/*
   Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   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 Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */

package com.mysql.clusterj.tie;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

import com.mysql.clusterj.ClusterJFatalInternalException;

import com.mysql.clusterj.core.store.Column;
import com.mysql.clusterj.core.store.Index;
import com.mysql.clusterj.core.store.IndexScanOperation;
import com.mysql.clusterj.core.store.Table;

import com.mysql.ndbjtie.ndbapi.NdbIndexScanOperation;

/** NdbRecordIndexScanOperationImpl performs index scans using NdbRecord.
 * Two NdbRecordImpl instances are used: one to define the bounds (low and high)
 * and one to define the result. The superclass NdbRecordScanOperationImpl
 * holds the NdbRecordImpl and buffer that define and hold the result.
 * <p>
 * This instance declares and holds the bounds while they are being defined.
 * Bounds are handled by creating two bound buffers: one for the low bound
 * and a second for the high bound. While the bounds are being created, the
 * number of columns and the strictness of the bound are recorded.
 * <p>
 * Bounds are calculated elsewhere based on the query parameters and delivered, in sequence,
 * to this instance. Bounds are delivered for the most significant index column first,
 * followed by the next most significant index column, until all columns that have bounds
 * have been delivered. There may be more columns for the low bound versus the high bound,
 * or vice versa. For each bound that is delivered, the method (assignBoundBuffer) determines 
 * to which bound, low or high, the bound belongs. The column count is incremented
 * for the appropriate bound buffer. The value is then applied to the bound buffer using
 * the setXXX method of the NdbRecordImpl that manages the layout of the bound buffer.
 * <p>
 * The superclass declares and holds the filter while it is being defined.
 * <p>
 * At endDefinition, the filter is used to create the scanOptions which is
 * passed to create the NdbIndexScanOperation. Then the bounds are set into
 * the newly created NdbIndexScanOperation.
 * The resulting NdbIndexScanOperation is iterated (scanned) by the NdbRecordResultDataImpl.
 */
public class NdbRecordIndexScanOperationImpl extends NdbRecordScanOperationImpl implements IndexScanOperation {

    /** The ndb index scan operation */
    private NdbIndexScanOperation ndbIndexScanOperation;

    /** The range for this bound */
    private int indexBoundRange = 0;

    /** The buffer that contains low bounds for all index columns */
    private ByteBuffer indexBoundLowBuffer = null;

    /** The number of columns in the low bound */
    private int indexBoundLowCount = 0;

    /** Is the low bound strict? */
    private boolean indexBoundLowStrict = false;

    /** The buffer that contains high bounds for all index columns */
    private ByteBuffer indexBoundHighBuffer = null;

    /** The number of columns in the high bound */
    private int indexBoundHighCount = 0;

    /** Is the high bound strict? */
    private boolean indexBoundHighStrict = false;

    /** Is this an equal scan? */
    private boolean equalScan = true;

    /** The list of index bounds already defined; null for a single range */
    List<NdbIndexScanOperation.IndexBound> ndbIndexBoundList = null;

    /** The single index bound for a single range scan */
    NdbIndexScanOperation.IndexBound ndbIndexBound = null;

    /** The buffers used for bounds; held here to prevent garbage collection */
    List<ByteBuffer> buffers = new ArrayList<ByteBuffer>();

    private Index index;

    public NdbRecordIndexScanOperationImpl(ClusterTransactionImpl clusterTransaction,
            Index storeIndex, Table storeTable, int lockMode) {
        this(clusterTransaction, storeIndex, storeTable, false, lockMode);
    }

    public NdbRecordIndexScanOperationImpl(ClusterTransactionImpl clusterTransaction,
                Index storeIndex, Table storeTable, boolean multiRange, int lockMode) {
        super(clusterTransaction, storeTable, lockMode);
        this.index = storeIndex;
        this.multiRange = multiRange;
        if (this.multiRange) {
            ndbIndexBoundList = new ArrayList<NdbIndexScanOperation.IndexBound>();
        }
        ndbRecordKeys = clusterTransaction.getCachedNdbRecordImpl(storeIndex, storeTable);
        keyBufferSize = ndbRecordKeys.bufferSize;
        indexBoundLowBuffer = ndbRecordKeys.newBuffer();
        // hold a reference to the buffer to prevent garbage collection
        buffers.add(indexBoundLowBuffer);
        indexBoundHighBuffer = ndbRecordKeys.newBuffer();
        // hold a reference to the buffer to prevent garbage collection
        buffers.add(indexBoundHighBuffer);
    }

    public void endDefinition() {
        // get the scan options which also sets the filter
        getScanOptions();
        if (logger.isDetailEnabled()) logger.detail("scan index '" + index.getName() + "' with options " + dumpScanOptions(scanOptions.optionsPresent(), scanOptions.scan_flags()));

        // create the scan operation
        ndbIndexScanOperation = clusterTransaction.scanIndex(
                ndbRecordKeys.getNdbRecord(), ndbRecordValues.getNdbRecord(), mask, scanOptions);
        ndbOperation = ndbIndexScanOperation;

        // set the bounds, either from the single indexBound or from multiple ranges
        if (ndbIndexBoundList != null) {
            if (logger.isDetailEnabled()) logger.detail("list size " + ndbIndexBoundList.size());
            // apply all of the bounds to the operation
            for (NdbIndexScanOperation.IndexBound ndbIndexBound: ndbIndexBoundList) {
                int returnCode = ndbIndexScanOperation.setBound(ndbRecordKeys.getNdbRecord(), ndbIndexBound);
                handleError(returnCode, ndbIndexScanOperation);
            }
        } else {
            // zero or one range defined
            ndbIndexBound = getNdbIndexBound();
            if (ndbIndexBound != null) {
                int returnCode = ndbIndexScanOperation.setBound(ndbRecordKeys.getNdbRecord(), ndbIndexBound);
                handleError(returnCode, ndbIndexScanOperation);
            }
        }
        // set the NdbBlob for all active blob columns so that scans will read blob columns
        activateBlobs();
        clusterTransaction.postExecuteCallback(new Runnable() {
            // free structures used to define operation            
            public void run() {
                freeResourcesAfterExecute();
            }
        });
    }

    public void setBoundBigInteger(Column storeColumn, BoundType type, BigInteger value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setBigInteger(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setBigInteger(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setBigInteger(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundByte(Column storeColumn, BoundType type, byte value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setByte(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setByte(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setByte(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundBytes(Column storeColumn, BoundType type, byte[] value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setBytes(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setBytes(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setBytes(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundDecimal(Column storeColumn, BoundType type, BigDecimal value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setDecimal(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setDecimal(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setDecimal(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundDouble(Column storeColumn, BoundType type, Double value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setDouble(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setDouble(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setDouble(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundFloat(Column storeColumn, BoundType type, Float value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setFloat(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setFloat(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setFloat(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundShort(Column storeColumn, BoundType type, short value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setShort(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setShort(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setShort(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundInt(Column storeColumn, BoundType type, Integer value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setInt(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setInt(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setInt(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundLong(Column storeColumn, BoundType type, long value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setLong(indexBoundLowBuffer, storeColumn, value);
            ndbRecordKeys.setLong(indexBoundHighBuffer, storeColumn, value);
        } else {
            ndbRecordKeys.setLong(keyBuffer, storeColumn, value);
        }
    }

    public void setBoundString(Column storeColumn, BoundType type, String value) {
        if (logger.isDetailEnabled()) logger.detail(storeColumn.getName() + " " + type + " " + value);
        // calculate the bound data, the buffer, and the strictness
        ByteBuffer keyBuffer = assignBoundBuffer(type);
        if (keyBuffer == null) {
            // BoundEQ put data into both buffers
            ndbRecordKeys.setString(indexBoundLowBuffer, bufferManager, storeColumn, value);
            ndbRecordKeys.setString(indexBoundHighBuffer, bufferManager, storeColumn, value);
        } else {
            ndbRecordKeys.setString(keyBuffer, bufferManager, storeColumn, value);
        }
    }

    public void endBound(int rangeNumber) {
        if (logger.isDetailEnabled()) logger.detail("range: " + rangeNumber);
        indexBoundRange = rangeNumber;
        ndbIndexBoundList.add(getNdbIndexBound());
    }

    private ByteBuffer assignBoundBuffer(BoundType type) {
        switch (type) {
            case BoundEQ:
                indexBoundHighCount++;
                indexBoundLowCount++;
                return null;
            case BoundGE:
                equalScan = false;
                indexBoundHighCount++;
                return indexBoundHighBuffer;
            case BoundGT:
                equalScan = false;
                indexBoundHighStrict = true;
                indexBoundHighCount++;
                return indexBoundHighBuffer;
            case BoundLE:
                equalScan = false;
                indexBoundLowCount++;
                return indexBoundLowBuffer;
            case BoundLT:
                equalScan = false;
                indexBoundLowStrict = true;
                indexBoundLowCount++;
                return indexBoundLowBuffer;
            default:
                throw new ClusterJFatalInternalException(local.message("ERR_Implementation_Should_Not_Occur"));
        }
    }

    /** Create an ndb index bound for the current bounds and clear the current bounds
     * 
     */
    private NdbIndexScanOperation.IndexBound getNdbIndexBound() {
        ByteBuffer reclaimed = null;
        if (indexBoundLowCount + indexBoundHighCount > 0) {
            if (indexBoundLowCount == 0) {
                indexBoundLowBuffer =  null;
            } else {
                indexBoundLowBuffer.limit(keyBufferSize);
                indexBoundLowBuffer.position(0);
            }
            if (indexBoundHighCount == 0) {
                indexBoundHighBuffer =  null;
            } else {
                indexBoundHighBuffer.limit(keyBufferSize);
                indexBoundHighBuffer.position(0);
            }
            if (equalScan) {
                reclaimed = indexBoundLowBuffer;
                indexBoundLowBuffer = indexBoundHighBuffer;
            }
            // create the index bound; use a local variable that will be used for either the single or list of bounds
            NdbIndexScanOperation.IndexBound ndbindexBound = db.createIndexBound();
            ndbindexBound.low_key(indexBoundLowBuffer);
            ndbindexBound.high_key(indexBoundHighBuffer);
            ndbindexBound.low_key_count(indexBoundLowCount);
            ndbindexBound.high_key_count(indexBoundHighCount);
            ndbindexBound.low_inclusive(!indexBoundLowStrict);
            ndbindexBound.high_inclusive(!indexBoundHighStrict);
            ndbindexBound.range_no(indexBoundRange);
            if (logger.isDetailEnabled()) logger.detail(
                    " indexBoundLowCount: " + indexBoundLowCount + " indexBoundHighCount: " + indexBoundHighCount +
                    " indexBoundLowStrict: " + indexBoundLowStrict + " indexBoundHighStrict: " + indexBoundHighStrict +
                    " range: " + indexBoundRange
                    );
            // reset the index bound for the next range
            // if equal bound, initialize and reuse previous buffer
            if (reclaimed != null) {
                indexBoundLowBuffer = reclaimed;
                ndbRecordKeys.initializeBuffer(reclaimed);
            } else {
                indexBoundLowBuffer = ndbRecordKeys.newBuffer();
                // hold a reference to the buffer to prevent garbage collection
                buffers.add(indexBoundLowBuffer);
            }
            indexBoundHighBuffer = ndbRecordKeys.newBuffer();
            // hold a reference to the buffer to prevent garbage collection
            buffers.add(indexBoundHighBuffer);
            indexBoundLowCount = 0;
            indexBoundHighCount = 0;
            indexBoundLowStrict = false;
            indexBoundHighStrict = false;
            indexBoundRange = 0;
            equalScan = true;
            return ndbindexBound;
        } else {
            return null;
        }
    }

    /** Free resources used by this scan after the scan is executed.
     * 
     */
    public void freeResourcesAfterExecute() {
        super.freeResourcesAfterExecute();
        // allow garbage collection for buffers used in IndexBound
        buffers = null;
        if (ndbIndexBound != null) {
            db.delete(ndbIndexBound);
            ndbIndexBound = null;
        }
        if (ndbIndexBoundList != null) {
            for (NdbIndexScanOperation.IndexBound ndbindexBound: ndbIndexBoundList) {
                db.delete(ndbindexBound);
            }
            ndbIndexBoundList = null;
        }
    }

}
