// Copyright 2018 bluss and ndarray developers.

//

// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or

// http://www.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.

//! Methods for dynamic-dimensional arrays.

use crate::imp_prelude::*;

/// # Methods for Dynamic-Dimensional Arrays

impl<A, S> ArrayBase<S, IxDyn>

where S: Data<Elem = A>

{

    /// Insert new array axis of length 1 at `axis`, modifying the shape and

    /// strides in-place.

    ///

    /// **Panics** if the axis is out of bounds.

    ///

    /// ```

    /// use ndarray::{Axis, arr2, arr3};

    ///

    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();

    /// assert_eq!(a.shape(), &[2, 3]);

    ///

    /// a.insert_axis_inplace(Axis(1));

    /// assert_eq!(a, arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn());

    /// assert_eq!(a.shape(), &[2, 1, 3]);

    /// ```

    #[track_caller]

    pub fn insert_axis_inplace(&mut self, axis: Axis)

    {

        assert!(axis.index() <= self.ndim());

        self.dim = self.dim.insert_axis(axis);

        self.strides = self.strides.insert_axis(axis);

    }

    /// Collapses the array to `index` along the axis and removes the axis,

    /// modifying the shape and strides in-place.

    ///

    /// **Panics** if `axis` or `index` is out of bounds.

    ///

    /// ```

    /// use ndarray::{Axis, arr1, arr2};

    ///

    /// let mut a = arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn();

    /// assert_eq!(a.shape(), &[2, 3]);

    ///

    /// a.index_axis_inplace(Axis(1), 1);

    /// assert_eq!(a, arr1(&[2, 5]).into_dyn());

    /// assert_eq!(a.shape(), &[2]);

    /// ```

    #[track_caller]

    pub fn index_axis_inplace(&mut self, axis: Axis, index: usize)

    {

        self.collapse_axis(axis, index);

        self.dim = self.dim.remove_axis(axis);

        self.strides = self.strides.remove_axis(axis);

    }

    /// Remove axes of length 1 and return the modified array.

    ///

    /// If the array has more the one dimension, the result array will always

    /// have at least one dimension, even if it has a length of 1.

    ///

    /// ```

    /// use ndarray::{arr1, arr2, arr3};

    ///

    /// let a = arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn();

    /// assert_eq!(a.shape(), &[2, 1, 3]);

    /// let b = a.squeeze();

    /// assert_eq!(b, arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn());

    /// assert_eq!(b.shape(), &[2, 3]);

    ///

    /// let c = arr2(&[[1]]).into_dyn();

    /// assert_eq!(c.shape(), &[1, 1]);

    /// let d = c.squeeze();

    /// assert_eq!(d, arr1(&[1]).into_dyn());

    /// assert_eq!(d.shape(), &[1]);

    /// ```

    #[track_caller]

    pub fn squeeze(self) -> Self

    {

        let mut out = self;

        for axis in (0..out.shape().len()).rev() {

            if out.shape()[axis] == 1 && out.shape().len() > 1 {

                out = out.remove_axis(Axis(axis));

            }

        }

        out

    }

}

#[cfg(test)]

mod tests

{

    use crate::{arr1, arr2, arr3};

    #[test]

    fn test_squeeze()

    {

        let a = arr3(&[[[1, 2, 3]], [[4, 5, 6]]]).into_dyn();

        assert_eq!(a.shape(), &[2, 1, 3]);

        let b = a.squeeze();

        assert_eq!(b, arr2(&[[1, 2, 3], [4, 5, 6]]).into_dyn());

        assert_eq!(b.shape(), &[2, 3]);

        let c = arr2(&[[1]]).into_dyn();

        assert_eq!(c.shape(), &[1, 1]);

        let d = c.squeeze();

        assert_eq!(d, arr1(&[1]).into_dyn());

        assert_eq!(d.shape(), &[1]);

    }

}