content: /*
   * 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 org.apache.asterix.optimizer.rules;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.commons.lang3.mutable.Mutable;
  import org.apache.commons.lang3.mutable.MutableObject;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
  import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalExpressionTag;
  import org.apache.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.base.PhysicalOperatorTag;
  import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
  import org.apache.hyracks.algebricks.core.algebra.expressions.ScalarFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.functions.AlgebricksBuiltinFunctions;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.core.algebra.functions.IFunctionInfo;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractBinaryJoinOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
  import org.apache.hyracks.algebricks.core.algebra.operators.logical.SelectOperator;
  import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
  
  /**
   * If the join predicate contains multiple conditions, in which one of them is spatial_intersect($x, $y), all other
   * condition will be pull out to a SELECT operator after the SPATIAL_JOIN operator.
   *
   * For example:<br/>
   * join (and(spatial-intersect($$52, $$53), lt(st-distance($$56, $$57), 1.0))
   * -- SPATIAL_JOIN [$$62, $$52] [$$63, $$53]  |PARTITIONED|
   *
   * Becomes,
   *
   * select (lt(st-distance($$56, $$57), 1.0))
   * -- STREAM_SELECT  |PARTITIONED|
   *     exchange
   *     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
   *         join (spatial-intersect($$52, $$53))
   *         -- SPATIAL_JOIN [$$62, $$52] [$$63, $$53]  |PARTITIONED|
   */
  
  public class PullSelectOutOfSpatialJoin implements IAlgebraicRewriteRule {
      @Override
      public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          return false;
      }
  
      @Override
      public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
              throws AlgebricksException {
          AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
  
          if (op.getOperatorTag() != LogicalOperatorTag.INNERJOIN) {
              return false;
          }
          AbstractBinaryJoinOperator join = (AbstractBinaryJoinOperator) op;
  
          if (op.getPhysicalOperator().getOperatorTag() != PhysicalOperatorTag.SPATIAL_JOIN) {
              return false;
          }
  
          ILogicalExpression expr = join.getCondition().getValue();
          if (expr.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) {
              return false;
          }
          AbstractFunctionCallExpression fexp = (AbstractFunctionCallExpression) expr;
          FunctionIdentifier fi = fexp.getFunctionIdentifier();
          if (!fi.equals(AlgebricksBuiltinFunctions.AND)) {
              return false;
          }
          List<Mutable<ILogicalExpression>> spatialVarVarComps = new ArrayList<Mutable<ILogicalExpression>>();
          List<Mutable<ILogicalExpression>> otherPredicates = new ArrayList<Mutable<ILogicalExpression>>();
          for (Mutable<ILogicalExpression> arg : fexp.getArguments()) {
              if (isSpatialVarVar(arg.getValue(), join, context)) {
                  spatialVarVarComps.add(arg);
              } else {
                  otherPredicates.add(arg);
              }
          }
          if (spatialVarVarComps.isEmpty() || otherPredicates.isEmpty()) {
              return false;
          }
          // pull up
          ILogicalExpression pulledCond = makeCondition(otherPredicates, context, op);
          SelectOperator select = new SelectOperator(new MutableObject<ILogicalExpression>(pulledCond));
          select.setSourceLocation(op.getSourceLocation());
          ILogicalExpression newJoinCond = makeCondition(spatialVarVarComps, context, op);
          join.getCondition().setValue(newJoinCond);
          select.getInputs().add(new MutableObject<ILogicalOperator>(join));
          context.computeAndSetTypeEnvironmentForOperator(select);
          select.recomputeSchema();
          opRef.setValue(select);
  
          return true;
      }
  
      private ILogicalExpression makeCondition(List<Mutable<ILogicalExpression>> predList, IOptimizationContext context,
              AbstractLogicalOperator op) {
          if (predList.size() > 1) {
              IFunctionInfo finfo = context.getMetadataProvider().lookupFunction(AlgebricksBuiltinFunctions.AND);
              ScalarFunctionCallExpression conditionExpr = new ScalarFunctionCallExpression(finfo, predList);
              conditionExpr.setSourceLocation(op.getSourceLocation());
              return conditionExpr;
          } else {
              return predList.get(0).getValue();
          }
      }
  
      private boolean isSpatialVarVar(ILogicalExpression expr, AbstractBinaryJoinOperator join,
              IOptimizationContext context) throws AlgebricksException {
          if (expr.getExpressionTag() != LogicalExpressionTag.FUNCTION_CALL) {
              return false;
          }
          AbstractFunctionCallExpression f = (AbstractFunctionCallExpression) expr;
          if (!f.getFunctionIdentifier().equals(BuiltinFunctions.SPATIAL_INTERSECT)) {
              return false;
          }
  
          // We only apply this rule if the arguments of spatial_intersect are ARectangle
          IVariableTypeEnvironment typeEnvironment = join.computeInputTypeEnvironment(context);
          IAType leftType = (IAType) context.getExpressionTypeComputer().getType(f.getArguments().get(0).getValue(),
                  context.getMetadataProvider(), typeEnvironment);
          IAType rightType = (IAType) context.getExpressionTypeComputer().getType(f.getArguments().get(1).getValue(),
                  context.getMetadataProvider(), typeEnvironment);
          if ((leftType.getTypeTag() != BuiltinType.ARECTANGLE.getTypeTag())
                  || (rightType.getTypeTag() != BuiltinType.ARECTANGLE.getTypeTag())) {
              return false;
          }
  
          ILogicalExpression e1 = f.getArguments().get(0).getValue();
          if (e1.getExpressionTag() != LogicalExpressionTag.VARIABLE) {
              return false;
          } else {
              ILogicalExpression e2 = f.getArguments().get(1).getValue();
              return e2.getExpressionTag() == LogicalExpressionTag.VARIABLE;
          }
      }
  }
  