use std::any::Any;
use std::sync::Arc;
use arrow::datatypes::{DataType, Field, FieldRef};
use datafusion_common::types::logical_string;
use datafusion_common::{Result, ScalarValue, internal_err, plan_err};
use datafusion_expr::expr::ScalarFunction;
use datafusion_expr::simplify::{ExprSimplifyResult, SimplifyContext};
use datafusion_expr::{
Coercion, ColumnarValue, Expr, ReturnFieldArgs, ScalarFunctionArgs, ScalarUDFImpl,
Signature, TypeSignatureClass, Volatility,
};
#[derive(Debug, PartialEq, Eq, Hash)]
pub struct SparkTimeTrunc {
signature: Signature,
}
impl Default for SparkTimeTrunc {
fn default() -> Self {
Self::new()
}
}
impl SparkTimeTrunc {
pub fn new() -> Self {
Self {
signature: Signature::coercible(
vec![
Coercion::new_exact(TypeSignatureClass::Native(logical_string())),
Coercion::new_exact(TypeSignatureClass::Time),
],
Volatility::Immutable,
),
}
}
}
impl ScalarUDFImpl for SparkTimeTrunc {
fn as_any(&self) -> &dyn Any {
self
}
fn name(&self) -> &str {
"time_trunc"
}
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(),
args.arg_fields[1].data_type().clone(),
nullable,
)))
}
fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue> {
internal_err!(
"spark time_trunc should have been simplified to standard date_trunc"
)
}
fn simplify(
&self,
args: Vec<Expr>,
_info: &SimplifyContext,
) -> Result<ExprSimplifyResult> {
let fmt_expr = &args[0];
let fmt = match fmt_expr.as_literal() {
Some(ScalarValue::Utf8(Some(v)))
| Some(ScalarValue::Utf8View(Some(v)))
| Some(ScalarValue::LargeUtf8(Some(v))) => v.to_lowercase(),
_ => {
return plan_err!(
"First argument of `TIME_TRUNC` must be non-null scalar Utf8"
);
}
};
if !matches!(
fmt.as_str(),
"hour" | "minute" | "second" | "millisecond" | "microsecond"
) {
return plan_err!(
"The format argument of `TIME_TRUNC` must be one of: hour, minute, second, millisecond, microsecond"
);
}
Ok(ExprSimplifyResult::Simplified(Expr::ScalarFunction(
ScalarFunction::new_udf(datafusion_functions::datetime::date_trunc(), args),
)))
}
}