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// 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.

use std::{any::Any, sync::Arc};

use arrow::{
    compute::SortOptions,
    datatypes::{DataType, Field},
};

use crate::sort_expr::PhysicalSortExpr;

use super::AggregateExpr;

/// Downcast a `Box<dyn AggregateExpr>` or `Arc<dyn AggregateExpr>`
/// and return the inner trait object as [`Any`] so
/// that it can be downcast to a specific implementation.
///
/// This method is used when implementing the `PartialEq<dyn Any>`
/// for [`AggregateExpr`] aggregation expressions and allows comparing the equality
/// between the trait objects.
pub fn down_cast_any_ref(any: &dyn Any) -> &dyn Any {
    if let Some(obj) = any.downcast_ref::<Arc<dyn AggregateExpr>>() {
        obj.as_any()
    } else if let Some(obj) = any.downcast_ref::<Box<dyn AggregateExpr>>() {
        obj.as_any()
    } else {
        any
    }
}

/// Construct corresponding fields for lexicographical ordering requirement expression
pub fn ordering_fields(
    ordering_req: &[PhysicalSortExpr],
    // Data type of each expression in the ordering requirement
    data_types: &[DataType],
) -> Vec<Field> {
    ordering_req
        .iter()
        .zip(data_types.iter())
        .map(|(sort_expr, dtype)| {
            Field::new(
                sort_expr.expr.to_string().as_str(),
                dtype.clone(),
                // Multi partitions may be empty hence field should be nullable.
                true,
            )
        })
        .collect()
}

/// Selects the sort option attribute from all the given `PhysicalSortExpr`s.
pub fn get_sort_options(ordering_req: &[PhysicalSortExpr]) -> Vec<SortOptions> {
    ordering_req.iter().map(|item| item.options).collect()
}