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// Copyright 2018-2022 argmin developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

use crate::ArgminMinMax;
use ndarray::{Array1, Array2};

macro_rules! make_minmax {
    ($t:ty) => {
        impl ArgminMinMax for Array1<$t> {
            #[inline]
            fn min(x: &Self, y: &Self) -> Array1<$t> {
                assert_eq!(x.shape(), y.shape());
                x.iter()
                    .zip(y)
                    .map(|(&a, &b)| if a < b { a } else { b })
                    .collect()
            }

            #[inline]
            fn max(x: &Self, y: &Self) -> Array1<$t> {
                assert_eq!(x.shape(), y.shape());
                x.iter()
                    .zip(y)
                    .map(|(&a, &b)| if a > b { a } else { b })
                    .collect()
            }
        }

        impl ArgminMinMax for Array2<$t> {
            #[inline]
            fn min(x: &Self, y: &Self) -> Array2<$t> {
                assert_eq!(x.shape(), y.shape());
                let m = x.shape()[0];
                let n = x.shape()[1];
                let mut out = x.clone();
                for i in 0..m {
                    for j in 0..n {
                        let a = x[(i, j)];
                        let b = y[(i, j)];
                        out[(i, j)] = if a < b { a } else { b };
                    }
                }
                out
            }

            #[inline]
            fn max(x: &Self, y: &Self) -> Array2<$t> {
                assert_eq!(x.shape(), y.shape());
                let m = x.shape()[0];
                let n = x.shape()[1];
                let mut out = x.clone();
                for i in 0..m {
                    for j in 0..n {
                        let a = x[(i, j)];
                        let b = y[(i, j)];
                        out[(i, j)] = if a > b { a } else { b };
                    }
                }
                out
            }
        }
    };
}

make_minmax!(isize);
make_minmax!(usize);
make_minmax!(i8);
make_minmax!(u8);
make_minmax!(i16);
make_minmax!(u16);
make_minmax!(i32);
make_minmax!(u32);
make_minmax!(i64);
make_minmax!(u64);
make_minmax!(f32);
make_minmax!(f64);

#[cfg(test)]
mod tests {
    use super::*;
    use ndarray::array;
    use paste::item;

    macro_rules! make_test {
        ($t:ty) => {
            item! {
                #[test]
                fn [<test_minmax_vec_vec_ $t>]() {
                    let a = array![1 as $t, 4 as $t, 8 as $t];
                    let b = array![2 as $t, 3 as $t, 4 as $t];
                    let target_max = array![2 as $t, 4 as $t, 8 as $t];
                    let target_min = array![1 as $t, 3 as $t, 4 as $t];
                    let res_max = <Array1<$t> as ArgminMinMax>::max(&a, &b);
                    let res_min = <Array1<$t> as ArgminMinMax>::min(&a, &b);
                    for i in 0..3 {
                        assert!(((target_max[i] - res_max[i]) as f64).abs() < std::f64::EPSILON);
                        assert!(((target_min[i] - res_min[i]) as f64).abs() < std::f64::EPSILON);
                    }
                }
            }

            item! {
                #[test]
                fn [<test_minmax_mat_mat_ $t>]() {
                    let a = array![
                        [1 as $t, 4 as $t, 8 as $t],
                        [2 as $t, 5 as $t, 9 as $t]
                    ];
                    let b = array![
                        [2 as $t, 3 as $t, 4 as $t],
                        [3 as $t, 4 as $t, 5 as $t]
                    ];
                    let target_max = array![
                        [2 as $t, 4 as $t, 8 as $t],
                        [3 as $t, 5 as $t, 9 as $t]
                    ];
                    let target_min = array![
                        [1 as $t, 3 as $t, 4 as $t],
                        [2 as $t, 4 as $t, 5 as $t]
                    ];
                    let res_max = <Array2<$t> as ArgminMinMax>::max(&a, &b);
                    let res_min = <Array2<$t> as ArgminMinMax>::min(&a, &b);
                    for i in 0..3 {
                        for j in 0..2 {
                        assert!(((target_max[(j, i)] - res_max[(j, i)]) as f64).abs() < std::f64::EPSILON);
                        assert!(((target_min[(j, i)] - res_min[(j, i)]) as f64).abs() < std::f64::EPSILON);
                        }
                    }
                }
            }
        };
    }

    make_test!(i8);
    make_test!(u8);
    make_test!(i16);
    make_test!(u16);
    make_test!(i32);
    make_test!(u32);
    make_test!(i64);
    make_test!(u64);
    make_test!(isize);
    make_test!(usize);
    make_test!(f32);
    make_test!(f64);
}