/*

 * // Copyright (c) Radzivon Bartoshyk 6/2025. All rights reserved.

 * //

 * // Redistribution and use in source and binary forms, with or without modification,

 * // are permitted provided that the following conditions are met:

 * //

 * // 1.  Redistributions of source code must retain the above copyright notice, this

 * // list of conditions and the following disclaimer.

 * //

 * // 2.  Redistributions in binary form must reproduce the above copyright notice,

 * // this list of conditions and the following disclaimer in the documentation

 * // and/or other materials provided with the distribution.

 * //

 * // 3.  Neither the name of the copyright holder nor the names of its

 * // contributors may be used to endorse or promote products derived from

 * // this software without specific prior written permission.

 * //

 * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE

 * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

 * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER

 * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

 * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#[derive(Copy, Clone, Default, Debug)]

struct DegenerationAmount {

    leading: usize,

    trailing: usize,

}

/// Counts amount of duplicates on each side of curve

fn count_leading_trailing_duplicated<T: PartialOrd>(lut: &[T]) -> DegenerationAmount {

    if lut.is_empty() {

        return DegenerationAmount::default();

    }

    let first = lut.first().unwrap();

    let last = lut.last().unwrap();

    let leading = lut.iter().take_while(|&v| v.eq(first)).count();

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u8>::{closure#0}

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u16>::{closure#0}

    let trailing = lut.iter().rev().take_while(|&v| v.eq(last)).count();

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u8>::{closure#1}

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u16>::{closure#1}

    DegenerationAmount { leading, trailing }

}

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u8>

Unexecuted instantiation: moxcms::matan::degeneration::count_leading_trailing_duplicated::<u16>

/// Finds out if curve is degenerated on the sides.

pub(crate) fn is_curve_degenerated<T: PartialOrd>(v: &[T]) -> bool {

    if v.is_empty() || v.len() < 2 {

        return false;

    }

    let degeneration_amount = count_leading_trailing_duplicated(v);

    if degeneration_amount.trailing <= 1 && degeneration_amount.leading <= 1 {

        return false;

    }

    let leading_percentage = degeneration_amount.leading;

    let trailing_percentage = degeneration_amount.trailing;

    ((leading_percentage / 20) > 0) || ((trailing_percentage / 20) > 0)

}

Unexecuted instantiation: moxcms::matan::degeneration::is_curve_degenerated::<u8>

Unexecuted instantiation: moxcms::matan::degeneration::is_curve_degenerated::<u16>