueFields;
    private Fields updateByFields;
    private Fields columnFields;
    private Tuple updateIfTuple;
    private String selectQuery;
    private String countQuery;
    private long limit = -1;

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param conditions        of type String
     * @param limit             of type long
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, String[] columns, String[] orderBy, String conditions, long limit, String[] updateBy )
    {
        this( inputFormatClass, outputFormatClass, new Fields( columns ), columns, orderBy, conditions, limit, updateBy != null ? new Fields( updateBy ) : null, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columnFields      of type Fields
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param conditions        of type String
     * @param limit             of type long
     * @param updateByFields    of type Fields
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, Fields columnFields, String[] columns, String[] orderBy, String conditions, long limit, Fields updateByFields, String[] updateBy )
    {
        this.columnFields = columnFields;

        verifyColumns( columnFields, columns );

        setSinkFields( columnFields );
        setSourceFields( columnFields );

        if( updateBy != null && updateBy.length != 0 )
        {
            this.updateBy = updateBy;
            this.updateByFields = updateByFields;

            if( updateByFields.size() != updateBy.length )
                throw new IllegalArgumentException( "updateByFields and updateBy must be the same size" );

            if( !this.columnFields.contains( this.updateByFields ) )
                throw new IllegalArgumentException( "columnFields must contain updateByFields column names" );

            this.updateValueFields = columnFields.subtract( updateByFields ).append( updateByFields );
            this.updateIfTuple = Tuple.size( updateByFields.size() ); // all nulls
        }

        this.columns = columns;
        this.orderBy = orderBy;
        this.conditions = conditions;
        this.limit = limit;

        this.inputFormatClass = inputFormatClass;
        this.outputFormatClass = outputFormatClass;
    }

    private void verifyColumns( Fields columnFields, String[] columns )
    {
        if( columnFields.size() != columns.length )
            throw new IllegalArgumentException( "columnFields and columns must be the same size" );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param conditions        of type String
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, String[] columns, String[] orderBy, String conditions, String[] updateBy )
    {
        this( inputFormatClass, outputFormatClass, columns, orderBy, conditions, -1, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columnFields      of type Fields
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param conditions        of type String
     * @param updateByFields    of type Fields
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, Fields columnFields, String[] columns, String[] orderBy, String conditions, Fields updateByFields, String[] updateBy )
    {
        this( inputFormatClass, outputFormatClass, columnFields, columns, orderBy, conditions, -1, updateByFields, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, String[] columns, String[] orderBy, String[] updateBy )
    {
        this( inputFormatClass, outputFormatClass, columns, orderBy, null, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass  of type Class<? extends DBInputFormat>
     * @param outputFormatClass of type Class<? extends DBOutputFormat>
     * @param columnFields      of type Fields
     * @param columns           of type String[]
     * @param orderBy           of type String[]
     * @param updateByFields    of type Fields
     * @param updateBy          of type String[]
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Class<? extends DBOutputFormat> outputFormatClass, Fields columnFields, String[] columns, String[] orderBy, Fields updateByFields, String[] updateBy )
    {
        this( inputFormatClass, outputFormatClass, columnFields, columns, orderBy, null, -1, updateByFields, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns  of type String[]
     * @param orderBy  of type String[]
     * @param updateBy of type String[]
     */
    public JDBCScheme( String[] columns, String[] orderBy, String[] updateBy )
    {
        this( null, null, columns, orderBy, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields   of type Fields
     * @param columns        of type String[]
     * @param orderBy        of type String[]
     * @param updateByFields of type Fields
     * @param updateBy       of type String[]
     */
    public JDBCScheme( Fields columnFields, String[] columns, String[] orderBy, Fields updateByFields, String[] updateBy )
    {
        this( null, null, columnFields, columns, orderBy, updateByFields, updateBy );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns    of type String[]
     * @param orderBy    of type String[]
     * @param conditions of type String
     * @param limit      of type long
     */
    public JDBCScheme( String[] columns, String[] orderBy, String conditions, long limit )
    {
        this( null, null, columns, orderBy, conditions, limit, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param orderBy      of type String[]
     * @param conditions   of type String
     * @param limit        of type long
     */
    public JDBCScheme( Fields columnFields, String[] columns, String[] orderBy, String conditions, long limit )
    {
        this( null, null, columnFields, columns, orderBy, conditions, limit, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns    of type String[]
     * @param orderBy    of type String[]
     * @param conditions of type String
     */
    public JDBCScheme( String[] columns, String[] orderBy, String conditions )
    {
        this( null, null, columns, orderBy, conditions, null );
    }

    public JDBCScheme( Fields columnFields, String[] columns, String[] orderBy, String conditions )
    {
        this( null, null, columnFields, columns, orderBy, conditions, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns of type String[]
     * @param orderBy of type String[]
     * @param limit   of type long
     */
    public JDBCScheme( String[] columns, String[] orderBy, long limit )
    {
        this( null, null, columns, orderBy, null, limit, null );
    }

    public JDBCScheme( Fields columnFields, String[] columns, String[] orderBy, long limit )
    {
        this( null, null, columnFields, columns, orderBy, null, limit, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns of type String[]
     * @param orderBy of type String[]
     */
    public JDBCScheme( String[] columns, String[] orderBy )
    {
        this( null, null, columns, orderBy, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param orderBy      of type String[]
     */
    public JDBCScheme( Fields columnFields, String[] columns, String[] orderBy )
    {
        this( null, null, columnFields, columns, orderBy, null, -1, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns    of type String[]
     * @param conditions of type String
     * @param limit      of type long
     */
    public JDBCScheme( String[] columns, String conditions, long limit )
    {
        this( null, null, columns, null, conditions, limit, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param conditions   of type String
     * @param limit        of type long
     */
    public JDBCScheme( Fields columnFields, String[] columns, String conditions, long limit )
    {
        this( null, null, columnFields, columns, null, conditions, limit, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns    of type String[]
     * @param conditions of type String
     */
    public JDBCScheme( String[] columns, String conditions )
    {
        this( null, null, columns, null, conditions, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param conditions   of type String
     */
    public JDBCScheme( Fields columnFields, String[] columns, String conditions )
    {
        this( null, null, columnFields, columns, null, conditions, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns of type String[]
     * @param limit   of type long
     */
    public JDBCScheme( String[] columns, long limit )
    {
        this( null, null, columns, null, null, limit, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param limit        of type long
     */
    public JDBCScheme( Fields columnFields, String[] columns, long limit )
    {
        this( null, null, columnFields, columns, null, null, limit, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columns of type String[]
     */
    public JDBCScheme( String[] columns )
    {
        this( null, null, new Fields( columns ), columns, null, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     */
    public JDBCScheme( Fields columnFields, String[] columns )
    {
        this( null, null, columnFields, columns, null, null, null );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     * <p/>
     * Use this constructor if the data source may only be used as a source.
     *
     * @param inputFormatClass of type Class<? extends DBInputFormat>
     * @param columns          of type String[]
     * @param selectQuery      of type String
     * @param countQuery       of type String
     * @param limit            of type long
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, String[] columns, String selectQuery, String countQuery, long limit )
    {
        this( inputFormatClass, new Fields( columns ), columns, selectQuery, countQuery, limit );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param inputFormatClass of type Class<? extends DBInputFormat>
     * @param columnFields     of type Fields
     * @param columns          of type String[]
     * @param selectQuery      of type String
     * @param countQuery       of type String
     * @param limit            of type long
     */
    public JDBCScheme( Class<? extends DBInputFormat> inputFormatClass, Fields columnFields, String[] columns, String selectQuery, String countQuery, long limit )
    {
        this.columnFields = columnFields;

        verifyColumns( columnFields, columns );

        setSourceFields( columnFields );

        this.columns = columns;
        this.selectQuery = selectQuery.trim().replaceAll( ";$", "" );
        this.countQuery = countQuery.trim().replaceAll( ";$", "" );
        this.limit = limit;

        this.inputFormatClass = inputFormatClass;
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     * <p/>
     * Use this constructor if the data source may only be used as a source.
     *
     * @param columns     of type String[]
     * @param selectQuery of type String
     * @param countQuery  of type String
     * @param limit       of type long
     */
    public JDBCScheme( String[] columns, String selectQuery, String countQuery, long limit )
    {
        this( null, new Fields( columns ), columns, selectQuery, countQuery, limit );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param selectQuery  of type String
     * @param countQuery   of type String
     * @param limit        of type long
     */
    public JDBCScheme( Fields columnFields, String[] columns, String selectQuery, String countQuery, long limit )
    {
        this( null, columnFields, columns, selectQuery, countQuery, limit );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     * <p/>
     * Use this constructor if the data source may only be used as a source.
     *
     * @param columns     of type String[]
     * @param selectQuery of type String
     * @param countQuery  of type String
     */
    public JDBCScheme( String[] columns, String selectQuery, String countQuery )
    {
        this( null, new Fields( columns ), columns, selectQuery, countQuery, -1 );
    }

    /**
     * Constructor JDBCScheme creates a new JDBCScheme instance.
     *
     * @param columnFields of type Fields
     * @param columns      of type String[]
     * @param selectQuery  of type String
     * @param countQuery   of type String
     */
    public JDBCScheme( Fields columnFields, String[] columns, String selectQuery, String countQuery )
    {
        this( null, columnFields, columns, selectQuery, countQuery, -1 );
    }

    /**
     * Method getColumns returns the columns of this JDBCScheme object.
     *
     * @return the columns (type String[]) of this JDBCScheme object.
     */
    public String[] getColumns() {
        return columns;
    }

    /**
     * Method getOrderBy returns the orderBy of this JDBCScheme object.
     *
     * @return the orderBy (type String[]) of this JDBCScheme object.
     */
    public String[] getOrderBy() {
        return orderBy;
    }

    @Override
    public void sourceConfInit( FlowProcess<JobConf> process, Tap<JobConf, RecordReader, OutputCollector> tap,
        JobConf conf ) {
        int concurrentReads = ( (JDBCTap) tap ).concurrentReads;

        if( selectQuery != null )
            DBInputFormat.setInput( conf, TupleRecord.class, selectQuery, countQuery, limit, concurrentReads );
        else {
            String tableName = ( (JDBCTap) tap ).getTableName();
            String joinedOrderBy = orderBy != null ? Util.join( orderBy, ", " ) : null;
            DBInputFormat.setInput( conf, TupleRecord.class, tableName, conditions, joinedOrderBy, limit, concurrentReads, columns );
        }

        if( inputFormatClass != null )
            conf.setInputFormat( inputFormatClass );
    }

    @Override
    public void sinkConfInit( FlowProcess<JobConf> process, Tap<JobConf, RecordReader, OutputCollector> tap,
        JobConf conf ) {
        if( selectQuery != null )
            throw new TapException( "cannot sink to this Scheme" );

        String tableName = ( (JDBCTap) tap ).getTableName();
        int batchSize = ( (JDBCTap) tap ).getBatchSize();
        DBOutputFormat.setOutput( conf, DBOutputFormat.class, tableName, columns, updateBy, batchSize );

        if( outputFormatClass != null )
            conf.setOutputFormat( outputFormatClass );
    }

    @Override
    public void sourcePrepare( FlowProcess<JobConf> flowProcess, SourceCall<Object[], RecordReader> sourceCall )
    {
        Object[] pair = new Object[]{sourceCall.getInput().createKey(), sourceCall.getInput().createValue()};

        sourceCall.setContext( pair );
    }

    @Override
    public boolean source( FlowProcess<JobConf> flowProcess, SourceCall<Object[], RecordReader> sourceCall ) throws IOException
    {
        Object key = sourceCall.getContext()[ 0 ];
        Object value = sourceCall.getContext()[ 1 ];
        boolean result = sourceCall.getInput().next( key, value );

        if( !result )
            return false;

        Tuple newTuple = ( (TupleRecord) value ).getTuple();
        sourceCall.getIncomingEntry().setTuple( newTuple );

        return true;
    }

    @Override
    public void sourceCleanup( FlowProcess<JobConf> flowProcess, SourceCall<Object[], RecordReader> sourceCall ) {
        sourceCall.setContext( null );
    }

    @Override
    public void sink( FlowProcess<JobConf> flowProcess, SinkCall<Object[], OutputCollector> sinkCall ) throws IOException {
        // it's ok to use NULL here so the collector does not write anything
        TupleEntry tupleEntry = sinkCall.getOutgoingEntry();
        OutputCollector outputCollector = sinkCall.getOutput();
        if( updateBy != null )
        {
            Tuple allValues = tupleEntry.selectTuple( updateValueFields );
            Tuple updateValues = tupleEntry.selectTuple( updateByFields );

            allValues = cleanTuple( allValues );

            TupleRecord key = new TupleRecord( allValues );

            if( updateValues.equals( updateIfTuple ) )
                outputCollector.collect( key, null );
            else
                outputCollector.collect( key, key );

            return;
        }

        Tuple result = tupleEntry.selectTuple( getSinkFields() );

        result = cleanTuple( result );

        outputCollector.collect( new TupleRecord( result ), null );
    }

    /**
     * Provides a hook for subclasses to escape or modify any values before creating the final SQL statement.
     *
     * @param result
     * @return
     */
    protected Tuple cleanTuple( Tuple result ) {
        return result;
    }

    @Override
    public boolean equals( Object object ) {
        if( this == object )
            return true;
        if( !( object instanceof JDBCScheme ) )
            return false;
        if( !super.equals( object ) )
            return false;

        JDBCScheme that = (JDBCScheme) object;

        if( limit != that.limit )
            return false;
        if( columnFields != null ? !columnFields.equals( that.columnFields ) : that.columnFields != null )
            return false;
        if( !Arrays.equals( columns, that.columns ) )
            return false;
        if( conditions != null ? !conditions.equals( that.conditions ) : that.conditions != null )
            return false;
        if( countQuery != null ? !countQuery.equals( that.countQuery ) : that.countQuery != null )
            return false;
        if( inputFormatClass != null ? !inputFormatClass.equals( that.inputFormatClass ) : that.inputFormatClass != null )
            return false;
        if( !Arrays.equals( orderBy, that.orderBy ) )
            return false;
        if( outputFormatClass != null ? !outputFormatClass.equals( that.outputFormatClass ) : that.outputFormatClass != null )
            return false;
        if( selectQuery != null ? !selectQuery.equals( that.selectQuery ) : that.selectQuery != null )
            return false;
        if( !Arrays.equals( updateBy, that.updateBy ) )
            return false;
        if( updateByFields != null ? !updateByFields.equals( that.updateByFields ) : that.updateByFields != null )
            return false;
        if( updateIfTuple != null ? !updateIfTuple.equals( that.updateIfTuple ) : that.updateIfTuple != null )
            return false;
        if( updateValueFields != null ? !updateValueFields.equals( that.updateValueFields ) : that.updateValueFields != null )
            return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = super.hashCode();
        result = 31 * result + ( inputFormatClass != null ? inputFormatClass.hashCode() : 0 );
        result = 31 * result + ( outputFormatClass != null ? outputFormatClass.hashCode() : 0 );
        result = 31 * result + ( columns != null ? Arrays.hashCode( columns ) : 0 );
        result = 31 * result + ( orderBy != null ? Arrays.hashCode( orderBy ) : 0 );
        result = 31 * result + ( conditions != null ? conditions.hashCode() : 0 );
        result = 31 * result + ( updateBy != null ? Arrays.hashCode( updateBy ) : 0 );
        result = 31 * result + ( updateValueFields != null ? updateValueFields.hashCode() : 0 );
        result = 31 * result + ( updateByFields != null ? updateByFields.hashCode() : 0 );
        result = 31 * result + ( columnFields != null ? columnFields.hashCode() : 0 );
        result = 31 * result + ( updateIfTuple != null ? updateIfTuple.hashCode() : 0 );
        result = 31 * result + ( selectQuery != null ? selectQuery.hashCode() : 0 );
        result = 31 * result + ( countQuery != null ? countQuery.hashCode() : 0 );
        result = 31 * result + (int) ( limit ^ ( limit >>> 32 ) );
        return result;
    }
}