use std::any::Any;
use std::sync::Arc;
use arrow::datatypes::{DataType, Field, FieldRef};
use datafusion_common::types::{NativeType, logical_date, logical_string};
use datafusion_common::utils::take_function_args;
use datafusion_common::{Result, internal_err};
use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext};
use datafusion_expr::{
Coercion, ColumnarValue, Expr, ExprSchemable, Operator, ReturnFieldArgs,
ScalarFunctionArgs, ScalarUDFImpl, Signature, TypeSignatureClass, Volatility,
binary_expr,
};
#[derive(Debug, PartialEq, Eq, Hash)]
pub struct SparkDateDiff {
signature: Signature,
aliases: Vec<String>,
}
impl Default for SparkDateDiff {
fn default() -> Self {
Self::new()
}
}
impl SparkDateDiff {
pub fn new() -> Self {
Self {
signature: Signature::coercible(
vec![
Coercion::new_implicit(
TypeSignatureClass::Native(logical_date()),
vec![
TypeSignatureClass::Native(logical_string()),
TypeSignatureClass::Timestamp,
],
NativeType::Date,
),
Coercion::new_implicit(
TypeSignatureClass::Native(logical_date()),
vec![
TypeSignatureClass::Native(logical_string()),
TypeSignatureClass::Timestamp,
],
NativeType::Date,
),
],
Volatility::Immutable,
),
aliases: vec!["datediff".to_string()],
}
}
}
impl ScalarUDFImpl for SparkDateDiff {
fn as_any(&self) -> &dyn Any {
self
}
fn name(&self) -> &str {
"date_diff"
}
fn aliases(&self) -> &[String] {
&self.aliases
}
fn signature(&self) -> &Signature {
&self.signature
}
fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> {
internal_err!("return_field_from_args should be used instead")
}
fn return_field_from_args(&self, args: ReturnFieldArgs) -> Result<FieldRef> {
let nullable = args.arg_fields.iter().any(|f| f.is_nullable());
Ok(Arc::new(Field::new(self.name(), DataType::Int32, nullable)))
}
fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
internal_err!(
"Apache Spark `date_diff` should have been simplified to standard subtraction"
)
}
fn simplify(
&self,
args: Vec<Expr>,
info: &SimplifyContext,
) -> Result<ExprSimplifyResult> {
let [end, start] = take_function_args(self.name(), args)?;
let end = end.cast_to(&DataType::Date32, info.schema())?;
let start = start.cast_to(&DataType::Date32, info.schema())?;
Ok(ExprSimplifyResult::Simplified(
binary_expr(end, Operator::Minus, start)
.cast_to(&DataType::Int32, info.schema())?,
))
}
}