// 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 crate::bit_iterator::BitSliceIterator;

use crate::contains_nulls;

use crate::data::ArrayData;

use crate::equal::primitive::NULL_SLICES_SELECTIVITY_THRESHOLD;

use arrow_schema::DataType;

use super::utils::equal_len;

pub(super) fn fixed_binary_equal(

    lhs: &ArrayData,

    rhs: &ArrayData,

    lhs_start: usize,

    rhs_start: usize,

    len: usize,

) -> bool {

    let size = match lhs.data_type() {

        DataType::FixedSizeBinary(i) => *i as usize,

        _ => unreachable!(),

    };

    let lhs_values = &lhs.buffers()[0].as_slice()[lhs.offset() * size..];

    let rhs_values = &rhs.buffers()[0].as_slice()[rhs.offset() * size..];

    // Only checking one null mask here because by the time the control flow reaches

    // this point, the equality of the two masks would have already been verified.

    if !contains_nulls(lhs.nulls(), lhs_start, len) {

        equal_len(

            lhs_values,

            rhs_values,

            size * lhs_start,

            size * rhs_start,

            size * len,

        )

    } else {

        let selectivity_frac = lhs.null_count() as f64 / lhs.len() as f64;

        if selectivity_frac >= NULL_SLICES_SELECTIVITY_THRESHOLD {

            // get a ref of the null buffer bytes, to use in testing for nullness

            let lhs_nulls = lhs.nulls().unwrap();

            let rhs_nulls = rhs.nulls().unwrap();

            // with nulls, we need to compare item by item whenever it is not null

            (0..len).all(|i| {

                let lhs_pos = lhs_start + i;

                let rhs_pos = rhs_start + i;

                let lhs_is_null = lhs_nulls.is_null(lhs_pos);

                let rhs_is_null = rhs_nulls.is_null(rhs_pos);

                lhs_is_null

                    || (lhs_is_null == rhs_is_null)

                        && equal_len(

                            lhs_values,

                            rhs_values,

                            lhs_pos * size,

                            rhs_pos * size,

                            size, // 1 * size since we are comparing a single entry

                        )

            })

        } else {

            let lhs_nulls = lhs.nulls().unwrap();

            let lhs_slices_iter =

                BitSliceIterator::new(lhs_nulls.validity(), lhs_start + lhs_nulls.offset(), len);

            let rhs_nulls = rhs.nulls().unwrap();

            let rhs_slices_iter =

                BitSliceIterator::new(rhs_nulls.validity(), rhs_start + rhs_nulls.offset(), len);

            lhs_slices_iter

                .zip(rhs_slices_iter)

                .all(|((l_start, l_end), (r_start, r_end))| {

                    l_start == r_start

                        && l_end == r_end

                        && equal_len(

                            lhs_values,

                            rhs_values,

                            (lhs_start + l_start) * size,

                            (rhs_start + r_start) * size,

                            (l_end - l_start) * size,

                        )

                })

        }

    }

}