gemfire-core/src/main/java/com/gemstone/gemfire/internal/redis/executor/sortedset/ZRangeByScoreExecutor.java

package com.gemstone.gemfire.internal.redis.executor.sortedset;

import java.util.Collection;
import java.util.List;

import com.gemstone.gemfire.cache.Region;
import com.gemstone.gemfire.cache.query.FunctionDomainException;
import com.gemstone.gemfire.cache.query.NameResolutionException;
import com.gemstone.gemfire.cache.query.Query;
import com.gemstone.gemfire.cache.query.QueryInvocationTargetException;
import com.gemstone.gemfire.cache.query.SelectResults;
import com.gemstone.gemfire.cache.query.Struct;
import com.gemstone.gemfire.cache.query.TypeMismatchException;
import com.gemstone.gemfire.internal.redis.ByteArrayWrapper;
import com.gemstone.gemfire.internal.redis.Coder;
import com.gemstone.gemfire.internal.redis.Command;
import com.gemstone.gemfire.internal.redis.DoubleWrapper;
import com.gemstone.gemfire.internal.redis.ExecutionHandlerContext;
import com.gemstone.gemfire.internal.redis.Extendable;
import com.gemstone.gemfire.internal.redis.RedisConstants.ArityDef;
import com.gemstone.gemfire.internal.redis.RedisDataType;
import com.gemstone.gemfire.internal.redis.executor.SortedSetQuery;

public class ZRangeByScoreExecutor extends SortedSetExecutor implements Extendable {

  private final String ERROR_NOT_NUMERIC = "The number provided is not numeric";

  private final String ERROR_LIMIT = "The offset and count cannot be negative";

  @Override
  public void executeCommand(Command command, ExecutionHandlerContext context) {
    List<byte[]> commandElems = command.getProcessedCommand();

    if (commandElems.size() < 4) {
      command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), getArgsError()));
      return;
    }

    boolean withScores = false;
    byte[] elem4Array = null;
    int offset = 0;
    int limit = -1;
    if (commandElems.size() >= 5) {
      elem4Array = commandElems.get(4);
      String elem4 = Coder.bytesToString(elem4Array);
      int limitIndex = 4;
      if (elem4.equalsIgnoreCase("WITHSCORES")) {
        withScores = true;
        limitIndex++;
      }

      if (commandElems.size() >= limitIndex + 2) {
        String limitString = Coder.bytesToString(commandElems.get(limitIndex));
        if (limitString.equalsIgnoreCase("LIMIT")) {
          try {
            byte[] offsetArray = commandElems.get(limitIndex + 1);
            byte[] limitArray = commandElems.get(limitIndex + 2);
            offset = Coder.bytesToInt(offsetArray);
            limit = Coder.bytesToInt(limitArray);
          } catch (NumberFormatException e) {
            command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), ERROR_NOT_NUMERIC));
            return;
          }
        }

        if (offset < 0 || limit < 0) {
          command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), ERROR_LIMIT));
          return;
        }

        if (limitIndex == 4 && commandElems.size() >= 8) {
          byte[] lastElemArray = commandElems.get(7);
          String lastString = Coder.bytesToString(lastElemArray);
          if (lastString.equalsIgnoreCase("WITHSCORES")) {
            withScores = true;
          }
        }
      }

    }

    ByteArrayWrapper key = command.getKey();

    checkDataType(key, RedisDataType.REDIS_SORTEDSET, context);
    Region<ByteArrayWrapper, DoubleWrapper> keyRegion = getRegion(context, key);

    if (keyRegion == null) {
      command.setResponse(Coder.getEmptyArrayResponse(context.getByteBufAllocator()));
      return;
    }

    int startIndex = isReverse() ? 3 : 2;
    int stopIndex = isReverse() ? 2 : 3;
    boolean startInclusive = true;
    boolean stopInclusive = true;
    double start;
    double stop;

    byte[] startArray = commandElems.get(startIndex);
    byte[] stopArray = commandElems.get(stopIndex);
    String startString = Coder.bytesToString(startArray);
    String stopString = Coder.bytesToString(stopArray);

    if (startArray[0] == Coder.OPEN_BRACE_ID) {
      startString = startString.substring(1);
      startInclusive = false;
    }
    if (stopArray[0] == Coder.OPEN_BRACE_ID) {
      stopString = stopString.substring(1);
      stopInclusive = false;
    }

    try {
      start = Coder.stringToDouble(startString);
      stop = Coder.stringToDouble(stopString);
    } catch (NumberFormatException e) {
      command.setResponse(Coder.getErrorResponse(context.getByteBufAllocator(), ERROR_NOT_NUMERIC));
      return;
    }

    Collection<?> list;
    try {
      list = getKeys(key, keyRegion, context, start, stop, startInclusive, stopInclusive, offset, limit);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }

    if (list == null)
      command.setResponse(Coder.getEmptyArrayResponse(context.getByteBufAllocator()));
    else
      command.setResponse(Coder.zRangeResponse(context.getByteBufAllocator(), list, withScores));
  }

  private Collection<?> getKeys(ByteArrayWrapper key, Region<ByteArrayWrapper, DoubleWrapper> keyRegion, ExecutionHandlerContext context, double start, double stop, boolean startInclusive, boolean stopInclusive, int offset, int limit) throws FunctionDomainException, TypeMismatchException, NameResolutionException, QueryInvocationTargetException {
    if (start == Double.POSITIVE_INFINITY || stop == Double.NEGATIVE_INFINITY || start > stop || (start == stop && (!startInclusive || !stopInclusive)))
      return null;
    if (start == Double.NEGATIVE_INFINITY && stop == Double.POSITIVE_INFINITY)
      return keyRegion.entrySet();

    Query query;
    Object[] params;
    if (isReverse()) {
      if (startInclusive) {
        if(stopInclusive) {
          query = getQuery(key, SortedSetQuery.ZREVRBSSTISI, context);
        } else {
          query = getQuery(key, SortedSetQuery.ZREVRBSSTI, context);
        }
      } else {
        if (stopInclusive) {
          query = getQuery(key, SortedSetQuery.ZREVRBSSI, context);
        } else {
          query = getQuery(key, SortedSetQuery.ZREVRBS, context);
        }
      }
      params = new Object[]{start, stop, INFINITY_LIMIT};
    } else {
      if (startInclusive) {
        if(stopInclusive) {
          query = getQuery(key, SortedSetQuery.ZRBSSTISI, context);
        } else {
          query = getQuery(key, SortedSetQuery.ZRBSSTI, context);
        }
      } else {
        if (stopInclusive) {
          query = getQuery(key, SortedSetQuery.ZRBSSI, context);
        } else {
          query = getQuery(key, SortedSetQuery.ZRBS, context);
        }
      }
      params = new Object[]{start, stop, INFINITY_LIMIT};
    }
    if (limit > 0)
      params[params.length - 1] =  (limit + offset);

    SelectResults<?> results = (SelectResults<?>) query.execute(params);
    if (offset < results.size())
      return (Collection<Struct>) results.asList().subList(offset, results.size());
    else 
      return null;
  }

  protected boolean isReverse() {
    return false;
  }

  @Override
  public String getArgsError() {
    return ArityDef.ZRANGEBYSCORE;
  }

}