// Copyright 2018-2020 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::core::math::ArgminEye;
use ndarray::Array2;

macro_rules! make_eye {
    ($t:ty) => {
        impl ArgminEye for Array2<$t> {
            #[inline]
            fn eye_like(&self) -> Array2<$t> {
                // TODO: Should return an error!
                assert!(self.is_square());
                ndarray::Array2::eye(self.dim().0)
            }

            #[inline]
            fn eye(n: usize) -> Array2<$t> {
                ndarray::Array2::eye(n)
            }
        }
    };
}

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

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

    macro_rules! make_test {
        ($t:ty) => {
            item! {
                #[test]
                fn [<test_eye_ $t>]() {
                    let e: Array2<$t> = <Array2<$t> as ArgminEye>::eye(3);
                    let res = array![
                        [1 as $t, 0 as $t, 0 as $t],
                        [0 as $t, 1 as $t, 0 as $t],
                        [0 as $t, 0 as $t, 1 as $t]
                    ];
                    for i in 0..3 {
                        for j in 0..3 {
                            assert!((((res[(i, j)] - e[(i, j)]) as f64).abs()) < std::f64::EPSILON);
                        }
                    }
                }
            }

            item! {
                #[test]
                fn [<test_eye_like_ $t>]() {
                    let a = array![
                        [0 as $t, 2 as $t, 6 as $t],
                        [3 as $t, 2 as $t, 7 as $t],
                        [9 as $t, 8 as $t, 1 as $t]
                    ];
                    let e: Array2<$t> = a.eye_like();
                    let res = array![
                        [1 as $t, 0 as $t, 0 as $t],
                        [0 as $t, 1 as $t, 0 as $t],
                        [0 as $t, 0 as $t, 1 as $t]
                    ];
                    for i in 0..3 {
                        for j in 0..3 {
                            assert!((((res[(i, j)] - e[(i, j)]) as f64).abs()) < std::f64::EPSILON);
                        }
                    }
                }
            }

            item! {
                #[test]
                #[should_panic]
                #[allow(unused)]
                fn [<test_eye_like_panic_ $t>]() {
                    let a = array![
                        [0 as $t, 2 as $t, 6 as $t],
                        [3 as $t, 2 as $t, 7 as $t],
                    ];
                    let e: Array2<$t> = a.eye_like();
                }
            }
        };
    }

    make_test!(isize);
    make_test!(usize);
    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!(f32);
    make_test!(f64);
}
