// 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.

#include "exprs/conditional-functions.h"

#include "exprs/anyval-util.h"
#include "exprs/scalar-expr-evaluator.h"
#include "exprs/scalar-expr.inline.h"
#include "udf/udf.h"

using namespace impala;
using namespace impala_udf;

#define IS_NULL_COMPUTE_FUNCTION(type) \
  type IsNullExpr::Get##type##Interpreted( \
      ScalarExprEvaluator* eval, const TupleRow* row) const { \
    DCHECK_EQ(children_.size(), 2); \
    type val = GetChild(0)->Get##type(eval, row);  \
    if (!val.is_null) return val; /* short-circuit */ \
    return GetChild(1)->Get##type(eval, row); \
  }

IS_NULL_COMPUTE_FUNCTION(BooleanVal);
IS_NULL_COMPUTE_FUNCTION(TinyIntVal);
IS_NULL_COMPUTE_FUNCTION(SmallIntVal);
IS_NULL_COMPUTE_FUNCTION(IntVal);
IS_NULL_COMPUTE_FUNCTION(BigIntVal);
IS_NULL_COMPUTE_FUNCTION(FloatVal);
IS_NULL_COMPUTE_FUNCTION(DoubleVal);
IS_NULL_COMPUTE_FUNCTION(StringVal);
IS_NULL_COMPUTE_FUNCTION(TimestampVal);
IS_NULL_COMPUTE_FUNCTION(DecimalVal);
IS_NULL_COMPUTE_FUNCTION(DateVal);

#define NULL_IF_ZERO_COMPUTE_FUNCTION(type) \
  type ConditionalFunctions::NullIfZero(FunctionContext* ctx, const type& val) { \
    if (val.is_null || val.val == 0) return type::null(); \
    return val; \
  }

DecimalVal ConditionalFunctions::NullIfZero(FunctionContext* ctx, const DecimalVal& val) {
  if (val.is_null) return DecimalVal::null();
  int type_byte_size = ctx->impl()->GetConstFnAttr(FunctionContextImpl::RETURN_TYPE_SIZE);
  switch (type_byte_size) {
    case 4:
      if (val.val4 == 0) return DecimalVal::null();
      break;
    case 8:
      if (val.val8 == 0) return DecimalVal::null();
      break;
    case 16:
      if (val.val16 == 0) return DecimalVal::null();
      break;
    default:
      DCHECK(false);
  }
  return val;
}

NULL_IF_ZERO_COMPUTE_FUNCTION(TinyIntVal);
NULL_IF_ZERO_COMPUTE_FUNCTION(SmallIntVal);
NULL_IF_ZERO_COMPUTE_FUNCTION(IntVal);
NULL_IF_ZERO_COMPUTE_FUNCTION(BigIntVal);
NULL_IF_ZERO_COMPUTE_FUNCTION(FloatVal);
NULL_IF_ZERO_COMPUTE_FUNCTION(DoubleVal);

#define ZERO_IF_NULL_COMPUTE_FUNCTION(type) \
  type ConditionalFunctions::ZeroIfNull(FunctionContext* ctx, const type& val) { \
    if (val.is_null) return type(0); \
    return val; \
  }

ZERO_IF_NULL_COMPUTE_FUNCTION(TinyIntVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(SmallIntVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(IntVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(BigIntVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(FloatVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(DoubleVal);
ZERO_IF_NULL_COMPUTE_FUNCTION(DecimalVal);

#define IF_COMPUTE_FUNCTION(type) \
  type IfExpr::Get##type##Interpreted( \
      ScalarExprEvaluator* eval, const TupleRow* row) const { \
    DCHECK_EQ(children_.size(), 3); \
    BooleanVal cond = GetChild(0)->GetBooleanVal(eval, row); \
    if (cond.is_null || !cond.val) { \
      return GetChild(2)->Get##type(eval, row); \
    } \
    return GetChild(1)->Get##type(eval, row); \
  }

IF_COMPUTE_FUNCTION(BooleanVal);
IF_COMPUTE_FUNCTION(TinyIntVal);
IF_COMPUTE_FUNCTION(SmallIntVal);
IF_COMPUTE_FUNCTION(IntVal);
IF_COMPUTE_FUNCTION(BigIntVal);
IF_COMPUTE_FUNCTION(FloatVal);
IF_COMPUTE_FUNCTION(DoubleVal);
IF_COMPUTE_FUNCTION(StringVal);
IF_COMPUTE_FUNCTION(TimestampVal);
IF_COMPUTE_FUNCTION(DecimalVal);
IF_COMPUTE_FUNCTION(DateVal);

#define COALESCE_COMPUTE_FUNCTION(type) \
  type CoalesceExpr::Get##type##Interpreted( \
      ScalarExprEvaluator* eval, const TupleRow* row) const { \
    DCHECK_GE(children_.size(), 1); \
    for (int i = 0; i < children_.size(); ++i) { \
      type val = GetChild(i)->Get##type(eval, row); \
      if (!val.is_null) return val; \
    } \
    return type::null(); \
  }

COALESCE_COMPUTE_FUNCTION(BooleanVal);
COALESCE_COMPUTE_FUNCTION(TinyIntVal);
COALESCE_COMPUTE_FUNCTION(SmallIntVal);
COALESCE_COMPUTE_FUNCTION(IntVal);
COALESCE_COMPUTE_FUNCTION(BigIntVal);
COALESCE_COMPUTE_FUNCTION(FloatVal);
COALESCE_COMPUTE_FUNCTION(DoubleVal);
COALESCE_COMPUTE_FUNCTION(StringVal);
COALESCE_COMPUTE_FUNCTION(TimestampVal);
COALESCE_COMPUTE_FUNCTION(DecimalVal);
COALESCE_COMPUTE_FUNCTION(DateVal);

BooleanVal ConditionalFunctions::IsFalse(FunctionContext* ctx, const BooleanVal& val) {
  if (val.is_null) return BooleanVal(false);
  return BooleanVal(!val.val);
}

BooleanVal ConditionalFunctions::IsNotFalse(FunctionContext* ctx, const BooleanVal& val) {
  if (val.is_null) return BooleanVal(true);
  return BooleanVal(val.val);
}

BooleanVal ConditionalFunctions::IsTrue(FunctionContext* ctx, const BooleanVal& val) {
  if (val.is_null) return BooleanVal(false);
  return BooleanVal(val.val);
}

BooleanVal ConditionalFunctions::IsNotTrue(FunctionContext* ctx, const BooleanVal& val) {
  if (val.is_null) return BooleanVal(true);
  return BooleanVal(!val.val);
}